924Board.org

[Brockoli]

I purchased the QA1 coilovers as recommended in the performance section sticky thread. Proma DS502 - Single adjustable coil over shocks with poly end bushings. I used Eibach 2.5" coil springs - 8" long, 200#.

Here are the coilovers compared to the Bilsteins



Test fit the coilovers





The QA1 coilovers come with a 1/2" bushing or a larger one. The rear shock bolts are 12mm so they would be sloppy if you used them. You can either drill out the shock mounts on the body or make custom bushings that fit the stock shock bolts. I didnt want to drill out the body so I had bushings made from 4140 and had them phosphate coated







Installed the bushings by pressing them in with my vise. Test fit in the car revealed the springs rub the lower shock mount pocket and the trailing arm





I made a test spacer from wood cut from a 2x4. This 1.5" long spacer looked like the right height to have the spring hat raised out of the lower shock pocket













I then made real spacers out of aluminum pipe. 1.25 Schedule 80 aluminum pipe is the perfect size to fit inside the QA1 spring hat and matches up to the shock lug nicely. This is where things might not work out... You need to unscrew the lug on the shock and install the spacer. This prevents the spring from contacting the trailing arm and the lower shock pocket. However, it reduces overall shock travel. I have about 2.5-3" of compression travel until it bottoms out. Even with stiffer springs this might be an issue.









I used JB Weld to hold the flat plate in the pipe. I'm not sure this is necessary but I didnt want the plate to pop out of the pipe during assembly. The palte had to be pressed in with a hammer so I doubt it would go anywhere. The JB weld is on the inside of the pipe.





You also need the custom eccentric bolt from Ground Control to lower the rear suspension more than possible with the factory eccentric bolt. The idea is to lower the rear too far and then raise it to the correct ride height using the coils. This allows a bit of preload on the coils



Installed everything and checked the height.









The rear is lower but not sure what height I want it at until I install the front coilovers. I bought the ground control kit for the 924 and used 8" long 2.5" ID springs that are 300#. This should match the rear TB+coil spring rate. Here is the car with the front coils installed too.








I have a few test km's on the car. The rear bottomed out lightly once. I'm not super happy about that However, the car is much stiffer and handles great so far.

I think I might change the rear springs to 2.25" ID springs. I will also need the spring hats to be machined to accommodate the smaller springs. This might also allow me to remove the aluminum pipe spacers since the spring hats might ride in the shock pocket nicely and the springs might not rub the trailing arms. Who knows.....

Is this easier than changing the rear torsion bars? I have done that on our teams 944 racecar. It is a lot of work and takes about 3 tries. Its also much harder if you want to change spring rates in the future. Cost wise its probably about the same when you factor in machining new bushings+shocks+springs. Also, I think corner balancing is easier with adjustable spring perches than adjusting the ride height eccentric.
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'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)

[morghen]

Looks badass!
Thanks for sharing.


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https://www.the924.com

[Carrera RSR]

Am I missing something? Should the rear shocks be installed the other way up and therefore not need the spacer? What you have done is shortened the shock stroke and increase the risk of bottoming out the shock on a big hit?
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
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[Brockoli]

Thanks Morghen!



Carrera RSR - They are installed upside down. That is the only way the spring will fit. In the third picture I have the adjustable spring perch as far up as it will go before it hits the banana arm (I think thats what its called?). The springs are about the same OD as the spring perch. Also, I'm not sure the adjustment knob on the shock body would fit in the lower shock pocket either.

The spacer pipe is required with the 2.5" ID springs so they rest on the lower spring hat. I dont like how it reduced shock travel. I need to see if 2.25" ID springs will alow me to remove the spacer pipe and free up some travel without the springs rubbing/binding on the trailing arm and still seating properly in the lower spring hat.
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'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)

[Carrera RSR]

Looks like you need 2.25 springs for a good install. If you bottom out the shock on a big hit, it will chuck you off the road/track for sure.

I have hit the bump stops at the rear at 100mph on a fast bend and my life passed in front of my eyes as I reeled in the ensuing tank slapper. I've done the same corner at similar speeds in a 2014 Audi A6 and whilst it unsettled the cars balance, I never felt at any time I was heading into the scenery. My rear coilover/torsion bars have been 'reset' since this event as have the underwear!
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[Carrera RSR]

I'm also a little nervous of the front where the spring comes unseated on full suspension droop. If the car lifts too much there will be big issues as the car returns to earth and the spring tries to refind its seat. Will create noise at best, damage at worst. That would not pass a UK road safety test. Alternative is to tether top an bottom of the strut to avoid the spring unseating or use helper springs/seats to slot fill in the gaps. Again, how much shock travel do you have when on the ground before bottoming out?
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[Brockoli]

Rear still needs some figuring out. I'm not 100% sure about these spring rates either.

As for the front, the sway bar was not attached in that picture which allows the control arm to droop more. Ill check the clearances next time I jack up the car.
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'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)

[ideola]

I think it would be worth revisiting flipping the rear shocks around. I did some minor grinding on the upper shock mount "box" in order to clearance it for the spring hat. It appears to me that the lower end would fit in the steel trailing arm. Did you actually try it?

I would also suggest shorter springs in the rear, along with helper springs (and the requisite spring divider) in both front and rear to prevent the springs from unseating in a full extension scenario.

Were you able to acquire the GC eccentrics by themselves, new, used??? I don't see them listed anywhere as a separately purchasable item.
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erstwhile owner of just about every 924 variant ever made

[Brockoli]

I might of tried them in the other orientation (right side up) but cant remember. Most of the rear coilover kits for 944's have the assembly upside down as well, GC for example. The KW, Spax, LEDA kits look to have a spacer that moves the upper spring hat down to keep the coil spring from interfering with the banana arm. Or maybe they use a smaller ID spring.

I've seen one fabricated kit where the springs cleared the banana arm however those were 1.88" ID springs. The body on the QA1's were approx. 2" OD so that spring wouldnt fit. I measured the shock body diameter but cant remember the exact size. I think 2.25" ID springs were the smallest that would work.

The 944 turbo cup rear coilovers also have a spacer that moves the upper spring hat down towards the trailing arm to avoid the spring hitting the banana arm, at least thats my take on it.

I'm not sure the dial for adjusting the shocks would fit in the lower pocket either. I definitely woudlnt want the lower shock pocket to hit the dial during trailing arm movement. No one has documented these QA1's being installed on a 924 with steel trailing arms so its a bit of trial and error.

Yes, GC sold me the eccentrics along with the front coilover kit. I had to call them on the phone and explain why I needed just the eccentric. The eccentric is from the 944 rear coilover kit thats why they arent listed by themselves.
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'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)

[Brockoli]

Bilstein escort cup - 951



GC coilovers




KW V3




SPAX RSX


944 turbo cup???



Fabricated kit with 1.88" ID springs will fit past the banana arm

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'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)

[Carrera RSR]

Had to remove the knurled adjustment knob and replace with a screw to enable the Gaz to fit the steel trailing arm. A hole was drilled into the arm so the shock can still be adjusted. I'm running the Gas the right way up with a helper spring to ensure the coil doesn't unseat. Front Gaz is fine in travel and full droop. No unseating.
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[Brockoli]

GAZ Gold also seem to have a spacer at the upper spring hat. What size of springs do those use?


_________________
'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)

[Carrera RSR]

[Carrera RSR]

I think the key thing is having enough travel in the shocks designed stroke and ultimately not bottoming out having looked at the Escorts and KW options

My Gaz rear springs are tight to the top mountings and have rubbed a little.
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[Brockoli]

I changed the rear springs to 2.25" ID coils and had the spring hats machined down to fit the small ID of the new springs. The smaller springs allowed me to remove the aluminum pipe spacer which increased my suspension travel by 1.5". No more bottoming out on bumpy roads! The springs seem to fit nicely and I do not think they are rubbing on anything. The shocks are still upside down since the spring would not fit on the body side but the smaller spring fits in the bottom pocket on the trailing arm.

I went from 250lb weltmeisters up front to 300lb coilovers and these QA1's with 225lb coils in the back. My lap times improved by 2 seconds. Not sure if this was from more camber up front or just stiffer springs and a slightly lower ride height. Either way the car feels good on track and has less understeer now that I have also made the rear suspension stiffer. My lap times had plateaued so I'm pretty sure this change was due to changing the suspension.

Was this the cheaper route? I'm not sure. It was an adventure and in the end it was fun. I had to pay for custom bushings to match the 12mm bolts and machining down the spring hats to fit the smaller springs. The QA1s are a decent price but the machining makes them less of a good deal. If I payed for torsion bars it might be cheaper but just as much work (maybe more) to install those and I wouldn't have adjustable rear shocks. Either way they are in and the car feels great. I might play with the adjustable rear shocks a bit more for fun. I think I have them set in the middle for stiffness.
_________________
'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)