kush07

Does anybody know how much air it takes to fill the air jack system in a 996 cup car? I trailer my car with my suv and don't have room for a tall tank. I went to the welders supply and they have a 60 or 80 cu ft tank that seem small enough that I would consider bringing to the track.

Is this adequate?

Also, is the pressure loss a linear equation like I was told? For example, if a full 80 cu ft tank is filled to 2100 psi, if I use 40 cu ft the pressure would be down to 1050 psi. Essentially, I would be down to about the 400 psi needed to lift the car after 65 cu ft.

Thanks

claykos

I have one of the small cylinders for filling shocks (about knee height or so) and I used it to play with the airjacks in the shop. It wasn't full to begin with (abuot halfway) but 4 or 5 lifts brought it down from 1200psi to around 400. So the small cylinder will work, but only a few times. Maybe adequate for a weekend, but will need frequent refills....

KaiB

The relationship btw pressure and volume is linear at these levels...

38D

I have a small tank (60) and a large one (300). The 60 lasts about a race weekend at ~240 psi operating pressure -- you can basically put the car up about 8 times. The 300 lasts me most of a season (5-6 races).

kush07

You lift at 240 psi? Manual and everything I've read says you need closer to 400 psi.

Thanks for all the responses. Great help.

spiller

fatbillybob

I don't know the car but start at 250 and see. then up it 50psi until you are up. My vette is 3500lbs and I need 350psi on 4 jacks.

hughp3

spiller

Viperbob1

400 psi plus is what is needed on any 996 Cup we ran. We usually use 105 cylinders. Good volume, and easy to move around.

porsche.

997.2 cup with 3 factory jacks, any idea on PSI and small enough system I can put in trailer or bed of pickup?

smf32s

I would think about 400-450 psi to lift the car all around. You can probably use a 40 gallon? Can't remember what they are measured in like liters or gallons. Either way the 40 and 80 size are what's available and the 40 will work filled with Nitrogen.

Hope that helps.

Stu

stujelly

Dont forget if you make prior arrangements with Airgas or their equivalent they will deliver a tank to the race track for the weekend.

Easiest way to deal with needing air, without carrying the tank!

scott40

any idea how many lifts the 40 cu ft tank will allow for?

fatbillybob

It is a math problem and you have to do the math because I don't know it, nor bother, because I use my N tank for powering air tools and inflating tires too. Basically need to know volume of jacks and figure you need 10psi/100lb of car so a 3500lb car needs 350psi at the regulator. That's a down dirty rule of thumb. Then add subtract 50psi for how fast or slow you want the car to jack up. So while 350psi is a good guess on a 3500 lb car you might need 400psi. So then you can do the math problem on your 40cuft tank @ about 2000PSI depending on who you get your gas from. Then some leave the tank attached to hold the car up and some fittings leak. I always cut the tank off and locked the nitrogen in the lines with a cut off valve so I do not waste gas. Some people's lines leak and they pop the car up place airjack locks to keep the car up. Then have to juice the jacks up to get the locks out to let the car down. All that uses gas. So your answer is it depends! I use the 55cuft tanks in my pickup truck they are easy to move around. When travel racing by tractor trailer it's the giant 5ft tall I can't move those tanks by myself ones.