I doing the opposite of what most people are trying to do. I am trying to slow the car down a bit. I have about zero self control on keeping my foot out of the throttle. Every day I see triple digits. I need the car to last me about 4 years without any major overhauls.

I am trying to figure out what the best way to set the rev limiter at 3K would be. My initail thoughts were to buy an MSD 6AL, which has a rev limiter with a few RPM choices. I am not sure what else (if anything) I would need to buy.

After thinking about it a bit, a decent prom tuner might be able to adjust this. I am not really sure though. I tried searching the forum, but couldn't find a direct answer to my "problem."

My car has the following:

305 TPI
5 speed
It's a 1992, LB9 (if that matters)

 

There is both engine RPM limiting and vehicle speed limiting in the ECM your car is using ($8D with a '7730). They use a fuel cut off to drop the engine power to zero. As such it can be rather harsh.

Although the vehicle speed limiter set to say 110 isn't too bad. The car just stops accelerating.

But setting the engine RPM limiter to 3K will be harsh. The engine is in the power band and the fuel cut is sudden. Then when the RPM drops and the fuel turns back on it again is harsh, as you still have the foot on the floor.

So for vehicle speed limiting doing it in the ECM is OK. But I wouldn't recommend doing a 3K or even 4K rev limit this way.

For engine rev limiting you can reduce the spark timing first. This will pull power and can be enough to force the driver to lift or upshift.

RBob.

 

If I understand correctly, this would mean changing the timing which would result in a power decrease?

The one thing I read about the MSD 6AL is that it alternates spark between cylinders when the limiter is being used. MSD explained it as a "soft" limiter because the cylinder will not fill up with fuel exceesively as it sparks the last one left off. What do you think. Are they just "selling it" to me?

 

Yes to the first question.

As far as the MSD limiter, I can't say how it is done. Whether random or done in a sequence. I do know that dropping spark and sending raw air & fuel to the cat-con will slag it in short order. So if your car has a cat on it, I wouldn't use any rev limiter that dropped spark events.

RBob.

 

Thanks RBob. I will have to do some research on timing.

 

i wonder if there would be a way to sequentially cut off 1 or 2 cylinders fuel each revolution when a certain speed was hit?
this would not be as harsh as suddenly dropping the fuel completely
also you could continue to accelerate slightly as you would essentially be running on 6 cylinders but you would slow down.

another option is lengthening the throttle cable or installing a throttle stop

 

You are right!!! A throttle stop is perfect fix for cheap. This is why I like this forum so much. Wonder how many times I will be pulling the car over to remove that stop! Way cheaper than the MSD6AL at any rate. Thanks!