Concerned About Over Rev and Rev Limiter in my Si

[Manatee Bob]

I have been reading some posts on these CivicX forums about over revving invalidating powertrain warranties. I was talking with a friend who stated that if you leave your Si stock without benefit of a tune, then the car's Rev Limiter prevents the car from throwing an over rev code unless you did something like trying to shift into third and accidentally putting it say in 1st gear.

Is it true that the engine's rev limiter prevents the car from going into an over rev condtion and throwing a code? Thanks for the input. Great forum.

Sponsored

 

[hobby-man]

Whether you're tuned or not, you won't throw an overrev from throttle input. It'll just result in a fuel cut where you bounce off the rev limit but don't actually exceed redline.

Similarly, tuned or not if you money shift it and force a mechanical overrev, that's when you're in trouble.

 

[Manatee Bob]

What's a money shift???

 

[fabrizzio71]

What's a money shift???

It’s the colloquial term for a mechanical over-rev. Like you described in your initial post, accidentally putting the car in a lower gear while traveling at speed, forcing the rpms beyond the redline.

 

[racerguy180]

What's a money shift???

Cuz it's normally associated with $$$.

Broken/bent rod, sucked valve, etc

 

[Manatee Bob]

Whether you're tuned or not, you won't throw an overrev from throttle input. It'll just result in a fuel cut where you bounce off the rev limit but don't actually exceed redline.

Do others share the same observation that Hobby-Man put forward that the throttle alone cannot cause an over rev condition?

 

[repeet]

Do others share the same observation that Hobby-Man put forward that the throttle alone cannot cause an over rev condition?

Yes.

 

[jlamb30]

What is the rev limit for the Si? I've been in the tach red area, but have never hit the rev limiter.

 

[fabrizzio71]

What is the rev limit for the Si? I've been in the tach red area, but have never hit the rev limiter.

Fuel cutoff is 6600 rpm.

 

[StanMan]

Do others share the same observation that Hobby-Man put forward that the throttle alone cannot cause an over rev condition?

Yes. Virtually all cars have a fuel cut off at the redline. If you hold the gas pedal down and don't upshift, it will hit the fuel cut off rpm(redline) which will lower the rpm a bit, then it will allow fuel again, then it will hit the fuel cut off rpm again, then it will drop rpm due to no fuel again. This will repeat indefinitely if you hold the pedal down. This is called rev bouncing.

It is not in any way dangerous for your car to hit the rev limiter from application of the throttle.

As mentioned in other posts, this does not protect you from forcing an overrev by downshifting to a gear at too high of a speed.

 

[Drake]

It is not in any way dangerous for your car to hit the rev limiter from application of the throttle.

I would agree this for the occasional rev-bouncing, but I think doing it frequently/for longer periods qualifies as abuse.

 

[StanMan]

I would agree this for the occasional rev-bouncing, but I think doing it frequently/for longer periods qualifies as abuse.

Am I saying you should just redline in 2nd for half an hour? No. But as long as you let the car warm up before driving it hard and keep up with proper maintenance the engine is going to last essentially forever regardless of how spirited you are with it. There's no reason to "worry" if you hit the rev limiter before shifting on a routine basis. All it means is you're losing acceleration due to not shifting correctly. No damage.

 

[Anjuna]

Do others share the same observation that Hobby-Man put forward that the throttle alone cannot cause an over rev condition?

Unless you're not in gear. I have a buddy who got a little too happy revving an Accord and blew it up. He assumed the cutoff worked while in neutral and it didn't.

 

[fabrizzio71]

Unless you're not in gear. I have a buddy who got a little too happy revving an Accord and blew it up. He assumed the cutoff worked while in neutral and it didn't.

I'm sorry, I don't think that's possible on this car. Also, any stock car should not permit a rev limit bypass in neutral. That would go against a lot of regulations. Think if you were flooring it and you accidentally knocked it in neutral and then blew up your engine...

 

[cryptolime]

can someone explain how i hit 7000 rpm in 1st gear? isn't that past redline? I just did a 1st gear pull and hit the limiter.

Sponsored