RSA Spring Rates?
05-07-2010, 07:30 PM
#16
I see. So the 'main' spring is stiff and the small 'tender' spring is soft......a little more cushion for small stuff, but still with the overall stiffness of the main springs? Generally.
So, 964Cup:
Front Main - 600
Front Tender - 200
Rear Main - 800
Rear Tender - 240
?
Is there much of a performance benefit to doing this as opposed to just a straight 600/800 spring setup front/rear?
Roland
So, 964Cup:
Front Main - 600
Front Tender - 200
Rear Main - 800
Rear Tender - 240
?
Is there much of a performance benefit to doing this as opposed to just a straight 600/800 spring setup front/rear?
Roland
05-08-2010, 03:15 AM
#17
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I track and race an RSA on the same tracks you are talking about. ORP and PIR can take a stiff setup, PR in Seattle cannot - period.
You need to get someone in Vancouver to work with you, or Colin at http://www.cantrellmotorsport.com/
considered by many in Seattle as a wizard at setting up Porsche's
or Steve at http://www.rennsportsystems.com/~porsche/993.html
Correct setrup is critical, and these guys know what they are doing - value added as said earlier
In the long run cheaper
You need to get someone in Vancouver to work with you, or Colin at http://www.cantrellmotorsport.com/
considered by many in Seattle as a wizard at setting up Porsche's
or Steve at http://www.rennsportsystems.com/~porsche/993.html
Correct setrup is critical, and these guys know what they are doing - value added as said earlier
In the long run cheaper
05-09-2010, 07:28 PM
#19
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Rich,
Thanks for the advice. I don't pretend to know more than I do and when I am not sure about things regarding my car, I ask for some advice/direction whenever possible. This will be my 3rd year on the track and I am no mechanic. I really do appreciate all the information from all the people on this site, and elsewhere, who know a lot about these cars.
I have exchanged emails with Steve before, along with Jeff Gamroth and Jae Lee......all very well versed in my opinion.
PR near Seattle is actually one of my favorite tracks. I am thinking something along the lines of 600/800....maybe with tenders. Thoughts? I think i'll be tracking mostly at PR and ORP in the future.
Roland
Roland
Thanks for the advice. I don't pretend to know more than I do and when I am not sure about things regarding my car, I ask for some advice/direction whenever possible. This will be my 3rd year on the track and I am no mechanic. I really do appreciate all the information from all the people on this site, and elsewhere, who know a lot about these cars.
I have exchanged emails with Steve before, along with Jeff Gamroth and Jae Lee......all very well versed in my opinion.
PR near Seattle is actually one of my favorite tracks. I am thinking something along the lines of 600/800....maybe with tenders. Thoughts? I think i'll be tracking mostly at PR and ORP in the future.
Roland
Roland
05-09-2010, 08:34 PM
#20
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I believe tender springs are a compromise. Why go to the trouble of upgrading your track set up if you're going to opt for a progressive-rate spring combination? If you want to optimize handling, skip the tenders.
The helper springs Bill described are usually fully compressed but extend when the suspension is at full droop and simply keep your main springs in place. They don't provide additional cushion or low-speed ride comfort.
As for spring rates, that's a personal call. You might want to grab a ride with someone who has 600/800's on a street car to see if, in your opinion, it's doable. On a glass-smooth track, they won't be a problem. It's just the stretch between your house and the track which might end up biting you.
Let us know how you end up.
The helper springs Bill described are usually fully compressed but extend when the suspension is at full droop and simply keep your main springs in place. They don't provide additional cushion or low-speed ride comfort.
As for spring rates, that's a personal call. You might want to grab a ride with someone who has 600/800's on a street car to see if, in your opinion, it's doable. On a glass-smooth track, they won't be a problem. It's just the stretch between your house and the track which might end up biting you.
Let us know how you end up.
05-10-2010, 12:30 PM
#21
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Thanks again all. I will let you guys know what I end up with. Still leaning towards a straight 600/800 setup without tenders. I think that will work well.
Roland
Roland
05-10-2010, 12:44 PM
#22
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Just to add another perspective; same setup different issue:
https://rennlist.com/forums/racing-a...ion-setup.html
I think you may be missunderstanding, when you start going up in spring rates tenders are not options they are required, the springs are short for ride height and stiff, under rebound over a bump/curb the shock will extend to the point where a short stff spring will be completely uncompressed and come off it's seat. Not good. With progressive springs the "soft" section keeps them on the seats not so with constant rate race springs...
You've got some good resources in the area I'd take the car over to Steve W...
https://rennlist.com/forums/racing-a...ion-setup.html
I think you may be missunderstanding, when you start going up in spring rates tenders are not options they are required, the springs are short for ride height and stiff, under rebound over a bump/curb the shock will extend to the point where a short stff spring will be completely uncompressed and come off it's seat. Not good. With progressive springs the "soft" section keeps them on the seats not so with constant rate race springs...
You've got some good resources in the area I'd take the car over to Steve W...
05-10-2010, 01:21 PM
#23
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One minor correction ...
Agreed. Helper springs are required when using short, stiff springs. Tender springs, however, are used in a combination with a stiffer, main spring to produce a progressive-rate set up and completely optional. Here's a little more info:
http://www.e30m3project.com/e30m3per...ings/index.htm
Just to add another perspective; same setup different issue:
https://rennlist.com/forums/racing-a...ion-setup.html
I think you may be missunderstanding, when you start going up in spring rates helpers are not options they are required, the springs are short for ride height and stiff, under rebound over a bump/curb the shock will extend to the point where a short stff spring will be completely uncompressed and come off it's seat. Not good. With progressive springs the "soft" section keeps them on the seats not so with constant rate race springs...
You've got some good resources in the area I'd take the car over to Steve W...
https://rennlist.com/forums/racing-a...ion-setup.html
I think you may be missunderstanding, when you start going up in spring rates helpers are not options they are required, the springs are short for ride height and stiff, under rebound over a bump/curb the shock will extend to the point where a short stff spring will be completely uncompressed and come off it's seat. Not good. With progressive springs the "soft" section keeps them on the seats not so with constant rate race springs...
You've got some good resources in the area I'd take the car over to Steve W...
http://www.e30m3project.com/e30m3per...ings/index.htm
05-10-2010, 01:56 PM
#25
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Joey, the easiest way to think about it is tenders are active and helpers are passive springs, nonetheless I was more concerned with the need for active rebound which is the tender spring, too often with a threaded body shock it's easy to adjust the collar down on a high rate spring thinking you've got it all taken care of but as soon as you go over your first curb you'll be wondering why the car is handling so strange...
I've even seen the spring in compression on the tube to the point where the spring rate would be in the 1600lbs inch and the owner wondering why it wasn't handling so well...
Anyway I would still get some help to get this set up...
I've even seen the spring in compression on the tube to the point where the spring rate would be in the 1600lbs inch and the owner wondering why it wasn't handling so well...
Anyway I would still get some help to get this set up...
05-10-2010, 02:13 PM
#26
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From the link, above:
A helper spring is used to keep the main spring tight between the perches when the suspension is at full droop. It "helps" keep the main spring snug, if you will. A helper spring has a very soft rate, on the order of 10 lbs/in. It's just strong enough to push the main spring up against the upper spring perch, but that's about it.
A tender spring happens to look very similar to the spring in the photo, but it is stiffer than a helper spring. A tender spring has a rate in the region of 150 lbs/in to 300 lbs/in (looking at the Eibach ERS catalogue). A tender spring is meant to be used in conjunction with a much stiffer linear rate main spring. Using the two springs together yields a "progressive" overall spring rate. In fact, the tender spring itself can be progressive.
A tender spring happens to look very similar to the spring in the photo, but it is stiffer than a helper spring. A tender spring has a rate in the region of 150 lbs/in to 300 lbs/in (looking at the Eibach ERS catalogue). A tender spring is meant to be used in conjunction with a much stiffer linear rate main spring. Using the two springs together yields a "progressive" overall spring rate. In fact, the tender spring itself can be progressive.
05-10-2010, 03:34 PM
#27
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Joey,
thanks, I'm not disagreeing or arguing the differences between tenders and helpers, what I was trying to point out is that a tender spring has a major function in rebound when the corner is unloaded on the track which is part of keeping the wheel in contact with the pavement rather than the common misconception that it's there just to get a progressive spring rate under compression...
And the bottom line that if he doesn't know all of this that he has some really good resources to get the car set up properly...
It's all good...
05-10-2010, 03:45 PM
#28
Drifting
I agree with Joe. My tender springs are around 30 Nm ( I don't remember exactly). When I stand on them (yes I've tried), I compress them by half. When the car is standing on its wheels they are fully compressed. If you don't have these the handling would be very aggressive from the main spring if it would come from full rest and back under load. The tender spring helps to create a more predictable and smother operation before the linear main spring comes in during the inital load. Then the main spring takes over and does all the damping when the "real" load builds up.
My main springs are 160 Nm front and 200 Nm rear on a 1200 kg car.
Thomas
My main springs are 160 Nm front and 200 Nm rear on a 1200 kg car.
Thomas
05-11-2010, 01:00 PM
#30
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I have got my Porsche guy talking with Lex from Moton and Steve from Rennsport......when the shocks get here this week we'll figure out what route to go. Most likely 600/800 at this point.
Roland
Roland
