ride height discrepancy

[shadrach74]

Greetings all,

So, I had my car on jacks for a few weeks working on it here and there. After finishing up I took it out and put about 10 miles on it to get all of the air out of the coolant system and then let it sit in the garage for a week. I noticed a slight discrepancy in the ride height from the px rear and driver rear tires. measuring from the ceter of the wheel, the pax side rear wheel center about 1/4" to 3/8" further from the top of the fender cutout. Which means that side is riding slightly higher than the drive's side rear.

Is this common/normal. or something to be concerned about? I notice nothing in the way of adverse handling when cruising or driving the bejesus out of it...

Thoughts?

[JFP in PA]

Porsche has always recommended against letting the car sit for prolonged periods with the suspension in full extension as the struts do not like it, and the strut shafts can develop corrosion on their surface which can lead to issues.

You car may settle out over time or as the shafts clear up.

[cameronzero]

also, Porsches/Boxsters should be corner balanced with 165lbs of weight in the drivers seat, which will lead to the driver side sitting higher when unloaded, if not the handling can be effected adversely.

[thstone]

Stock suspension?

If the suspension is stock, then I'd give it about 200 miles or a week to see if it returns to a more normal ride height. As JFP said, having the car in the air for a long period can extend the shocks beyond their normal range and the car may not "settle" back immediately. Corner balancing a car with stock suspension is impossible because the ride height is not adjustable.

If you have an aftermarket suspension like PSS9's, then I'd still give it a few hundred miles and a week's time to see if it regains equilibrium. If not, then having the ride height manually adjusted or having the car corner balanced would seem to be the next step.

[cameronzero]

Originally Posted by thstone

Corner balancing a car with stock suspension is impossible because the ride height is not adjustable.

i'm gonna go read again, but i remember reading that the car has to be balanced and aligned with 165lbs in the drivers seat to facilitate the best possible handling, regardless of suspension setup. i could be confusing it with the track suspension information i was reading also.

EDIT: if it's factory suspension, you could also be suffering from sag due to the age/wear of the suspension.

[woodsman]

time will tell--I hope you don't have a toasted strut

[shadrach74]

Thanks guys! I believe the set up is stock sport suspenision (02 S). I'll put some real miles on it in June and we'll see. I do not believe that the struts are toast as the dampening still feels solid, as does the the handling. Is there a spec for ride height difference? Seems to me I've heard that some variance is not uncommon from wheel to wheel...

[thstone]

Originally Posted by cameronzero

i'm gonna go read again, but i remember reading that the car has to be balanced and aligned with 165lbs in the drivers seat to facilitate the best possible handling, regardless of suspension setup. i could be confusing it with the track suspension information i was reading also.

EDIT: if it's factory suspension, you could also be suffering from sag due to the age/wear of the suspension.

Here is a good tutorial on corner balancing: ELEPHANT RACING Tech Topic, Corner Balance

"Corner balancing is the process of shifting the weight carried by each wheel to approach optimal values. Although some weight can be shifted between wheels by physically relocating parts of the car, the corner balance process is focused on shifting weight by adjusting the suspension spring height.

Street cars are rarely corner balanced and typically have no provision for adjusting spring height. That's because their spring rate is relatively low, perhaps 100 lbs/in. With such low spring rates it would take a huge imbalance in spring height to have a significant affect on corner balance.

Performance and race cars may have spring rates of 300, 400, 500 lbs/in and higher. Corner balance becomes much more important due to the high spring rates - small changes in height greatly impact weight carried. Additionally, we are much more concerned with handling and performance with race cars so corner balance becomes very important."

You have to be able to adjust the spring/ride height in order to change the loading of the spring - which almost universally means a "coilover" shock with an adjustable perch. Stock Boxster struts have no such adjustment.