stall up or flash

I finally got to make some runs since installing the 5C. Footbraking to 4000 i was only able to hit 1.71 60's. I really expected to be in the 1.6's. Im on 305/35/20 ET street SS. 25 psi with ZERO wheel spin.

Ive been told i should flash the converter so it hits harder. my mods are:

solo catback....lund tune...Circle D 5C.... 3:15 gears.

i have waiting to be installed a PMAS Cai and cat deletes are coming this week. I dropped 6 tenths just with the stall itself...Im happy with that.

The convertor dropped 6 tenths; that is pretty damn nice.

What did the car run?

I have found that with my 5C footbraking it is the only way to really get it to 60ft hard. Idle just didn't 60ft as hard.

A technique ive used to get the converter to flash a little sooner is to footbrake the car and right before youre about to go floor the car still on the brake slightly. This will flash the converter a little sooner and still allow you to foot brake the car.

Remember that most cars going faster than 1.6X have boost or really good DA. For a simple NA bolt on car to go 1.6X or 1.7X is still fairly impressive.

bobbyh said:

The convertor dropped 6 tenths; that is pretty damn nice.

What did the car run?

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had a horrible head wind... went 12.3@108

I have a Circle-D 4E converter that flashes to 5,000 rpm's. My car is very mildly modded (mods in signature) and still naturally aspirated. It's heavy at 3800 lbs with me in it. I preload the converter to about 1800 rpm's so that there's no slack in the suspension. Then, on the 3rd amber I mash the loud pedal and release the brakes. On an M&H Racemaster drag radial and 100% factory stock suspension, I cut sixties in the 1.59-1.64 range consistently.

I've tried launching off idle and I've tried stalling up until the front tires almost push, and have found that preloading to 1800 rpm's nets my quickest passes. YMMV.

Five Oh Brian said:

I have a Circle-D 4E converter that flashes to 5,000 rpm's. My car is very mildly modded (mods in signature) and still naturally aspirated. It's heavy at 3800 lbs with me in it. I preload the converter to about 1800 rpm's so that there's no slack in the suspension. Then, on the 3rd amber I mash the loud pedal and release the brakes. On an M&H Racemaster drag radial and 100% factory stock suspension, I cut sixties in the 1.59-1.64 range consistently.

I've tried launching off idle and I've tried stalling up until the front tires almost push, and have found that preloading to 1800 rpm's nets my quickest passes. YMMV.

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thank you!!! ill give that a try..

Good info, I'm hitting the track this week with my current build which includes a 5c converter!

DO NOT run your 20" MT DR at 14-15psi. I agree 25psi is on the high side, but given our weight best performance should be around 17-18psi cold. The SS sidewall deforms badly below 15-16psi, you will gain nothing.

I am still learning the tune side of things but there is much to be done on the launch in the tune, lots of torque management via spark and throttle control that might be pulling power on your launch.

TooSoonJunior said:

DO NOT run your 20" MT DR at 14-15psi. I agree 25psi is on the high side, but given our weight best performance should be around 17-18psi cold. The SS sidewall deforms badly below 15-16psi, you will gain nothing.

I am still learning the tune side of things but there is much to be done on the launch in the tune, lots of torque management via spark and throttle control that might be pulling power on your launch.

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Post your best timeslip. I'll post mine!

TooSoonJunior said:

DO NOT run your 20" MT DR at 14-15psi. I agree 25psi is on the high side, but given our weight best performance should be around 17-18psi cold. The SS sidewall deforms badly below 15-16psi, you will gain nothing.

I am still learning the tune side of things but there is much to be done on the launch in the tune, lots of torque management via spark and throttle control that might be pulling power on your launch.

Click to expand...

I agree. Last year I run my MT ET Street S/S 285/40R18 at 22 psi.

TooSoonJunior said:

DO NOT run your 20" MT DR at 14-15psi.

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+1. You want to find a PSI that shows wear across the entire tread width for the maximum contact patch and keep as much air in the tire for less rolling resistance. I typically start each race day at 25 psi, then air down a bit each pass until I see wear all the way across the tread and dead hook. I usually end up at 21-23 psi, depending on weather & track temp.

As a side note, front tires should be aired up to their maximum PSI for less rolling resistance down the track and for more runout at the starting beams.

Additionally, shallow stage (barely lighting the second staging light) to get a little more run at the starting line before tripping the beam and you'll net slightly improved ET's.