empowered3

Was there a change in AP1 ECUs which changed how the rev limiter was managed with later model years. Fuel Cut versus Ignition Cut?

I'm trying to change how the limiter is approached with an early model AP1 (2000) and want to make sure I can tune it with a Greddy Ultimate Emanage. This means I need the ECU to have a fuel cut, not an ignition cut.

User 121020

I've seen logs from AP1 and AP2v1 ECUs showing success with the EMU rev limit extending feature. Mine is a MY2000, if that helps.

cdelena

I think it varies depending upon how the limit is approached and maybe other factors. I have had the ignition cut which is a dramatic end to power but I have had many times on the track where I rode the limiter and I assume that was a fuel cut.

s2000Junky

No, they are all fuel cut. E manage uses ignition cut and its a lot softer. Probably safer also, if you find yourself riding it often.

djsilverjohnson

I have an '03 AP1 and I've hit the hard limit twice. The first time was an autocross where I tried staying in first gear for the first two, tight turns. It did the stutter ------ limit the first time, but the second time it shut down completely until I let completely off the throttle and got back on.

Yesterday I was going thru a couple of elements at the top of 2nd gear. I hit the soft limit between the first & second element. When I exited the second element I just bumped the limiter and it hammered me by shutting down again.

The soft limit feels like an ignition cut-stutter, but the hard limit feels like a fuel cut. If it was an ignition cut there would be unburned fuel that would light off in the exhaust system when it comes back to life and make lots of noise and smoke.

s2000Junky

There is only one limiter, not two. The car should never entirely drop off throwing you forward. Sounds like your describing cold limiter when vtec is trying to engage but ecu wont let you. That is a very abrupt/hard limit. You may be experiencing another issue. Any cel?

User 121020

I've experienced the same occurrence many times in my AP1 during auto-x events. My solution in STR trim was to impose the rev limiter using the Greddy EMU. The consistency of the limiter is much better than the stock ECU.

Here's an old thread I started inquiring about the stock limiter: Engine Management FAQ - Rev Limiter