Ride height

mark houghton · 09-17-2009, 10:17 AM

I've never changed the ride height to my car, and seem to remember measuring it years ago out of curiosity...and coming up with it being lowered to European specs. Even though, it looks to be higher than a lot of your cars so I'm guessing that many people lower theirs considerably more than even the stock European settings. Stock tires and wheels for 1987.
How much lower can I go beyond Euro and not have to worry about alignment or bump stear issues?

DDDD · 09-17-2009, 12:11 PM

Quote:

Originally Posted by mark houghton

I've never changed the ride height to my car, and seem to remember measuring it years ago out of curiosity...and coming up with it being lowered to European specs. Even though, it looks to be higher than a lot of your cars so I'm guessing that many people lower theirs considerably more than even the stock European settings. Stock tires and wheels for 1987.
How much lower can I go beyond Euro and not have to worry about alignment or bump stear issues?

Your bump steer will run out of play pretty quick but you can just get a bump steer kit and set it up real nice.

full quack · 09-17-2009, 12:11 PM

Wow Mark, now thats a loaded question.
How low you want to go, is directly proportional to, how much your willing to spend. My personal experience says, 1" below euro spec, yields no alignment or rubbing issues. However, at that ride height you would want to install a tie-rod bump steer kit.
Furthermore, Dependant on your tire size & wheels & spacers, you could rub on your windshield washer bottle with full steering lock.
Any lower than that, you end up with what I have, and most people will not be willing to accept the trade off of looks, for proper geometry/handling/road clearance.
My .02 worth
Mark

mark houghton · 09-17-2009, 12:56 PM

Quote:

Originally Posted by full quack

Wow Mark, now thats a loaded question.
How low you want to go, is directly proportional to, how much your willing to spend. My personal experience says, 1" below euro spec, yields no alignment or rubbing issues. However, at that ride height you would want to install a tie-rod bump steer kit.
Furthermore, Dependant on your tire size & wheels & spacers, you could rub on your windshield washer bottle with full steering lock.
Any lower than that, you end up with what I have, and most people will not be willing to accept the trade off of looks, for proper geometry/handling/road clearance.
My .02 worth
Mark

Yeah, and if I recall you're so low you scrape manhole covers when going over them!
I kinda figured I could drop her another inch, and doing the bump steer kit (either tie rod ends or steering rack cheapo kit) is not a problem. Dropping the front end...simple...but the rear...I have visions of spring plates and torsion bars going boing.

Turboo934 · 09-17-2009, 01:37 PM

Bump steer kits DO NOT work on 930's, do to the fact the rear of the A arm is raised in the chassis. Is better to have spindles raised, keeps the geometry right.

full quack · 09-17-2009, 01:59 PM

Hey Mark,
Yes, the front is easy to a degree. As I have read in several Porsche books, on unmolested American 930's, you might find a little plastic/rubber donut spacer sitting between your strut tops & the inner fender pocket. It's about 1/2" thick and was there to help raise the car to American spec.'s. Or so I have read!
Removing this will instantly drop the car a bit.
As far as tie-rod bump steer kits, I used the RSR unit from Rebel racing. I installed this kit and test ran the suspension through it's entire arc range & from full lock to lock, & everything in between. Granted this was a static test with the car in the garage, but I found that at NO point did the linkage arc travel bind or try to exert any abnormal geometry. Before installing the kit & having already lowered the car, there was a high degree of arc error & potential bind when the full test was performed.
So I can neither confirm or deny, if the geometry is ideal with the bump steer kit. However my static test reassured me that there was nothing grossly wrong, and driving the car it exhibits NO felt bump steer.
As far as lowering the rear, it's simply a matter of indexing the torsion bars to yield the ride height desired. Yes, there is a lot of trial-n-error. Yes, it takes all damn day until you get it right. But man you'll know your cars suspension when your done!!!
Last is a good alignment......happy slamm'n.
Mark

billjam · billjam's Garage

Quote:

Originally Posted by Turboo934

Bump steer kits DO NOT work on 930's, do to the fact the rear of the A arm is raised in the chassis. Is better to have spindles raised, keeps the geometry right.

How can you say they don't work!
There have to be hundreds of 930s running around with bump steer kits fitted and working OK.
For sure it's better to raise spindles, but only because it keeps the tie rod and steering arm closer together in the horizontal plane (to minimize twisting loads on the steering arm) and it keeps the suspension working at closer to the middle of shock absorber travel rather than having it riding too close to the bump stops.
Personally, I'd rather have my suspension bottom out before the underside of my car hits the road, so I am happy to live with limited, but sufficient, bump travel. I also have slightly stiffer torsion bars (21mm), so they help to keep me off the bump stops more than if I was running standard TBs.

BTW, if you have lowered your car, the difference that the bump steer kit (or spindle raising) makes is amazing. You won't notice any difference around town, but those nice country drives become much more relaxing when you don't have to continually fight the car on undulating or bumpy roads.

I dropped mine a little too low at the rear but I haven't mustered the enthusiasm to lift it yet, but here's where it's at now ...

Turboo934 · 09-17-2009, 08:32 PM

If you look where the back of the A arm mounts, the chassis is notched moving the rack higher already. So putting the spacers in will bind the steering under load.

billjam · billjam's Garage

Quote:

Originally Posted by Turboo934

If you look where the back of the A arm mounts, the chassis is notched moving the rack higher already. So putting the spacers in will bind the steering under load.

T, that's correct, there isn't enough space to lift the rack, I've tried.
When I read your earlier post I assumed you were referring to the bump steer kits that replace the tie-rod ends like this, not the rack spacer type. My mistake.

mark houghton · 09-18-2009, 07:34 AM

Quote:

Originally Posted by billjam

T, that's correct, there isn't enough space to lift the rack, I've tried.
When I read your earlier post I assumed you were referring to the bump steer kits that replace the tie-rod ends this this, not the rack spacer type. My mistake.

So, a person is better off using the rack spacers vs. the tie rod end replacements...is that what you're saying?

Turboo934 · 09-18-2009, 07:52 AM

No!

full quack · 09-18-2009, 08:31 AM

Hello Mark,
Under no circumstances should you raise the rack, that is a REALLY BAD band-aid fix attempt! This leads to problems you don't even want to know about.
Use the tie-rod bump steer kit, and you will have no worries. These kits are adjustable through shim packs, and allow for fine adjustment of the tie-rod spacing for just about any ride height one decides on. Even stupid low like mine!
Mark