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George

A different approach to 1G front coil-overs.

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I'm going to post here as well for easier searching.

 

I was able to use the factory upper strut mount and bump stop by using some springs that have a 4 1/8" ID top and a 2 1/2" ID bottom.

The springs are listed as "GM series" coil springs and are available from 250 to 600lb. The 250 and 300lb springs are 11" long. The 350lb and above springs are 10" long.

The springs I used for my 1994 Cutlass Supreme Convertible were the springs rated at 300lbs /in.

I ground down the factory upper spring isolator to make a tapered spacer (3/8" thick on one side and 1/8" thick on the other) to keep the spring parallel with the strut. Install the tapered spacer on the upper strut mount, then install the poly spring isolator and spring with thrust bearing, adjusting sleeve and nut. The guys at QA1 racing said to use never seize on the thrust bearing.

I cut the bottom two rings off the bump stop.

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Parts List:

(2) HAL-11HTBF300 springs $65.97 ea at summit racing

(1) ENS-9-6101G Spring isolator $20.97 pr at summit racing.

(1) HAL-7888-109 Thrust bearing kit $25.97 pr at summit racing.

(2) COK-12452-H Coil over adjusting sleeve about $40/pr A1 Racing.

(2) COK-12460 Coil over adjuster nut about $26/pr A1 Racing

Total investment around $250

 

Wheels: 17X8 + 38 offset

Tires: 255/45-17

 

Tire clearance at 1 3/4" drop. I've since went 2" drop and no tire rubbing on either the springs or the fenders yet.

This is as low as I feel comfortable with so this is where I stop.

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2" drop front. 2 1/2" drop rear.

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Edited by George
Corrected part number.

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The second to last photo shows the black adjusting sleeve (threaded) and the gold adjusting nut. Just turn the nut up or down for the desired amount of drop.

I should have just included this photo.

56a44ba86491513dc7086a9c67c0e0d5.jpg

 

If the 350lb springs (10" long) were used an additional 1" drop could be achieved due to the shorter spring, and would be stiffer to keep the strut from completely bottoming out. IMO

I'm not sure I would go stiffer, it rides like a mid '90's Corvette already.

 

 

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Edited by George
Added photo

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It can still be done, ahh, with your luck at getting alignments, never mind.

 

 

Sent from my iPhone using Tapatalk

 

Well the rear is the one that they mostly bitch about. I've noticed the fronts are hit and miss. Of course if the rear coil overs get rid of the monoleaf, then it would definitely get adjustable rear lateral links which would probably "fix" the issue... then again my area really does have a lot of special people. I'ma leave it at that.

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Damn, I kinda wish I didn't do my struts now. I have new struts in the front, 2 year old struts in the back. I would have done this as well.

I am in the exact same boat, but I do not too much mind the bouncy buick ride for a DD. Yea yea, I can see you calling me old man already.

 

Either way, very cool option for the right folks. So is the knuckle still part of the macpherson strut then? Are you still able to change out the strut cartridges from the top?

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I am in the exact same boat, but I do not too much mind the bouncy buick ride for a DD. Yea yea, I can see you calling me old man already.

 

Either way, very cool option for the right folks. So is the knuckle still part of the macpherson strut then? Are you still able to change out the strut cartridges from the top?

It's the factory knuckle, just trimmed a bit. (The coil bucket and flat vertical plate removed for adjusting sleeve install) Yes you can still change the strut cartridges from the top.

Edited by George
More specifics on trimming.

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hmm...... if the suspension on the 91SE starts giving me trouble, I'm definitely going this route.

 

seems like all 4 corners can be done for ~$500?

 

$250 for front

$175 for rear

$425 total + some shipping I would say closer to $450 than $500.

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It's the factory knuckle, just trimmed a bit. (The coil bucket and flat vertical plate removed for adjusting sleeve install) Yes you can still change the strut cartridges from the top.

Is the adjusting sleeve just sitting against that strut/knuckle lip? It looks like you have a ring that threaded on there to keep it from flanging out? Nope, just a zip tie.

Edited by vipmiller803

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The front side (outside of car) of the strut/knuckle is approx. a 1/4 in higher that the backside, so I ground some material off half of the sleeve so it sits on both surfaces and the sleeve cannot rotate.

Yes, the zip tie is just a zip tie that holds the ABS sensor wire until get a split loom retainer to replace the factory one that broke.. Cheap 20 yr old factory plastic crap. Lol

 

 

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I am in the exact same boat, but I do not too much mind the bouncy buick ride for a DD. Yea yea, I can see you calling me old man already.

 

Me either, I enjoy the bouncy ride as well. Makes it fun when the road dips IMO. I get a lot of people that way hahaha

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This is the correct photo for the bump stop. This is all that is left and the top of the strut contacts it from time to time over dips as there is 1 1/4in clearance between the bump stop and the strut.

 

post-4629-143689183304_thumb.jpg

 

 

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Probably a dumb question but the rear of my 93 Cutlass convertible sags slightly IMO. Would coli overs allow me to adjust it up?

 

Yes. Depending on sizes of springs/sleeves, you can adjust up or down. For example, I could jack mine up to higher than stock with my setup (not that I ever intend on doing that :lol: )

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Probably a dumb question but the rear of my 93 Cutlass convertible sags slightly IMO. Would coli overs allow me to adjust it up?

 

Maybe you would like to lower to front to match the rear?

Cutting a 1/2 coil off the top of the front springs is about a 1 inch drop. That should make the front a little lower than the rear right?

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I don't thonk you can/should cut just a half coil off. Others with more experience should chime in here, but I think you need to cut off complete coils to keep the spring fitting in the odd, lopsided configuration.

 

My 95 GPSE back end was sagged. I cut a whole coil off of some FE3 springs and now my front sits 1/4" lower than rear and looks perfect IMO.

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