Airbags, psi?

[DCEPTCN]

Okay, I ran a search but couldn't find the info as it pertains to this. On my posi '87, what should I set the psi in my airbags to when at the track? I'll be running street tires, if that makes a difference. TIA

 

[salvageV6]

I ran 20-25 psi. in the right and about 5 in the left with my Nittos.

If you can get someone to go with you to the track and watch the car launch you can see if you are spinning or hopping on the first passes and adjust accordingly.

My guess is you will be spinning on the street tires, not much you can do for that except leave with less boost or no boost.

 

[XLR8]

I usually run 5# in drivers side and 20# in passengers side. I had bad wheel hop before the air bags and they solved my problem. I'm still running the ORIGINAL stock suspension - shocks, springs, etc.

 

[DCEPTCN]

Thanks alot, guys.

 

[2FAST4U]

Another suggestion is to have someone measure the bumper distance from the ground on each side while you are boosting the car to whatever boost that you are launching with. Ideally, you want the bumper to be paraellel to the ground when you launch. You will probably find that the pressures previously given are very close.

 

[DCEPTCN]

Originally posted by 2FAST4U
Another suggestion is to have someone measure the bumper distance from the ground on each side while you are boosting the car to whatever boost that you are launching with. Ideally, you want the bumper to be paraellel to the ground when you launch. You will probably find that the pressures previously given are very close.

Duly noted!

 

[wantan87]

What should it be just driving around town? And having 27x10.5 in the rear

 

[UNGN]

I power braked on the track scales, one back tire at a time, adjusting the air pressure in the bag until the weights were the same

I settled at around 20 psi.

 

[n20junkie]

i could be wrong here, but from what i know of rear susp physics the bumper being parallel to the ground just prior to launch doesn't seem all too correct, twisting of the body is a prouduct of the drive shaft input to the rear end pushing the driver side tire, down, and is directly proportional to the amout of HP being developed, say you have 2 cars, one making 400hp and one making 500hp, say both cars are setup the same, with the bumper parallel to the track prior to launch, with but both cars just prior to launch might be making the same hp due to brake limitations, the 500hp car is going to induce more body twist when its making full power becaue its planting the drivers side tire harder, and if set up like the lower hp car then the passenger side tire won't be loaded properly. one of the better ways to tune a cars rear traction is to check the pattern left on the track by the rear tires, the street worksgood to, all cars have a slight ammount of tire slip on launch and you can see if the pattern left is even, if the drivers side tire leaves a darker patch or on the track a more scuffed patch then its getting more pressure than the passenger tire, not that the bumper being parallel is not a good starting point, but sometimes people take the starting point adjustments as gospel on how to final tune a car, which isn't usually true, thats my 2 cents
Grant

 

[UNGN]

I noticed about a 300 lb weigh shift from one side of the car to the other (right to left) during power braking on the scales with no airbag.

The airbag will preload the right side so the weights will be equal at launch.

I also saw the running no spare and a full tank of gas required MORE air in the right side bag to equal the weights on the tires at launch. something to think about.