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Removing Rev Limiter From My A4???

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by jey, Oct 12, 2008.

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  1. jey
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    jey Member

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    [Oct 12, 2008]
    Anyone know how to remove or override the rev limiter on a b6 a4 saloon 2.0 fsi???

    very annoying! have to change gear b4 it hits the red or cuts out!
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  3. evilscotsman
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    evilscotsman Space Cowboy

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    [Oct 13, 2008]
    are you serious mate? the rev limiter is there to stop you blowing up the engine!

    It should just hover at the redline - some cars have a smooth-cut limiter that just holds or bounces the revs at the limit, some cut the fuel so you have to release the throttle and change up to get power again. Unless its faulty I would leave it alone unless you want to shell out 3 grand for a new motor.

    If you really want to you can get the limit removed by having the ecu reflashed but if the timing belt or some other part lets go at full pelt you'll be picking up your engine with a shovel.
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  4. james0808
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    james0808 Active Member

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    [Oct 13, 2008]
    Why would you want to keep revving it to the redline anyway,much better to change a bit earlier.
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  5. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Oct 13, 2008]
    No there is a lot of hidden power beyond 6,000 revs the rev limiter is purely there to stop you going really fast. Only really good drivers know this!
    #4
  6. evilscotsman
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    evilscotsman Space Cowboy

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    [Oct 15, 2008]
    LOL - yeah and adding stripes up the side or over the bonnet makes you go even faster!

    For information tho, look at the dyno map from any car, the power falls off sharply before the upper rev limit is reached, ours may rev to 6.5k rpm at the redline, but power drops off from 5800 onward anyway!

    The reason is one of energy conservation from newtons third law of motion.....the flywheel builds excessive centrifugal forces at high rpms, this starts to reduce the power, since power is torque x angular velocity (rpm is just angular velocity expressed in revs per minute instead of radians - simply rotational speed of a disc)

    so it would initially seem that increasing rpm would give increasing power, all the way to infinity.....except that centrifugal forces increase in log fashion and above a certain rpm they become quickly massive, causing the forces generated to act radially on the flywheel (toward the outside rim at 90 degrees to the axis of rotation) instead of acting in a circular motion in the direction of rotation, and start reducing shaft horse power at the same rate as the centrifugal forces increase.

    Thats why increasing rpms doesnt work beyond a limit determined by the engine torque output and the rotating mass of the flywheel.

    Think about this:

    Bike engines, tiny flywheel, low torque, high rpms before centrifugal forces act.

    diesel engines, large heavy flywheel, massive torque, low rpms.

    petrol car engines....in between :)
    #5
  7. J7USS
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    J7USS Shuddup Foooool!!

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    [Oct 15, 2008]
    :) evil, you make me laugh mate!very good info though.Dont think id dare get into a debate with you,lol!
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  8. evilscotsman
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    evilscotsman Space Cowboy

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    [Oct 15, 2008]
    hehe all part of the service LOL
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  9. jey
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    jey Member

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    [Oct 15, 2008]
    my limiter cuts the fuel! in my opinion i have more power left in each gear then i get cut of! near go through the windscreen wen fuel cuts out! lol

    the bouncing limiter described b4 wud be better!!
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  10. evilscotsman
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    evilscotsman Space Cowboy

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    [Oct 15, 2008]
    mate you dont have more power left since the power drops off like a stone at 6500 rpm!!! Look at the following dyno plot for the 03 1.8T:

    [​IMG]

    As you can see the torque also drops away LONG before that. You DON'T have ANY MORE power to get - you are imagining it. I guess its your dad's car too since no one would buy an expensive luxury car then try to rev the ****** off it past the redline....?

    LOL
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  11. dantdi
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    dantdi ...

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    [Oct 15, 2008]
    LOL at go fast stripes
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  12. jey
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    jey Member

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    [Oct 15, 2008]
    my dads car!! could get cheeky at that comment m8 but ill bite my tongue!

    its my car and yes i luv reving the **** outa it rite past the red! i own it so can rev it smash it or burn the fuckin thing if i wanted to!

    the car is gaining speed rite into the red b4 cutting out! seein is beliving!

    i appricate ur reply in detail but i can see my speedo and whats happenin...
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  13. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Oct 15, 2008]
    It will obviously continue to gain speed when you are redlining it, but i bet it will accelerate quicker in a higher gear. However if you are able to change the laws of physics etc, get the car chipped, it will have a little more power and probably a raised rev limit, but it will cost you a min of £250.

    My car now has a rev limit of 7200, but i never use it since the useful power has dropped off nearly a 1000 revs before that and i would have changed up
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  14. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Oct 15, 2008]
    Do you get charged by the letter? Cut the ******* knobhead txt speak, and stop trying to get your poor car to do things it quite obviosuly can't. If there was a way to remove the limiter, you would quite simply have blown up your engine by now. Revs do NOT = speed or power, get used to it or better still get a remap.
    #13
  15. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Oct 15, 2008]
    Or a Type R.... :w00t:
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  16. evilscotsman
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    evilscotsman Space Cowboy

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    [Oct 15, 2008]
    Ok mate, nuff said on the subject. Its not going anywhere and when you asked the question I just pointed out the pointless-ness, you can indeed blow it up or whatever you like, as you say, it is yours to do with as you please.

    :icon_thumright:
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  17. jey
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    jey Member

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    [Oct 16, 2008]
    knobhead! wasnt doin any name callin at anyone so watch ur mouth son!

    its the fact thecar dies wen hittin the limiter, id like the option to change gear wen i want not wen the car decides...

    wat wud a remap acheave for a 2.0 fsi 150bh engine??

    always thought remaps only worked well for turbo'd cars??
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  18. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Oct 16, 2008]
    Wasn't name calling, just referring to the style of typing and I'm thankfully not your son.
    What don't you understand about "your engine will destroy itself"?
    I'd also bypass all the fuses in your house so you can get more power from the mains!
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  19. alijames
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    alijames Active Member

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    [Oct 16, 2008]
    :box: LOL Andy!!


    :end_of_discction:

    Cheers,
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  20. J7USS
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    J7USS Shuddup Foooool!!

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    [Oct 16, 2008]
    :haha:
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  21. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Oct 16, 2008]
    The car will die when it hits the limiter to protect the engine internals from self destructing. There is absolutely nothing to be gained from reving higher, as showed by Evil's dyno plot earlier in the thread. The only possible outcome that can happen from removing the rev limiter is that you will, and you WILL trust us, eventually blow your engine. I'm sure thats not what you want.
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  22. jey
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    jey Member

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    [Oct 16, 2008]

    no dont want that! jus dont like how it cuts out, means ive to look at rev counter b4 changing gear! not the handiest at speed wiv eyes on the road!

    andy!! bypassin all the fuses in ur house doesnt gain u more power mate! but u do talk some *****! son...
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  23. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Oct 16, 2008]
    A remap can gain a few BHP on a NA car usualy gain a slightly higher revlimt and a smoother pickup.
    Turbo cars have the best results from remapping, but certainly an NA car can benefit.

    On another subject, you shouldnt need to look at the rev counter, surley you are able to tell what the engine is revving at and whether its stopped pulling etc.I know i can.

    Any chance of a video of this 20 fsi engine that pulls up the red line? before this turns into a slanging match as i am intruiged !
    #22
  24. HAWKEYE
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    HAWKEYE IT CANT RAIN ALL THE TIME

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    [Oct 17, 2008]
    Quite frankly I think he's talkin out of his ass!!! :no: Its obvious he cant drive properly.
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  25. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Oct 17, 2008]
    I talk shyte and you're the one who can't hear when to change gear and has to look at the rev counter. I really don't think you should be driving anymore dad! Nurse? He's out of bed again!
    #24
  26. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Oct 17, 2008]
    The power drops off due to the cam profile causing the engines VE to drop because the valve isnt open long enough to fill the cylinder, or in a turbocharged engine, the turbo running out of flow capacity to maintain boost pressure. Its nothing to do with the flywheel or centrifugal forces. You cant increase the valve opening time on a stock engine becuase a) it wouldnt idle or pass emissions, and b) your pistons would hit the valves.

    If you revved it any higher than the stock limiter on a standard cam profile, the valves would be open for a shorter and shorter time as the revs rose and simply wouldnt be able to take in enough air. If your not half stoned or braindead when driving you can feel this power drop as the car approaches the rev limiter, and that tells you when to change gear. Even if you do overshoot it and hit the limiter, you should have already be expecting it to happen (because you can hear and feel it) and have been just about to shift anyway, therefore the loss of power is irrelevant.

    Hondas rev to 9k and still make power because they have a VTEC system which switches cam profile as the revs rise to allow the engine to breath at the higher revs, not to mention the conrods, pistons and crank are all designed to spin at that speed.
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  27. jey
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    jey Member

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    [Oct 17, 2008]
    think u talk outa ur ass, can smell ur **** breath from here ***** bucket!

    1st gear reved to near 6500 revs then i changed up at the 6500 i think i felt it flattin out as described, 2nd gear reved to 7000 didnt feel it flattin out an changed up b4 limiter kicked in, road wasnt long enough for 3rd, was really only 1st an 2nd i was interested in!!

    was in my bro's sti sub an most cars jus feel dead as f**k now! think thats y i want more outa my revs to lol
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  28. HAWKEYE
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    HAWKEYE IT CANT RAIN ALL THE TIME

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    [Oct 18, 2008]
    Its a shame i cant slap you sensible! If you wanted a car that revved to 10,000 revs why did you not just buy one, did you not test drive it before you bought it???? Even so as already said banging it up to the limiter says you really REALLY REALLY dont know how to drive :keule:
    #27
  29. AudiSport
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    AudiSport Member

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    [Oct 18, 2008]
    I've never raced a car, but I've spent a lot of time racing motorcross / supercross bikes at a good level. These bikes don't have rev counters however, as the guys say above you know from the sound of the engine when the optimum time is to change gear - you really shouldn't need a rev counter to watch. If you do need to watch the rev counter to gauge when to change I would suggest you spend a little more time behind the wheel before you start driving at high speeds.

    Also, rev counters are not put in to limit the cars performance, they are put in to limit the damage done to the engine by OVER reving it.

    Trust me, all the guys on this site are really knowledgeable, they ALL want to help any of us out with our problems so lets just 'cool-it' as I have a hunch you maybe back with another post later in the year you want some advice on..
    #28
  30. james0808
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    james0808 Active Member

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    [Oct 18, 2008]

    Dont even worry about what revs you are changing gear,change gear as soon as you feel the torque falling and the car will be faster.
    #29
  31. ian52
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    ian52 2000 a4 1.8tqs-yellow

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    [Oct 18, 2008]
    if you want a car that will rev buy a jap car with variable valve timing.
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  32. jey
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    jey Member

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    [Oct 18, 2008]
    i no how to drive! i also grew up wiv motocross bikes so hav plenty of experience on wen a gear has reached its limit and how an engine should sound!
    #31
  33. james0808
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    james0808 Active Member

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    [Oct 18, 2008]
    So why dont you do that then and stop asking stupid questions about removing rev limiters.Some people havent got the brains they was born with.:tocktock:
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  34. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Oct 18, 2008]
    Don't think he had much to start with. He can't spell, can't type and can't drive. My 5 year old has a better grasp of both English and how an internal combustion engine works.
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  35. jey
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    jey Member

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    [Oct 18, 2008]
    My mouth is going to get me in trouble
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  36. jey
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    jey Member

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    [Oct 18, 2008]
    No really, it will...
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  37. bubstar
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    bubstar Member

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    [Oct 19, 2008]
    [​IMG]
    #36
  38. yellowgti
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    yellowgti Whats going to break next??... VCDS Map User

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    [Oct 19, 2008]
    lol i cant stop laughing but totally agree with what ur saying,

    jey, wouldnt have thought that removing the limiter would give extra power, mates got a 2.0 fsi and it couldnt catch a cold after 6000rpm, yours is probally a one off limited edition which revs to mars and back!

    oh hold on a min ive got it, have you got......

    hks
    peco,
    cobra,
    ripspeed,
    kumho tyres

    down your doors in that style? if you have thats why its faster because ive heard you get 10bhp per sticker, i bet youve even got led washer jets on it ;-)

    give urself a pat on the back for probally pi55ing a fair few good people off on the site:applaus:
    #37
  39. james0808
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    james0808 Active Member

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    [Oct 19, 2008]

    You should be sorry too,ignorant peasant.

    Now run along and go redline your painfully slow 150 bhp heavy car and imagne its fast.Just use your mirrors when you do as there might be an old dear in a metro or micra waiting to overtake you.[​IMG]

    I like it when morons like jey come on here.I know you shouldnt laugh at the mentally challenged but i just cant help myself sometimes.
    #38
  40. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Oct 19, 2008]
    Pissing us off? On the contrary, this is hilarious.
    I'm assuming it's a wind up as no one could possibly be that much of a brain dead, illiterate moron, but very entertaining non the less!
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  41. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Oct 19, 2008]
    ^^ I agree ^^
    I thought on the whole Audi drivers were more sensible.This post has shown me otherwise.

    Obviously Audis are now classified in the same league as Paxos and 106's etc.
    Its a sad day..
    #40
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