What pressure for air bags?

[81GrandPrix383]

Hi,

I have an issue with my tires rubbing so I installed air bags in my rear springs to keep the fenders off the tires.
The tires are basically flush with the fenders so rolling the fenders wouldn't have done it.

My question is, what air pressure should I set these at?
I figure a little fine tuning will be needed so I'm looking for a starter setting i guess.
Likely will never have anything heavy in the trunk and if my kids get in the back seat they weigh about 70 lbs total between the two of them plus car seats. (100lbs? max)

The car will go to the track so I expect to set the passenger side a little stiffer.

Thanks in advance.

 

[dogsht]

Start with like 15 & 8 psi and then come down in pressure with each until you get the right burn out marks for each for maximum traction and for how much pressure you need to keep the tires off your fenders on moderate bumps. Have tires at the same air pressure and do a no brake pedal burnout on flat smooth surface and stay in it until they are both done spinning. Adjust tire pressure so that both tires leave flat even complete black marks across the width of the tire mark. The pinion is always trying to climb the ring gear so you will need to pre-load the suspension with more air in the one side adjusting them so that each tire starts to leave a black mark at the same place and ideally ends at the same place. Naturally you can't totally control the where each tire stops spinning with just air bags.

After that adjusting the pinion angle to plant the tires instead of lifting the rear of the car and unloading the tires can help a lot as well has videoing your runs and working with weight transfer shocks especially the front shocks. Something like a 70/30 often helps keep the weigh transferred & traction longer and rides nicer than a 90/10 that most people think they need to try first.

 

[81GrandPrix383]

Thanks Vern,

That was a lot more information than I asked for but all good.
I wont get the car on the road for a while yet. Still snow up here and I'm having starter issues. Not sure what is going on this time but I thought I had it corrected. Started fine 2x then the bendix started grinding on the flexplate again. That's another thread after I get under the front of the car and see what happened.