How bad is it to hit the rev. limiter?

Discussion in '2005 - 2014 S-197 Mustang -General/Talk-' started by GreyDiesel, Nov 7, 2009.

  1. I have hit the limiter a few times, and it feels horrible. Afterwards I have this nagging feeling that I broke something. My is set relatively low, 6500, and I hear I can bring it to 6700 no problem. And, if you go to the track, sometimes you see 4 bangers hitting the limiter at the line before launch. And I mean, not an accidental one time tap, they are just railing on it. Does it hurt the engine to hit the limiter?
  2. better not, I hit mine @ least twice a week lol
  3. Yeah I think i hit mine 3 or 4 times today! Its there to keep you from over revving. So its safe to hit it but does suck when you do:lol:
  4. remind me not to buy your car when you eventually sell it hah
  5. I'm just going by what I hear and see but drag racers with 2-step/3-step rev limiters bounce on their limiters for ~5 seconds before launching. So it can't be that bad?
    It also depends on how the limiter is limiting the engine. Fuel cut = bad, spark cut = not bad.
  6. +1 to that.
  7. they would never cut the fuel to limit over rev. its an ignition deal so it kills spark. And this baby will never be for sale
  8. Ford and other manufacturers use fuel cutoff rev limiters for emissions purposes. There is so little fuel present that there is not enough energy to hurt anything - cylinder pressures are pretty low - so fuel cutoff rev limiters are not bad. One of the tests Ford does on cars it to take it on the test track and run it on the limiter for 30 minutes. I do not suggest you do that - because it's not totally harmless - the rapid speeding and slowing of the rotating assembly is not great for parts and that happens no matter the method of rev limiter.
  9. I can't speak for the S197's, but cutting fuel is "exactly" how Ford did it with the '87-'04 cars. You had to by an aftermarket ignition box like a MSD 6AL or the like if you wanted the "soft touch" limiter that cut spark instead.
  10. great info guys, thanks. :nice:

    I am not going to feel so bad for hitting the limiter now.
  11. Shouldn't be a big deal, I just wouldn't make a habit of it. :nono:
  12. i've heard bad things about running spark cutting limiters with cats though. people using the MSD 2 step and fouling their cats.

    if i foul mine they are coming off and staying off, so it wasn't a big concern of mine. but for those looking to keep theirs they may want to keep it in mind.
  13. It's not necessarily bad, on a N/A car, but not something you'd want to do constantly. On a F/I car, it's a big no-no, because Ford's rev limiter cuts fuel, which causes a lean condition. If you're NA, it won't be a big deal, but if you're FI, that could blow the engine.

    The reason you see drag racers do it is because they use aftermarket rev limiter boxes, which cut spark. The only bi-product of that is maybe a small fireball. But it's not harmful to the engine.
  14. By that logic shouldn't it harm N/A cars that have been tuned be also susceptible to blown engines because of the leaning of gas and advanced timing?
  15. Wow, I looked into that fuel/spark issue and you guys are absolutely right the fuel is cut, that blows my mind and makes me wanna install a shift light in the car. I always ran a MSD box on the foxes and relied on the limiter on that and thought all limiters were based on the same concept. Boy was I wrong!!!:D
  16. No one read what I posted I guess - the fuel is cut so much that it goes so lean there is not enough energy available to hurt anything. And as I said, Ford tested ALL their cars (GT500's with blowers, Ford GTs with blowers, Lightnings with blowers, 03/04 Cobras with blowers and I assume Ecoboost turbo motors) by holding them on the limiter for 30 minutes. Doubt anyone with a street car would do that a lot.
  17. i think darkfires mainly leaning towards aftermarket forced induction cars where they are tuned towards performance, not daily driving.

    i've seen several posts where people are running nitrous the car runs lean for some reason [mainly the zex kits just spraying straight nitrous and no fuel to compensate] nitrous backfire and a giant fireball. i know thats different from hitting the limiter but they are both cutting fuel in some odd way with bad consequences. not sure the problems you can run into with a turbo or supercharger, but that was just one example.
  18. Nitrous + Rev limiter IS very bad - that does not apply to what I said - there is a LOT more energy present. Always set the window switch below the rev limiter.
  19. LOL, yeah really. I hit mine bye accident a few times. Usually becuase I have the radio to load and I forget about it....:rlaugh:
  20. Sorry, I should've specified. I was tired. Yes, I meant nitrous, though it wouldn't be good with a radical race setup on a SC or Turbo either.