I know this is my first post. I wouldn't normally answer a question on a forum with a first post. However, I have unique knowledge in this area. (I have done it)It was for traction control using front wheel speed vs rear wheel speed. Slightly different application, same outcome.I tried spark cut first because it was easy with the ignition setup used in the car at the time. The results where undesirable and sloppy.Spark cut is a terrible way to rev limit the engine. You have an Arduino. You can do better.Put in an up stream flapper in the intake. You can easily move it with a server. Center bias the flapper so it can not get sucked closed.Failure mode = OPEN.Track engine RPM(several different ways). When the RPM reaches the limit, close flapper whatever amount you are happy with.This will work for all fuel injected cars Alpha-N or Speed Density. **DO NOT DO THIS IF YOU USE A CARBURETOR**You have been warned. I wash my hands. ]
What car/engine?What sort of ignition system is in the car?Is it single coil with a distributor, or individual coils per cylinder?Knocking out spark to a single coil is pretty rough. . it gives the rev limiter very harsh operation.Racing ignitions will generally alternate which cylinder they drop, and then make sure that cylinder is fired on the next compression stroke so as not to load up that cylinder with fuel.The difference is night and day with a digital MSD style ignition limiter to an older 6AL style analog box.I've run both (in an 8 second carby car) and the digital one is so much smoother, sounds a lot nicer on the engine then the older style.Fuel cut rev limiting in a boosted application probably doesn't sound great to me either (unless it's a diesel), as it's going to cause a very lean-burn situation in the cylinder it's dropping fuel to (assuming fuel injected?).Maybe there's an aftermarket option for the computer in your car to allow different RPM limits (for your 2/3 step)?
You definitely don't want to use timing retard for traction control on a big engine, it'll cook the exhaust valves.You also don't really want fuel cut on anything with decent specific power because it'll run lean before and after the missed injection cycle.A spark cut with a walking pattern works great in my experience. You can make it progressive by varying the proportion of missed sparks. Unless you have hugely excessive power and a driver who can't hear the engine you may find you only need to drop a single cylinder, because (ime) the roughness is easily detected and the driver soon learns to recognise that as a cue to feather the throttle. If that doesn't work and if you want this to control power for longer than a fraction of a second it'd be better to fit a cable stretcher rather than run with a misfire.If you do use spark cut on a high power engine you might want to set up your cut pattern to alternate exhaust headers because the unburnt air/fuel is going to go up in the header and you don't want consecutive cuts in the same header if you can avoid it.
This is going in a drag racing car with a transbrake (and remember, turbo car).
My first thought was place a brick under the gas pedal
Please enter a valid email to subscribe
We need to confirm your email address.
To complete the subscription, please click the link in the
email we just sent you.
Thank you for subscribing!
via Egeo 16