I'm running 180/180 on Motons with fairly good results at Putnam. 850/900 front/rear springs.

Alan C.

 

Are you guys setting that pressure cold and not checking it hot? If I set my car at 180 cold I would be on my roof by the 3rd lap on any track. My springs are pretty soft close to Als set up.

 

Bill,
I check it cold and with the tires off the ground. Not concerned about hot pressures, but don't know if I should be??

I run 1100f/1250r springs and plan on increasing it this winter if we get the chance to maybe 1250/~1450.

 

All,

I check mine cold with wheels on the ground. Is that not the best/accurate way to do it ? How should I be doing it ?

Norm

 

For the CMP race I am filling my damper remotes with a dark German beer.

Greg, 1100/1250? The space shuttle has softer springs.

 

Greg -

I just moved up to stiffer springs from the 900 and 1,100 I was running. I just ran at one of the bumpiest tracks I know of. The car handled better and the ride was not noticeably harsher. Less roll, but overall it really did not feel that different. You should be fine with 1,250 - 1,450.

I did read on the Racers Group site that JRZ need to be re-valved over 1,200 pounds. I have an email into them about that.

Bill

 

Bill and Bill,

I believe the 993 Cup cars has over 1500lb springs. My set up isn't all that stiff and as Bill in Chicago mentioned it really didn't make the car more skittish. What rates did you end up using Bill E.?


And great idea on the beer but you might want to try something from Holland since the JRZ's are made there.

 

I moved up to 1,300 - 1,500. I ran one day with new setup and so far so good.

 

OK, let me open up a huge can of worms here. Will one of you race engineers mind explaining when and why we need to change our spring rates for Sebring vs Watkins Glen vs Lime Rock? I know the ultra quick GT cars make these set up changes but simplify this for me and the lurkers. Why I am way fast (for my car) at one track and struggling for grip at another? If there is some magic formula that will move me up the grid do not post it here but PM me ;>

 

Bill,
I don't have the budget to change spring rates from one track to another. I try to pick something that works well at all the tracks I frequent. I know the variable that makes the most difference and that I have the hardest time controlling is the driver. To get the most from set up changes you have to be consistently fast. I have a tendency to peak late in the weekend, where a pro will be fast right off the bat.

I can also give you the number of the guy who helped set up my car, he has lots of experience in 911's and other race cars. And I don't mean just at the club level but at the pro level, with factory Porsche drivers.

 

A couple contributions regarding modern remote-reservoir shocks:

The nitrogen pressure MUST be checked with the car sitting on its wheels. The shock shafts displace shock oil, which then displaces the nitrogen in the reservoir which increases the pressure. Since the nitrogen part of the reservoir is small, a small shock shaft movement produces a large change in pressure.

If you set the pressure with the shocks extended then the pressure will probably double when you set the car down. Moton recommends a range of 6 to 20 bar. The nitrogen charge has no effect on the damping, but it does have other effects.

It is nice to mount the reservoirs somewhere where they are not subject to engine heat so the pressure does not change during a session. I always mount them inside the car.

Nitrogen expands when heated just like air does. The only advantage nitrogen has over air is that the bottles that nitrogen comes from are free of water vapor.

Springs lighter than 1000 lbs/in or so really don't have a place on a modern racing Porsche. Stock class racers are going to need heavy springs because they weigh a lot. If you use really heavy springs, you will likely be using the upper end of the shock's adjustment range.

Stiff springs have a bad rep because rarely are stiff springs designed and applied properly. When they are designed and applied correctly, they out perform soft springs, given the right damping, under all conditions.

I don't change springs for different tracks. I run the same springs at Sebring as Road America. The shocks do get adjusted, however.

 

Stupid question while we are on the subject of remote shocks. Does everyone go down to your local gas supplier and buy a nitorgen tank and regulator? I stopped by a place today, and it was like $400 for the full setup. I don't use nitrogen in my tires, so this is just for the shocks. What do you guys do here?

Thanks

 

A buddy of mine use a big Nitrogen tank/regulator for everything. One tank works the air jacks, impact gun, and fills the tires. PRETTY NICE! Changes all 4 wheels in about 5 minutes!

Its big, but not all that cumbersome to deal with. Using one just for shocks might be a bit much though. There must be a way to buy a smaller quantity.
This is a 993 3.8 Cup Car. He is on this board, maybe he can chime in.

 

Chris C,

Thanks for the info, it helped clarify for me...

Norm

 

Thanks for your input Chris C.. That information takes the mystery out of the remote dampers.

What would be the "ideal" spring rate for a 2800# 993 track only car? JRZ's, evo uprights, no rubber in the suspension or mounts. Do you still use helper springs?