I have done vast research over 1000 km just test driving and setups on tdi cam timing or torsion value as it is said on vag tdi. I made a custom program that injects same amount of fuel 16mg/stroke all the time for full rev range on a 1.4TDI which is 3 cylinder diesel engine. So its not exactly same amount of fuel if rpm rise there is more fuel injected per hour, but still its constant amount per stroke. If you would have level road for testing you would get even better results, but you have to use what you have.
Test road was 6,3 km long full of uphills and downhills and I doubled that for fine tuning. Just by changing the timing, meaning adjustable cam you are able to get 5-10% improvements on a diesel engine at least. Problems arise when you change your drivebelt it often does not go exactly same place.
I moved adjustment from -2,2 torsio to 2,2 which was best setup for this car and the time went from 267 seconds to 243 seconds and to back direction from 278s to 253s. I started the test from 70 km/h speed and put the pedal to the floor. This way car would accerelerate and the small differences in start speed would not have so big impact to end result.
-2,2 =12600m/267s+278s=12600m/545s=23,1 m/s--> 83,1 km/h avg speed car needs about 8,5 hp for this avg speed
2,2=12600m/243s+253s=12600m/496s=25,4m/s-->91,4 km/h avg speed car needs about 10,5 hp
During the testing top speed got 10 km/h higher from 105->115 km/h and car was able to keep much higher speeds at uphills and steady sections as well.
https://ecomodder.com/forum/showthre...ToStep=40-65-1
As you can see there is big differences out there you just need to dig them out in testing.
All those values were inside VW tolerance +-3,0 degrees for diesel engines!!! It is well known fact that some diesel get much better fuel consumption than others, and I believe this is the main reason for those differences.
1.4TDI Audi A2 can now drive on 6th gear from 75 km/h and before any ecu modifications limit was aroung 90-95 km/h speed range. 100km/h is about 1750rpm. Now I am able to go 80 pretty easily if there is no big uphills.
I did same testing also on 1.9tdi and results were pretty much the same, there drive speeds got higher so avg speed wise it was not so big high speed difference but energy consumption was higher at higher speeds...
Best torsion values were not same for different cars so you need to find out which is best setup for your car. Cheap and easy method would be to make a stopper under gas pedal or hand throttle to have always same throttle position on diesel car. But for this stopper method you really need flat road as pedal request changes based on rpm and many other factors...
How to find the best values tips from
TDIclub:
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I found this kind of instructions: Quote:
Originally Posted by MPG MASTERS 1 View Post
Since I am apparently out of range of the cam sensor because I get 0.0 TV on block 4, my question are:
1. Does the TV number send that number to the ECU to tell it when to fire the injector or is that number only given for the mechanic to see where the cam is in relation to the crank?
The cam position sensor works in tandem with the crank position sensor. Cam sensor tells the next cylinder to fire. Crank sensor tells what timing.
2. Is it the crank sensor telling the ECU when to fire the injectors?
Yes and no. It must have the cam sensor feed or it's a 50/50 chance the crank sensor will get it wrong.
3. Since I am out of range and the TV is zero 0.0 and the engine runs fine, I wonder what or where the injector id getting its firing signal.
If you have a failed crank sensor, the engine will not run. If you have a failed cam sensor, the default is 0.0. The engine will default from the crank sensor and try option #1, then option #2. The choice being which piston is on the firing stroke.
4. (More Scary) Will the slot range on the pulley keep you from moving so far as to damage the engine by hitting a valve with the piston?
If you have the cam sprocket bolts centered in the adjustment with the crank lock and cam lock installed, you can move the adjustment all the way from stop to stop and not cause an interference hit.
Block 15 at -1.4 was .401/h, at +1.5 it was .601/h at unknown - value it showed .201/h, then I moved cam Clockwise a fair amount to try to get back in range and the TV still showed 0.0 and the Block 15 also still showed .201/h.
All Block readings were at idle.
We use the VCDS block 15 liter per hour block to get the engine to get some windage of the range of fuel usage. The lowest read will still be a range of about 1 degree. Once we find the range, we use block 13 for the lowest variance between injectors. We also will run block 15 at 2000rpm, looking for the lowest fuel usage. Usually around 2.4l/hr is relatively normal.
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That is how you can find lowest idle fuel consumption but it is not the best for drive speeds rpm. You can try to find it by revving it standstill at 2000rpm but on road you have boost and its not constant so driving tests are required.
My lowest idle fuel consumption was at +6,6 torsio 0.3 l/h and best drive consumption was at +2,2 where idle was about 0,35-0,4 l/h. From start it was at -2,2 and idle fuel consumption was 0,6 l/h. To get more data on idle fuel consumption you can put fan at full and long ligths on to get two figures to compare.
So if your TDI is not getting the same fuel consumption figures on road as your friends at same speeds its fault could be badly timed torsion value. Your idle fuel consumption tells already something
On working TDI values should be
1.2TDI 0,3 l/h
1.4TDI 0,3-0,4l/h
1.9TDI 0,4-0,5 l/h
If you have installed some huge wheels etc that rise the fuel consumption it wil be higher. If torsion value and the idle fuel consumption is within spec you need to search the fault from dragging brakes etc.
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