Webinar - RPM Limiter (Fuel + Ignition Hard Cut)

Hi Andrei,

When I saw the RPM Limiter webinar pop up it was one of those universe throwing me a bone moments... I have just in the last week been studying up and better configuring these on my own car (Evo 8)! It was great getting confirmation that most of what I had done was safe and acceptable. The couple of rare occasions where I have ended up relying on my RPM limits I have found them to be quite harsh so everything you said about making them smoother and more gentle was great.

One thing I did want a little more clarification on is setting a hard limit of Fuel & Ignition 100%. In my mind cutting everything seems like a good option if I end up xRPM past the limiter, but is there any detrimental effect to using a dual cut? As someone who is quite paranoid, I like the idea of the hard limiter (even though it appears to be quite unnecessary).

As another thought - due to the 4G63 being wasted spark (have not converted mine), is there anything extra to consider when setting up cuts?

There's no issue with using dual cuts individually as I demonstrated in the webinar. Essentially if you have a 100% cut of either fuel or ignition you should be perfectly fine though. With the 4G63 you do need to be a little wary since they use hydraulic lifters that can pump up if the exhaust valves are popped off their seats by pressure in the exhaust.

Wasted spark doesn't really change anything fundamental in the rev limit configuration.

Hi Andre!

Great presentation, thank you. You touched on how you need to make special considerations if you had equipped something like added additional/staged fuel injectors, etc where they may not be controlled in the same way as the standard injectors. This got me thinking, is there any special considerations needed for something like meth injection? Or is the time you spend at a rev limiter typically so short that there is no need for special considerations to also cut something like a water/meth injection system?

Thanks!

Thanks for the reply. The wasted spark config had me wondering. Nice to know its not a concern! I have been wary of my lifters and only used fuel cuts in every scenario (even my launch limiter despite it being less effective). Using a dual cut would only be for hard limits.

@Matt, if you're using an auxiliary injection method like WMI then you'll need to either disable this or use an ignition cut to provide an effective rpm limit.

Thanks Andre - I guess fuel cut is out of the question if you have no way to also cut the methanol :) I see these systems come with failsafes but never see anything mentioned about these failsafes also being able to cut off flow in the event of hitting a limiter.