How low can I go?

[Campbell]

I don't know that much about suspensions and since I have coil overs, I was wondering..

How low can you effectively get an A1 VW (83 Scirocco)? what are the "rules" and trade offs about lowering? thanks

[Dead Skunk]

Don't go too low at the front. If the A-arm is higher than parallel to the ground (i.e. the outer end is higher)the roll center starts going down faster than the center of gravity and the car will roll more in corners the further you lower it. At the rear height won't matter much as the roll center is fixed. Lowering the rear will bring the CG down slightly (about 1/3 the amount you lower by)
Warren Martin
27 ITB

[Bill Miller]

There's a 5" minimum ride height in IT.

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MARRS #25 ITB Rabbit GTI

[il8apex]

Remember, the 5" minimum ride height rule is measured at the rocker panels. This does not include any seams, exhaust, suspension, etc. Only "hard" body panels (i.e. unibody "frame rails"). You can go as low as you like with the front spoiler, if you choose to run one.

-T


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Tom Southworth

'93 Honda Civic
Currently prepping for IT Roadrace, CSP AutoX
Remember: Racecar backward is still Racecar!

[Bildon]

If you go lower than 7" you probably have messed up your geometry.

Also the front spoiler can't be "as low as you like" It may be no lower then the wheel rim.

- Bildon

[tderonne]

Originally posted by il8apex:
Only "hard" body panels (i.e. unibody "frame rails").

Where did you hear that part?
The ITCS clearly states rocker panel. As do you.
Has there been something happen on this issue?
Tim
[email protected]

[Bill Miller]

From the 2001 GCR

Ride Height:

Minimum ride height is five (5) inches, to be measured w/o the driver at the lowest point of the rocker panel, but not to include welded seams or fasteners.


Spoiler: (actually the section immediately after the spoiler)

No part of the car, except for the exhaust system and the suspension components, shall be lower that the lowest part of the wheel rims.


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MARRS #25 ITB Rabbit GTI

[Campbell]

Thanks for your comments, I am trying to understand the dynamics of taking the car to 5", as Bildon says the A arms tilt upwards and it seems the strut piston travel is limited. I just don't know how to translate those items being like that to track performance. I am giving thought to the "body roll" that Warren talked about. The A arms seem to be the limiting factor, no way around that?

[Bill Miller]

<font face=\"Verdana, Arial\" size=\"2\">I am giving thought to the \"body roll\" that Warren talked about. The A arms seem to be the limiting factor, no way around that? </font>[/b]

Not in IT.


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MARRS #25 ITB Rabbit GTI

[Ryan Williams]

As Warren Martin said, a steep inclination of the lower control arms (LCA) causes the roll center of the front suspension to go quicky below ground level. With the LCA's level, the front roll center is about 2 to 3 inches above the ground. With the ball joint end inclined (or raised) one inch, the roll center is about 0.5 inches below ground level. This lower roll center increases the length of the front moment arm with a corresponding increase in the front roll couple, resulting in an even worse roll couple distribution behind the front and rear of the car.

Given the constraints of IT, I would set the front ride height with the LCA's almost level, maybe with a very slight incline. The "slammed" look for a VW is not the best thing for good handling. Regards, Ryan.

[Bildon]

Run the rear as low as possible. Looks terrible but it's a way to lower the CG and on a slow ITC or B car it doesn't really hurt aerodynamically.

- Bildon

[Campbell]

Bildon,

You stated if I go lower than 7" I will mess up the geometry, where/how do I measure the 7"? what if being higher than 7" has the a arms tilted up? thanks