Coilover spring length

fastfiat

fastfiat

Daily Driver
OK. I am going to switch over to coilovers with my KYBs. Nobody seems to have the QA1s in stock in 8" length. Can I use the 7" length with no problems? I want to lower it some but not have it slammed. I also want to use the powdercoated QA1s that are $37 each and not the $60 springs. I plan on running around 200lb and 250lb front to rear.

I believe 9" springs are too long right?

Thanks for any help!
Tony
 
Do you have coil-over sleeves?

If so the spring length becomes slightly less critical.

The problem with going to a shorter spring is that you are running more risk of bottoming out, either by suspension parts contacting the body/chassis, or by coil-binding the spring.

On my Scorp (which admittedly is a custom set-up, and the shock towers are different), 10 inch in back is about right, while 8 inches up front works well. This is with 250 lb/in back and 300 lb/in front. Even with these longer springs and higher rates, I can bottom out over rough roads.

If you are not running sleeves, I would recommend it, so you can dial in final ride height. I have used kits intended for 2003 Mitsubishi Eclipses with good results, they are about $40 on ebay. If you measure your strut tubes above the spring perch I can tell you if it will fit or not.

The X looks good, I got your update a few days ago. Keep after it!

Pete
 
I just had 8" springs put on front/back recently and couldn't be happier with them. I have 250lb Hypercoils on the rear and 225lb QA1's on the front. I lucked out and found the QA1's on eBay with a guy selling a brand new set for $30 total. Great deal.

Brian
 
Thanks Pete

I plan to buy a cheap Prelude set from ebay and tossing the springs for the QA1s.

Tony
 
Sounds like a plan

That's pretty much what I did. The springs that come with most of those coil-over kits are around 350 lb/in, which was too much for me. Not to mention, the KYB strut inserts could not dampen them, too much spring rate. That's why you see lowered Hondas pogo-ing down the road.

Let us know how it comes out.

Pete
 
Spring Lengths

I talked to Steve H. a while back and he says that 10" springs are too long. I never did ask him about 9" or 7" springs. I do not want it to bottom out either. I would rather go with the 9s if possible as the 7s only come in 250 and 300lbs. The 9s I can get 180 and 220lbs.

Tony
 
I'd go with the 9's.

The springs have to get longer as the rate goes down, because the weight of the car will compress them more. The sleeves should allow enough adjustment to get the ride height where you want it. Also it's better if the spring is still under tension when the suspension is in "droop" with the tire off the ground. It will help when you get the car airborn...

Pete
 
I just did some measurements on my '85 last night. The front IAP springs are roughly 6.25" compressed, and I think the nose is still too high. So a 7" spring should be about right there by the time it's compressed.

The stock rear springs are roughly 7.5" compressed and I think it's a bit too high as well. But I'm afraid an 8" spring might be just a little short by the time it's compressed.

I'll know more tonight after I install the rear IAP springs and weigh the car. But right now it appears that you'd need to lower the existing spring perches in order to use threaded sleeves with anything longer than a 7" rear spring and a 6" front spring.

If you'll check SteveH's response to my Koni adjustment question below, I think he recommended 7-8" rear springs and 6-7" front springs *without* threaded sleeves.

HTH,

///Mike
 
Mike makes a good point...

That I hadn't really factored in when talking about spring lengths, and that is that my statements assume you will relocate the spring perches on down to where the strut "ears" are.

I can't really comment on what spring lengths you need with the stock spring perch as the lowest setting. My coil-over sleeves go down to the ears and allow at least 3" of adjustment, so my spring selection is a bit wider.

What are your plans for the the stock spring perch?

Pete
 
spring perches

My plan is to cut off the stock spring perches and use just the coilover sleeves on the "ears". I have seen several posts on here of people doing just that. I really do not want to reinvent the wheel.. lol... I am just curious of other length of springs will work. Namely 7" or 9" springs.

Thanks!
Tony
 
I dunno guys, the 8"'ers on mine seem to work fine with no sort of mods to "level" the car out. I have a pic of what it looked like before when it was smashed to the ground (most of you all have seen it already), and I can take a pic of what it looks like now with the 8"s on it. Like I said, nothing special was done, just a matter of dialing them in. It definitely sits higher, but we're not talking 4X4 style or anything. Ride quality is pretty sweet as well. Don't know how the cornering is going to be, haven't dogged a sharpie since I've had the springs installed.
 
Cool..

My problem is that 8" springs are hard to get. Most do not have them in stock. I have not been able to find any on ebay also. Just trying to see if 7 or 9" springs would work.

Tony
 
???

8" springs are a very common length. Should be no problem to source them. Check with Chris at The Shock Shop-- he can have Hyperco ship you whatever you need.

But if you're going to cut the perches off you'll need longer springs than 8"s. My guess is 10"s, depending on the length of the threaded sleeves you're using. Would have to measure more to be sure-- I'm going to make new perches for my threaded sleeves so I can use shorter/lighter springs. I don't like the idea of just setting threaded sleeve on the angled profile at the top of the mounts-- I want a flat surface with a lip to keep the sleeves concentric and (hopefully) quiet.

But I digress. I think PeteW said he did what you're planning so his spring lengths should work great for you, assuming the threaded sleeves are similar and length.

///Mike
 
Hmmmm

The more I dig into this the more I learn. I was working my through the archives and I finally found a photo with KYB's and coilovers. I remember seeing that photo long ago. I was under the assumption that the lower spring perches on the rear shocks were cut off like the front. Not so!!

I also admit that I want to be a cheap b*ast*rd and try to use the $38 QA1 springs instead of all the $60 brands. QA1s in 8" are ~$60. 7s and 9s can be had for the $38. I think the 7s would be too short and bind, but what do I know?? :)

I don't like the idea of cutting off the rear spring perches because the "ears" are at such a steep angle compared to the front. This was mentioned above. I don't think the sleeves would wear to well at such an angle.

The only option is to weld the sleeve to the strut, but again I think that would be a VERY BAD idea since it is sealed and under pressure.

So... I guess I will have to suck it up and save the pennies for 8" springs all around and just cut the perches off the front struts.

Thanks for walking me through this and all the comments!

Tony
 
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