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Discussion Starter #1 (Edited)
I just finished my 95 Cobra with Stock 5.0 motor except for:
C&L Cold Air kit, long tubes, o/r x pipe, 255 lph w/adj reg. and spraying 150 nitrous shot.

Suspension mods include:
Lakewood 70/30 & 50/50, Eibach drag springs all 4 corners with airbag on right rear, Hotchkis lower and Granatelli adj upper control arms, full length subframe connectors, Front Sway Bar removed, 3.73 gears

Skinnies and 15x10 with 26 x 11.5 M/T ET Streets

5 speed car

Now with all that info if you owned the car what would u set the:

Air pressure in tires?
Air pressure in bag?
Launch RPM?
Shift RPM?
Nitrous on RPM
Nitrous off RPM

Any help would be appreciated..I will be making passes Friday night....

Any estimates on E/T?

1,157 Posts
Air pressure in tires? I run 15 N/Z but will be trying out different pressures to see if anything makes a difference. You should do the same.
Air pressure in bag? not sure I run coilovers.
Launch RPM? not sure of trans you are running but if it were a stick I would try 4000 or so and see what happens...then if it spins try less or more...its all about testing.
Shift RPM? what cam are you running?
Nitrous on RPM...shift near the cam
Nitrous off RPM---same as above.

I don't think I have answered much for you but testing helps a lot...don't be disappointed by low times when you are can learn a lot by testing. i def. have.

1,305 Posts
If it were me:

1. I would start my tire pressure off at about 18lbs. The more pressure you can run while still hooking, the faster you will go. Play with it, find out what works. Less psi will help it hook, more psi will help you on the top end. Find a sweet spot.
2. In my experience, 10lbs is a good starting point. I would get a reliable person to watch my launch. If the car leans bad, I would add a few lbs of air to the bag, and continue untill it launches nice and square. (I'm sure you know this, but a drag bag is kind of a band aid, but they work)
3. I would raise the launch RPM untill it stopped hooking. More than likely, if the suspension is doing its job, and the track is good, you could just about launch it off the limiter.
4. Shifting is something you have to play with. For the most part, shift a couple hundred RPM above peak hp.
5. I never run n2o below 3000rpm's because it puts alot of stress on the engine. A 150 shot is a 150 shot no matter what RPM your at. Cylinder pressures shoot through the roof at low RPMs on the bottle.
6. Whatever RPM I shift at is where I would kill it.

3,979 Posts
ET, you should be able to crack some low 12s if not high 11s with it.

Tire pressure, Start at 15 and drop. If no rim screws, don't go lower than 12.5 psi.
Airbag pressure really depends on how hard the car is rolling over on the passenger rear and how hard its squatting. If the track is in great shape, the stiffer the rear, the better. If its not hooking so great, let some air out and let it squat. Start at 25-30 lbs, if it doesn't hook, let some out about 5 lbs at a time.
As far as kicking the nitrous on and off, I'm assuming you have a window switch. Do you also have a 2 step to limit your launch rpms? If you have a two step, set it to where you want to launch, then set the nitrous about 200 rpms above that. Or you can set the nitrous to 3500, wire in a relay off the two step that will interrupt the nitrous (keep it from coming on by breaking the ground signal) while on the 2 step. Shut it off at 5800 and shift at 6000. I'm assuming its a stock cobra cam, not much point pulling beyond 6000 rpms.
Hope this helps and good luck!
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