Engine is a 13bt semi pp and being that the cars on a Microtech the rev limiter and rev cut are both fuel cuts(halfs supply then full fuel cut). This is currently how the car is setup half cut at 7250 and full cut at 7650 and results in a very loud backfire

It is also an option to have these settings reconfigured to be ignition/spark cuts but heard this too can be quite jarring all around.



After seeing it in action in some data logs (above is 4th gear dyno) im looking at just permanently setting up the "2 Step" function as our red line which will reduce timing to a specified deg. along with add/subtract fuel.

This to me sounds like it meets the criteria as most effective and safe if set up properly but curious to hear what others think of my given options for a limiter

 

I don't like rev limiters, they are better at killing a rotary than an overrev.

I have my computer set to add 25% fuel over 9000rpm. This keeps the engine from getting away too much when the tires spin or the transmission breaks, but it doesn't shock the engine like a limiter will.

 

The only rev limiters that hurt rotaries were on ecus with porly implemented rotary control fudged from 4 cylinder control doing half cuts taking out smaller primary injectors but not secondaries. All the factory cars and countless street and track cars have been running for decades with rev limiters and even external traction control units successfully. A kissed housing or broken gear from an on load overrev is a very real probability without appropriate rev limiters, especially on anything built to breathe at high rpm.


If you intend to ride the limiter be mindful of higher EGTs, you may effect apex seals and turbo.

 

If you have a DBW throttle, and an ECU that supports that, implementing a soft RPM limit is pretty easy. In this example here (Link G4+), I had a soft RPM limit that starts to take effect at around 7750 RPMs (linear interpolation between the last two columns - see part of the throttle map that's in the yellow oval; you can set these columns to whatever RPM limits you desire). You're basically telling it to limit the throttle to 1/2 of whatever your accelerator pedal is commanding above that RPM.

 

While its already on the wish list im very glad to know that's an option for the future. DBW seems like it has so many benefits and configurations

I also misspoke before, our LT-10c is already configured as a soft ignition cut followed by a full fuel cut, I think I just need to set the limits of them a bit further apart, 8000 IGNlim and 8750 REVcut to anticipate rpm "bouncing" a bit but some further testing will determine that

Our last runs on just 93oct warranted a pair of egts and o2s in the manifold so i'll be keeping a close eye on them during the next few test logs

 

I damaged two engines with an ignition cut rev limiter. One was carbureted. The other only hit the limiter once. The apex seals shattered. 3mm seals in a naturally aspirated engine shouldn't break at only 7000 or 8000rpm. I actually drove the 13B home with a three piece apex seal but the 12A was a nightmare of FOD.

I have seen heavy carnage from bouncing the stock limiter under load. Stat gears died at max RPM. 12 pin rotors shouldn't kill stationary gears at only 7800.

 

I appreciate the info peejay, i've adjusted the fueling accordingly and set the ign lim at 9250 and rev cut to 9950



​​​​​​
It seems to have worked for us, but the key word is "seems" we were at low boost (5-7psi) and 7000 ignlim. Going to give the "fuel wall" a go, i have it a bit more hefty than 25% but will see how it reacts