rear spring plate angle.

[rattlsnak]

Ok Im going from 23 to 31 t-bars and am trying to get a starting point. Ive tried reading this scale below, but it focuses on static droop height, or weight on wheels. Well, I dont have that calculation available, the engine is out of the car. I do have the weight off wheels droop measured. Im guessing about 12-15 degrees up from where I am now.
Anyone???


>>http://vintagebus.com/cgi-bin/spring.cgi<<

[rattlsnak]

Bueller?

[Shuie]

Can you make a good guess at your weight?

I guessed my weight at 2500lbs and then split it 38/62 (used the 40/60 option on the calculator) front to rear. It must have been a good guess becuase Thoms angle dangle calculator got me within .5" on each side of where I needed to be the first time off the jackstands.

[76911S]

My experience has been take a guess and put it on the ground, but it is going to be basically impossible without the motor and gearbox to know if your right or not.

[Wil Ferch]

There is enough documented info on engine / trans weights that you should get close. All non-turbo 911's are ( as a default) close to 40/60 distribution....biut you gotta take a stab at overall weight. The static ride height 3.8" value for the plate will get you ( when you're on the ground) to Euro-type ride height. If you want to get to ( say) 1" below Euro..you'd use 2.8" for that value.
Feedback indicates that the calculator works well....but as they say "garbage-in-garbage-out"...you have to use some valid input data.
--- Wil

[Neilk]

Use Ferch's calculator with an estimate of your weight and 23mm torsion bars. Then enter 31mm and see what the difference is. Whatever the difference is, apply it to your spring plate angle.

[rattlsnak]

OK, Ill give it a try and let you guys know. Im guessing it to weigh @2,200 LBS, but it will have a 3.6 instead of the 2.4, and I do want it LOW!!

[Wil Ferch]

Why don't you post the input data you *intend* to use and have guys here comment on suitability before you go at it. The whole deal with me coming up with the calculator is to avoid the "I had to do it three ( five ?) times to get it right" syndrome.
--Wil

[rattlsnak]

Ive done this about 10 times so far, and Ive only had to redo one side on about 4 of those cars, so Ive been lucky so far! (Ive just always used the rule of thumb of 1.3~1.5 degrees per mm of increase.)
Assuming a low ride height of the 2.8 angle, using a 2200 lb car with 31" bars, I'm looking at @ 14-15" angle.