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Dynamite76 · Joined: 13 Mar 2007 Posts: 21 Location: Richmond, Virginia

I have an '88 924S. The clutch is shot as best as I can tell; thrashing in rear end as I apply and remove throttle inputs. So, I have the task of replacing the clutch coming up.

I would also like to work on the rear suspension at the same time. Initially I wanted to prep the car as a spec racer, but am now considering saving some time and money by adding coil overs and leaving the torsion bars alone.

I am thinking, that I am about 1 1/2 years away from driving in the more advanced groups on the track, possibly at some point either becoming an instructor or racing the car, or both. But, I am a good number of track sessions away from that.

The car is a track only car for the most part, unless my daily driver needs major work like rebuilding the front right brake caliper

. There is always things that I need to spend time and money on with the 924S, like a roll bar, AC delete, stripping interior, tires, engine maintenance, all the good stuff to turn the car into a better track machine.

So, I was thinking, mostly concerning the savings in time, of adding coil-overs to the rear and leaving the torsion bars alone. Will this even work, or will the geometry of coil-overs and torsion bars together cause the rear end to be all funky? If they will compliment each other, what spring rates should I be looking for? Torsion bars are stock, 23.5 mm and I imagine, worn below the factory 126 lbs spring rate.

I will index and lower the rear, and already have lowering springs and camber plates for the front. Need to replace the front inserts though. My goal is a better handling car than what I currently have. Another thing that limits what I can do is that I have to do the work in the parking lot and it is against local regulations to leave a car jacked on stands. 4 tires have to be on the vehicle and supporting it if unattended.

Sorry for the long post and thanks for any feedback.

Paul C.
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88 924S

Dynamite76 · Joined: 13 Mar 2007 Posts: 21 Location: Richmond, Virginia

Update:

I "discovered" Koni 30 series mono dampers. Anyone else using them? For the cost and ease of installation, I cannot see a reason not to use them, especially since I am not bound by class rules as a DE driver.
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88 924S

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

dgz924s · Joined: 03 Nov 2002 Posts: 592 Location: Kansas

Most often the T bars are removed and coilovers are used in their place. The CO will allow easier adjustment vs a T bar. Having said that most series for stock prod cars do not allow CO's. Also do not confuse real coilovers for rear helper springs that look like CO's but are not, but only a booster to the T bar.

Adding CO's to a T bar is added weight and 2 things to adjust vs 1, the T bars and the CO's. T bars also keep the weight lower than a CO will even if the CO are lighter....nick picking here but relevant.
Cost of a CO is much higher too.

Dal
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Dal Glassinger

Dynamite76 · Joined: 13 Mar 2007 Posts: 21 Location: Richmond, Virginia

My desire for frugal optimization congruent with my skill level means that I will be reverting back to a more stock front suspension. Maybe after I tackle the seemly daunting task of replacing the clutch I will have the confidence to start considering the rear suspension. I just knew the front was too easy for a reason and was searching for a way to do the same in the rear

I was considering assisting springs as a temporary fix, between stock and 30 mm torsion bars. However, since adding them is half of the process of upgrading the t-bars themselves, there seems to be no point. When the time comes, I'd rather be the only spec racer than the only frugal non-spec racer.

Aside: getting there for me means getting a garage with a house attached. HPDE 3 or 4 is the contingency plan. Another HPDE 1 is the next step in the process though.

I was at VIR with NASA last week. I had so much fun and gained so much experience, breaking some nasty Honda habits to boot. Like downshifting into the turns and keeping the RPM's pegged just below red. It took the rear end of my car trying to pass me in 11 in the rain to learn this lesson

. Not sure because I didn't test it, but I think they meant 2 feet in... only if you have ABS. Brakes in a spin = snakes on a plane, or that is the association my brain cannot get over.

The next and last session was by far the most rewarding. I got more positive feedback from my instructor, was easier on the equipment, and I suspect, turned faster laps times. One of my instructor's last comments was "Wasn't that more fun? You did much better when you were not worried about going fast, like most of the times before."

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88 924S

Paul · Posted: Mon Apr 09, 2007 9:19 am Post subject:

The rear suspension is a cake walk compared to a clutch job!!!

I suggest you find someone who has done this before to at least watch (drinking your beer on a lawn chair) while you do this. (BTW how far away are you?)

And of course read all about it at:

http://www.clarks-garage.com/shop-manual/clutch-01.htm
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.