is it true? (rev limiter question)

All it does is cut sparks. Cutting sparks = no more revs.

There's nothing which will prevent your engine doing a gazillion revs if you manage to shift into 1st at 85mph when you really wanted 5th.

I guess that's what he's talking about.

I think that rev limiters generally work by cutting fuel and/or spark after a certain rpm is reached.

Think about it, how can cutting the spark or fuel stop an engine being pushed past an electronically governed rev limit by the inertia of the car? It can't, the rev limiter has no way of actually slowing the engine down or preventing you from engaging too low a gear at too high a speed, it can only prevent the engine from driving itself too fast.

Driving the engine way faster than its meant to go is bad mmmkay.

HTH

Rev limiters work electronically, i.e. they won't let rev the engine over the limit using the accelerator alone. If you accelerate to 150mph in fifth then change to 2nd and drop the clutch the mass of the car will now drive the engine and the electronics won't be able to do a thing about it. I used to have a nice picture of what happens to Jaguar XJ220 valves somethere when you do this.

No, it's not true. If you down change to exceed the rev limit in a lower gear, the engine won't be producing any power.

If you've been too extreme, little bits of engine will disintegrate.

Heh.

Dumping a 1.0 corsa into 2nd at 90 is most entertaining.

And useful, providing a service to road users everywhere.

Richard

Try it in your BMW before the engine gets sorted out (1st at about 70 should do it), and make sure you take some pics of the result!

I did something silly like that in one of my 205s - admittadly it didnt have a rev limiter, but changing to 2nd (missed 4th) from 80mph sent the rev counter straight off the scale :)

Sadly in Tim's case it wasn't useful, the Corsa survived.

I'd got bored, it was a rental and I really wanted it to die, but it refused to.

"Carl Gibbs" wrote in news: snipped-for-privacy@individual.net:

Valve bounce = rev limiter :-)

I did this in my other march super turbo - went into 2nd instead of 5th oops. That really hurt my and the cars feelings of well-being. fortunately both survived.

I've changed down too early. The spark gets cut, and a lot of petrol goes BANG BANG BANG BANG in the exhaust pipe.

Many ecus cut fuel before ignition to stop this.

lol well not only did it answer my question you guys even supplied evidence as well as practicing you're own experiments :)

On a Cat equiped car (without anti lag) ALL ECU's cut fuel before sparks (if at all) at the rev limiter.

Tim.

I have not tried every ecu so I was not willing to say that on the basis I would be talking about something I do not have personal experience with.

It'd be a sane idea to save cats though. I suspect K-jet cars with cats don't.

True, Cats don't like anti lag for example. Which is why I remove it (the cat that is)... ;)

Yes they do- they use the tachometric relay which controls the fuel pump to cut the fuel, and a bendy-wendy rotor arm to cut sparks.

Tim.