rev limiter question efi tt 481x

Hi, ive got a fuel injected twin turbo 481x in an outlaw drag radial car. Ive been hurting parts left and right on passes that it spins and hits rev limiter (9500rpm). When it spins it happens so fast i guess i cant lift quick enough to not hit limiter. Ive bent a few pushrods, connecting rods and broke a few rockers and one spring over the last year. My question is this, currently the rev limiter is a fuel cut in my big stuff 3 efi. I just put a grid on the car and can now switch to a spark cut instead. Do you guys think a spark cut will be a lot less violent then fuel cut? Or does anyone have any other reccomendations? I dont really see any other combos like mine hit the limiter so violently like mine does. When it happens it produces a large backfire and motor dies. Blew a burst panel once and taco shaped a throttle body blade once also. Any opinions or help is much appreciated!

 

I've never shut the fuel off at high rpm because I thought it would lean out the engine and kill a bunch of parts. With that being said, I have broke the fuel pump shaft off and we didn't hurt anything.

Is there anyway its not cutting ALL the fuel from going to the engine?

When the RPM comes back down does it give the fuel back?

If it were mine I would use ignition rev limiter.

 

It fires in bank to bank so i assume some fuel is still in some cylinders right as it shuts off. And yes it puts fuel back in when it drops back under the set limiter rpm but every time it happens it backfires violently and kills the motor. Ive got the grid on now and also just bought a arc module for it so hopefully i have better luck next time out.

 

The thing that stuck out to me was when you said the rev limiter was a FUEL cut. That seems like the culprit to me.
When it starts banging off the limiter and then it cuts the fuel supply, you're asking for trouble.

Ignition/spark cut would be the way to go. Blown, Turbo or anything. Fuel cut is not the answer.
I think you are on the right track with the grid change.

 

i have a twin turbo 481X my BS3 rev limiter cuts spark one cylinder at a time in order. I have a clutch car so i 2 step WOT and rev limiter works perfect even at 6000 rpm it never goes over so at 9500 it should catch that just fine.

do you have a valve train issue when the motor hits 9500 floating valve causing backfire

 

Yeah i found out that the bs3 can be updated to a spark cut instead of fuel cut but im just going to use the grid spark limiters now that i have them. Hopefully hitting a spark limiter will be much less violent and hard on the motor. Luckily it hasnt broke a rod yet but has bent some bad!

 

Would not just passing air through the cylinder( and cutting spark ) be better than injecting fuel and not sparking it ? It is very hard to grasp the concept but a electronically fuel injected ECU can do one or both simultaneously , very easy ,accurately, and at virtually any speed . There are no lean holes because no fuel is injected into them and no spark to light it .