PD Engines - The Problem of Setting Torsion Value

truman

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For some short mileage run comparisons, which measuring blocks in VCDS would be helpful?
 

Mako

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Be aware that deviating from the factory setting in either direction will bring valve meeting piston events closer. There is a limit from which you may not be able to turn back. If one is set on deviating beyond factory limits at least remove the glow plugs and turn the motor over by hand to make sure there is no contact. With a big deviation you may not have any contact but you don't know if you have enough 'running clearance'.
 

JPS06JW

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My understanding is that injection timing for optimum efficiency and timing for reduced NOx are mutually exclusive in a diesel. Hence, the later diesels have retarded injection timing to imrove NOx numbers. Since we are not seeing efficiency improvements with significant positive KW, this suggests that KW does not influence injection timing but instead, is intended to optomize cam to crack timing for best valve to piston clearance and for optimum fuel pressure ramp-up through the injector cam and that injection timing is controlled completely by the crank sensor alignment and ECU, as mentioned earlier.

The Dodge HPCR engines respond positively to a slight advanced rotation of the crank sensor wheel or with an offset crank sensor. Of course on any of the diesel programmers, the tuner has access to and can optimize injection timing for efficiency of power or both.

Is there any way to adjust the crank sensor position or crank sensor pick-up wheel angular location to gain some timing advantage?

Just some thoughts. Please correct if any are off base.

Regards, John
 

Mako

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There's no way to adjust the timing wheel or the sensor. ECU is the only way. Off topic but non USA ECU's exhibit more advanced SOI (start of injection)
 

PDJetta

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There's no way to adjust the timing wheel or the sensor. ECU is the only way. Off topic but non USA ECU's exhibit more advanced SOI (start of injection)
That makes perfect sense, since European NOx standards are more lax than in the United States (more advanced injection timing increases combustion pressure and temperature (and performance), thus creating more oxides of nitrogen). I for a long time thought our TDIs ran sub-optimal injection timing. I do hope chip tuning advances the timing some during operation, more towards optimal.

--Nate
 

truman

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I checked the sticker on my timing belt cover. In the box to the left of "WK", it appears to have written 1,73. Below the box it is written 0,5. What do you make of it?
 

Mako

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If the entry on the label is indeed torsion value I would guess that the value was read on factory diagnostics when the motor was test run and the operator simply entered the recorded value onto the sticker. This would then have allowed to them to sign off that stage.If the value was outside of tolerances it would have been reset and the operator only wrote in the value he reset it to. I like the idea that it was 'optimised' on high resolution kit but doubt it.
To answer an earlier timing question (not hijacking the thread) N. American TDI's do run retarded SOI compared to Euro spec's in model to model comparisons. I verified this a long time ago by comparing VE to VE and PD to PD maps. If Mike Mars has a map of his 1.4 PD I can send him mine for comparison and posting in a relevant thread.
 

runonbeer

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Below the box it is written 0,5. What do you make of it?
Thats the number I was talking about. The lower one.

If the entry on the label is indeed torsion value I would guess that the value was read on factory diagnostics when the motor was test run and the operator simply entered the recorded value onto the sticker. This would then have allowed to them to sign off that stage.If the value was outside of tolerances it would have been reset and the operator only wrote in the value he reset it to. I like the idea that it was 'optimised' on high resolution kit but doubt it.
Yes. this is probably the case.
 

Mako

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Some useful info. I was on 0kw. I tried a -5 setting and ran into a situation where the IP was opening before any meaningful pressure had built up and a huge lack of flexibility.Went to +5 ish and found more performance than I had at 0.
I run 5 degrees more SOI than stock (through the range) because I run 100% bio. Retarding the cam to -5 took me onto the range where fuel pressure was still ramping up, not at idle where it coped but in the area above 1500 RPM where extra advance is required it fell off the ramp so to speak.
I learned that the SOI is within five degrees or so of the required fuel pressure.
 

TonyJetta

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I guess my cover is too aged / heat worn to see any number written on it.

Oh, well.

Tony
 

jsrmonster

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This has been discussed alot in the past (I can look up my old posts). The european fuel and timing mappings account for better (available) fuel quality (ie. 50 cetane) vs crappy USA fuel imho. Thats why the euro110 tunes were preferred here, they just ran better.

I recall doing alot of this PD testing in 04, and found that you must unhook the coolant temp sensor (inlet & exit on 06's), and fuel temps sensor, to get meaningful data (cuz the idle torsion number varies with engine temp). The PD's use an average temp between the 3 sensors to get a semi-useful data point to work with the mappings. Poor man's PD tuning = make ecu think its cold and get more power, note, 1st pd tuning box was a resistor on fuel temp sensor!

I could go on here about what is best setting, but since ecu makes the final decision where SOI-start of injection occurs wrt cam/crank/TDC I think TDC is optimal for all conditions. Like said before, make it negative, and get a bit more performance on top, and make it + and get tiny FE improvement on bottom (low rpm driving).

I spent alot of time with advancing and retarding cam-to-crank timing on PD's and 5-6k rpms tunes. Decided that TDC & 5k is best on PD's while 6k rpms works well on rotary pump tdi's (with supporting mods of course).

Idle IQ/torsion is set/adjusted in mapping on PD, and mechanical (and vagcom tweaks) in Rotary-pump tdi's.

Jeff
 
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Mako

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Torsion is fixed mechanically and The ECU has to live with it. All the ecu reads form torsion is which injector to fire when starting the motor. If the cam sensor fails the motor will run normally other than having to crank for longer to work out which cylinder is compressing and it does this by measuring the deceleration of the flywheel.
 

Henrick

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Interesting reading. I checked my TB cover. It is a little different than all those posted here and it does not have the 'box' as seen here. Also, there aren't any human-written numbers or letters on the sticker. And I inspected it really close with much light and there are no signs of anything being written in the past. My engine code is BKC (PD-105).
 

oilhammer

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There are just too many to list....
From my experience, BHWs and BEWs with manuals and 09A autoboxes are best at '0'. BEWs with 02Es and all BRMs seem to like a slight positive, +.5 or so.

This can really impact fuel economy, especially on the BHW, if it is off.
 

jdhunt0

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Interesting. My car was at -2.5 when I got it, and mileage was good, but the idle was rough. I moved it to 0.0 and everything smoothed out at idle. After a few long trips with reduced fuel economy I started looking for a problem. EGR was removed due to a suspected problem with no change to my MPG. Next the cam was changed by Frank with still no change in my economy. I think I have tried 0.0 and +1.5 with the new cam. Maybe it is time to do a little more experimentation.
 

PDJetta

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After my timing belt change at 100,000 miles (and I used the lockdown tools and was very meticulous) I checked the torsion value (actually about a year after replacing the belt) and it was at +3 or something. I lowered it to +1.5 and noticed better fuel economy and a couple of months later lowered it to +0.5, for a total mileage improvement (over the +3 setting) of about 3 MPGs. I get 50 - 51 MPGs now, so I will leave it alone (I also drive conservatively).

--Nate
 

lbirunner

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I wish I had checked mine before doing the timing belt last month. I also replaced the cam with Colt stage 1 at the same time. Thanks to this thread I checked it Sat and it was at +0.5. I changed it to 0.0.
MPGs at +0.5 were 40-42 (I have an 09A). I'm hoping for better economy with the new setting.
Also, my belt cover doesn't have any writing left on it, I'm assuming it's all faded away.
 

oilhammer

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There are just too many to list....
Checking it before, on a used and about to be replaced belt is kind of useless. Unless the crank lock tool and the cam lock pin slide it perfectly centered beforehand, and the tensioner tang is exactly in the middle beforehand, which they never are.
 

oilhammer

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There are just too many to list....
I never assume someone can do the job correctly, even with the right tools. Some people just should not attempt this job. I can only comment on my own experiences.
 

PDJetta

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Mine ended up being pretty positive with the use of the lock tools, and I was careful (first time replacing the belt on a BEW, though). I thought it was at about +3, but maybe it was not that high, but it was over 1.5, I know that. There must be a normal amount of play in the tools and lock points, which create a variance among engines.

--Nate
 

TonyJetta

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There must be a normal amount of play in the tools and lock points, which create a variance among engines.
There is a continual stackup of tolerances, in EVERYTHING:

Cam lobe center lines
Cam lobe height
Lifter height
Lifter pump-up / pump-down differences
Valve stem length
Piston top-to-wrist-pin height
Connecting rod lengths
Rod journal center line to crank center line
Crankshaft rod journal angle to timing belt keyway
And THEN, you add in the tolerances of the lockdown tools
And more, that I can't think of, right now.

All of these can be managed in the manufacturing process, but they will all still stack up. That is why software needs to be able to compensate.

Tony
 

whitedog

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There is a continual stackup of tolerances, in EVERYTHING:

Cam lobe center lines
Cam lobe height
Lifter height
Lifter pump-up / pump-down differences
Valve stem length
Piston top-to-wrist-pin height
Connecting rod lengths
Rod journal center line to crank center line
Crankshaft rod journal angle to timing belt keyway
And THEN, you add in the tolerances of the lockdown tools
And more, that I can't think of, right now.

All of these can be managed in the manufacturing process, but they will all still stack up. That is why software needs to be able to compensate.

Tony
Cam centerlines.
Deck height

I hadn't thought about all of that before, Tony. It explains why one car runs so differently from it's twin. I'm talking about ANY car, not just the PD. Yes, things will be close, but stack up all of the differences and there ya go.
 

Henrick

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Yep. Judgiung by all those 'difference' statements, some PD engines might also work with 505.01 and not everyone'll necessary need to switch to truck oil.
 
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