has anyone made a diy rev limiter using a shift light and a relay. I saw that today on youtube and was wondering if it would work on the v 6 engine. from my understanding you hook up the light how is it supposed to be except on the ground side of the light is so there is a relay connected to the ignition coil on the negative wire that is normally closed and when the light turns on it opens the relay cutting spark which should sloW the engine down and make some firey exhaust pops.
Two thoughts here:
1) I'm not sure what you describe would work, as I imagine the shift light would need the ground connection to function - in other words, you couldn't hook the ground up to a relay, it would need to hook up to ground. Now, if the shift light offers a signal out wire or something like that, then yes, using the light to trigger a relay to cut ignition might be do-able. It would depend on how you wired the relay. And I don't see why this wouldn't work on a V6 engine - or any engine for that matter, as long as you tap into the correct wire for ignition signal.
Which brings me to 2) spark cut is typically worse than fuel cut. If you have a choice between the two, fuel cut is generally superior. No, it doesn't make your car run super lean. It makes your car not run at all. Which is kind of the point. Spark cut results in tons of un-burned fuel dumped, which, as you said, can cause pops and whatnot in your exhaust (which is in fact exploding fuel - a good way to damage your pipes) and will pretty much demolish your cats if you still run them.
OEMs chose fuel cut over spark cut for a good reason. But to summarize, what you asked can be done given what I said in item number 1.
