Hi everyone. I was wondering what options there are for the $8D code as far as enabling a rev limiter. The car is an 89 six speed Vette with a solid cammed 398stroker with the new Eliminator comp ported heads and a converted Victor intake set up for EFI using an intake elbow. The good thing is that it revs easily to 7200+. The bad part is that it easily revs to 7200+. I need to put some kind of RPM control on this. Short of going to an MSD type digital ignition, will the rev limiter built into the code work effectively? What is the usual spread between the limits? Meaning if I want to cut it out at 6800, what threshold should I use to turn it back on? 6750? 6700?

Thanks

 

The rev limiter built into the code is effective, it shuts the injectors off (0 PW). The down side is that it is abrupt, not something you want to hit unless it is required to save the engine (broken drive-train, loss of traction, ...).

In this case it is best to put the 'back on' RPM rather low. This is to give the driver enough time to get their foot off the gas.

Otherwise, when the fuel is re-enabled the power is right back. Which on a high power engine can have unexpected results.

The other way to set it up is to have the disable & enable RPM thresholds close together. That way it acts more of a power limiter. But, truth be known, I don't care for this. As the engine could take it as being lean and start to melt.


RBob.

 

Thanks Rob. So it looks like an aftermarket ignition solution is the better option?

 

I believe so over the stock fuel cut rev-limiter. This may also be way GM never used the rev-limiter in the $8D code. The speed limiter, yes, but the rev-limiters were set to something like 9,000 RPM.

RBob.

 

Is there a way to set the rev limiter to just reduce fuel by a certain percentage instead of cutting it completely? Or is the code programmed into the ecm permanently?