[William Miller]

These are 16'' by 8" in the front and 9" in the rear.......Tires are Toyo TS-1's and only one month old. Fronts are 225/45/16, and rears are 245/45/16.

The suspension has mostly be redone:
My Torsion bars are 22 F / 28 R
Front:Elephant poly bronze bushings, stock strut tops. Bilstien HD, stock sway from a turbo. Torbo tie rods. no bump steer washers. (are they 5/8"?)

Rear: Stock control arm bushings, Netrix rubber spring plate bushings,
Looking for 86 carrera sway or used weltmiester 22mm adjustable (Cheap?) Koni Adjustible shochs. (Set on 2)

I had the turbo sway on the back but it rubbed the trans cross member.
I put the stock SC sway back on yesterday. (I plan to reinforce the rear sway mounts when I get the stiffer sway bar.)

With Ted's wheels it's now time to dial in the suspension.

In the picture I sit 24.5 Front 23.5 rear. (These are both in the center of the height adjustment range.) The left rear wheel is tilted way out at the top because the camber adjustment is way out. Other rear tire is not that close. I plan to get alignment over the next several days, but I want to get the height close so I don't have to pay the shop to re-index that T-bar splines.

I want to set the car up for mostly street ( 75% daily driver) and to start out in HPDC and DE's hopefully this year. (I don't want it so low that the front rubs every speed bump or ramp.) I upgraded everything because, frankly, it was all worn out. (258K miles). I was going to spend the money anyway.

I ultimately would like to give the alignment tech the ride hieght spec. Using the factory measurement system. (This accounts for tire wear.)
BTW Ted's tires are new and have a ton of tread.

So let me have it!

Thanks!

[Alan Herod]

Short answer - raise it.

ok - first what do you mean by the 'In the picture I sit 24.5 Front 23.5 rear. (These are both in the center of the height adjustment range) '? Do you mean that you have reindexed the bars and you are now in the middle of the adjustment range, because you are already about 1.5 inch below Euro ride height? Today Euro ride height may look like an off-the-road vehicle to you and lower in theory is better as long as you can retain suspension geometry. You could do this and get the car really low by using offset spindles in front and relocating suspension pickup points.

Your car looks great and to me your ride height looks great; but, on the track looks can be deceiving. You can lower you ride height to the point that your theoretical roll center is below ground level. When you achieve this, your handling at the limit is truly diabolical. I have personal (and very scary) experience with this in SCCA car. If it wasn't bad enough that handling is compromised, your shocks may now be permitted to bottom out and destroy themselves.

You should read Bruce Anderson's, 'Porsche 911 Peformance Handbook'. for the final word on this. Measure ride height as the difference between center of axle/wheel and center of T-bar. Euro Front 108mm +/- 5mm. Rear 12mm +/- 5mm. Quote concerning rear from BA book 'We have found that for lowered cars the center line of the tosion bar can go as far as 1 1/2 inch below the center line of the axle and that 1 1/4 inch works very well.'

[markwemple]

I'm with him. Most cars look best and work best a euro ride height which is in Bruce's book. Unfortunately until I fix my driveway (or move) mine will have to remain US regs .

[William Miller]

Thanks guy's. I'm really trying to maintain the correct suspension gemoetry. (Looks would be secondary.)

I looked up in my "little spec book"
It confirms 108mm in front but 16mm in rear 12 is listed as for Turbo.

I lent my brother the"bible" (Bruce Anderson's book)

If I have the math right Anderson is suggesting that 1.25 - 1.50" is good. That's 47.75-54.1 mm lower than the euro (16mm) spec.

If that back is that low, what would the front be?

Alen, please confirm that your thinking is that the Euro spec. is optimal for suspension geometry.

Thanks!

[Jazzbass]

I found Euro spec to be a tad high for my tastes, but not by much. My car is set at 24.75 front and rear. The equal measurement here is because I, like Ted, run 225/45s up front, which are 1" smalled in diameter than the stock 205/55 or 225/50s.

Personally, I'd raise the car up to at least 24.5 in the rear and likewise in the front, and make sure the a-arms are angled down from the attachment point on the car, not up. Do this by reindexing, which should be easy with the Elephant bushings all arond. Leave the adjusters in the middle for the guy who does your alignment and corner balancing.

[Alan Herod]

I get confused whenever I read the book. Your math is correct if you use 16 - but I figure you should go with the 12 number because you are running stiffer T-bars. Regardless, I would measure the numbers the old fashioned way and go from there. There is no clear indication in the book on what to do with the front once you have lowered the back to achieve the 1.25 T-bar lower then axle.

The good thing about using the relationship between centerline of T-bar and axle is that it is independent of tire diameter.

The book suggest a 1 degree slope toward the front which 'results in 0.5 inch higher ar front fender lip then the rear'. I have no idea if this relationship should be maintained when the back is lowered to BA's suggested 1.25 measurement. The solution might be as easy to solve as observing that the factory raised the front spindle 18mm for the RSR struts to avoid lowering the roll center excessively. I suspect when BA lowers to the 48+mm lower then Euro, that he is using offset spindles in front.

[William Miller]

Alen, I got my book (BA 911 performance handbook) back from my brother. On page 202 under "Adjusting Rear Torsion Bars" he makes the comment " If you use stiffer-than-stock torsion bars, you will be able to lower the 911 about 1 inch without suspension travel problems, but you may have to modify the alignment slots to facilitate a proper alignment and you will have to be careful going in and out of driveways."

I have installed 22/28mm bars so I believe this would be safe in my situation. 1" = 25.4 mm. To keep the same geometry / slope I sould drop the front and rear the same amount. I do not have the shock spacer (Mine started out as a ROW car) and I'm getting the rack spacers.
So by caluclation I would adjust the Euro spec by 25 mm.
Add 25 to the front = 108+25 = 133. Subtract 25 from the rear 16-25= -9 so the wheel center will be 9mm above the cross tube.
I would consider this the limit the BA would recommend lowering with his caution about driveways.

I might go most of the way and see where it get's me. (I'm not re-indexing the bars again!) As a compromise, I'm thinking make the rear wheel center even with the center of the cros tube. That would make the front height measurement 108+16=124.
(O/124) also seems like it's easy to remember!

Any comments? Do any of you low rollers rub your valance all over the place? Wish you were a little higher? Some I'm sure wish they were lower!

[Jazzbass]

Originally Posted by William Miller

Do any of you low rollers rub your valance all over the place? Wish you were a little higher? Some I'm sure wish they were lower!

Yes, I rub in certain areas - not the spoiler, but the tow hooks on the bottom. Mostly driveways, but never anything I couldn't handle. I like the ride hegiht, and don't want to be higher or lower.

[racer]

Originally Posted by William Miller

Do any of you low rollers rub your valance all over the place? Wish you were a little higher? Some I'm sure wish they were lower!

I try not to rub.. it would ruin my oil cooler There is the occasional thud, but its usually the tow hooks.

[William Miller]

Thanks! I was thinking of getting a tow hook for both sides.
I have no oil cooler and no A/C condensor.
Chris did you ever find your measurements using the factory method?
I think I recall you mentioned 135 on the front (was the the total height from the ground up or difference between the tbar center and the whel center?) , but don't think you posted the rear.

Thanks again!