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30mm below US height is ROW height, I run RS height (which is 50mm below US) and there are NO issues with getting a factory spec alignment.
I think post #52 shows that US is 20mm higher than ROW, but I also disagree with pp000830 that lowering beyond 30mm from US spec will be a challenge to drive on.
I'm 52mm lower than US spec, and can negotiate roads, driveways etc just fine. In fact, much better than my VW Corrado which is not nearly as low. The 993 bumper overhangs and sloped shape make clearance very good (in comparison).
Attached is a chart you may find useful in comparing ride heights. It seems that anything more than 30mm below US height may interfere with getting a factory spec. alignment. At 30mm below US height you may have scraping issues on a US street car especially on driveway aprons. 15 to 20mm below US specification may be as low as you want to go for a street car.
Also the values on the chart are not absolute as most aftermarket struts/shocks have threaded barrels that allow for substantial adjustment range well in excess of what the suspension can be adjusted for while retaining the ability to achieve proper alignment.
Andy :-)
This is incorrect ... US spec cars were raised to meet DOT bumper height regulations and handled poorly as a result. Lowering the car will correct the geometry and improve handling.
Just completed installation of a set of Koni FSD shocks on my '97 C4S.
I have stock US springs and wanted to stay at or close to stock ride height.
I drive my car all year round here in MN and we get enough snow to convince me to stick
with US ride height. Measurements here are with stock 18" turbo look twists.
I did not measure the ride height prior to taking out the stock Monroe shocks,
but I'd guess the ride height was very close to stock (174f/157r mm).
The ride height in the back is now 139 (left) and 140 (right), about 17 mm lower than US,
and 7 mm lower than RoW. In order to keep the same 'rake' from rear to front, that
meant that the front should be set to about 157.
The best I could do was to run the front collars all the way down to the lowest setting.
The result in the front is 161 (left) and 158 (right). I still have maybe 3mm of
adjustment on the right front, but the left front is all the way down.
So Koni FSD lowered my car 17 mm. Not saying that is bad. Time will tell.
With Koni FSD and stock US springs, it is not possible to achieve ROW rake (7 mm
difference front to rear, vs. 17 mm difference front to rear for US).
Ride height specs with Koni FSD and ROW M033 springs 144F 127R
Recently installed this set up on my car. The rears are non adjustable and will end up at +/- 127mm. The fronts for the correct rake should be at 144mm, but there are enough threads to lower the front +/- 10mm if you wanted to.
So the rears are about 10-12mm lower than optimal but roughly within minimum height. Since the rears aren't adjustable, it's a good thing they are no lower than that.
The fronts are right on target but there is room on the damper height adjustment threads to lower them at least 10mm, maybe lower.
Should I leave the fronts as-is, or have them dropped to be in the same range (ie to bottom of tolerance, around 134mm) as the rears?
I'd get that front lowered so it is comparably under the spec. That will put you at RS+10 all around (if my math is correct), which is where I am at and I love it.
Next on your project list is fixing that front bumper.
I finally got around to EXACTLY measuring my ride height. The previous owner put these Bilsteins HDs + RoW M030s on over 10 years ago. Putting this here to add to the tribal knowledge.
The results are measured against the official measurement points as seen in the photos (rather than "generic" RS+X type measurements which don't take into account the fact that there are actually FOUR measurements).
LF - 117mm RF - 121mm LR - 115mm RR - 117mm
Note at this level, there is a rake down to the front, and the rake is measured at -1.0 degrees. I would be interested to see @P-daddy 's ride height measurements as your Koni SA + H&R combo is perhaps visually quite similar --- thank you for informing me @P-daddy about what is OE level of rake and what is not!
Here’s my 96 with Bilstein B6XT on stock US springs. Installer told me rears are about as low as they will go but fronts could go down another quarter inch or so..
10-21-2015, 10:35 AM
