Issues with hitting the bumpstops on lowered 944's?

[Steve Rea]

I'm coming along on my car and will be ordering the suspension today or tomorrow, and thus this question. On the miata's, when we lowered them too far, it reduced the shock travel to the point of hitting the bumpstops, unsettling the car and therefore naturally hurting the handling. Spec-miata guys often run higher just so they can get full travel of the shocks.

 

Chuck at Paragon Sports said the difference between the ground control and racer's edge camber plates is:

 

ground control - has camber and caster adj., raises the car about 1" . racer's edge - has camber only adj. and doesn't raise the car.

 

So if it raises the car, of course we can lower it with the adj. spring perches, but this will then cut into the shock travel.

 

If this is all true, then my decision will be based on:

 

1) How much caster can we get with -3.5 camber up front (w/o caster plates)?

 

2) With the car lowered, and with the GC camber plates installed, does the car hit the bumpstops?

 

While the top guys are winning with the GC on their cars, one could say it works. Yes, but they also would likely make a brick on wheels go fast with their driving.

 

Any experiencially based input appreciated.

 

Thanks,

 

Steve

[944-Spec#94]

Well here is my take.

 

I lowered my car as far as I could before I thought I'd run into problems. I have maybe 1"-2" travel before the bumpstops front AND rear.

 

I run the GC camber plates and have thought about this exactly. With the spring rates I run 350 front and 30 mm rear bar I have NOT had any issues at all. Even a Las Vegas at the turn 1 chicane. I do think I bottomed the REAR once in an off track excursion as there a little mark on the frame, but front seems non the worse for wear.

 

typicaly you can get -2 to 2.5 with stock struts, maybe more, but is it hard as they tend to not be very even. So one side is good for -3, but other is only -2... Guess what you are stuck to -2.

 

3.5 negative is easy on GC plates

 

So I think that even with the GC plates rear ride height at least with my car limits me to the same ride height and at my current height I have not noticed any bottom issues.

 

I think my ride height about 100 mm per the standard aligment readouts.

[Steve Rea]

Thanks Joe, that's the exact actual experience I appreciate.

 

So most simply, you're saying that the rear shock travel is the limiting factor, so even if the Racer's Edge camber plates allowed more travel, you couldn't use it all because you'd be hitting the bumpstops in the rear?

 

Thanks,

 

Steve

[944-Spec#94]

Currently I want go lower I'd worry about the front and the rear travel. With GC plates both front and rear are limiting. I'd guess that with the Racer's edge plates the front could go lower, but I still would not go any lower in the rear. So because I like to have the car level front to rear I can't go much lower.

 

Another thing to note is that going lower in the front makes ball joint angles worse. I am probably beyond the limits of the joints, but since I run cheap steel arms and $11 replaceble ball joints I don't care much. I would be more concerned with the aluminum arms.

 

Also logistically getting the car on and off the trailer this low is challenge. I have it worked out, but every now and I then is still drag the rear sway bar on the wood floor of my trailer.

 

I can't say 100% that I will never hit my bumpstops, but with my weight and spring rate it does not seem to be an issue. Go with softer spring and this ride height and it might be. Go with a heavier car and it might be. My car currently is about 2400lbs min weight so I have added in 60lbs of balast to ensure I make the 2600lbs with me in the car and virtually no gas. Somecars are heavier. If you are 150 lbs over then you might run into issues. I can't say for sure.

 

HTH!!!