eZ

Hey guys I thought you would have a little more knowledge about this one.

I currently have a 4-link set up in the rear with coil-overs. Im finishing up designing a coil-over for the front. both front and rears will have single adjustable QA1's. My question is what spring rate should I get for both front and rear. I want it so that the suspension can be set for the street and then maybe make some adjustments that are better for the 1/4 mile.

I would think I would need to know the weight of my car in the front and rear which I do not. The total car weight should not be more than 2800. I would imagine that both the front and rear springs would have to work together. In other words front cant be too saft and rear too stiff?

Some specs
65 mustang
ford 9'' detroit locker
4.11s
street/strip AOD 3k-3.5k stall
347 that dynoed at 353rwhp 333trq dyno session is a whole nother subject
285 nitto nt05r

thanks

Dan

Stone629

I would focus more on the rear spring rate since there will be lift on the front. Keep the front end stiff for better handling (personal preference). As light as your car is, I would think a 180-200lb spring rate should be about right for the rear (for launching purposes). I've used AGX adjustable shocks in the past and loved them. I set the rear on 1-3 at the track for good transfer, and 8-9 on the street for handling. I never adjusted the front. The way I figured it, I wanted the front end to stay up as long as possible and having the front shocks set on a stiff setting would slow the weight transfer back to the front (drop). Nice car btw!

eZ

thanks for the input...how much does the angle of the spring affect the net spring load? The font of my car the spring is only about 10 degrees from perfectly straight up and down, where as the back is angled much more maybe 30 degrees or so

Stone629

Thats a good question. Might want to get up with someone a little more knowledgeable than myself. You basically saying your car is "toe in", right?

eZ

no refering to the angle the rear springs set


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67mustang302

Depends on how it's set up. You might have to play with it some, the joy of not stock stuff. Keep in mind though that something setup for drag racing will generally sacrifice handling, and vice versa. You can get a decent handling car with some minor changes at the strip for good launches, but don't expect it to out corner cars set up for road racing.

Mine is the opposite direction, set up for cornering, so there's not much load transfer to the rear on launch...but it takes corners quite fast.

Spring rates you use will be dictated more by use and driving style, as well as configuration.

eZ

So what should I start at?

67mustang302

Who made the 4 link? What did they advise? Otherwise go with what's listed above, 180-200lbs to start and see where you're at. You might have to change springs several times to find what works.

eZ

I made the 4 link..I did not advise LOL

67mustang302

Was it a universal kit from CE or some place? If so call them and they can give you some starting guidelines. Otherwise I'd find a manufacturer that makes a kit that mounts real similar to yours and see what they advise.