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I want to set up a car to go autocross in and from what i hear these springs are taller than stock. How much is tyoical to cut for this application? 3/4 coil? Also have cc635 coils, how much to cut on those 1/4 coil? Thanks!
If you are doing autocross you should buy the proper lowering springs for the application.
The Moog springs are not taller than factory; the factory springs sag over 20-30 years. It takes new springs 6-12 months to drop back the stock ride height.
Those springs will restore STOCK ORIGINAL ride height.
Remember, the STOCK, ORIGINAL ride height - what the 5664 is designed and intended to replicate - is likely to be AT LEAST 1½" higher than wherever the car is sitting at now.
Those springs are somewhere around 750 lbs/in IIRC. The absolute stiffest springs Moog makes for these cars. Cutting them is going to increase their rate further, and most likely make the car UNBEARABLY tight (tend to slide the front wheels) because around corners ALL the load will be on the outside front tire, unless you put some kind of ungodly stiff rear springs in at the same time, in which case you may be able to get it to almost handle neutral but just won't have any "side bite" around corners at all because all the load will be on the 2 outside tires. It will ride like it doesn't even have a suspension, besides; like a scooter. Doesn't sound like the right thing to do IMO.
My 92 RS 5.0/auto had 5664s in the front and was almost exactly 27in ground to fender.
stock height is 28in ish ground to fender.
so a v6 would sit at stock height or a little higher.
Buttttt cutting MOOG springs are a bad choice for Autocross.
If your new, just run some SFC and a wonder bar for an entire season.
you need seat time not go fast parts
It took me an entire season with 3 events a month just to get kinda used to AutoX.
5664 is a linear spring. Cutting them will barely increase the rate if at all.
5665 would be the rear spring to run if you want to cut. The rate is 107.
The CC635 are progressive the rate will increase.
Originally Posted by sofakingdom
5664 is a front spring. The stiffest one Moog makes in the configuration for these cars. 7xx lbs/in.
5665 and CC635 are rears.
Yes I know lol.
He asked about cutting 5664s which are front springs. I said yes you can cut because they will not increase the rate or negligible amount . They are not progressive springs.
5665 which are rear LINEAR springs can be cut.
I think we all know CC635 are rears so I didnt think I had to mention it again.
Cutting the 5664, the rate will increase, and the amount is not unconditionally negligible. To a certain extent that depends on what one might call "negligible"; but in pure numerical terms, the rate goes up IN A HURRY whenever one cuts springs.
5665 are rears. CC635 are rears. 5664 are fronts. Results one observes from altering rears, are not the same as what one obtains from altering fronts. The effect goes deeper than linear rears vs constant-rate rears.
The real problem is all the replacement MOOG springs are fairly generic "one-size-fits-all". They aren't even thirdgen specific. If you look up on Rock Auto and click the part number you'll see all the applications the part number is listed under. You'll see things like Blazers, and S10 pickups, El Caminos, Malibus, all kinds of cars. And people wonder why the ride height is dramatically different when you replace a very specific factory spring with a generic replacement...
Cutting the 5664, the rate will increase, and the amount is not unconditionally negligible. To a certain extent that depends on what one might call "negligible"; but in pure numerical terms, the rate goes up IN A HURRY whenever one cuts springs.
5665 are rears. CC635 are rears. 5664 are fronts. Results one observes from altering rears, are not the same as what one obtains from altering fronts. The effect goes deeper than linear rears vs constant-rate rears.
Linear and constant rate means the same thing. Did you mean linear vs progressive?
From what I've always understood a linear spring keeps the same rate unless maybe drastically cut.
I cut a half coil on my front springs on the Trans Am. The car feels and rides exactly the same as it did before.
Same thing with my GT.
Originally Posted by Drew
The real problem is all the replacement MOOG springs are fairly generic "one-size-fits-all". They aren't even thirdgen specific. If you look up on Rock Auto and click the part number you'll see all the applications the part number is listed under. You'll see things like Blazers, and S10 pickups, El Caminos, Malibus, all kinds of cars. And people wonder why the ride height is dramatically different when you replace a very specific factory spring with a generic replacement...
Lololol I noticed that. It's crazy sometimes how one part number can have so many different applications. Here's a funny one for you
I don't see anywhere here why you want to replace the springs you have. Are they too low? Do you want it stiffer? Do you think they are worn out? What are the goals for the car besides autocross. If you've been doing autocross already, you should know what the car needs based on how it performs. If not, you should take it out the way it is and adjust from that point based on what it's doing as a car. Remember, you and the car together are completely different than any other combination out there, and YOU need to get what YOU and YOUR car need.
After this many years of modifying and racing these cars and this forum existing you'd think it would be easier to get correct information about basic topics like this.
WRT to the MOOG springs Drew hit the nail on the head, the MOOG springs are pretty much generic springs that are close, though what I don't know about that is how much overlap there was over the product lines originally. For example, our front LCA's were used on other cars, so were our rear control arms, many other GM cars had the same size spring pockets and it was common for GM to go into different model line parts bins for parts. They are not "this is what it sat like at stock ride height," heck, as the years went on factory ride hight got lower on the same option package cars, and if you look at an original '82-84 car they sat like a 4x4, and I've posted pics of my '87 TA with stock springs in it that don't appear to have sagged (they have correct tags on them, no idea why they haven't sagged like others) you won't believe how high it sits, were the '90's cars look like they're lowered from the factory.
As far as "Cutting springs bad, buy the 'right' springs..." Bullshit. Progressive vs LINEAR springs, oh come on, you're... forget it... just no. BTW, they're called specific rate springs.
As long as you do it right, end up with the correct configuration (basically, don't cut off the pigtail on the rear spring) and the spring rate/height that you need there is no problem with cutting springs. As far as ride heights and spring rate changes, I've at times tried to publish very detailed information on this forum about what works and what doesn't for V8 cars, but not having owned a V6 car and only having worked on them occasionally I can't really do much more than a guess for that. If you want to look up some of those old answers to get a good idea of the concerns when cutting springs in these cars. BTW, I believe that a long time ago I may have even published all the factory spring codes that were used in these cars (though that was compiled in the late 80's/very early 90's, before production ended)
Past that, the OP didn't really give enough information to answer the question- are you using the Moog springs to stay in a stock class? Does it matter? What is the rest of the suspension setup? What have you tried and liked?
To a certain extent that depends on what one might call "negligible"; but in pure numerical terms, the rate goes up IN A HURRY whenever one cuts springs.
