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140mph+ Limiter?

Discussion in 'A3/S3 Forum (8L Chassis)' started by Ryan_W, May 23, 2011.

  1. Ryan_W
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    Ryan_W Member

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    [May 23, 2011]
    Guys,

    Took the car down my local private runway last night.

    The car pulls like a dream to around 140mph, but then after than it seems to stop and go, like it's hitting a speed limiter? The car has power and then dies off, then has power and dies off...

    Thing is, the car does it from around 140-150mph (clock readings).

    I did think it may be an over-boost issue, but why would it only do it at V-max?

    I thought these cars were good for 160mph-ish with a Stg 1 remap (which mine has)?

    Cheers all,

    Ryan
    #1
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  3. Lee172
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    Lee172 GT3071

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    [May 23, 2011]
    I got mine to about 150 when it was stage 1, it would struggle to do 160 though, if atall. Maybe you have a leak?
    #2
  4. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [May 23, 2011]
    I suspect EGT protection is kicking in as the engine has got hot and dumping fuel killing your power...

    If the only mod to your car is a stage 1 map then it will be glowing like the sun under the bonnet...

    <tuffty/>
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  5. Dane
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    Dane Faster than a V12 Q7

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  6. Welly
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    Welly VX220 SC Driver :)

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    [May 23, 2011]
    No, private runways allow me off the clock now without issue.

    No limiters on the 8Ls.

    As Tuffty says, EGTs will be like the surface of the sun, the engine will be dumping lots of extra fuel in to dissipate the heat, killing the power off.
    #5
  7. Ryan_W
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    Ryan_W Member

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    [May 23, 2011]
    Intercooler and exhaust needed then!

    What's the standard book speed for these?
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  8. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [May 23, 2011]
    I think book top speed is 149mph...

    <tuffty/>
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  9. s3dave
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    s3dave TFSI Hybrid

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    [May 23, 2011]
    I had mine on a similar test track yesterday and was quickly up to 150mph leaving a stage 2 mk5 gt and mapped skoda vrs in my wake...
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  10. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [May 23, 2011]
    3" downpipe should help the exhaust temps too.
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  11. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    [May 23, 2011]
    I've seen 150 on my clocks and it was still going, took almost forever to get to 150, I think 152/3 maybe it's limit on the clock for a stage1 map, but I have nothing to verify the exact speed.
    #10
  12. Jgould
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    Jgould MY ARS3!!!

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    [May 23, 2011]
    Had mine 2 yearsAnd is standard never gone over 80 lmao
    #11
  13. Welly
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    Welly VX220 SC Driver :)

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    [May 23, 2011]
    I have not once, ever, done more than 77. EVER.

    :lmfao:
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  14. Dane
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    Dane Faster than a V12 Q7

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  15. Welly
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    Welly VX220 SC Driver :)

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    [May 23, 2011]
    Absolutely.
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  16. colicabcadam
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    colicabcadam Guest

    [May 23, 2011]
    i have had 155 out of my s3, but it took forever from 140mph, you have to remember that at that speed you are loosing a lot of torque due to the turbo not being able to provide as much boost at such high RPMs
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  17. superkarl
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    superkarl MAN OF STEEL

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    [May 23, 2011]
    that coupled with the fact the 8l has a drag coefficient of around 900
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  18. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [May 23, 2011]
    What does this mean in English Karl, anything to compare it with?
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  19. Welly
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    Welly VX220 SC Driver :)

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    [May 23, 2011]
    I would compare it to a barn, which has a drag coefficient of about 901.

    OK, I made that up.
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  20. superkarl
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    superkarl MAN OF STEEL

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    [May 23, 2011]
    wellys right, a barn complete with a cockeral weather vane would be a good comparison.

    im just saying its not the most aerodynamic of shapes. i did find the drag coefficient of the 8l once.
    thinking about it you could probably work out how much power you'd need to acheive a certain speed. hmmmm.....
    #19
  21. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [May 23, 2011]
    Yeah I meant like an F1 cars coefficiency is around 200 and a Scania HGV is around 1000. Like a spectrum of aerodynamics ;)
    #20
  22. superkarl
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    superkarl MAN OF STEEL

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    [May 23, 2011]
    f1 car is very high, but thats due to its need for downforce and has the power and aerodynamics to overcome it because it has such a small frontal area.
    the 8l has a drag coefficient of 0.31, same as a citroen ax lol, but also the same as a 911 turbo or lexus lfa. its the actual drag force itself thats pretty high, because its such a fat stubby car and the frontal area is quite big.
    #21
  23. sportstractor
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    sportstractor Chugger

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    [May 23, 2011]
    Yeah... 160 ain't going to happen on a standish car. You need alot more power to be hauling the s3s fat arse near those speeds
    #22
  24. Ryan_W
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    Ryan_W Member

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    [May 23, 2011]
    I was mostly concerned about the lack of power and the surging.... It must be down the EGTs, but why would it happen on my car and not on others? Bad map by AMD maybe?

    Ryan
    #23
  25. kwistof
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    kwistof South East Events Moderator Regional Rep

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    [May 23, 2011]
    Ummmm, I have my car booked into AMD :s

    So hope its not to do with there Re-map- I've only ever heard positive things from them?

    Chris
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  26. 16Klappe
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    16Klappe Princess Clap.

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    [May 23, 2011]
    Have had an indicated 155 out of a certain persons stage 1 A3 with 3" downpipe and decat on a certain persons private runway. I've also had the same on another persons stripped stage 2 A3 on a similar private runway with the same downpipe and decat.
    #25
  27. Welly
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    Welly VX220 SC Driver :)

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    [May 23, 2011]
    LOL, everyone here has some rich friends with their own runways.

    My mate with his private runway is minted.... his name is Dave Davison the 3rd.

    :lmfao:
    #26
  28. Dane
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    Dane Faster than a V12 Q7

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    [May 23, 2011]
    Speaking of airfields are we going to try and get to kemble or whereever it was?
    #27
  29. Welly
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    Welly VX220 SC Driver :)

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    [May 23, 2011]
    Yeah, I'm sure it would be no probs. They seemed keen enough. When everyone is sorted I'll get back on it.
    #28
  30. Dane
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    Dane Faster than a V12 Q7

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  31. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [May 23, 2011]
    The chances of you 3 with your highly tuned 1.8Ts every being "sorted" at the same time is slim ;)
    #30
  32. Welly
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    Welly VX220 SC Driver :)

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    [May 23, 2011]
    Bah, humbug!! lol
    #31
  33. 16Klappe
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    16Klappe Princess Clap.

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    [May 23, 2011]
    I've got a friend who works for Air Salvage International who operate from Kemble, I could get us a bit of time there ;)
    #32
  34. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [May 23, 2011]
    I'm a realist mate ;)

    If you want a mint example of a maxed out K04 running on the strip, let me know ;)
    #33
  35. Welly
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    Welly VX220 SC Driver :)

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    [May 23, 2011]
    Could you find out. Won't be for a few weeks really, but would be good to find out sooner rather than later.
    #34
  36. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    [May 23, 2011]
    I was running AmD stage1. :)
    #35
  37. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [May 23, 2011]
    Subjective at best mate tbh... facts are that K04 turbo'd cars have high EGT's... Audi realised this which is why they fitted the EGT probe to the later models (AMK/BAM)... stage 1 mapped S3's with no other mods will just get hot... ECU will dump fuel when EGT's hit 925 degrees... you can mitigate against this by fitting a 3" DP and sports CAT and a decent FMIC... all those mods help keep things cooler but do not prevent it from ever happening...

    I have seen maps from less scrupulous tuners run quite lean and this will get highish power figures (once!) but get things hot quickly and heatsoak and high EGT's will kill top end power (which you would need to achieve 150 odd mph)

    <tuffty/>
    #36
  38. jcs356
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    jcs356 Brum brum

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    [May 23, 2011]
    Sorry to interject with my usual dose of cynisim, but surely what ultimately governs your top speed is the gearing on the car?
    So unless you have:
    Removed the rev limiter;
    Re-geared the car; or
    Fitted tyres with a different rolling circumference
    all S3's should in theory eventually max out at very similar top speeds. You might have to take it to Ehra-Lessien to get there, but it in theory will get there eventually. OK, more power/torque might mean you get to Vmax quicker but having 1000bhp won't actually mean you will go any faster.

    I appreciate that at the limit the discussions about the engine protecting itself and hence cutting power will mean that in reality some cars won't ever get there.
    Last edited: May 23, 2011
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  39. 16Klappe
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    16Klappe Princess Clap.

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    [May 23, 2011]
    Have posted on his wall on Facebook, no promises but I will try ;)
    #38
  40. 16Klappe
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    16Klappe Princess Clap.

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    [May 23, 2011]
    You have edited yours since I originally posted.

    However, theoretical top speed of an S3 is 187MPH IIRC.
    #39
  41. Dani_B19
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    Dani_B19 Audi-sports own special child.

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    [May 23, 2011]
    Who was that bole now that used to be on here, dave bryeson or sumet like that, he worked put the exact speed a s3 could achieve with the current gearbox that most of us run and the aerodynamics that the s3 has.

    Was quite an interesting thread.
    #40

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