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Ride Height Adjustment
Bruce Anderson in the July, 2000, issue of Porsche Panorama recommends
an alternate to the factory method (described below) which is to measure
from the ground to the top of the fender lip. He recommends 25 inches
for the rear and 25.5 inches for the front for the best ride height.
He says the the car should have a slight nose down attitude (about one
degree). The fender cut out is flattened on the rear which explains
the the additional distance on the front measurement above.
My car as received measures 27 3/8 in. at the front and 26 in. at
the back. The front should be lowered nearly an inch to achieve the
desired nose down attitude. I plan to restore the front pan in the
next couple of months. A four wheel alignment will be done at the
time which may include lowering the car.
Front Ride Height
Here's the factory method.
- Make dead center mark on dust covers of front wheel hubs.
- Depress front of car several times, by pushing down on the bumper
horns and allowing the body to come up by itself on the rebound, to
set the suspension at proper attitude.
- Measure the vertical distance between the front wheel center and a
level part of the level floor (see dimension "a" in the following
diagram.
- Value "a" minus 104 mm equals value "b". A height marker adjusted
to value "b" can be effectively used for taking measurements at the
torsion bar center.
- Remove torsion bar dust cover at the adjusting lever to gain
access to the torsion bar centering mark which should be used as a
reference point.
- Loosen or tighten the torsion bar adjusting screw until value b is
obtained at the torsion bar center.
- Depress the front of car, allowing it to come up by itself, and
recheck height of both sides for value b, correct if necessary.
Note!
Even though a plus/minus 5 mm deviation is possible for value b on
either side, difference in height between right and left sides must
not be more than 5 mm.
Example
Value a = 315 mm
- 108 mm
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Value b = 207 mm +/- 5 mm (- 202 to 212 mm)
Based on the above example where value b measures 207 mm with
permissible deviations anywhere between 202 and 212 mm, the following
adjustment possibilities become evident:
- If value b on left side is 202 mm ( = 207 minus 5 ), then value b
on right side can be 202 to 207 mm (up to +/- 5 mm difference.
- If value b on left side is 207 mm ( = 207 +/- 0), then value b on
right side can be 202 to 212 mm (up to +/- 5 mm difference).
- If value b on left side is 212 mm ( = 207 plus 5), then value b on
right side can be 212 to 207 mm ( up to - 5 mm difference).
Rear Ride Height
- Depress read of car several times by pushing down on the bumper
horns and allowing the body to come up by itself on the rebound to set
suspension at proper attitude.
- Measure the vertical distance between the rear wheel center and a
level part of the floor ( see dimension "a" in the diagram below).
- Value "a" plus 12 mm equals value "b"; however, value "b" cannot
be measured since the torsion bar is off center due to mounting in a
rubber bushing.
- Value "b" less bushing-cover radius ( 1/2 diameter) equals value
"b1".
- Measure height of vehicle (value "b1") with the help of a height
marker or similar device. The actual value b1 should not differ from
the calculated value b1 (pts 3 and 4 above) by more than +/- 5 mm; in
addition, the height difference between the right and left side should
not be more than 8 mm.
Example:
Value a = 315 mm
+ 12 mm
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Value b = 327 mm Value b = 327 mm
- Bushing - cover radius = 30 mm
---------------------------------
Value b1 = 297 mm
Permissible tolerance for Value b1:
- If value b1 on left side is 292 mm ( 297 minus 5), then value b1
on right side can be 292 to 300 mm (up to + 8 mm difference).
- If value b1 on left side is 302 mm (297 minus 5), then value b1 on
right side can be 294 to 302 mm( up to - 8 mm difference).
If proper suspension adjustment values cannot be achieved,
proceed as follows:
- Check height adjustment of front suspension and correct if
necessary.
- Check rear torsion bar adjustment and correct if necessary.
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