Thrasher 108 1500 rpm stutter?

[BuickTom]

Ran my T108, no stutter, no lockup, for the first time at the track this weekend. When I would stage it would seem to stutter or hit a rev limiter at 1500 rpms. I'm not sure what the stutter is supposed to feel like, but I would have expected it to hold the rpm steadier, this bounced between 1000 and 1500 rpms. I didn't really notice it at all driving around the pits, just staging. Is there anything that would cause this? If it was the stutter feature it should have been at 2300 rpms, so I'm totally confused.

Thanks,
Tom Caspar

 

[JayC]

Stutter is controlled by cutting off the injectors, not the spark as a true two step does. The problem with cutting the fuel is that it still allows the RPMs to climb despite the fact that you are cutting fuel. Eventually you will push right past your stutter point and the RPMs will go up and down like a yoyo. I played with this with a hardware mod back in like 95 and found the whole stock ECM two step thing was worthless so I abandoned it then.

I believe I have read elsewhere that you need to play with the throttle to try to maintain the RPMs on the Thrasher two step. Kind of defeats the purpose of having one but unfortunately using the built in rev limiter, that's about all you can do. With a two step that controls the spark, you can basically just put the pedal on the floor and it will hold it at your preset RPM.

If you should decide you want a real two step for the DIS ignition, the Accel DIS ignition has one built into it.

Good luck

 

[Drewster]

what the heck is that!!??

i just tried mine out and got the same thing. almost stalls at 1800 if not, rum, rum, rum, rum. its not supposed to have stutter?!? rips pretty good if i nail it though. i reset the IAC,TPS no luck so i pulled it and put the 92 thrasher back in. smooth as ever....it may be the big mouth cold air kit i have. Do you have one also? i noticed the O2 were less than 100. i lowered the FP from 47 to 45 and that helped a little but still does the yo yo thing.

let me know if you figured it out.
not gona use it at the track tomorrow like i planned

drew

 

[BuickTom]

I never got it figured out, that was the last weekend the track was open, so I haven't been able to run good gas again. I was going to send mine back to Russ and try a different chip, but just haven't gotten around to it yet. For an intake my cars got a k&n and a 3" maf pipe, so I doubt thats it. I didn't really notice any difference with the fuel pressure. Like you I put my T92 back in and the car was fine. I never thought to check O2's though. The car ran great otherwise, just a huge pain to launch. The only other thing that I thought might be a factor was the connector for the tranny was unhooked (TC problems) so the computer may have thought it was in 4th gear. Let me know if you figure it out.

Tom