Author Topic: Cup Car Suspension  (Read 3837 times)

Offline Tav

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Cup Car Suspension
« on: August 23, 2008, 08:40:15 pm »
Just wondering about cup car suspension...what do we know about it?  Spring sizes/stiffness?  Damper specification and manufacturer?  Modification to strut?  Availability?  I presume it'd make a good place to start when choosing track suspension so just curious to see what they used way back when...

Offline G40motorsport

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Re: Cup Car Suspension
« Reply #1 on: August 24, 2008, 07:50:52 pm »
Manufactured by Sachs with a non adjustable insert.
See pic for spring id and rate. Shown is as used in standard Cup form.

Still using them on my car, the rears work fine as they are, the fronts can be improved by fitting a better insert with a heavier spring, I have adjustable Koni's in my struts.




« Last Edit: August 24, 2008, 08:12:23 pm by G40motorsport »

Offline Yoof

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Re: Re: Cup Car Suspension
« Reply #2 on: August 24, 2008, 08:55:09 pm »
Think twice before considering even the wet set-up for road use...

Unless you're a professional driver  :ph34r:

Offline Tav

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Re: Re: Re: Cup Car Suspension
« Reply #3 on: August 24, 2008, 10:50:13 pm »
It's not for road use, no chance!  So front spring there is 278lb/in?  I presume the wet stuff is softer?

Offline G40motorsport

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Re: Re: Re: Re: Cup Car Suspension
« Reply #4 on: August 25, 2008, 10:11:09 pm »
[quote pid=3539 author=Tav date=1219614613]It's not for road use, no chance!  So front spring there is 278lb/in?  I presume the wet stuff is softer?[/quote]

Nope, when fitted that was it, when it was wet you took off the slicks and put wets on.
You could play with the angles but that is about it, other than play with brake balance.

Offline Tav

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Re: Re: Re: Re: Re: Cup Car Suspension
« Reply #5 on: August 27, 2008, 12:52:53 am »
How about rears?

Offline Yoof

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Re: Re: Re: Re: Re: Re: Cup Car Suspension
« Reply #6 on: August 27, 2008, 06:09:32 am »
[quote pid=3557 author=G40motorsport date=1219698669][quote pid=3539 author=Tav date=1219614613]It's not for road use, no chance!  So front spring there is 278lb/in?  I presume the wet stuff is softer?[/quote]

Nope, when fitted that was it, when it was wet you took off the slicks and put wets on.
You could play with the angles but that is about it, other than play with brake balance.[/quote]

Interesting- I've got ex cup car springs saying 'Wet- xxxlb' and Dry- 'xxxlb' I'm sure they could change spring rates (which where free IIRC before a race meeting?)


Tav- rears are a platform height adjustment, with 2 settings, and are also very stiff- I'd stich weld your shell and chassis legs before considering these.

Offline Tav

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Re: Re: Re: Re: Re: Re: Re: Cup Car Suspension
« Reply #7 on: August 27, 2008, 12:30:07 pm »
[quote pid=3585 author=Yoof date=1219813772]  Tav- rears are a platform height adjustment, with 2 settings, and are also very stiff- I'd stich weld your shell and chassis legs before considering these.[/quote]

Any idea on the rates people used?  Just to help get a ball park figure for a first set up.

Planning on getting a full cage + welding shell in future for sure...don't want any suspension induced damage  >_<
« Last Edit: August 27, 2008, 12:30:49 pm by Tav »

Offline G40motorsport

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Re: Re: Re: Re: Re: Re: Re: Re: Cup Car Suspension
« Reply #8 on: August 27, 2008, 11:22:50 pm »
[quote pid=3585 author=Yoof date=1219813772][quote pid=3557 author=G40motorsport date=1219698669][quote pid=3539 author=Tav date=1219614613]It's not for road use, no chance!  So front spring there is 278lb/in?  I presume the wet stuff is softer?[/quote]

Nope, when fitted that was it, when it was wet you took off the slicks and put wets on.
You could play with the angles but that is about it, other than play with brake balance.[/quote]

Interesting- I've got ex cup car springs saying 'Wet- xxxlb' and Dry- 'xxxlb' I'm sure they could change spring rates (which where free IIRC before a race meeting?)


Tav- rears are a platform height adjustment, with 2 settings, and are also very stiff- I'd stich weld your shell and chassis legs before considering these.[/quote]


During the G40 cup you were only allowed to fit the springs supplied with the kit, there was a kit revision in 1993 that allowed the use of a shorter & stiffer revised front spring so you could choose either.

The rears allowed 2 methods of modification to achieve the ride height, you could cut a maximum of 30mm extra on the piston rod allowing compression of the spring and the lowering on the upper spring pan.
The other was to cut an additional circlip groove 35mm lower than the original allowing the lower spring pan to be lowered.

You were supposed to only fit the G40 kit parts, but people used to fit different snide inserts in the struts and have different springs made up to look like the originals during the Super Coupe days so your springs probably date from then as we were all looking to find an edge.

Personally I never found the time to swap springs on race day but it wouldn't surprise me if some did it.