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PM3L, and front c/o Spring choices

1K views 7 replies 4 participants last post by  BLiND 
#1 ·
Looking to make some changes, and wondering what would be the best way to go.

1989 LX coupe, h/c/i/10psi intercooled, T5, 3.73 gears

Currently the car has:
MM FLSFC's
MM C/C plates
MM Bilsteins (older style, not the new race3's or whatever)
MM HD Adj rlca's
Stock UCA's
MM PHB
MM Alum rack bushings
MM front strut brace
FRPP 'B' springs
Stock v8 swaybars front/rear, with MM poly bushings and endlinks up front
`95 spindles
Fox-length 5 lug rear
Mach1 13" front / 11.65" rear *cobra brakes*
17x8 wheels with 245/45 Potenza re-01r tires all around, I do plan on 17x9's with 275/40's all around in the future.

I was considering going with the MM TA street and track rear springs (Spring rate: 415-515 lb/in. Approximate lowering values from stock: 1.1" to 1.4" Rear)

And not sure what length and rate springs to go with in the front that would be a good match, considering stock k-member and fox a-arms.

Street comfort is not really a concern, this is my weekend track toy, but it is a street car that is driven to the track.

Would 10" 350# springs be the way to go, or something stiffer?
 
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#2 ·
If this is a track toy, you should probably set it up for the track instead of the drive to/from the track. On my Fox, I run 450 c/o's in the front (Talk with MM to see if your struts are up to the challenge). In the rear I have 350 c/o's.

With this setup, you can tune with sway bars to get the turn in the way you want it. Beware that you very well may end up with some high speed oversteer. I had to add a rear wing for rear down force to stick the rear end for high speed sweepers.
 
#3 · (Edited)
what front c/o spring rate would give me the best turn in when combined with the 415-515# rear TA springs?

I believe I can run 350lb - 400lb with my struts.
 
#4 ·
Best bet is to call MM. Tell them about your set up and get some solid recommendations from them. Whenever I have called them they have been more than willing to spend a lot of time talking about my handling issues and making good recommendations. With the right rear sway bar, that spring might be just the ticket.

They will probably recommend an adjustable rear sway bar. You will need it to fine tune the combo to the track.

The way I look at it, springs are cheap and relatively easy to change. If you choose wrong the first time, no big deal. Corner weighting after install can get a little pricey unless you have scales or friends with scales, but if you get the general set up close, you don't burn up that much shop time.

Regarding the PM3L. I would not run it with anything but a solid steel bushing in the rear end. With rubber or even urethane, you will get some scary movement of the rear axle and it will handle different in left vs right turns. I had two "clamshell" type steel bushings machined that were held in by a 3/4" grade 8 bolt. One side was tapered to clear the rod end for the link. I used a solid link with 3/4" rod ends as the connector. The front of the link was located using an old urethane bushing sleeve turned down to fit in the rod end. The rod end was located laterally by the old urethane bushing cut in two and tapered to allow clearance.

Good luck.

Its a Poor Man's 3 Link, but you still have to spend a little to do it right.
 
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