15:1 or How low can you go...?

RabbitGTDJoe

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Now that is a blast from the past... when I first asked about lower CR. and shaving pistons in another thread I remembered reading that when I first came onto Fred's...different screename at that time...but I def. remember but could never find it. Nice digging...

Those were the 2.5 van pistons though correct?

Joe
 

mojogoes

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Has anyone seen the clip of audi's le mans tdi-racer in action and also the pistons there using , the pistons just got a large deep bowl smack bang in the center keeping the lip also and the center pyramid is rounded and not sharp.
 

RabbitGTDJoe

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I've seen the clip and read the article but didn't see any in depth pictures of the engine internals including the pistons... Do you have them that we could all see as well?

I've been interested in finding out more about the 16v TDI PD pistons as well... Simon could probably shed light on this too...but in another thread that I had opened up we discussed how the "lip" that VW used on the TDI pistons was initially really just used to cause the folding donut effect to enhance the engines ability to meet the strict emissions requirements coming onto diesels in both the UK and the US. The one picture I was able to find is sketchy at best, was actually from a VW dealer "parts" box that I have here... Shows the 16v TDI piston....but no lip. The pic isn't the greatest...nor the clearest...but, makes you wonder.



Either way... you have pics of the audi pistons? That'd be cool...

Joe
 

mojogoes

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No i have no clips i most say at this point i'm not very good in moving things around on computer like movies ex but i will say unlike the picture on the box if this is in fact the pd 16v piston the audi v12 piston only had the bowl in the center plus the lip still intact , it also showed the block and cam in some detail where a guy was wrenching and assembling the cam sprocket.
 
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mojogoes

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I would also like to have a look at the intake on the v12 setup because i've just read an article saying it has a restrictive intake system to keep within the rules and regulations and restricts it to the 650hp level , makes one think.........i'm aware its got big displacement ( v12 ) and all but because of the so called fact/theory that there's excess air available in tdi's its an odd thing to say/imply to associate the restricting of the air intake with limiting the power of the engine:eek: .
 
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RabbitGTDJoe

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It is indeed "in production" somewhere... I was told by my friend, and parts manager at a dealer in WNY that he can get me more info on it, etc. That is indeed a 16v PD TDI piston though... I'd like to see a picture of the real deal though...

There is a thread about the 16v on here somewhere with "display" pics of the see through cut away motor, etc. but nothing with the piston in detail...suppose someone could zoom it at one angle... but someone on here from either across the pond or around here must have something on it. Man, wish Simon could chime in...he is working on the PD 16v if I remember you telling me correctly...
It could be this is a VWMS TDI piston as well. Would be interesting to see pics of either, either way :)

I too am curious about the intake manifold design too... looks pretty "plentiful" in the pics :)

Joe
 

mojogoes

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I never said there was a restriction/ed on the manifold but it could be in the manifold , it may be way of having to use crushed pipes or maybe they make them fit some form of screens to cut down on the air flow :rolleyes: .
 

QuickTD

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The way I undestand it, all vehicles running in LMP2 must run 30mm restrictor plates just ahead of each turbocharger inducer and are also limited to 2.96 bar (43psi) boost pressure. That 43 psi would probably only be available at fairly low rpm due to the restrictor plates choking the flow at high engine rpm.
 

TDIMeister

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Audi is entering the R10 into LMP1, just like the R8. For Diesel engines, this class sets a displacement limit of 5500cc (no limit on cylinder count and arrangement) and a choice either of a single-55.9mm or two-39.9mm air restrictors located at the inlet of the intake manifold (i.e. post turbo). Audi is opting for the latter.

Full ACO technical rules for the 2006 LeMans prototype cars can be found here: http://www.mulsannescorner.com/2006LMP12.pdf

Also of interest is that an independent engineer who attended the R10 launch in Paris and had a close-up view of the car indicates here that the R10 uses VNT turbos. I have written to him seeking to clarify and substantiate this, and told him about TDICLUB and asked him to chime in.

Edit: Upon closer reading of the rulebook, I made a mistake: the air restrictor is located PRE-turbo -- which makes sense... Apologies for the confusion.
 
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TDIMeister

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By the way, credence to the R10 using VNT turbos is strengthened because under ACO rule, VNT turbos are SPECIFICALLY allowed. This last distinction is important to note, because the rules state that anything that is not specifically and expressly permitted, is NOT permitted.

5.2.2 - Charging devices incorporating ceramic components,
variable diameter inlets and adjustable internal vanes are
forbidden. Adjustable internal vanes fixed on the turbine
housing are permitted for the diesel engines.

 
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mojogoes

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I would agree with all these facts on the vnt's and a big fact relating to this would be the amount of displacement this engine has and money audi has if they blow.
 

TDIMeister

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RabbitGTDJoe said:
While we're sharing pics and info...wondering if anyone has seen this ...

They are the TDI Grp A/N FIA Homologation Papers for the 110 PD TDI as downloaded from Bildon Motorsports tech site...

http://www.bildon.com/catalog/about/TechDocs.cfm

This is just a partial of the complete PDF...

Joe
Yes, I have seen the homologation papers; they used to be hosted at the vwmotorsport web site but the links I had bookmarked from some years ago no longer work, and searching through vwmotorsport's website seems to indicate they've removed them.

There is, however, a catalogue of parts for the VW Motorsport Group N TDI kit car. It lists a complete engine, code ZSB, but before you salivate and clamour to buy one of these, note that it's only rated for 143HP. However, I have seen pictures that suggest that it comes out of the box with a VNT-20 and may have some upgraded components that are not found in the OEM VAG parts bin.

Here's the link: http://www.rallypartsireland.com/cataloge/G4NDCatalogueABRevB020710.pdf

Years ago I was acqainted with someone within VW Motorsport but unfortunately he is no longer there and have therefore lost contact.
 

TDIMeister

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mojogoes said:
I would agree with all these facts on the vnt's and a big fact relating to this would be the amount of displacement this engine has and money audi has if they blow.
I don't understand :confused: I would think that Audi's primary interest is to win LeMans and not spend money for the sake of spending money of they're using a known inferior component. Blowing a turbo is not an option if the checkered flag is their goal.

But hey, if you know something they don't :rolleyes: I'm sure your consultation would be much prized.

And I don't know how engine displacement has anything to do with the choice of a VNT turbo...
 

mojogoes

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Yes i must addmit the phone never stopped ringing 12 months ago , and on the money side of things as long has these turbo's last 24 hours and have to be thrown in the bin afterwards w.g.a.f .

And because of the size of the engine used but being limited to only 650hp i wouldn't think two stonking great turbo's wouldn't have been implemented , so a couple of little vnt's would fit the bill nicely retrospectively speaking of course.
 

TDIMeister

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650 HP is the limit primarily because of the air restrictor and because of the boost limit to 2.94 bar absolute that is stipulated in the rules. If Audi could make more out of this engine within the framework of the rules I'm sure they would. Given a certain flow area, pressure and temperature, the mass of air that can inducted into the engine is fixed. This sets an upper limit of the amount of power an engine can produce, regardless of whether it's a gasser or Diesel.

But you're right inasmuch as they would only use as big a turbo as needed for the most optimum matching to the prevaling operating conditions in the race, but it still doesn't not explain why a VNT turbo is chosen instead of WG.

Anyway, nothing is substantiated so I won't go any further with this.

However, going back to the topic of thread, if we want to speculate a little about the compression ratio on the R10, I would put it between 15.0 - 16.5:1. Cold start is hardly an issue for a race car, and the key factor here would be choosing a CR for optimum thermal efficiency and minumum PCP. Best efficiency actually occurs around a CR of 14-16:1, so it is a safe assumption that the R10 would be somewhere in this area.
 

mojogoes

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Would i be right in thinking that the power produced here of 650hp could be easily doubled out of this engine or somewhere close , so in fact we'll probably look back in time and say it was well in a de-tuned state , and given/looking at the new bmw motor that's going to be put in the 272hp X5 at around 16.1 i would think the R10 would be 15.1 or lower as you've implied.
 

TDIMeister

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I don't think we can say in the future with the benefit of hindsight that this engine was "de-tuned" at 650 HP, just like we can't say that the first generation TDIs were de-tuned with only 90 HP when current ones are pushing nearly double that value from the factory with only 0.1L more displacement. Technology has and will continue advance and people will find ways to wring more output out of the engines over time; that much is a safe bet.

That being said, it's the technology of the time that limits what is possible. Based on current technology, I would bet the farm that we will not see future R10s making double of today's HP numbers. For one, I said before restrictors and boost limits will set an upper limit for horsepower that cannot be breached due to the laws of physics and thermodynamics.

And in fact, if it turns out that the R10 dominates Le Mans, you can be sure that next year Diesel entrants in general or Audi specifically will be slapped with further penalties to level the playing field, such as a weight penalty or more likely even smaller air restrictors or reduced boost limits.

We will see incremental improvements as technology advances; that's exactly what Audi wants to accomplish by putting Diesel power into Le Mans. Doubling the horsepower as you propose implies several possibilities: 1) Doubling the BMEP (analogous to engine torque) and hence cylinder pressure for a fixed given RPM limit; 2) Doubling the RPM at the same BMEP as current; or 3) some compromised combination of both.

At least from the best forecast of technology within the next 5 years, I can guarantee you that we will not see 1) or 2) in the R10. Firstly, doubling PCP in an aluminium crankcase will not happen even with the best design methodologies we currently know of without an unacceptable penalty in weight and bulk. Also, the gearbox has to be considered, and significantly increasing the torque also means beefing up the transmission, which adds weight. Second, to speak nothing about combustion rate limits, a doubling of RPM in a present-state DI-Diesel is challenging because of the minuscule amount of time available for fuel injection, mixing and burning. Further, forces in reciprocating components increase exponentially with increasing RPM. Doubling mean piston speeds roughly quadruples G-forces in the reciprocating parts, compounded by necessarily heavier components for a Diesel. Assuming the engine can run unrestricted, I think 150 HP/L will be a highly challenging barrier to break while maintaining competitive weight and reliability. This implies 825 HP for the current architecture and 5.5L displacement.

Now I know the Cummins boys are going to chime in and say that the 5.9s are pushing over 1000 HP, but I'm going to preempt their argument and just ask them to compare everything that I have just talked about: weight, torque limit, RPM, reliability (over a 24-hour race with over 80% at full-throttle, not just a 1/4 mile at a time or 95% part-load operation on the street), smoke-free emissions, engine architecture, etc...
 

mojogoes

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UUmmm yes miester you've just about covered every conceivable angel here for not being able to increase the power output of this engine , but it could go the other way in that the rules may be relaxed for everyone but the diesel entries.

I was talking with a nice guy today who rally's in the group N class with the evo 8's 9's and he said that there restricted to a 34mm pipe b4/at the turbo which limited power he said to around 320hp , but now there back up to around the 400hp some of which is by the way ( i've forgotten the term ) milling groves on the inside of the pipe work to increase velocity and flow , something they've been doing for some time i know but i may have it done.
 

fastvicar

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RabbitGTDJoe said:
I've seen the clip and read the article but didn't see any in depth pictures of the engine internals including the pistons... Do you have them that we could all see as well?
Download the Audi R10 clip and pause at 48 sec. mark. You can see the piston fairly well, but who's to say that is the actual piston? If I were Audi I'd probably show a 1.6 IDI piston being ringed. The general public wouldn't know the difference & they wouldn't be revealing their hand. ;)
 

TDIMeister

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Google Video does not support downloads from Germany. Man, you'd think I were in Iran or something :rolleyes: Did anyone download the full-length video and host it somewhere who can share me the link?

The video currently available from Audi's website is a shortened promo-version without much technical content of substance.


Thanks
 

RabbitGTDJoe

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Yeah, I def. like to see the vid but I can't seem to find it or get it either... have a source link for it?

Oh, by the way...the modified pistons are now back from SwainTech and look great... snapped a few pics... TBC top coating and PC-9 dry film for the skirts...







Turn around was so awesome...almost a week exactly to the hour!

Joe
 

IndigoBlueWagon

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So when's the engine going back together? How much boost do you plan to run?
 

RabbitGTDJoe

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:D yeap yeap... close to 30psi... hoping to get a Holset next winter...unless someone has one they'd like to donate this year. Otherwise, I'll be running a wastegated T3 base from a 300D that'll easily do 25-30psi all day long....
I'd really like to do the holset though in the NEAR future
Engine is currently "complete" to the bottom end. Working on the head now and waiting for tax $$$ to come in and a few parts to sell so I can get some of what is needed in the remainder... here is a pic "currently"



Here is a link to the thread now in the "Conversions" forum...
http://forums.tdiclub.com/showthread.php?t=129127

Joe


http://i18.photobucket.com/albums/b109/joeallison_99/TDI%20ENGINE/100_2125.jpg
 

TDIMeister

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My, that looks purty all painted and new looking! :thumbup:

Can't wait to hear your report when it runs!
 
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