J_D_

I need to slow my car down to 9.0 from 8.3 in the 1/8 mile to fit an index class. Can I just limit the max MPH in the chip to 75 or so ? 6E/ARAP.

93V8S10

You can give it a try, but I suspect that it'll be very inconsistent. You can also drop timing some and fatten-up the PE AFR to kill some power. With the timing, bringing the advance in slower and latter should have a better effect than just limiting the top end.

J_D_

Ok, somehow I got the idea, the speed limiter would cut the fuel. Killing off some timing may be good.

93V8S10

Yes, the speed limiter will cut the fuel off. I think that you should try it and see if it works for making the index or not. I just have concerns that the ECM won't do it accurately enough to keep you running at the index for each pass.

The timing can make a big difference, but like all things there is a point of diminishing returns. Approaching the task from several angles should work best. Changes in air quality will be your worst enemy.

J_D_

May as well do both. May total the advance at 30* and set the mph limit at 75. Seems like when it was stock it ran 9.1s at 78. Id rather just drive it than pedal. If its not raining tomorrow I can give it a try on the Parkway. Speed limit is 75 so I wont be getting in trouble.

dan0617

Do you shift manually? If so, just shortshift more and more and more till you figure out what RPM you need to shift at in order to achieve the time you want.

J_D_

I did the chip. Cut fuel at 77 mph. As soon as I felt the fuel cut, I lifted. Car never died. Felt like it would work great. Truth is, it was 92*, too hot for racing and I had a chance to make some quick $$$ so I never made it to the track.

93V8S10

Let us know how it works out when you make it to the track.

J_D_

may give it a try on a time trial. The index class was a one time deal.

J_D_

I never shift. In the 1/8th mile it only uses 2 gears. I leave it in 2 and cross the finish line at 6000 rpm in 2nd. Running the 1/4, it hits 3rd on its own at the 1/8 mile mark and stays there.