Creating a "rev limiter"

[trippyjoey]

So I'm stilll working from a stock bin file while I save for an Ostrich 2.0 and I noticed that there is no rev limiter. I searched and only found one thread of a guy that tried doing a "ghetto" rev limiter.
Would it be safe to modify the tables so that 100rpm above my expected rpm limit the there will be an increase in fuel (to help in cooling and prevent a lean air fuel ratio) and decrease the spark advance to 0* BTDC.
In essence the fuel that gets ignited would not have time to burn enough before the exhaust valve opens decreasing power and slowing down the rpm.:idea:

[JeepsAndGuns]

What ecm will this be on? On the few I have messed around with, there were rpm limiters that cut fuel at a specific rpm. This value could be changed.

[RobertISaar]

that's better than what some people have attempted with trying to make it shoot lean instead, but rich + late spark is going to put a LOT of heat into the exhaust.

also keep in mind that the tables are interpolated, so if you're operating at 6200 RPM(let's ignore MAP for a moment) and you have a cell at 6000 and 6400, you're going to have a perfect blend of 6000 and 6400 for VE. if you're at 6300, there will be a 75% weight to the 6400 cell and 25% to the 6000 cell.

[trippyjoey]

It's a 7427 with $0D mask.

Should I keep the advance the same and just rich out the air fuel ratio?
I would prefer to just cut ignition completely instead of fuel but with the distributor I doubt that would be possible. I've heard some factory rev limiters cut fuel but since I'm planning on maybe running a small nitrous shot in the future I'd rather not have anything that will intentionally cause a lean condition.

[RobertISaar]

...... all of the 7427-compatible masks should have rev limiters in the code....

also, i've created a few "cut spark instead of fuel" patches, i MIGHT be able to do the same for a 7427 but that would require some research first.

[Six_Shooter]

It's a 7427 with $0D mask.

Should I keep the advance the same and just rich out the air fuel ratio?
I would prefer to just cut ignition completely instead of fuel but with the distributor I doubt that would be possible. I've heard some factory rev limiters cut fuel but since I'm planning on maybe running a small nitrous shot in the future I'd rather not have anything that will intentionally cause a lean condition.

In cases like this I always recommend an MSD box, such as a 6AL, that will not only improve spark, but allow you to set a limiter, that is spark based. You can set it below the factory fuel cut limiter.

[trippyjoey]

Well while window shopping online I found this I think I'll just go with this instead much easier.
http://www.summitracing.com/parts/msd-83647/overview/make/chevrolet

[Six_Shooter]

Well while window shopping online I found this I think I'll just go with this instead much easier.
http://www.summitracing.com/parts/msd-83647/overview/make/chevrolet

That's all fine and dandy, but it won't work for you.

[trippyjoey]

Why not?

[EagleMark]

It's not an EFI module!

$0D has rev limiters!

[Six_Shooter]

It's not an EFI module!

THIS ^^

Also, it's for a large cap dizzy that has the coil built into it, and you should have a small cap dizzy with a remote coil.


$0D has rev limiters!

While $0D definitely does, I would not want to use a fuel cut with nitrous, which is why I recommended the MSD 6AL.

[trippyjoey]

Okay found the compatible 6AL for my truck, I knew they had them for the LS series engines I didn't know they had tbi compatible models.
Thanks guys, gonna add it to the wishlist hopefully start ordering parts for my new engine build mid next month.

[Six_Shooter]

Ummm, the 6AL has been around since the '70's. Anything for the LSx is just an extension of what MSD started decades ago.