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Discussion Starter #1
Hi All,

I just need some recommendations on the appropriate springs rates as I am starting the rear setup with MM's adjustable LCA's, MM TA, and a MM PHB. I will be shortly moving to front afterward so I have some questions on that as well. Note..this is a 90% street car with probably only 1 or 2 track sessions per year so the suspension should be geared toward the street. Right now the suspension consists of:

Rear:
H&R street Springs
Tockico adjustable shocks
Subrames (I guess that counts as front too)
17x10.5" wheel w/315/35/17 tires
BBK Lower control arms

Front:
H&H street springs
Tockico adjustable struts
MM camber plates (they are the old ones so I might have to replace)
Strut tower brace
17x9" wheel with 275/40/17 tires

For the rear I am mostly concerned about the spring rate (not sure what the street H&R spring pressure comes at) and I really want to do things the correct way by installing the "correct parts only once" so I am assuming I should install a coilover conversion kit for the rear to go along with the TA, PHB, and LCAs. What spring rate rate should I use for the rear for the coilover kit (i know MM does not make a coilover for tockico so I have to replace the shock with either a koni or bilstien as well).

Now that I asked that..what about the front? I am planning on installing a MM coiliver in front next month and what spring rates should I go for (remember this is a 90% street car)? Can this kit be used with the stock k-member, a-arms..etc..etc? I don't plan on changing the k-member until my 347w is done in a couple of months so I was wondering if I could slap the coiliver on to gel with the new rear setup I am installing.

Thanks for any information....
 

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Before I had coilovers up front, I had H&R Race Springs up front, and H&R Torque Arm spring (390-430) in the rear. The ride was very streetable. My car is my daily driver. The ride is even better w/ the coilovers up front (MM coilovers for Bilsteins, 325lb springs) You may want to just jump to those. I wish I had done them long ago
 

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The first bit of advice I'd give would be to call MM directly and ask them, they have many more data points than any individual on this board. I would then seriously consider what they suggest.

My personal experience is 2000 Cobra R Bilsteins struts with MM coil overs and 400 lb 8" springs, and Bilstein Racing take-apart shocks with my own coil over kit and 250lb 9"(?) springs on the rear. Car was built with the sole purpose of track usage but I do drive it occasionally on the street. Ride is firm but not harsh. The ride quality improved drastically with the coil overs however my spring rates might be a little stiff for a daily driver but its a reference point for you....
 

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I run 350 lb/in coilovers up front and 450 lb/in coilover type springs in the stock position with the weld-in adapters in the rear. I already had the coilovers up front and the rear rate was recommended to me by MM when I added my torque arm to match the front. This is on my daily driver. It rides well IMO, not too harsh, and handles well and has cornering good balance.
 

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Discussion Starter #5
Thanks for all the information guys. I talked to MM and they recommended that I use a 325lb coilover spring for the front and a 250lb coilover spring for the back. Since I would probably be going for a 351w for my car (instead of the weak block 347w I was planning) then a 350lb coilover spring was recommended instead (but the same rear spring though).

The question I have now is what length of front spring will I need? The front 350lb spring comes in 7, 8, and 9 inches..?
 

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CobramanPhil said:
Thanks for all the information guys. I talked to MM and they recommended that I use a 325lb coilover spring for the front and a 250lb coilover spring for the back. Since I would probably be going for a 351w for my car (instead of the weak block 347w I was planning) then a 350lb coilover spring was recommended instead (but the same rear spring though).

The question I have now is what length of front spring will I need? The front 350lb spring comes in 7, 8, and 9 inches..?
MM recommended 8" for my car. Daily driver, then 2-3 Open track events a year. So far I'm very pleased. The springs seem to have settled about /1/2", so I need to raise them a tad....otherwise I wish I had done these years ago. FWIW, ground to apex of the fender is 25.5". I'm going to raise it back to 26" (how we 1st set it). They also recommended 250lb springs for the rear once I go coilover. Looks like we're on the same page somewhat :)
 

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CobramanPhil said:
The question I have now is what length of front spring will I need? The front 350lb spring comes in 7, 8, and 9 inches..?
Do the math...
Measure the free spring length "availability" (maximum distance between spring perches on your coilover).
Figure out the rate of spring (ie 350#), and then figure in the weight (900#) and then how far that will make it compress...

Probably looking at 9".
 

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Thought I'd bring this back up as my questions are relevant to this thread. I'm planning on front coilovers this fall and am trying to figure out the appropriate spring rate. The car is an '89 coupe primarily used for autox with a few track days per year; street driven as well. It's pretty much full weight and makes about 270 rwhp/303 rwtq. Current set up is MM phb/ta, lca's, 390-430 rear springs, 750-850 front springs and HD bilstein struts/shocks. I'm also running 245/45 V710's on 17x8's. Brakes are +99 gt/v6 front and cobra rear.

I spoke to MM about rates and they suggested something in the 250-275 rate for the front. The reasoning is that these would match up the best with the rear rates. While I understand I'll have higher wheel rates than I've got now, these still seem a bit soft based upon what's is mention in this thread and others I've searched. I had planned on going with something in the 350-400# range but the MM tech felt I'd have way to much understeer. What do you guys think? Is there a rule of thumb of thumb on matching the front springs with the rear?

Appreciate any input / ideas.

John
 

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Depends...check the MM site. If you want to keep your standard HD struts, you'll be limited to the rate you can have, maybe (pulling a number outta my butt) 350 lb/in, so if you go higher you'll need Sport or Race versions.
 

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350# is the max for the HD bilsteins. I was most concerned with MM's recommendation to go with 250-275#, which to me seemed soft in comparison with what others are having good results with.
 

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CobramanPhil said:
Thanks for all the information guys. I talked to MM and they recommended that I use a 325lb coilover spring for the front and a 250lb coilover spring for the back. Since I would probably be going for a 351w for my car (instead of the weak block 347w I was planning) then a 350lb coilover spring was recommended instead (but the same rear spring though).

The question I have now is what length of front spring will I need? The front 350lb spring comes in 7, 8, and 9 inches..?

I had those spring rates and had quite a bit of over steer. Even going slow through the corners. So I went 350 up front, and that helped a lot. I think I'm going to go 225 in the rear (had 250s) and be done with it
 
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