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N75 Valve - Vag Com

Discussion in 'A3/S3 Forum (8L Chassis)' started by mnadeem1984, Sep 26, 2006.

  1. Tallpaul

    Tallpaul Member

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    Defratos is losing about 2psi at the top end.

    Assuming the pressure drop IS because of his FMIC and not a simple boost leak, then that amount is excessive. A drop of 1psi is 'normal' for a FMIC.

    BUT... Defratos is running the Stock ECU and hence stock boost. The S3 doesn't need a FMIC at that boost, it simply doesn't generate the charge temps, especially in winter. If his logs are recent then ambient air must be less than 10°C, i'd be suprised if he was hitting more than 35 - 40°C inlet temps with a FMIC - I get 60°C!

    So, basically he's introduced a pressure loss that the car doesn't need. He's not even offsetting that against a usefull drop in inlet temps because the car doesn't need them either! It'd be interesting to see what CF's he's getting cos i doubt even without a FMIC that an S3 needs any timing correction, except perhaps on the hottest of days or running the sh*ttest of 95ron fuel.

    Get a remap and whack the boost up, use 99ron fuel (v-power) and you'll be able to run aggressive timing and boost with that FMIC. Then it won't matter if your actual boost isn't quite meeting requested because you just won't care. I'd also imagine that the differance between requested and actual would reduce to much nearer the 1psi mark. At which point spending £750 on a Forge FMIC would be pointless!
     
  2. loftgroover

    loftgroover Member

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    Its true, the SMIC will be more than capable of dealing with the charge temps produced by the K04 at std boost, or even at higher boost.

    If the FMIC is causing that pressure drop, i think this may be a case of bigger is certainaly not always better.

    Th S3 runs active knock so it will always advance the timing ( within limits ) to the point of knock and then add the correction factor based on the knock sensor output. But in standard form it will be very little if any as you suggest.
     
  3. Defratos

    Defratos You’re Dethpicable!!

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    lol no mate, that's coming soon "hopefully" probably more like next year :sob: . What you're saying makes sense (a FMIC is not needed on a standard S3) and I'm not planning on splashing out on £700 for a Forge, more like £150-£200 on just the core unit and fit it myself, hopefully just before a remap, should sort things out a bit. cheers for the detailed feedback mate :beerchug:
     
  4. Defratos

    Defratos You’re Dethpicable!!

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    Cheers for the clarification, mine at the moment has a few bends, hopefully I'll get around to sorting that out when fixing the FMIC (before remap), thanks for the lil lesson in physics (I was never quit good at that in school :p ) :beerchug:
     
  5. Tallpaul

    Tallpaul Member

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    So are you going to change to a FMIC similar to Dubhyper's or have Forge quoted you that sort of price for supplying their core?
     
  6. Defratos

    Defratos You’re Dethpicable!!

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    well I want something similar to Dubhyper but I'm not too sure about it fitting right. Probably going for something of E-bay with similar sizes to the Forge, no way in hell am I paying silly money again (already spent too much on the current FMIC)
     
  7. Defratos

    Defratos You’re Dethpicable!!

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  8. Defratos

    Defratos You’re Dethpicable!!

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    Any idea how I can check my BHP with Vagcom?
     
  9. Tallpaul

    Tallpaul Member

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    lol, so yet another unproven intercooler. well, good luck.

    Although you should still try the remap before you change FMIC. After all, it will improve the pressure differential and you have no idea whether a new (unproven) core will be any better; it could be worse!
     
  10. Tallpaul

    Tallpaul Member

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    You can estimate it from your g/s airflow. Only a rough estimate though.
     
  11. loftgroover

    loftgroover Member

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  12. Tallpaul

    Tallpaul Member

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    I think the torque figures are even more fanciful than the bhp ones, but they are usefull estimates.
     
  13. Defratos

    Defratos You’re Dethpicable!!

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    sweet, cheers mate :beerchug:
     
  14. loftgroover

    loftgroover Member

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    BHP is calculated from torque so if one is right they should both be right ( or wrong!)

    Alternatively, you can convert your g/s MAF into lb/min and use 9 hp per lb/min of airflow, but now we really are guessing...
     
  15. Tallpaul

    Tallpaul Member

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    sorry, i meant the torque figures calculated from engine load are even more fancifull than bhp calculated from air flow :p
     
  16. loftgroover

    loftgroover Member

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    I think we're all speculating now..:blahblah1:

    On a different subject, ive logged 198g/s @ 6240 airflow on block 002 on VAG-COM - is this what you expe ct from revoed S3? seems a little low.
     
  17. Tallpaul

    Tallpaul Member

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    Apparantly (according to REVO) anything from 190g/s up is acceptable.
     
  18. Defratos

    Defratos You’re Dethpicable!!

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    whats the g/s supposed to be on a standard 225 S3? if anyone knows?
     
  19. Tallpaul

    Tallpaul Member

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    160g/s+
     
  20. AL_B

    AL_B Active Member

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    Tend to get in the 180g/s+ range on my standard S3. Usually about 185. Yep it is standard, had it since new, first owner etc etc.

    AL
     
  21. Defratos

    Defratos You’re Dethpicable!!

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    right I just did this and got 154hp with 176lbft now am I missin something? or am I doin it wrong? cause shouldn't I have more like 200hp?
    [​IMG]
     
  22. loftgroover

    loftgroover Member

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    can you post the raw excel data, ill have a look tomorrow while at work!
     
  23. Defratos

    Defratos You’re Dethpicable!!

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    sorry for the delay, just realised someone replied. Ok not too sure how I can post it? I can e-mail it to you if you're ok with that? or if you can tell me how I can post an Excel doc on here?
     
  24. Defratos

    Defratos You’re Dethpicable!!

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    I did the same test earlier on today to try and see if I did something wrong, but I got nearly the same, actually lost 2hp lol.

    Much smoother curve
    [​IMG]
     
  25. Defratos

    Defratos You’re Dethpicable!!

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    As for my MAF, for some weird reason I only got 130gs

    [​IMG]
     
  26. loftgroover

    loftgroover Member

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    Hmmm,

    130 is very low. My S3 made only 160hp with a faulty MAF, can you log the boost pressure, block 115?
     
  27. AL_B

    AL_B Active Member

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    Its bloody low, you sure someone hasn't put a 1.6 in it?
     
  28. dultanur

    dultanur all promises, no action :)

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    maybe a faulty MAF buddy? would also explain the low power (130g/s equals around 160hp)?

    how does the car feel?
     
  29. Defratos

    Defratos You’re Dethpicable!!

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    This was block 115. Do u want me to mail you the excel bit?
     
  30. Defratos

    Defratos You’re Dethpicable!!

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    The car feels solid to be honest, maybe a bit laggy, but now way does it feel like 150bhp lol honestly I hope I'm doing something wrong, cause the car seems quick "I think". Do u think my back box would restrict the power by that much?
     
  31. dultanur

    dultanur all promises, no action :)

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    nope, unless it's solid :w00t:
     
  32. loftgroover

    loftgroover Member

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    unless your back box was completly blocked there is no way it would lose 40+ bhp.

    Your boost is about .75bar max ((1750mbar-1013.25)/1000) which is about right for std S3.

    Firstly, i would ignore the calculated power output and concentrate on getting your MAF reading OK, when this is done you can go back and see what the power readings are....

    Do you have a friends S3 or TT you can swap the MAF over and log again, as if the ECU thinks there is only 130g/s air mass it will adjust fuel accordingly and your power will be significantly reduced.
     
  33. AL_B

    AL_B Active Member

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    Defratos,

    This may be a daft question, but have you tried unplugging the MAF, does the car feel better?

    When I've been investigating MAF problems, I've unplugged the MAF, I've never done any logging at the same time. MAF readings might be zero, but also the ECU might revert to basic settings and perhaps give a fixed value XYZg/s? Who knows? Would be interesting to see.

    AL
     
  34. Defratos

    Defratos You’re Dethpicable!!

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    Would a MAF from a 2002 V6Golf work? I'll try sorting out the MAF reading first, I should be looking around 160 right?
     
  35. Defratos

    Defratos You’re Dethpicable!!

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    never tried unplugging it but I guess its worth giving it a go. Will let u know how it goes :beerchug:
     
  36. loftgroover

    loftgroover Member

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    Check the MAF part numbers, if same you are OK, if not assume it will give you spurious readings...

    If you unplug the MAF im pretty sure you will get an instant engine warning light on, i believe this will also implement limp home mode so you wont get any decent readings.

    Worth a go but dont forget to reset any fault codes before doing further runs..

    Also have a look on the ross-tech page for throttle body adaption http://www.ross-tech.com/vag-com/cars/throttlebody.html might make some difference.
     
  37. Defratos

    Defratos You’re Dethpicable!!

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    u know what I just remembered when I did checkes to see if I had any fault codes I got one, something to do with the boost pressure or valve. I'll do a fault check later on today and see what happens. cheers :beerchug:
     
  38. Defratos

    Defratos You’re Dethpicable!!

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    u know what, I've cleaned and changed a few bits before I tried VAG on it, I should have taken test results before I started changing bits and cleaning them. I'm thinking this could be down to a few things:

    1-DV I cleaned it a few weeks back and put on the springs some grease (the same one I use for my gear shift) and I'm not sure if that's ok, it said don't use any silicone based stuff, and I don't think this was.anyway..

    2- installed new samco pipes from Turbo to SMIC and from FMIC to throttle body.

    3- I also cleaned out the throttle body but with it fully closed, now I think I shouldn't have done that, and I think it's something to do with the throttle body, what's the right way of going about doing this properly? do I need to have the engine on?

    I think that's about it, ohh no
    4- I changed my MAF to a slightly bigger one with a 4.bar FPR now this could be doing something, but it shouldn't give me the results I'm getting now.

    5- I also unplugged the battery lol

    I'll be looking at a few things over the next week, will let u guys know how I get along, thanks for the help :beerchug:
     
  39. Tallpaul

    Tallpaul Member

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    lol, nothing like a bit of logical fault finding :blink:

    So, what are your peak g/s now you've fettled everything?
     
  40. loftgroover

    loftgroover Member

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    "4- I changed my MAF to a slightly bigger one with a 4.bar FPR now this could be doing something, but it shouldn't give me the results I'm getting now."

    I think thats the first place to start, the MAF will be sized for a different capacity engine so may give you spurious readings..
     

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