Torsion values effects for BRM?

sptsailing

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In April of this year, I replaced my timing belt, but I do not have a VCDS. Prior to the change, I was able to obtain 50+ mpg at times. After, not so much. Now, about 45 highway is its best, even though for combination, 42 is typical. I suspect something may not be optimally adjusted. It has about 88,000 mi. and no, I have not yet looked at the cam. (fear of failure?) To what degree do sub-optimal torsion values affect mpg? Also, at random times, I think I am seeing smoke in my rear view mirror if I accelerate hard, but it is intermittent. During the day, I do not see it, but at night it appears, so I do not know what color it may be.

I love 95% of this car and hate the other 5%, but it appears to be a keeper anyway. I will probably have to spring for a VCDS. Could someone direct me to an explanation of what may be the issues regarding torsion values to mpg?

Other than the airbag light staying on now, this car rocks. One of my sons has a 2012 Civic, the other a 2012 Corolla, neither of which can hold a candle to the Jetta.
 

dieselpony

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Yes it can have a big effect - there are some threads on it. Franko6 has some thoughts on it in some threads.

For BRM engine, most say 0.0 - 0.5 is best. Just be careful b/c apparently sensor also registers 0.0 when it's out of spec.

I've experimented some with mine, and I got a lot of smoke if it was either too far advanced or retarded. Best fuel economy around 0.0 too.

Get VCDS - it's worth it!
 

slamhouse

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A torsion value of "0" is the general concensus for optimal timing.

VW spec is +1.0 - +1.5 for the new belt to account for belt stretch and this is what i set everybody's timing belts at everytime I change a belt.

Every belt I set the torsion value on usually returns better fuel economy than before the change.

My belt is at +1.0 currently and I see 48mpg routinely and 51-53mpg when i'm good to it.
 

D-Cell_Mekanick

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A torsion value of "0" is the general concensus for optimal timing.

VW spec is +1.0 - +1.5 for the new belt to account for belt stretch and this is what i set everybody's timing belts at everytime I change a belt.

Every belt I set the torsion value on usually returns better fuel economy than before the change.

My belt is at +1.0 currently and I see 48mpg routinely and 51-53mpg when i'm good to it.
Is this figured manually or by the mfd?
 

slamhouse

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This is figured manually at the pump, you can check my fuelly.

I'm about to see a bunch of good tanks as I experienced some clutch slip a few days ago while driving like an a** and I'd like to make it last as long as I can...

I've been rather lazy these last few tanks but I usually log what my MFD is telling me as well.
 
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D-Cell_Mekanick

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What about a BEW cam in a BRM. My mpg dropped 4 after my cam change...
Did you check the torsion value before you did the cam swap? Just wondering, because before my cam was changed under warranty I did not. I didnt have vcds at that time. Have you played with torsion to try and zero in on a setting for mpg?
 

metallocene

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When I installed the new BEW cam this summer, I bumped the torsion # from -0.5 to +1.5, read some threads where it seemed to help with mileage. So far the mileage is quite similar to the old BRM at the original -0.5. Tough to tell now that snow and winter diesel is here. At +1.5, cold starts seem "easier", need some -30C weather to prove that one out and who really wants that. :)
 

cobra390t

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A torsion value of "0" is the general concensus for optimal timing.

VW spec is +1.0 - +1.5 for the new belt to account for belt stretch and this is what i set everybody's timing belts at everytime I change a belt.

Every belt I set the torsion value on usually returns better fuel economy than before the change.

My belt is at +1.0 currently and I see 48mpg routinely and 51-53mpg when i'm good to it.
Where or how to check this , I just recently got my TB done by a good TDI mechanic and every thing seems the same 48mpg -52mpg ..

Is this a software setting or a mechanical setting ???
 

dieselpony

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Where or how to check this , I just recently got my TB done by a good TDI mechanic and every thing seems the same 48mpg -52mpg ..

Is this a software setting or a mechanical setting ???
It's a mechanical setting that you read with software (VCDS, formerly known as Vag-Com). If the mechanic used the proper lock-down tools, you're likely in spec. Someone near you may have VCDS and be willing to help you. Check out the list - I think at the top of the TDI 101 sub-forum.
 

cobra390t

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. If the mechanic used the proper lock-down tools, you're likely in spec. Someone near you may have VCDS and be willing to help you. Check out the list - I think at the top of the TDI 101 sub-forum.
The way he explained it to me there is a special tool that was included he had to use to set the proper tension on the belt and there is a notch that must be seated correctly ..if that has any thing to do with above mentioned i assume it's right on ....

i live in the East of NC state ..It would be great to find some one with the VCDS close by so i can at least have them program my spare key and do a health check on the PD
 

dieselpony

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Here's the VCDS locator thread: http://forums.tdiclub.com/showthread.php?t=296841 There's a link to a google map there to find the nearest VCDS owner willing to help near you.

Sounds like he got the tensioner set and adjusted correctly. The lock-down tools are very particular to this specific car, particularly the crank lock. I'd have it checked to make sure it's set right. If the mechanic himself didn't have VCDS, I'd wonder if he did it correctly. Where did the parts that he used come from? There have been a lot of problems with chinese parts, bought and put on by shops, that don't last more than 20k miles. If the belt, water pump, idler, tensioner, and new bolt kit didn't cost you $250 - 300, that would be highly suspect. Do you remember any of the brand names of the parts?

Hopefully it's all fine, just some things you'd want to check out.
 

cobra390t

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Here's the VCDS locator thread: http://forums.tdiclub.com/showthread.php?t=296841 There's a link to a google map there to find the nearest VCDS owner willing to help near you.

Sounds like he got the tensioner set and adjusted correctly. The lock-down tools are very particular to this specific car, particularly the crank lock. I'd have it checked to make sure it's set right. If the mechanic himself didn't have VCDS, I'd wonder if he did it correctly. Where did the parts that he used come from? There have been a lot of problems with chinese parts, bought and put on by shops, that don't last more than 20k miles. If the belt, water pump, idler, tensioner, and new bolt kit didn't cost you $250 - 300, that would be highly suspect. Do you remember any of the brand names of the parts?

Hopefully it's all fine, just some things you'd want to check out.
Bought the kit from Marquette AKA metalmanparts www.metalmanparts.com ,All German parts nothing Chinese .You got to hate that Chinese junk they control the market .

 

sptsailing

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VCDS ordered

OK, I ordered a VCDS from Ross Tech. I will post results when I find them. Thank you for the advice.

A torsion value of "0" is the general concensus for optimal timing.

VW spec is +1.0 - +1.5 for the new belt to account for belt stretch and this is what i set everybody's timing belts at everytime I change a belt.

Every belt I set the torsion value on usually returns better fuel economy than before the change.

My belt is at +1.0 currently and I see 48mpg routinely and 51-53mpg when i'm good to it.
 

Ken140TDI

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Golf mk5 GT TDI
Hi guys.
Since buying my 140 tdi 16 valve PD golf I have been doing a lot of reading and doing some experimentation to try to improve my mpg. It's not bad but with the cost of fuel in the uk every little helps.
Having seen a lot of posts in torsion value for the older 1900 cc pd engine I have been wondering if tuni g the cams on the bkd engine would help in any way.
The fundimental difference between the 8 valve pd and the newer 16 valve version is that the newer bkd 16 valve engine is a double ohc not a single ohc engine.
Now, other than either retarding the cam timing to move the power band up the rev range a little or advancing it a bit to move the power down a little which would possibly improve fuel consumption a bit at one end or the other I am wondering what efect the can sensor has other that to tell the ecu which cylinder is at TDC. Does it alter when the ecu decides to start injection ??????
If it does I can understand why a small change in torsion or cam timing makes such a noticeable difference in fuel figures. If on the other hand the cam sensor Is only for telling the ecu which cylinder is at tdc I can't see Why some of you have seen such changes in fuel economy.
As for my engine the cam sensor is on the front or inlet cam but the cam lobes that drive the injectors is the exhaust cam which has no sensor.
So if I use the torsion value to dial in the inlet cam is there a way to use vcds to set up the exhaust cam ?????
I have seen several posts over different forums that sujest that altering the cam timing on the pd engine changes the way the mfd reads so all figures need to be made tank to tank and worked out manually. Also that moving the cam timing also alters the amount of fuel that can be injected for a given opening time due to the ramps of the lobes that pressure up the fuel in the injector. But my thoughts would be that the lobes which operate the pd injectors are not pointed enought or have a fast enough ramp rate to be affected by only 2 or 3 degries of alteration either side of the Center position.

So my questions are does movement of the cam afect the ecu descision on injector timing, does cam timing affect the amount of fuel injected or the pressure its injected at or is it simply the valve timing that afects the fuel figures.
I got into all this as when I got my car it had the infamous engine shake at idol and when I checked the cam timing just with the normal locking tools my exhaust can was retarded by quite a long way but the inlet cam was advanced. Not too much but enough that the locking pin would not go in.
Correcting my cam timing has cured the engine shake but I have lost about 2 or three mpg. I have had the car remapped and the egr valve removed and hopefully males out but vcds still shows expected and actual egr flow which I find odd.
I'm an engine reconditioned and have spent many years tuning petrol cars and own a mk 2 ford escort RS2000 which runs a programable injection system 35 pounds of boost and 500 bhp and is still capable of 34 mpg at 80 mph on a motorway. I did all my own research and development work and all my own tuning. So I'm not new to modding and tuning engines but I have not done tuning work on oil burners before.

There is one last thing I have noticed and would like an opinion on if any if u know about the requirements for soi or start on injection timing n diesels.
On a petrol car when under light load or cruise conditions the ignition timing is advanced to produce better power from the fuel that is going In and improve fuel economy.
On my gt tdi I notice in vcds that at say 2000 rpm on very light load the SOI is around only 4 may be 5 deg BTDC. But as I put my foot down and increase load and boost the timing or SOI advances Nd under full load its at almost 16 deg BTDC.
I would have thought that even a diesel would need more advance at light load to produce better fuel figures. Unless its being left retarded deleberatly to reduce the nox gasses.

Your thoughts would be most welcome guys and advice if any one knows any of the answers to my thoughts and questions.
 

slamhouse

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Camshaft timing plays no effect to injection timing, duration, or pressure. The ECU injects based on crankshaft position.

Nox Emissions is the killer on the potential for our TDI's. Although tunes are available to fix this.

Camshaft timing is a touchy zone. retarded, you will experience better fuel economy but engine shake at idle. Advanced, you will get better performance in the upper power band, but reduced fuel economy.
 

cobra390t

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Camshaft timing plays no effect to injection timing, duration, or pressure. The ECU injects based on crankshaft position.

Nox Emissions is the killer on the potential for our TDI's. Although tunes are available to fix this.

Camshaft timing is a touchy zone. retarded, you will experience better fuel economy but engine shake at idle. Advanced, you will get better performance in the upper power band, but reduced fuel economy.
After TB replacement mine was set at-2.5 and noticed the slight shake at idle as you said , I adjusted to Zero and it's pretty smooth . not looking for performance as much as am looking for fuel economy . In my own opinion My TDI and i are happy with value of Zero ...

Thanks to my Local TDI club Memeber Jajohn with the VAG-com set up
 

James & Son

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Hi guys.

There is one last thing I have noticed and would like an opinion on if any if u know about the requirements for soi or start on injection timing n diesels.
On a petrol car when under light load or cruise conditions the ignition timing is advanced to produce better power from the fuel that is going In and improve fuel economy.
On my gt tdi I notice in vcds that at say 2000 rpm on very light load the SOI is around only 4 may be 5 deg BTDC. But as I put my foot down and increase load and boost the timing or SOI advances Nd under full load its at almost 16 deg BTDC.
I would have thought that even a diesel would need more advance at light load to produce better fuel figures. Unless its being left retarded deleberatly to reduce the nox gasses.

Your thoughts would be most welcome guys and advice if any one knows any of the answers to my thoughts and questions.
I believe it is only the pre-injection that takes place before top dead center and that is based on a number of inputs including coolant temperature for example. I am pretty certain the main injection comes after top dead center. I find your questions interesting. I would also ask what if someone set the adjustment screw on the injection rocker arm at an improper clearance. What affect would that have. It looks like the injection ramp is straight cut on my car so the further up the ramp the greater the velocity, but at a constant acceleration or a constant increasing velocity. So minor mechanical miss adjustments might have an effect on fuel mileage. You must remember at part load is when the egr is most effective. At high loads and acceleration I think it is cut way back but can't be sure on the vw specific.
 

slamhouse

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The pilot injection and main injection events are not controlled seperately in the PD.

The main injection event takes place just after the pilot injection via hydro-mechanical fluid channeling in the injector. The ECU only controls Start of injection and End of injection.
 

James & Son

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The pilot injection and main injection events are not controlled seperately in the PD.

The main injection event takes place just after the pilot injection via hydro-mechanical fluid channeling in the injector. The ECU only controls Start of injection and End of injection.
Thanks Slamhouse, That is a very clearly worded statement of how that event is started, interconnected and finished.

Ken140TDI
If on the other hand the cam sensor Is only for telling the ecu which cylinder is at tdc I can't see Why some of you have seen such changes in fuel economy.
Edit2:
I am going to take a crack at this question based on my statement from previous post.
It looks like the injection ramp is straight cut on my car so the further up the ramp the greater the velocity, but at a constant acceleration or a constant increasing velocity.
Now from what I have read etc. lets take a rough estimate that the start of the ejection event takes place over a minimum of 5 degrees, the idle event would around tdc for instance and a full load event at a maximum of 40 degrees( say 16 degrees btc and 24 after tdc. as a possibility). This is crank angles. We are interested only in the difference 2.5 degrees( 1.25 cam degrees) would have on the time as well as the displacement of the injection event. we know the velocity is constantly increasing and the ECU would initially rely on time to start and finish the ejection event. Lets say at 2000 rpm the ejection event takes place over 20 crank degrees which is 10 cam degrees. You now can break out the time, distance and mass formulas which is not going to happen. But as a ratio a variation of 1.25 degrees compared to 10 degrees is substantial. Doing a bit of trigonometry shows a variation of 1.25 degrees has a substantial effect on distance assuming a 20 to 60 degree start and finish ramp angle and the ECU is tying to make everything happen in the 35 to 45 degree range in our example. Without going any further I think we can say it would have an effect.
 
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Ken140TDI

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Golf mk5 GT TDI
Argh I've missed this convo for a day or so. Lots to take in and comment on
Ill get back to u all later but for now I have some readings for u.
I've been driving round with vcds running on my lap top lol :).
The maximum advance I have seen is on full boost at around 4000 rpm and the Start Of Injection timing was about 19 deg BTDC.
On light loads it retards off massively from there and when warm idle SOI is only 4 or 5 BTDC Onl light load cruse around 27 % throttle and 2000 rpm its around 5 or 6 BTDC.
But there is a possible conflict here as when I had it mapped I asked for the EGR to be removed as I'm running with it blanked of. (We all know why don't we)
In polluted intake charge and no more clogging up of the inlet manifold and ports with black sludge.
But in vcds I can still see expected and actual egr readings and according to my thoughts and some one I've got to know in the last few days who has been mapping for a while now if the egr has been removed properly I should not have anything under egr in the fields in VCDS. :(.
As for cam timing retarding pushes power band up the rev range and advancing brings it down but will also get u a slightly faster spin up on the turbo.

I will post again later when I have had chance to read all your comments properly.
By the way are you all on the 1900 8 valve pd or are some of you on the 2.0ltrr 16 valve like me.
 

slamhouse

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In the egr field, with a stock tune, you will see numbers like 200/400. With is mapped out, you will see numbers like 400/800. This is at idle.

A tuner just raises the allowable amount of clean air charge.
 

Ken140TDI

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ok ill get a set of reading from the two fields tomorrow. But it would help if I knew what the reading in the egr field actually mean. is the reading in the egr fields measuring the flow through the egr ????
 

slamhouse

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The values are as follows:

EGR Actual: 200 EGR Specified: 400

EGR Actual is the amount of clean air traveling through the intake. a higher number means cleaner air.

EGR Specified, is the allowable amount of clean air in the intake.

Stock, egr drops your first number by half of that of no EGR. If you simply delete the EGR physically, the ECU will see an EGR Actual of maybe 450 and with an EGR specified of 400, the engine will throw a code and run poorly.

A tune will raise the amount of allowable clean air in the intake to prevent the code and driveability issues. essentially changing the way the computer thinks(A tune) instead of tricking it(tuning boxes).
 

Ken140TDI

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Right. well if I remember what i was seeing I think in the first window i was seeing a number of something like 600 and in the window to the right i think it was around 800 But like i said I will check tomorrow and report back.

I am in the middle of getting hold of the needed equipment for reading the maps from my car and re flashing a new map into the ecu my self. and I have just recieved the software to install to open the maps so I can really see whats going on and how its done:).
I also have managed to get hold of a standard map for my car to compare it with the map that was installed by the rolling road tuner that put the map in for me..

just out of interest does anyone know if a deisel works in the same way as a petrol in regards to the fact that on a petrol engine to get the light load economy you advance the ignition timing up by something like 20 deg. Just like a vacume advance pod would do on an older petrol car.

I might have said somwhere in my very long posts LOL that the whole point of me havibng my car mapped was to get better fuel economy and not just to get extra power. BUT I havwe gained absolutly nothing at all and thats driving it very carefully both before it was mapped and after.

Between 3 and 6 or 7 deg BTDC for the SOI seems very retarded in my opinion But i do not know yet weather a deisel requires advancing like a petrol does under lighter loads to get the best fuel economy.
 

Ken140TDI

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Golf mk5 GT TDI
It was a blend tune. The map was read on a kess 2 and re installed from a lap top using the kess2
Unfortunately I do not know the name of the company where the map came from. Buy I do know that they uploaded the map to the mapping co. and asked them for a blend file for my car but with the egr turned off.
May be it was done right. May be not. I do not know. But like I said before I was hoping to have seen a few mpg better. Shame we can't live map these cars as it would be a lot easier. Lol
 
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