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VAGCOM Torque/BHP graph

Discussion in 'A3/S3 Forum (8L Chassis)' started by Westy, Feb 16, 2009.

  1. Westy

    Westy Double Dark Side! Diesel & 8P

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    Deece posted up the guide to do this from Ross-Tech's website last week so I thought I'd gove it a go. This is what I got:

    [​IMG]

    For those of you that have had dyno graphs done and or have done this graph in VAGCOM can you tell me if it looks ok?

    I hit max power of 221HP at 5700rpm and max torque of 227lbft at 4500rpm
     
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  3. MintyS3

    MintyS3 Works 60% the time, Everytime.

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    Not bad. Fairly smooth power curve apart from the slight flat spot at 4500rpm.
     
  4. jimbobery

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    Looks ok to me, not that I've had a dyno graph done, or that I know what I'm taking about :)

    But, I do know that your torque and power are supposed to cross at exactly 5252 rpm, which yours does. Its to do with how bhp is calculated from torque and rpm (5252 is in the formula)

    I did a graph at the weekend actually so I'll post it tonight - then you'll see why you should have a remap!
     
  5. Westy

    Westy Double Dark Side! Diesel & 8P

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    Yeah get your graph up matey.

    I was only doing this to make sure I didn't have a problem because I had fluttering noises when boosting but its only occaisionally. I think this graph and my boost graph prove I'm running ok. A remap is on the cards soon. Just need to decide where to get it done.
     
  6. jimbobery

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    Here's my latest one. Its a bit smoother than yours, but I think it would depend on road conditions etc so probably nothing to worry about.

    I got a maximum of 265ftlb and 265bhp, which is what its supposed to be with the remap, and I've only read on here etc that the torque calculation from the bosch sensors is accurate.
    I think the thing to remeber with this is that vagcom only logs once every 1/4 of a second or so, therefore you might actually miss your maximum reading, I definiately found this to be the case with checking the maximum MAF reading.

    [​IMG]
     
  7. metricspaces

    metricspaces Member

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    Where is the guide to get produce these graphs? I've got VAG-COM, so I wouldn't mind trying it out for myself.
     
  8. 666markyboy

    666markyboy Well-Known Member

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    yeah i wouldn't mind a look at the guide and give it a go..
     
  9. jimbobery

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    Its not so much a guide, more a collection of all the vagcom logging info I could find pasted into a word doc.

    I've pm'd you both :)
     
  10. MickM

    MickM Member

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    Couldn't shoot it this way could you mate.
     
  11. jimbobery

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    No probs - PM me your email and I'll send it over
     
  12. MickM

    MickM Member

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    Thanks for that mate
     
  13. Westy

    Westy Double Dark Side! Diesel & 8P

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    Post up your graphs lads when you've done it.
     
  14. fishman85

    fishman85 New Member

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    PM Sent
     
  15. Westy

    Westy Double Dark Side! Diesel & 8P

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  16. jimbobery

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  17. thorsy22

    thorsy22 Member

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    Thanks for the pm earlier deece.
     
  18. Andy_S3

    Andy_S3 Member
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    Just had a play with mine and got virtually identical results to these, so it cant be that bad!
     
  19. Westy

    Westy Double Dark Side! Diesel & 8P

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    Good i'm glad i'm not the only one with un smooth power curves :happy:
     
  20. freegeek

    freegeek Member

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    Would be interesting to compare one run with the this method and the bhp = MAF/.8 to compare the two sets of results.

    Mine looks like this with the maf method, I used this as I had heard that the torqu calculationfor the ECU could be innacurate when mapped, but that could be incorrect.

    If I get time i'll mod the code to plot the curves with both sets of data.

    [​IMG]
     
  21. jimbobery

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    I did a MAF run straight run after the torque one above (same road, same conditions etc) and got this:
    Engine RPM: 6600
    Air Mass: 220.97

    Thats the highest air mass flow I've ever got, although all other runs I've done were in 18degC or above last year (not sure if that makes a difference).

    So thats 220/0.8 = 275bhp. I'm very sure my car doesn't have 275bhp!!! I think the MAF/.8 calulation is only a general guide.

    I've only read that the ECU torque calcultations are actually accurate, even when mapped (except on Passats for some reason ?!?).

    Measuring lbft and bhp is all a bit random anyway, what with the stories you hear of dynos giving higher than true readings and then people quoting figures as fact. I only log this stuff to check I haven't actually lost any power due to faulty MAF, DV etc.

    I am impressed with the 'liquid' though - looks to be a well thought out bit of kit!
     
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  23. Westy

    Westy Double Dark Side! Diesel & 8P

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    I alos was only interested in this to rule out a boost leak as I was hearing some strange fluttering noises when boosting.

    It would be very interesting to see how different the readings are between the 2 methods.

    Post up the graph if anyone gets time to do it.
     
  24. s3wil

    s3wil New Member

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    [​IMG]

    Hi. New to the forum. Hi everyone. Just put my figures into the Spreadsheet. A little dissapointed with the results. Straight road in 3rd pulling from about 1300RPM up until Redline.

    HP = 230
    Torque = 260

    It has had a revo Stage 2 supposibly 260HP/280lbft.

    Have I done this correctly. Car seems to be pulling smoothly, throwing no fault codes.

    Thanks
     
  25. Carl.S

    Carl.S Member

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    vagcom dyno's aren't accurate with performance software as the calculation's used are based on stock software so they are a compleate waste of time for power figures!

    bst off getting the car dyno'd properly!
     
  26. s3wil

    s3wil New Member

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    Thats what I was hoping. Just wondered why some people were getting expected figured even running tuned software?

    Extras are:

    Miltek Race Re-Circ Valve
    Powerflow Full Exhaust/Decat
    GruppeM Intake

    Would you advise any changes?

    Thanks
     
  27. MintyS3

    MintyS3 Works 60% the time, Everytime.

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    Allways been wary of custom exhausts. Not saying its certain but Ive known people to lose power with the custom powerflow exhausts. Depends on garage that did it though.
     
  28. jimbobery

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    This is a bit of a sweeping statement! How is it that so many people get expected results using this method?

    This quote from the guy who made the vagcom software is more likely to be accurate:
    That depends on the approach the chip-tuner takes. Sometimes they have to "fudge" the torque calculation in order to bypass other limitations in the firmware. (from here)

    So some remapped cars don't produce accurate results using vagcom and some do, but not Revo as they fudge the torque calculation (not putting down Revo tho).
     
  29. s3wil

    s3wil New Member

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    Just logged the MAF under WOT and it gave 205g/s. A website indicated to multiply by 1.31 as a rough guide = 268BHP.

    Interesting topic. Keen to get it done on the rollers now as it would really clear up some theories. Although as someone pointed out the VAG Dyno method is a great way of testing how modifications affect performance.

    Thanks for your input.
     
  30. freegeek

    freegeek Member

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    Guys, I am trying to improve the accuracy of the liquidS3 BHP and Torque figures. Today I calculate bhp and torque using the maf data but I am not sure if this is the best/most accurate way.

    So I use;

    bhp = maf/0.8

    torque = bhp * 5252 / rpm

    however vag-com also provides a torque figure directly thus bhp can be calculated with this;

    bhp = torque * rpm / 5252

    To verify which is best I need some vag com logs from both stock and mapped cars, the logs need to be done in 3rd gear, from 1k rpm to the red line with full throttle logging only block 2 and block 122.

    I have plotted the data from my car doing two identical runs below. The plots on the left are what you would get from the liquidTT the ones on the right are using the alternative calculation metod.

    I hope you can send me your logs.

    Cheers Jim

    [​IMG]
     
  31. jimbobery

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    The problem with the MAF calculation is that is misrepresentative when you get up the top of the rev range.
    You can see BHP continue to rise all the way to the redline, but this isn't likely as its common for power to drop off at the top of the rev range; over 5500rpm you can feel the power reduce on the S3 and I've read many comments that the best time to change gear is at 5500rpm as this is where peak power occurs.

    Anyways, bearing this in mind I think your graphs show that using the VAG Torque Method is more realistic.
    Prehaps you could display both methods making it clear about the differences between the two, MAF readings are still useful to know?

    Out of interest what language are you using to capture and display the info from the ODBII port? I just wonder if you can open out to Developers like Facebook has?
     
  32. jimbobery

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    I have some logs I can send you, PM me your email address.
     
  33. MintyS3

    MintyS3 Works 60% the time, Everytime.

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    To be fair that "feeling" of reduced power is the drop off of torque. Thats what pushes the car and thats why its best to change well before the limit.
     
  34. freegeek

    freegeek Member

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    Can you remember where you read this, getting good data on this is very difficult, I had read that the ECU torque calculations were inaccurate for mapped cars, but again that was just forum speculation.
     
  35. s3wil

    s3wil New Member

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    Well after feeling the car wasnt quite going as it should and getting less than expected vag com logs, yesterday I followed a guide found to test for vacuum leaks.

    Blue peter style I connected a sweetcorn tin up the the intake with a pressure line adapter on, clamped off PCV pipe and raised to around 10psi. Instantly I heard alot of leaking air. Firstly a pipe near the dipstick had split and secondly once I fixed that I could hear the pink 90 degree hose pipe coming from the turbo at the rear of the engine hissing also. Once I removed this, easier said than done! I could see it was badly cracked inside and out.

    The stealers wanted £89 for this so ended up getting a silicone pipe off the internet for £17!

    With slight modification fitted. I then retested and couldnt find any more leakjs but is it right for the air to be escaping from oil cap (removed)

    Now the car pulls alot more smoothly and although the placebo affect maybe playing a part the car feels a little bit more powerfull.

    Job done. I highly recommend the pressure test. Will post Vag Com LOGS soon. Great forum, shame full audi servicing didnt pick this up!
     
  36. Westy

    Westy Double Dark Side! Diesel & 8P

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    Nice work Wil get the logs up. I would like to do this too as I have strange noises when boosting but the car feels ok most of time.
     
  37. MintyS3

    MintyS3 Works 60% the time, Everytime.

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    Well there you go. Proof the the Turbo pipe at the back of the engine can fail...
     
  38. Westy

    Westy Double Dark Side! Diesel & 8P

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    Can someone stick up a pic of where this pipe is because i've now heard of several boost issues that were caused by that pipe.
     
  39. ianysm

    ianysm Active Member

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    Have you got a link to this vacuum leak guide?

    All interesting stuff.
     
  40. Westy

    Westy Double Dark Side! Diesel & 8P

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    I've just done a quick search on Ross-tech's website and cant find anything so a link to the guide would be greatly appreciated S3Wil.
     
  41. MintyS3

    MintyS3 Works 60% the time, Everytime.

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    Its at the top back of the engine. Just under the strut brace. 90 degree bend and red. Comes straight off the turbo.
     
  42. Westy

    Westy Double Dark Side! Diesel & 8P

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    Many thanks Minty I'll check that tomorrow.
     

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