SDS TDI?

[MrDave]

Food for thought:
has anyone thought of approaching a company like
SDS for an engine controller for a TDI engine?

There are tons of reasons this is a good idea:
-eliminate EGR completely
-totally customizable injection maps

Think of it as an infinitely adjustable chip upgrade.

More boost? program it in.
More fuel? program it in.
Dead MAF? no problem whatsoever.

Programming injection and smoke maps couldn't be
that different from spark advance, could it?

Discuss....

-Dave

 

[therabbittree]

believe me some one needs to make a aftermarket diesel management system the market is big..the oge cummins guys would eatit up so far the is only one guy hacking the dodge/ cummins vp44 ecu and it still has a few bugs (marco is his name, from europe somewhere ha)..but it still is not a standa alone user programed system..he the diesel racers would love it also
strena ie super truck racing series is starting again, diesel drag racers, land speed racers etc..
i think the problem is the injectors and injection pumps are different on different platforms etc whereas the gasssers pretty much have two styles high and low impedance etc..if some one wants to start something here im more then willing to help and i have a fellow diesel nut or two that are programmers..lets figure out something etc..
later
deo
\x/ hillfolk

 

[GoFaster]

I've read about the SDS programmable EFI system. A system of that general design concept will not work on a distributor-pump TDI engine. (Please note, this is different from saying it cannot be done. I'm saying that their existing engine controller design is not suitable, it has to be an entirely different design.)

If one agrees to eliminate EGR and to use a mechanical boost controller then a distributor-pump engine expects two servo-positioning signals which are not synchronized with engine speed (one for injection quantity and one for injection timing). You need signals from the 3rd injector and crankshaft pulse as a feedback signal for injection timing. If you're not using EGR then you don't need the MAF sensor. If you're not concerned with emissions then the MAP and IAT sensors are also not required. The only inputs are accelerator pedal, coolant temp, and the two timing signals!

The P-D system, on the other hand, expects injector pulses much like those used on a gasoline engine. Still need the crank sensor, don't need injector feedback. P-D must be a sequential injection system for obvious reasons, and the existing SDS system does not allow for that.

It's technically possible, but I'm not qualified to be among the electronics and programming geniuses required in order to figure this out...

 

[therabbittree]

I still think it would nee a map sensor at leats a 3 bar unit. this would measure boost . Definately needed.. i had a sds em3e system for my 20v 2.0L aba turbo project ..but i have since sold it, now i just have a g60 management with chip set up...but back to diesel electronics..i don't think you'd nee the needle lift sensor either for the system as the tractor trailers with electronic management don't have them or the 24 cummins ..i think the ford power choke and maybe a series 60 or isx cummins "might " have a sensor on the injectors ..but i do know most of these systems work on a return line from the injector pressure setup ..and by drilling out the return line fitting you can greatly increase the fueling...just more food for thought.
I definately want to figure out a stand alone electronic management system for a diesel
later deo
\x/ hillfolk!

 

[RogueTDI]

Food for thought:
has anyone thought of approaching a company like
SDS for an engine controller for a TDI engine?

There are tons of reasons this is a good idea:
-eliminate EGR completely
-totally customizable injection maps

Think of it as an infinitely adjustable chip upgrade.

More boost? program it in.
More fuel? program it in.
Dead MAF? no problem whatsoever.

Programming injection and smoke maps couldn't be
that different from spark advance, could it?

Discuss....
-Dave

<font size="2" face="Verdana, Helvetica, sans-serif">Probably this would never make for a successful business venture, and even if it did, it would be very expensive, for one simple reason: The market would be very small.

The vast majority of diesel owners (or car owners for that matter) and enthusiasts do not have sufficient engineering expertise, and thereby competence, to be able to comfortably "customize" their engine control maps. Very few people would really know what to program into such a device. I doubt most people would consider it worthwhile spending hundreds or thousands of USD just to be able to "tinker" with their engine settings, only to then worry about whether their engine will explode. Most people are content (as I would be) to just purchase a "chip" that is optimized for performance (the ultimate goal of your proposition, I presume).

And now, a personal gripe (read editorial). The apparent misconception in the opening post of this thread should not go uncontested. All forum readers and contributors should feel a sense of obligation to maintain this forum's credibility. It is such a sense that has inspired me to make the following statement, which I have wanted to make ever since I first viewed these forums shortly after purchasing my 1998 Jetta TDI.

This forum harbors way too many self-proclaimed diesel experts, whose advice is garnering way more respect than it deserves. Case in point: Why do so many forum contributors think eliminating EGR is a good thing?! Why would you want to eliminate it completely?! This misconception has lived in these forums for as long as I can recall. EGR reduces NOx formation and has no bearing on engine performance! It is essentially, if not completely, off under full throttle. Aside from the crud that builds up in the intake, the EGR is a good thing - and that crud could likely be eliminated in other ways, like improving fuel standards.

THIS FORUM OFTEN SEEMS LIKE THE ART BELL SHOW OF CHAT FORUMS!!! For those that arent familiar with Art Bell, his radio show serves as an incredibly (and unfortunately) successful mechanism for the promulgation of COMPLETE, AND UNCONTESTED NONSENSE (i.e. UFO, government conspiracies, we never landed on the moon, etc.).

I am sorry. It just kills me when I see average TDI/diesel owners listening to the wanna be gurus on this forum, not realizing that most of the people here have no competence to make sound recommendations about much of what they are discussing.

It is also a shame that patrons of this forum have to dig through pages of extensive, self indulgent, and totally questionable technical explanations to find REAL information.

I have no problems with people posting personal experiences, anicdotes or thoughts. As a proud TDI owner and enthusiast, I wholeheartedly support the potential of this site to provide a place for people to share their love and knowledge of these great engines/cars. I just wish forum contributors would be more careful about promoting and/or offering incredulous information and explanations. It just contributes to a reduction of credibility of these forums to the point that it becomes a waste of time to read most of these postings.

 

[GoFaster]

Originally posted by RogueTDI:
And now, a personal gripe (read editorial). The apparent misconception in the opening post of this thread should not go uncontested. All forum readers and contributors should feel a sense of obligation to maintain this forum's credibility. It is such a sense that has inspired me to make the following statement, which I have wanted to make ever since I first viewed these forums shortly after purchasing my 1998 Jetta TDI.

This forum harbors way too many self-proclaimed diesel experts, whose advice is garnering way more respect than it deserves. Case in point: Why do so many forum contributors think eliminating EGR is a good thing?! Why would you want to eliminate it completely?! This misconception has lived in these forums for as long as I can recall. EGR reduces NOx formation and has no bearing on engine performance! It is essentially, if not completely, off under full throttle. Aside from the crud that builds up in the intake, the EGR is a good thing - and that crud could likely be eliminated in other ways, like improving fuel standards.

THIS FORUM OFTEN SEEMS LIKE THE ART BELL SHOW OF CHAT FORUMS!!! For those that arent familiar with Art Bell, his radio show serves as an incredibly (and unfortunately) successful mechanism for the promulgation of COMPLETE, AND UNCONTESTED NONSENSE (i.e. UFO, government conspiracies, we never landed on the moon, etc.).

I am sorry. It just kills me when I see average TDI/diesel owners listening to the wanna be gurus on this forum, not realizing that most of the people here have no competence to make sound recommendations about much of what they are discussing.

It is also a shame that patrons of this forum have to dig through pages of extensive, self indulgent, and totally questionable technical explanations to find REAL information.

I have no problems with people posting personal experiences, anicdotes or thoughts. As a proud TDI owner and enthusiast, I wholeheartedly support the potential of this site to provide a place for people to share their love and knowledge of these great engines/cars. I just wish forum contributors would be more careful about promoting and/or offering incredulous information and explanations. It just contributes to a reduction of credibility of these forums to the point that it becomes a waste of time to read most of these postings.

<font size="2" face="Verdana, Helvetica, sans-serif">I feel obligated to answer to this.

I'm not entirely clear on what the misconception was in the opening post. I don't see it. (Although I agree that the market is too small to make what is being suggested commecially viable.) Picture the hapless owner who has gone through five of those g**d*** MAF sensors on the later model (yours is not subject to this failure mode). VW has so far refused to do anything about it. That's enough incentive to investigate how the darn thing can be eliminated.

Regarding EGR, ask someone who has been quoted US$900 by the dealer to solve this problem whether it's really such a good idea.

I am not in favor of eliminating the EGR completely. Indeed, it does not directly affect performance or fuel consumption or anything else ... until it clogs the intake manifold. I have seen graphs of soot emission and NOx emission as EGR percentage is varied at a given load, and while NOx smoothly goes down as EGR is increased, soot remains at a very low level until a critical air/fuel ratio and EGR percentage, and then skyrockets. The stock system is known to be treading very close to those critical conditions. If the system is off-calibration on the "lean" side, all is well. If the system is off-calibration on the "rich" side, clogged manifold in no time flat. The solution is to make sure that the system is calibrated towards the "lean" side (less EGR). To do this properly requires all sorts of dynamometer testing and NOx and soot emission measurements, which are not possible for the typical owner to do. Best compromise is leave the EGR connected but recalibrate it to minimum specs. Or halfway between stock and minimum. Or wherever a particular owner's balance between concern for NOx emissions, and not wanting to have to clean the intake manifold, happens to strike.

Improved fuel may indeed help this situation, but given the circumstances that exist NOW, it isn't really an option right NOW for most owners.

If there is nonsense on these forums (and indeed there is), I would like to think that it isn't coming from me. As often as not, I'm one of those urging caution ...

And by the way, just for the edification of those reading:

Mechanical engineering graduate 1991, specialized in thermodynamics and fluid mechanics.

Hobby - roadracing motorcycles. I build my own race engines because a) I don't trust anyone else to do it, (b) I wanna know what's in there, (c) at one time I could not really afford big-time "professional" engine builders. (I can now, but now I don't want to use them.) The same conservative approach (gotta do something, but without going too far) is applied there as well.

There are a few other voices on these forums who I have great respect for because they also have (in my judgment) a very thorough understanding of what is going on under the hood. I'm not naming names, I will leave it as an exercise to the reader to make such judgments for themselves.

There are powertrain engineers on these forums who have even greater understanding of the processes happening inside a diesel engine than I do. I'm just a wrench-turner ...

 

[therabbittree]

ROGUE TDI have you cleaned out your CYLINDER HEAD LATELY? No not the intake only, the cylinder head?. Cuz were does the egr sludge build up go? Does it stay in your intake where clean ups are relatively easy no. It sticks to everything in the air way. I had a 20,000 mile tdi engine with over a 1/8 of a inch of sludge in some spots, a 1/4 inch of sludge in the cylinder heads ports, let alone the intake and the egr. I do not have access to ULSD fuel, especially in ny. Do you run ULSD? If so let us all know where to buy some so we can re install our egrs

. In NY diesels are exempt from emissions also. The only diesel that I own with egr is the vw, and it is soon to be disabled. Sorry if its politically incorrect. Now you have to realize people have many different goals for their tdi's..many want to just get 45-50 mpg and drive to work, and smile as they pass the fuel stations, others want gasser performace with the tdi mileage, others just love diesels and won't ever own a gasser again even a gas lawn tractor is taboo, and then there are others that are trying to get as much power as mechaniclly possible from the tdi engine by what ever means possible. Have you ever heard of Diesel drag racing? The DDRA? The Diesel Hot Rod Assocation? The STRANA Racing www.stranaracing.com ? GATOR Racing? BIG RIGS PULLING SERIES www.bigrigspulling.com? etc?. Have you gone to diesel only races and shows? Gone to diesel tractor and truck pulls? Or looked at any of the posts about trucks on the diesel pickup sites like the dodge cummins www.turbodieselregister.com? There are many, many people that would buy a stand alone diesel management system. Same as gassers. How many of your gasoline friends have stand alone management systems?. I bet not too many, I have a few friends running them, and I even had my own at one time (but sold it). But the point is that the market is there for one. Even with the limited # of gasoline users they sell enough to sustain the market, so I think the diesel market is similar. But that is my own twisted opinion. I guess some forum moderator will delete my post now, because my opinion doesn't match yours? Or the majority of conservative tdi buyers or something??! Is that how the forum is supposed to work?
ha
later
Deo
\x/ hillfolk!
If your notbreaking parts your not learning
check out some of my diesel links
www.cumminsracing.com
www.forddiesel.com
www.largecarmag.com
www.laybutterflypullingteam.com
www.pullingpoweronline.com
www.diesel-central.com
www.teamdiesel.com
www.stranaracing.com
www.evsracing.com
www.enterpriseengine.com
www.piersdiesel.com
www.cfidrive.com/media/redracernews.cfm
etc

[ November 23, 2002, 21:03: Message edited by: therabbittree ]

 

[RogueTDI]

Ok. I admit in hindsight that I carried my rants a little farther than necessary. I'm sure there are plenty of knowledgable and educated people here, and I knew I would probably be offending a few people. I guess at the time of writing, I was just a little "peeved," and I let my temper get a little out of hand (not a good habit to get into). I am usually not so taken to writing inflamatory posts.

So, as to the responses, I appreciate them. Actually, I should probably thank you for restraining yourselves!

The misconception I was referring to was the MrDave's attitude that EGR should be completely deactivated (sorry, I didnt take much time to edit my post - the composition took long enough).

As for my attitude about people tinkering with technical things they do not understand, I have very high standards. I cultivated my cautious attitude towards "amatuer engineering" while achieving my BSME, 2002. During those years, I participated closely in Formula SAE design competition, and specialized in gas turbine analysis. I also gained an appreciation for how many things you DONT know CAN hurt you when modifying complex engineered systems you are not qualified to understand, with deliberate use of the word qualified.

As a mechanical engineer myself, having years of personal experience with volkswagen diesels, I would STILL feel VERY cautious about making modifications to engineered systems, i.e. a modern automotive engine. If you are going to try to modify to your TDI, without being fortunate enough to run your ideas past a qualified engineer, you are taking a chance (has anyone considered posting qualifications with their posts or would that threaten anonymity?). If you can find a performance solution that has been engineered for you, i.e. a chip, at least that gives some peace of mind. Even then, you should ask for guarantees (does Upsolute offer any engine warranty?). The simple fact is, despite what Upsolute's website claims, bumping torque up 30% across the band WILL lead to increased rates of component failure. The question is how much - I question their claim of 3-5%, and what it applies to - other parts will likely fail before the engine, but with no lesser consequences. Automotive engineers design their engines with plenty of safety margin for a reason, and it is not just to accomodate fuel standards, emissions, etc. Reliability is an important priority in mass production automobile engines, especially when offering 100k/10year drivetrain warranties.

Of course, in the end, you have to compromise. I am currently looking at getting an Up chip for my 1998 TDI, and I intend to thoroughly research the possible consequences first. I just emailed an Up rep, asking him about turbo surge/failure issues, and he said it is not a problem. I am just not sure, and I intend to do a little thermo/fluids analysis myself. But their $275 installation sale is helping me decide!

(The point here being to reach a compromise between safety concerns, costs in time and repair bills, and driving pleasure.)

I just want people to be aware that, even for a qualified engineer, any modifications of a modern automotive engine should be performed with utmost caution. And any engineer worth his credentials would agree. A LOT of thought and design goes into these engines, and even a simple change could potentially cause major consequences. That being said, I know these engines (TDI and others) are mechanically very robust. So if you want to take a chance, go ahead. It all depends on your priorities. I prefer the peace of mind I get knowing that I can drive my car as hard as I like with no fear of failure. I dont know how I will feel with a chip until I do my own analysis.

Well damn, I've done it again - my fingers are tired. Who has time for this stuff?! I do see now why so many of these messages get so long - knowledgable/experienced people enjoy sharing that knowledge and experience with others. And it is nice to think others appreciate it.

 

[RogueTDI]

OK. On the EGR issue, I can imagine that some parts of the country might have fuel that leads to serious clogging, in which case, reducing/deactivating it might indeed be warranted. I guess I am lucky to live in CA with its ULSD - I just checked and my intake is not too bad ~ 1/16 inch max build up after 60k. I'm no liberal though (election day was painful here).

As for a market on stand-alones, I still question that, considering the number of diesels vs gasser in America. I dont doubt there is SOME market, just not worth it right now. NOW, as those beautiful new VW TDIs get introduced over here, I dont doubt you will start to get your wish. But currently, most VW performance tuners don't even offer diesel chips (last time I checked at least, not so long ago), not that it matters - Upsolute definitely looks like a great option.

Anyway, I guess I may have stepped into a little something here.

 

[RogueTDI]

This forum is not supposed to read like a book. It is supposed to read like a conversation. A conversation where things can be discussed and people can be wrong. If people go ripping things off their cars at the advice of others, they are not being forced to, and most would place the blame where it is due if it breaks: on themselves.

<font size="2" face="Verdana, Helvetica, sans-serif">Good points, of course.

I just figure that sometimes people need to be warned of their own ignorance. This is based on my readings of many of the posts on this forum, which demonstrate, to me at least, that many readers are blindly following advice and then suffering unfortunate consequences. Are they to blame? To some extent sure, but what would you have them do - ignore this forum all together? That is why I am stressing personal responsibility when making suggestions to others, and caution to those who would follow those suggestions.

Plenty of good points in those responses.

 

[speakerboy]

Also in response to the editorial 2 posts above:
I am a TDI owner who is 24 years old. I have been a member of this club for quite some time, and through reading these pages, have gained much knowledge about how my car works and how to fix it when it doesn't.

If any owner goes to do something which they: a.) don't fully understand, or b.) can't pay for if it breaks, then that is on their heads. Whether they read this forum or not, chances are the same thing will happen. If they don't own a TDI, chances are that they will do it to whatever other car takes it's place. The only thing that can protect them is more knowledge. Knowledge that comes from testing such as: oil analysis, dyno's, filter paper, electron microscope pictures, and whatever else. The only people that provide this information are ones that are willing to risk their cars longevity and health to find out what's going on.

This forum is not supposed to read like a book. It is supposed to read like a conversation. A conversation where things can be discussed and people can be wrong. If people go ripping things off their cars at the advice of others, they are not being forced to, and most would place the blame where it is due if it breaks: on themselves.

 

[MrDave]

Ouch.

I started this, I suppose. Maybe I should step in.

So where should I start?
<rant>
EGR is both a good thing, and a bad thing.
Does it reduce emissions? Yes.
Does it clog the intake? Yes.
Which is better/worse?

I started this thread to discuss the benefits and
possibilities of a diesel stand-alone system, not
to have these forums compared to Art Bell.

I take offence at "apparent misconception".
I mentioned eliminating the EGR, since there are
so many who are struggling with the CEL and other
things since removing the EGR.

The glory of a programmable management system is
that you could choose to run EGR or not.

It could also be set up to run a propane injection
system, and to even honk the horn and flash the
lights when the car is at full throttle.

As for replacing the chip in the ECU, I'm confident
that there are lurkers on this list with more
knowledge on engine tuning than the guys who
program many of these chips. (I'm thinking 1.8T
chips)

For the hardcore enthusiast, the more control you
have, the better. Not everyone has the patience,
nor the desire, to plug-in the laptop and tune a
custom system. Many people are too happy to just
put the car in drive and go, let alone the
apparent confusion of shifting the gears and
working that there clutch thingy.

Knowledge and education are two different things.
Since we're comparing educations, I have an MSc-ME.
That doesn't mean I know what I'm doing while
I'm tinkering with my cars.

For my set of circumstances, I would prefer to run
a programmable management system. It would make
some things a great deal simpler, and it would
give me greater control. Said systems do
not appear to exist, however. Thus I will have to
continue to forge ahead with my current project:
2002 TDI engine into 1982 Pickup.

Will I run the EGR? No. The truck didn't come
with EGR, it won't continue with EGR. Similarly,
I won't be running a catalytic converter either.
Is that immoral or irresponsible? I will pay the
consequences or reap the rewards of my own decisions.
</rant>

My humblest apologies to this forum.
Let us not turn this into a mud-slinging contest.

-Dave

 

[GoFaster]

Also keep in mind that there are people on these forums who have been around here a helluva lot longer than you have ... I can see that you're a newbie by your member number

I understand your concern about re-engineering vehicles, and I completely agree about the issues concerning people who are doing things without understanding their consequences. However, there have been a large number of people that have already done the appropriate research and contributed that knowledge back to the forums, and a fair chunk of the useful information about what works and what does not work (and what the risks are) has been compiled in the Performance section of the TDIFAQ.

There are various SAE papers that have been written about the design of these engines, and technical information has been published on some of the components that go into them. We know what the turbo is good for; we know what the permissible peak cylinder pressure is; we know what the permissible exhaust temperature is.

We know what many of the limitations of stock components are. Sometimes you have to learn by breaking things, and believe me, that has happened, too ...

We know what a good many of the weak points are with the stock setup - which is not pefect. The EGR system is one of those (uses too much EGR in the interest of reducing NOx, that clogs intake, clogs VNT mechanism in turbo). On models equipped with a VNT turbo, the stock calibration asks for too much boost at low revs - it's too close to the surge regime for comfort. There are ways of adjusting that. Yours doesn't have that problem. I've never heard of a KO3 or GT15 breaking in a way that was related to performance mods. (Wrong oil - cheap crap - coking up in the lube system ... that's been done. Late injection timing resulting in high exhaust temperature ... this was on a stock vehicle ... that's been done. Clogged catalyst due to crappy fuel causing excessive back-pressure ... that's been done. Insufficient air filtration due to poor installation of air filter or neglect of the air filter ... that's been done. Foreign object damage due to something that was missed during a collision repair ... that's been done. But NEVER have I heard of one of those blowing up due to performance mods.)

Not everything is known, of course, but there is enough experience with certain combinations to know that the reliability is acceptable.

Mine has been modded in some form or another for the last 124,000 km (and that was on top of 160,000 km that it had at the time it was chipped). Don't worry about chipping it; it'll be fine. It takes a heck of a lot more than that to break one of these.

 

[GoFaster]

Too many people typing at the same time. My "quit worrying so much!" response is obvously aimed at RogueTDI. Back to topic at hand ...

 

[RogueTDI]

I didnt, and do not, mean to promote any "mud slinging." However...

I was not the first to mention education. I have enough experience to know that an MS, or even PhD, doesnt necessarily mean anything.

I am a new member, but no "newbie" - I have followed these forums on and off for almost 7 years. I think that more than qualifies me to make my comments.

As for worrying too much, I really do not. It simply annoys me to see SOME people doing and believing things they would not otherwise if they only knew better. It is especially annoying when people arrogantly flaunt their ignorance in the process. Then, to see still others following suit - that just pushes me over the top. Hence, I feel compelled to provide a little enlightenment (I'm sure I am not the first person here to attempt this). In the end though, I dont waste my time worrying about it, and this subject has already consumed more time than it is worth, to be sure.

So, I wont needlessly defend myself anymore, in the interest of cutting this little spat off now.

No hard feelings.

 

[RogueTDI]

I guess I just needed to thump my chest one more time with that last post.

But really, there are a number of members who I have respect for as well, and I had no intention of offending anyone.

I hope at least that my points are understood.

 

[jjvincent]

I can see in the future that there will be a diesel engine management system that will be customizable. I have a feeling that when diesels become more popular in the future, we will see a system become available. Here is what I imagine for the future; a diesel with pneumatic valves (4 or 5 valve motor) and electrically actuated direct injectors. I believe we will see this in the near future. Just imagine how customizable the system could be then!

What makes this site interesting is the fact that many individuals post different ideas. Even though some of the ideas are far fetched, they can get you thinking. You don’t have to be an engineer to be able to modify an engineered system. Most of the “hot rodders” over the last 50 years were not engineers and look at the successful ideas they have come up with. . This site is full of people who are “TDI hot rodders”. They are constantly thinking of a new idea. You have to filter out the not so good ideas. Some of those bad ideas people try and when they don’t work, we get to see the results. This kind of experimentation comes at no cost to most of us.

Start going to various races and you’ll find out that there are many participants that are not engineers but they are more successful than those with a higher education. Having practical experience goes a long way. Being an engineer can take you a long way but it is not absolutely necessary. I have personally dealt with many “old timers” who have spent their life running a successful business increasing the performance of various vehicles and they only have a high school education. I have always been amazed by the amount of engineering knowledge they have.

Don’t get me wrong; being an engineer is still a good idea. It gives you the knowledge of how to attack a problem and where to find the necessary information. One other thing it allows you to do to is to wear a blue and white striped hat and the permission to blow the whistle to get the cows off the track.

 

[christi]

I have the EGR totally disabled on my car. There is no legal requirement for me to run EGR where I live, and few other cars on the road here have EGR.

I disabled it because EGR wears out the engine faster. It will last maybe 25% longer without it.

Running EGR is a bit like constantly tipping sand into the engine.

As far as the environmental argument goes, you have to offset the increased NOx emissions against the environmental impact of manufacturing a new car more often, or running a more worn out engine in the car in its later years.

That said, if you have a legal requirement to run EGR in your country then I suppose that it would be a little irresponsible of me to encourage you to break the law....

NOx emissions are caused by the engine having such an excess of oxygen that it then burns the nitrogen in the air itself. EGR is a bodge to get round this. Diesel engine manufucturers need to find a better way to limit air intake somehow without wrecking the engine.

 

[RogueTDI]

I am no longer defending my previous comments. Just responding.
jjvincent:
You say

Don’t get me wrong; being an engineer is still a good idea. It gives you the knowledge of how to attack a problem and where to find the necessary information. One other thing it allows you to do to is to wear a blue and white striped hat and the permission to blow the whistle to get the cows off the track.

<font size="2" face="Verdana, Helvetica, sans-serif">I am sorry to see what a poor reputation the engineering profession seems to have, deserved or not.

It is clear that you do not understand the value of an engineer's opinion. I dont want to put much more effort into this issue, at least not here - maybe a new thread.

There is an important distinction between an engineer, and a technician or experienced engine tuner. An engineer does not just solve problems, he solves them properly . What makes an engineer's judgement valuable is his officially sanctioned competence to solve a problem (recognized by the degree accreditation). The training an engineer receives gives him an understanding of all the fundamental concepts needed to competently and properly solve problems in a broad range of areas in which he may have no experience. A technician/tuner can offer and apply much knowledge gained through experience, but does not have the prerequisite understanding needed to solve problems outside his specific area of experience.

You need not be an engineer to tune a car for performance. That is obvious. But the professional tuners you speak of would not dare market a performance solution before it went through a competent degreed engineer, and was aftwerwards tested to some reasonable extent. There is nothing wrong with obtaining a performance solution from a professional tuner and installing it yourself, or performing routine maintenance on your car. You can comfortably do these things because you can be instructed and trained to do these things. The engineering has already been done.

Now of course, if you compare a newly graduated, inexperienced, engineer with a nondegreed car tuner that has years of experience, the experience may very well win out. But I have run across such experienced people, and I always laugh when they, at times, demonstrate a fundamental lack of understanding, regardless of the vast quantities of knowledge they may possess. It is this lack of understanding which can lead to "fatal" mistakes. It is this understanding of the fundamentals which gives an engineer's opinion real value.

I am not saying that you need an engineering degree to play with your car. I AM SIMPLY WARNING PEOPLE THAT THEY DONT KNOW WHAT THEY ARE DOING, to be blunt.

When tinkering with complex engineered systems, you do so at your own risk, and here's why. I have a degree, and I still feel wary about modifying my car. Even the most experienced engineer faces this problem, because he has no way of knowing what thought and design went into the system without conferring with the engineers who designed it. For eg, if the designers of the tranny/block mating mechanism of your TDI engines didnt inform you of its proper operation, you would have no idea how to pull it apart. In the same manner, when you tinker with your car, you really have no idea what the consequences may be.

With modern cars as complex as they are, this moral is especially important.
Modern engineering has allowed impressive amounts of power to be drawn from small powerplants, mainly by large improvements in efficency. This all means a limit is rapidly approaching where tuning will be pointless, since the full potential of an engine is virtually reached by the factory.

It may surprise you to know, and it bears repeating, that I have come to have these attitudes very much because of my engineering education, not despite it. One thing my education taught me is that THERE ARE A LOT OF THINGS YOU DONT KNOW YOU ARE UNAWARE OF, AND WHAT YOU DONT KNOW CAN AND WILL HURT YOU. This is not worrying too much (not to say you should worry about things you cant change/help/etc.), it is being responsible.

OK, thats enough. I have to stop somewhere. TOO long!

 

[RogueTDI]

Had to start a new one - I was getting way off on a tangent.

I have the EGR totally disabled on my car. There is no legal requirement for me to run EGR where I live, and few other cars on the road here have EGR.

I disabled it because EGR wears out the engine faster. It will last maybe 25% longer without it.

Running EGR is a bit like constantly tipping sand into the engine.

As far as the environmental argument goes, you have to offset the increased NOx emissions against the environmental impact of manufacturing a new car more often, or running a more worn out engine in the car in its later years.

That said, if you have a legal requirement to run EGR in your country then I suppose that it would be a little irresponsible of me to encourage you to break the law....

NOx emissions are caused by the engine having such an excess of oxygen that it then burns the nitrogen in the air itself. EGR is a bodge to get round this. Diesel engine manufucturers need to find a better way to limit air intake somehow without wrecking the engine.

<font size="2" face="Verdana, Helvetica, sans-serif">I dont know where you live, but unless it's europe, then I am not sure if you can compare your diesel cars to the other cars on the road, which are likely mostly gassers, which dont really need EGR, not for NOx anyway.

Please explain how EGR is like putting sand into the engine.

Even with the 25% reduction, I dont doubt these engines will last far longer than you will care to keep it.

NOx is not caused by having an excess of oxygen, although oxygen concentration can affect localized flame temperatures. NOx is caused by achieving the high combustion temperatures needed for its formation. Inert gas injection from a refillable reservoir is the only substitute for EGR I can immediately think of. A throttle plate without variable compression ratio would mean an engine that doesnt run. Can you suggest another way to reduce NOx?

 

[christi]

I dont know where you live, but unless it's europe, then I am not sure if you can compare your diesel cars to the other cars on the road, which are likely mostly gassers, which dont really need EGR, not for NOx anyway.

<font size="2" face="Verdana, Helvetica, sans-serif">I do live in Europe and I was comparing with other diesels circa 1996. Look at the bottom of my post.

Please explain how EGR is like putting sand into the engine.

<font size="2" face="Verdana, Helvetica, sans-serif">It causes the engine to re-ingest exhaust gases. These gases contain particulate matter that is abrasive.

Even with the 25% reduction, I dont doubt these engines will last far longer than you will care to keep it.

<font size="2" face="Verdana, Helvetica, sans-serif">For many years I have bought three year old cars and then run them until they are scrap. My last one got to 207,000 before it lost compression due to worn out exhaust valves and the body fell apart. This Passat will last longer, as it has never been crashed and is much better rust proofed, plus I look after it neurotically well.

Even if I don't run it into the ground, then someone else will. Are you really aware how much pollution it causes to manufacture an entire car? If I can make mine last 25 - 30 % longer then maybe I am helping.

By the way I didn't make up that figure, it came from a Japanese scientific paper, I think it might have been Hino. I posted the details on this forum before it went ubb. Probably members 1-99 remember it.

NOx is not caused by having an excess of oxygen, although oxygen concentration can affect localized flame temperatures. NOx is caused by achieving the high combustion temperatures needed for its formation.

<font size="2" face="Verdana, Helvetica, sans-serif">Yes it is! What is NOx? It is oxidised Nitrogen. No oxygen = no NOx. Diesel oxidises rather more easily than nitrogen. If there is only just enough air in the cylinder to burn all of the diesel then there isn't enough left to oxidise any nitrogen. That is how EGR works. There is an EGR map that says how much clean air is needed, and the exhaust gasses are allowed in until the MAF sensor readings indicate a reduction in the amount of clean air as specified by the map.

EGR works by limiting clean air intake and thereby oxygen intake.

Lowering combustion tempuratures below the point that nitrogen oxidises will also help.

A throttle plate without variable compression ratio would mean an engine that doesnt run.

<font size="2" face="Verdana, Helvetica, sans-serif">Actually it would run. There was a device called OMAC that was sold here that was exactly that, a throttle plate. A throttle plate will reduce air intake and therefore excess oxygen. The problem with a throttle plate is that it reduces efficiency as the engine has to pull air past the throttle plate increasing the work that it has to do.

Can you suggest another way to reduce NOx?

<font size="2" face="Verdana, Helvetica, sans-serif">Well we could just live with the NOx. Cars are already significantly cleaner than they ever used to be. Diesels are cleaner still, especially on CO, hydrocarbons and CO2. NOx emissions are also quite high on semi-worn gassers, but nobody legislates for that.

Diesels are inherently lean burn, in fact lean burn gassers suffer from NOx too. EGR reduces the lean-ness, and causes more particulates and lower efficiency.

We could also look at computer controlled valve trains and turning off some cylinders under part load conditions, and de-NOx cats.

I believe that deNOx cats are poisoned by sulphur which is why low sulphur fuel is important.

Also I guess that if particulate traps become more popular (currently only Peugeot/Citroen are there) then we could feed filtered exhaust gasses back in which would address the longevity issue.

 

[jjvincent]

<font size="2" face="Verdana, Helvetica, sans-serif">I am sorry to see what a poor reputation the engineering profession seems to have, deserved or not.

It is clear that you do not understand the value of an engineer's opinion. <font size="2" face="Verdana, Helvetica, sans-serif">The poor reputation that the engineering profession seems to have, is from individuals that have to announce, "I'm an engineer"! It kind of belittles the ones who are not.

I do understand the value of an engineer's opinion, if it's valid. An engineer who spends his career designing plastic bottles would probably have valid opinions about that product. I would really not trust his opinion on automotive related matters. Now, if in his free time, he spends it dealing with automotive related matters, and then his opinions can be more valid.

Dealing with many engineers over the years has given me an understanding of how they think. They are just like any one else. Put 10 of them in a room to solve a problem and there will be at least 5 different opinions on what the problem is and how to solve it. Some of them will be wrong too.

I respect someone who could spend the time to get a higher education. I like to listen to them as to be able to pick up on any new knowledge. I look forward to reading your future posts and learn from them. I have a feeling you will be able to enlighten me on how some of the systems on a TDI are engineered. Challenge me, I am like a sponge and soak up knowledge to the best of my ability. I admit, “I am not a smart man” but I am good with my hands. I like to take things apart and try to figure out what the engineer was thinking.

Thank you in advance for your help.

 

[christi]

Engineers always have a chip on their shoulder. I am entitled to say this as I am an engineer and I also have a chip on my shoulder and understand the problem well.

The problem is that the definition of "engineer" is not very clear. Technicians think that they can call themselves engineers, whilst degree qualified engineers think that they should not.

Either of them probably has a good case.

If I walk into a pub and tell someone that I am an electronic engineer then most people will ask me if I can mend their TV, VCR, washing machine or whatever.

This is a terrible dent in an engineers ego and we all end up with chips on our shoulders.
It doesn't happen to Doctors, Lawyers, Solicitors, Accountants etc. and us engineers end up horribly jealous. On top of that we do jobs that no-one else on the planet understands, and so we feel that we should be treated like Gods.

These days I call myself a Telecom Consultant rather than an engineer, and if I have to call myself an engineer then I am a Chartered Engineer.

Luckily this never really mattered in the work place as an engineer's boss does know the difference between an engineer and a technician.

It also never mattered because engineers could always get jobs easily etc, though for the moment that isn't true, my previous employer has shrunk from 120,000 people to just 35,000 in just one year.

I hope that the good old days of high wages, guaranteed employment, and comfortable jobs will be back some day.

 

[RogueTDI]

Engineers always have a chip on their shoulder. I am entitled to say this as I am an engineer and I also have a chip on my shoulder and understand the problem well.

The problem is that the definition of "engineer" is not very clear. Technicians think that they can call themselves engineers, whilst degree qualified engineers think that they should not.

Either of them probably has a good case.

If I walk into a pub and tell someone that I am an electronic engineer then most people will ask me if I can mend their TV, VCR, washing machine or whatever.

This is a terrible dent in an engineers ego and we all end up with chips on our shoulders.
It doesn't happen to Doctors, Lawyers, Solicitors, Accountants etc. and us engineers end up horribly jealous. On top of that we do jobs that no-one else on the planet understands, and so we feel that we should be treated like Gods.

These days I call myself a Telecom Consultant rather than an engineer, and if I have to call myself an engineer then I am a Chartered Engineer.

Luckily this never really mattered in the work place as an engineer's boss does know the difference between an engineer and a technician.

It also never mattered because engineers could always get jobs easily etc, though for the moment that isn't true, my previous employer has shrunk from 120,000 people to just 35,000 in just one year.

I hope that the good old days of high wages, guaranteed employment, and comfortable jobs will be back some day.

<font size="2" face="Verdana, Helvetica, sans-serif">I really appreciate this quote.

Look, I understand these points. I am not discovering this "chip," as you call it, for the first time here. I have long since reconciled my position with respect to other members of society. I know that god-like sensation of comprehending things that others likely will never. But I dont hold it against people. Really I dont, even though it sounds here like I do.

I just see people that do not understand what they are talking about and I feel compelled to either educate them, or at least inform them that they need to educate themselves some more. I consider it a responsible thing to do.

About the value of an engineer. This quote from jjvincent illustrates something:

Dealing with many engineers over the years has given me an understanding of how they think. They are just like any one else. Put 10 of them in a room to solve a problem and there will be at least 5 different opinions on what the problem is and how to solve it. Some of them will be wrong too.

I respect someone who could spend the time to get a higher education. I like to listen to them as to be able to pick up on any new knowledge. I look forward to reading your future posts and learn from them. I have a feeling you will be able to enlighten me on how some of the systems on a TDI are engineered. Challenge me, I am like a sponge and soak up knowledge to the best of my ability. I admit, “I am not a smart man” but I am good with my hands. I like to take things apart and try to figure out what the engineer was thinking.

Thank you in advance for your help.

<font size="2" face="Verdana, Helvetica, sans-serif">First, I am happy to offer my expertise where it may be valid. I have no doubt that you ARE a smart person. I never meant to be condescending. Our technical understanding and knowledge are probably similar in many ways, I dont doubt. The primary difference is that I hold a degree in mechanical engineering. Now, I dont go around flaunting this fact, but I do demand some level of respect for having earned the degree, as well I, and other engineers, should.

My points about the value of an engineer is simply this. The value is not in how much he knows, but what he knows - he has the bases covered.

There is a key difference between learning and accumulating information by your own means throughout life, and passing through a (properly certified at least) engineering curriculum. The curriculum an engineer receives is not just a batch of uncorrelated information, which IS what you get when you learn things on your own. It is a carefully selected range of topics which is designed to provide an engineer with the basis to make competent engineering decisions. Try looking up the word competent at Merriam-Webster.

Now, I am a Mech Eng, which is really the oldest type, the original, the type that has the broadest education, so maybe I have tried to live up to a very big reputation, and now maybe I feel I should defend it. Maybe not. Either way, I do feel that all engineers should try to live up to a higher standard, and so I feel compelled to make others respect that standard, engineer, "lay person" or otherwise.

Please take a look at the first paragraph of this address (dont include the brackets): [http://216.239.37.100/search?q=cach...ng+ethics:+concepts+and+cases"+ncees&hl=en&ie =UTF-8]

You might also look at this site: asme.org page

I take these ideals seriously, as vain a cause as some people might think it.

 

[GoFaster]

RogueTDI, what is your general area of expertise?

I'm just curious about this, because my background is automation equipment design, and I have yet to see anything other than the simplest situations, that did not have multiple possible solutions, with arguable advantages and disadvantages to each, and no clear winner (the winner will depend on the evaluation criteria).

The other background - engine building! - comes from my hobby, and even if you look at engine designs, although they are all variations on the same theme, all designs differ in the details, often still with no clear winner (what's best will depend on the evaluation criteria).

Going back to TDI engines and EGR: The original design is satisfactory to the manufacturer because it conforms to the applicable regulations concerning NOx emissions over the EPA Federal Test Procedure. It is hopefully satisfactory to the manufacturer concerning warranty costs because most of the time when an intake manifold clogs, it will happen beyond the warranty period. Sometimes they've been hit with cleaning the manifold before the warranty is up, but it is a necessary compromise to pass the mandated test procedure for NOx emissions.

But from MY point of view: I don't care about the EPA Federal Test Procedure. I don't want to emit any more NOx than necessary (so my EGR and crankcase vents are still connected) but MY constraint isn't passing the FTP, MY constraint is that I don't want to clean the intake manifold!! So my EGR is still connected but not calibrated the same as the factory settings - I use a bit less EGR. Different set of constraints leads to a different solution.

Emissions is the #1 thing that is going to be affected by doing stuff to these engines (and this is the same situation for ANY engine). People that are not OK with that shouldn't be doing anything to them ... but don't go complaining to me about clogged intake manifolds! The solution is known and documented, and it involves making more NOx. No two ways about it.

Now, consider performance. One of the factory's constraint is to have the total cost of EPA compliance and manufacturing cost and warranty cost being as small as possible. In view of no competition in this market, and in view of a lower-powered engine being easier to get through the EPA FTP than a higher-powered engine, their solution was to get the 90hp engine EPA certified and, in view of NO competitive pressure, not bother with anything else.

We know that the 110hp is IDENTICAL except for bigger injectors, different ECU, and a bigger oil cooler. We know the approach used for the VW TDI-R endurance race engine. (Stock crank, stock block, ported stock head. Rods and pistons were different. Biggest available injector pump and special injectors with HUGE holes - but close to stock injection timing and duration. Bigger turbo, etc. etc.) We know that a lot of the intake and exhaust components are there in order to be in common with the gasoline engine models (not because it is an optimum design for this engine). We know the limits on cylinder pressure and exhaust temperature. We know the limits on the stock turbo. We know the stock boost control system has a cheap crappy solenoid valve that doesn't respond very quickly and because of this, it uses less boost than the turbo can do.

Take all these factors into account, shake well, countermeasure where necessary, and you can get a LOT more poke out of these engines without blowing anything apart PROVIDED that you can live with potentially somewhat greater exhaust emissions (it'll still pass "Drive Clean" in my area with no problem at all).

*BUT* the person doing the setup has to do it RIGHT ... or else.

I think the TDIFAQ provides adequate information on this subject. But providing the information doesn't mean people will try to follow it ...

Lots of stuff can be done to improve performance without blowing anything apart. NOTHING (worthwhile) can be done to improve performance without affecting emissions. Position yourself on this spectrum wherever you see fit.

 

[mickey]

If there were only one "correct" engineering solution to each problem, we'd all have identical vehicles.

Common Rail, or Unit Injectors? Neither is "most correct." They have their engineering advantages and disadvantages. Both are used. Both have their supporters and detractors.

-mickey

 

[RogueTDI]

Look, I got carried off on all sorts of tangents. I already made all the points I wanted to make.

As for the recent responses, I dont argue with them, and in fact for the most part, my previous posts are not inconsistent with them.

Of course many engineering problems have multiple solutions with no clear "winner." I am running long at the keys and getting myself into trouble.

The whole impetus for all my comments is simple - I am sick of being disappointed by the mediocre level of logic and intelligence routinely filling up these forums. I am guilty of wanting to come to this forum and learn something without having to dig through page after page of questionable drivel and pointless commentary. As the "best" site on the web for TDI enthusiasts, it is a shame that most of what's written here isnt worth reading. This ruins the credibility to the point where it isnt worth reading any posts at all - THE BOTTOM LINE AND MY POINT EXACTLY

Even so, I will still come here because it is THE PLACE to go for news and general info about these cars.

Maybe you think I am arrogant. I certainly have a low tolerance for nonsense, I can say that for sure. That is why, when I see it, I have to point it out. Perhaps in my zeal, I got carried away.

Oh, and I dont doubt that unit injectors are the clear winners for one simple reason: higher injection pressures. I view common rail as an aberration and inferior - destined to go extinct (although there is still plenty of industry development ongoing). In the development of diesels, that is THE key route to improved performance. I dont see many down sides - would you mind naming some?

 

[MrDave]

I certainly have a low tolerance for nonsense, I can say that for sure. That is why, when I see it, I have to point it out. Perhaps in my zeal, I got carried away.

<font size="2" face="Verdana, Helvetica, sans-serif">Yes, you did.

The purpose of the original post was to get people talking about a programmable management system for modern diesels. The result, 28 messages later, a great deal of banter about almost everything but...

There was no nonsense in my original post.
If you look at programmable managment for gasoline engines, most don't include EGR.

A simple programmable system for TDI or similar modern diesel could easily be operated with only rpm/crank position and throttle position as inputs, and injection quantity for the pump as the output. (this is assuming a mechanical control for boost pressure)

Further advancement could include incorporation of fuel temperature and IAT and boost pressure as inputs. Add a VNT style turbo for dynamic boost control.

The base system is essentially nothing more than a mechanical system, with the management system performing the roll of the throttle cable. An expensive throttle cable, yes, but oh the possibilities.

A fully advanced programmable management system could include all the stock TDI's sensors, including MAF and even EGR control. For fun, let's add EGT for more programmability options.

Will programmable management for diesels show up? I believe so. Will it show up soon? Well, that's a good question. My '84 gas Jetta has a computer to fine tune the fuel injection. My 1983 didn't. Conversely, North American diesel VW's up to 1997(?) were still purely mechanical. A 2003 TDI is nearly as complex as a 2003 1.8T. The science of passenger diesel has advanced significantly in a very short length of time.

Programmable management in gasoline is still quite new. Programmable management for diesels, since there are so few in North America, will probably emerge from Europe, or will strictly be based on a Cummins. That, or it will be developed by people on this forum, and sold by DieselGeek.

-Dave

 

[RogueTDI]

quote:
--------------------------------------------------------------------------------
Please explain how EGR is like putting sand into the engine.
--------------------------------------------------------------------------------

It causes the engine to re-ingest exhaust gases. These gases contain particulate matter that is abrasive.

<font size="2" face="Verdana, Helvetica, sans-serif">Does this come from that Japanese paper also? Could you please provide a cite, or a site?

Is there evidence that the particulate matter substantially increases in size due to recirculation? If not, then this is a non issue, since nothing is going into the engine that didnt already go through the engine. Now, the intake valves may take a little more abuse, but I would argue the exhaust valves are already the limiting factor.

quote:
--------------------------------------------------------------------------------
NOx is not caused by having an excess of oxygen, although oxygen concentration can affect localized flame temperatures. NOx is caused by achieving the high combustion temperatures needed for its formation.
--------------------------------------------------------------------------------

Yes it is! What is NOx? It is oxidised Nitrogen. No oxygen = no NOx. Diesel oxidises rather more easily than nitrogen. If there is only just enough air in the cylinder to burn all of the diesel then there isn't enough left to oxidise any nitrogen. That is how EGR works. There is an EGR map that says how much clean air is needed, and the exhaust gasses are allowed in until the MAF sensor readings indicate a reduction in the amount of clean air as specified by the map.

EGR works by limiting clean air intake and thereby oxygen intake.

Lowering combustion tempuratures below the point that nitrogen oxidises will also help.

<font size="2" face="Verdana, Helvetica, sans-serif">Hmmm. Hate to be the one to correct you, but I believe my understanding is correct on this issue. This to me is another example of people who are convinced they understand something when in fact they do not (no offense, mind you - I have been in such a position myself on many occasions, so I feel I can talk).

Your explanation would have to presume that there is a chronological, sequential order to the diesel engine combustion process, which on the whole is not the case. Your explanation would mandate that first all the diesel burns, then, if there is any oxygen left, it is the nitrogen's turn to burn. Well, it doesnt happen that way. No oxygen may = no Nox, but will also equal no diesel combustion products either. They are affected simultaneously. NOx forms, just as diesel combustion products form, when a sufficient activation temperature is reached - look it up, this is common knowledge. NOx just requires a higher temp than diesel. The reason NOx is a bigger problem in diesels is because high compression leads to high temperatures and efficient combustion, but these high temps support nitrogen oxidation as well.

EGR works for two basic reasons, as I understand. I am not fully versed in EGR principles, but here is what I know.

First, EGR decreases the concentration (relative quantity) of oxygen, which lowers the flame front temperature.

Second, exhaust gases have a higher specific heat than air, thereby requiring more heat input to a combustion charge to reach a certain temperature, or conversely, a lower temp for a given heat input. Lower temp = less NOx.

Again, I have not studied EGR much, so I may be in error. But I can guarantee that excess air is not THE culprit in NOx formation. Diesels need excess air to give good combustion, mostly I believe because the combustable mixture is heterogeneous.

quote:
--------------------------------------------------------------------------------
A throttle plate without variable compression ratio would mean an engine that doesnt run.
--------------------------------------------------------------------------------

Actually it would run. There was a device called OMAC that was sold here that was exactly that, a throttle plate. A throttle plate will reduce air intake and therefore excess oxygen. The problem with a throttle plate is that it reduces efficiency as the engine has to pull air past the throttle plate increasing the work that it has to do.

<font size="2" face="Verdana, Helvetica, sans-serif">What does OMAC stand for? I found just 1 reference on a Google search.

Well, my point is that, at part and low load conditions it would in fact not run. If you throttle a diesel engine to say stoichiometric air/fuel ratio, and the engine does not have a variable compression ratio, you will not achieve enough compression at low loads to reach proper combustion temperature and conditions. This seems obvious to me, but if you can explain otherwise, please do. Besides, if this was a simple solution, why hasnt VW made use of such a device? (I know the new 5L V10 has butterfly valves in the intake, but I think this has to do with eliminating engine shutter at shutdown)

 

[RogueTDI]

One other thing I wanted to comment on.

jjvincent says

Dealing with many engineers over the years has given me an understanding of how they think. They are just like any one else. Put 10 of them in a room to solve a problem and there will be at least 5 different opinions on what the problem is and how to solve it. Some of them will be wrong too.

<font size="2" face="Verdana, Helvetica, sans-serif">Well, there may be several opinions on how to solve an engineering problem, but for most engineering problems, there is usually one solution that is most correct, and many times there is only one correct solution.

In the former case, a good engineer will be able to tell you the "pros and cons" of the solution.
If an engineer is wrong, and doesnt state that he is uncertain about his conclusions before offering them, then he is doing a disservice. A good engineer has the obligation to not offer judgements in areas not in his competency. If he does otherwise, he must at least give warning of his uncertainty.

If an engineer's opinion is routinely wrong, his credibility is no better than a lay person's, and he is incompetent.