Hypercoils..anyone used em?
06-09-2003, 09:44 PM
#16
Technical Specialist
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Erick,
If you want to go with linear springs, you'll need springs, obviously, and probably hats. This is on my to-do list, after finishing up with brakes, rear ERP bushings, and front cup forks. My plan is for 350 front 550 rear. Not quite as stiff as cup cars, but stiffer than the RS suspension I have today.
Sway bars should be part of the equation. The Porsche 24mm adjustable is popular in front. I went with a 21mm adjustable bar in back (instead of the Porsche 18mm bar), to help tame some of the inherant 964 understeer. I think TRG makes a 22mm adjustable rear bar, too.
On braking, I upgraded to the Turbo 60 bar bias valve, which puts more braking to the rear, and I felt an improvement. I know several others who have done that, and have been pleased with the results. Even though I had the 55 bar bias valve (which you also have), going to 60 added some more stability.
When I added the rear Carrera/RSA tail, I also added a RUF front valance extension, which together feels pretty balanced.
If you want to go with linear springs, you'll need springs, obviously, and probably hats. This is on my to-do list, after finishing up with brakes, rear ERP bushings, and front cup forks. My plan is for 350 front 550 rear. Not quite as stiff as cup cars, but stiffer than the RS suspension I have today.
Sway bars should be part of the equation. The Porsche 24mm adjustable is popular in front. I went with a 21mm adjustable bar in back (instead of the Porsche 18mm bar), to help tame some of the inherant 964 understeer. I think TRG makes a 22mm adjustable rear bar, too.
On braking, I upgraded to the Turbo 60 bar bias valve, which puts more braking to the rear, and I felt an improvement. I know several others who have done that, and have been pleased with the results. Even though I had the 55 bar bias valve (which you also have), going to 60 added some more stability.
When I added the rear Carrera/RSA tail, I also added a RUF front valance extension, which together feels pretty balanced.
06-09-2003, 10:24 PM
#17
Rennlist Member
Eric - I would recommend starting with the sway bars. You will want them anyway, and you may find that it resolves your concerns (for now). Go with something pretty beefy. Try for front and rear adjustable, or atleast rear adjustable. Front should be pretty thick. I bought used ones and I would need to measure them again, but they work very well with my H&R coilovers.
06-09-2003, 10:34 PM
#18
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I have nothing to add, but just want to say I love Steve Lavigne's avatar!
Reminds me of this old ghost story link. Don't forget to turn the volume up so you can hear them.<a href="http://home.attbi.com/~n9ivo/whatswrong.swf" target="_blank">http://home.attbi.com/~n9ivo/whatswrong.swf</a>
Reminds me of this old ghost story link. Don't forget to turn the volume up so you can hear them.<a href="http://home.attbi.com/~n9ivo/whatswrong.swf" target="_blank">http://home.attbi.com/~n9ivo/whatswrong.swf</a>
06-10-2003, 05:10 PM
#20
Burning Brakes
Bill and Jack,
Thanks for the info.
For the springs, I'm a little confused about what "hats" you are refering to. Are these the same as the threaded spring perches on the top and bottom of the shock that the spring contacts? If so, it seems like I wouldn't have to replace these, no?
Also, how can I determine what linear spring rate I could go to without "overloading" the shock? I'd like to go quite a bit higher, but I'm sure that I'm limited by the shock capacity. I was told by H&R (USA) that it would cost ~$80/shock to have them revalved. Maybe this is a "less" expensive alternative.
Bill, how did you come up with the 350 lb/in. front 550 lb/in. rear combination? Is there a formula for determining optimal front/rear spring rate combinations?
I will continue to pursue beefy, adjustable front and rear sway bars to.
Interestingly, I talked to H&R about their recommendations. Their answer - get the Supercups for $3900. Ouch. But from what I can tell, this is a rip-off. Besides fitment issues that have been discussed here, they are just a revalved shock with higher spring-rate linear shocks and monoballs. Would I be way better off financially having my shocks revalved ($80 ea.), buying 4 springs ($75 ea.), and buying monoballs ($? ea.). I'm sure this doesn't even approach the cost of the Supercups! Am I missing something?
Erick
Thanks for the info.
For the springs, I'm a little confused about what "hats" you are refering to. Are these the same as the threaded spring perches on the top and bottom of the shock that the spring contacts? If so, it seems like I wouldn't have to replace these, no?
Also, how can I determine what linear spring rate I could go to without "overloading" the shock? I'd like to go quite a bit higher, but I'm sure that I'm limited by the shock capacity. I was told by H&R (USA) that it would cost ~$80/shock to have them revalved. Maybe this is a "less" expensive alternative.
Bill, how did you come up with the 350 lb/in. front 550 lb/in. rear combination? Is there a formula for determining optimal front/rear spring rate combinations?
I will continue to pursue beefy, adjustable front and rear sway bars to.
Interestingly, I talked to H&R about their recommendations. Their answer - get the Supercups for $3900. Ouch. But from what I can tell, this is a rip-off. Besides fitment issues that have been discussed here, they are just a revalved shock with higher spring-rate linear shocks and monoballs. Would I be way better off financially having my shocks revalved ($80 ea.), buying 4 springs ($75 ea.), and buying monoballs ($? ea.). I'm sure this doesn't even approach the cost of the Supercups! Am I missing something?
Erick
06-10-2003, 07:22 PM
#21
Technical Specialist
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Erick,
On spring rate, I looked at the 964 cup car rates and 964 race spring recommendations, and backed off them a bit. More scientific than a wet thumb in the air, but not much.
On spring rate, I looked at the 964 cup car rates and 964 race spring recommendations, and backed off them a bit. More scientific than a wet thumb in the air, but not much.
06-13-2003, 10:14 AM
#22
My data may not be accurate (it's from a hand written table of all the springs for various 964 models), but I was given the following ratings a few years ago when I decided to upgrade my 1993 C2 to linear hypercoils with double adjustable shocks and adjustable sway bars:
Fronts
964.343.531.80.504, Carrera RS, 65-280
964.343.533.70, Carrera Cup Car, 150-550
Rears
964.333.531.80.504, Carrera RS, 146-550
964.333.533.70, Carrera Cup Car, 252-686
According to the list I have, most front springs and all rears are progressive for the 964 chassis. The progressive ratings are based on one inch from rest and one inch from coil bind.
The breeze was blowing in a slightly different direction from Bill's when my wet digit was up and I selected 400 front and 450 rear, because I drive on the street, at least to get to the track and the frost heaves and potholes in the northeast are BAD NEWS. Although the spring rates are a compromise, the car handles reasonably well. The best part about the coilovers is that it's quite easy to change springs if you want to - but you'll have to corner balance again.
FWIW, I know an RSA with 550F/600R linear springs which handles really well on the track; stiffer seems to work better.
Shocks MUST be set to match the spring rate, but the adjustable shocks can be softened for driving on the street and then stiffened at the track.
Hopefully the technical gurus will correct any errors in the spring data I've posted.
Fronts
964.343.531.80.504, Carrera RS, 65-280
964.343.533.70, Carrera Cup Car, 150-550
Rears
964.333.531.80.504, Carrera RS, 146-550
964.333.533.70, Carrera Cup Car, 252-686
According to the list I have, most front springs and all rears are progressive for the 964 chassis. The progressive ratings are based on one inch from rest and one inch from coil bind.
The breeze was blowing in a slightly different direction from Bill's when my wet digit was up and I selected 400 front and 450 rear, because I drive on the street, at least to get to the track and the frost heaves and potholes in the northeast are BAD NEWS. Although the spring rates are a compromise, the car handles reasonably well. The best part about the coilovers is that it's quite easy to change springs if you want to - but you'll have to corner balance again.
FWIW, I know an RSA with 550F/600R linear springs which handles really well on the track; stiffer seems to work better.
Shocks MUST be set to match the spring rate, but the adjustable shocks can be softened for driving on the street and then stiffened at the track.
Hopefully the technical gurus will correct any errors in the spring data I've posted.
