QA1 coilover spring rate

Carrying on from this thread:

http://pro-tourings10.com/index.php?topic=1160

I got the truck on a lift yesterday and had a shop try to locate the creaking noise.  It seems like the noise is coming from the bottom coils collapsing into the ones above them.  The paint is rubbed off the lower coils and two mechanics spent about 45 minutes checking over everything else to isolate it to the coils (they didn't charge me  ).  I run the 450 lb versions based on advice from QA1 and it looks like they've either worn out in the 2 years I've had them or were never heavy enough in the first place.  They probably only have 6000 miles on them but the may have done 30 auto-X events over that time.

I will probably need to replace the coils (again) so does anyone have any suggestions on the rate I should go with?  I have about 20 threads (maybe 3") of adjustment on the shock collar that I could use to bring the ride height down with the truck at its current stance (I'm content with it at this ride height):



I'm also going to look into getting it corner scaled since this trial and error crap is expensive and time consuming.

i like to have the "current set ride height" at the middle of the adjustment range.

before you swap coils, get a corner weight, and then choose your rate based on a corner frequency you want.

if you aren't dailying this truck, i'd say you can go 1.8hz ish (# is out of my ass btw)

When I ran some numbers last year, using some old corner weights from my Blazer, 600 seemed to be the number I kept coming up with.  Unfortunately QA1 only has coils up to 550lbs for the S10 style springs.

When I ran some numbers last year, using some old corner weights from my Blazer, 600 seemed to be the number I kept coming up with.  Unfortunately QA1 only has coils up to 550lbs for the S10 style springs.

I just talked to QA1 tech and using your corner weights (I have your pic saved) they said it's right on the edge for them recommending a 450 vs. a 500.  You had a front weight of about 2050 with driver.  I have my battery in the bed and will be deleting the AC but I'm guessing that won't make a huge difference.  I'll probably have to go with the 550's.

I just talked to QA1 tech and using your corner weights (I have your pic saved) they said it's right on the edge for them recommending a 450 vs. a 500.  You had a front weight of about 2050 with driver.  I have my battery in the bed and will be deleting the AC but I'm guessing that won't make a huge difference.  I'll probably have to go with the 550's.

just curious, what were the qualifications of the tech, + how did he come up with that number

I have no idea.  He didn't sound particularly knowledgeable to me and had clearly never heard of an S10 auto-Xing.  I got the impression that he was looking through some sort of file with a record of which springs they had recommended in the past. 

The last time I spoke to one of their techs they seemed much more experienced but clearly that didn't work out so well since I'm changing springs again.

I went back and dug through some notes and conversations with Ryo about the springs.

I started with the ZQ8 rate - 600 lbs and ran the numbers with the same corner weights as you have.  Comparing it to the ride frequency of a Corvette, they came out very close.  That was how I decided on that number.

For reference the S10 550lb coil part number is 10GBF550.  I had trouble finding it without that number.  The only other information/help I was able to get from QA1 is the S10 springs are 10" long, tapered with 2.5"/4.1" diameters, and have flat spring ends.

With the binding I've seen up front in the shock/spring combo, not to mention I don't like the bolt through shock mounting, I'd like to modify the front to run 2.5" style springs, but not going to delay the project anymore to fit it in this time around.  I've got several frames laying around I can mock it up on, anyway.  That would give much more freedom in spring selection as well.

Ok - thanks for the information.  I'm away for a few weeks but I'm going to try to sort this out as soon as I get back.

Ok - the 550 lb coils are in and they're a huge improvement over the 450s. The creaking noise is gone and the ride is 100% better.  It just didn't feel right with the 450 lb coils but now it feels like a normal car.  The ride is firm but it handles bumps so much better without darting around or transferring motion from side to side like it used to.  I drove it on some really horrible roads this afternoon which I avoided completely in the past and it was totally tolerable.

Just for posterity's sake, this is the stance with the adjusters about an inch above the lowest ride height setting on the shock body.  I have stock height spindles with an extra 0.5" of drop from the tall lower ball joints.



I know when I searched QA1's originally a lot of people were worried that the 550's would make the ride height far too high so now people can judge for themselves.

Thanks for the update.  I was already committed to the 550# coils, but it is always nice to have proof.  It is also encouragement that my engineering thought process is on track.  Sounds like my experience with the 350# springs is similar to what you had with the 450# springs.  Seems backwards that the 550# would ride better, but goes to show it isn't always straightforward.

It does seem backwards - it never crossed my mind that the weird handling and harsh ride on my truck would be from the springs bottoming out because everything I read earlier (not on here) suggested the 450's would be on the stiff side.  Lesson learned!

Could be that the others' experience was stiff?  I feel that my 350# springs have a rough ride and the softer I made the shocks the worse it got.  That's one reason I ran the numbers.  Along with the fact that ZQ8 springs are 600# and I'm a sucker for calculations.  Once the 600# gave me a similar ride frequency to the Corvette I was really questioning what we were told and thinking before.

I hadn't bothered to look at the old springs yesterday - apparently there was a bit more going on then them just being too soft...



I wonder if this has anything to do with the hybrid coil over design of the QA1s?

Are the lower coils bent?  We already know the spring perch and shock aren't perfectly aligned, so that would make sense.  One of the plans for my old Blazer frame before scrapping it would be to cut up the spring pockets to see how easily/if I can package standard coil overs (cue Ryo saying I'll never get to it).

Are the lower coils bent?  We already know the spring perch and shock aren't perfectly aligned, so that would make sense.  One of the plans for my old Blazer frame before scrapping it would be to cut up the spring pockets to see how easily/if I can package standard coil overs (cue Ryo saying I'll never get to it).

well i wouldnt say never.... probably just not in the next decade or so...

im surprised on those coils failing in that manner.
someone didn't run the numbers right....

further reinforcing my idea that the bolt-on coilovers are of no benefit over the separate coil and shock arrangement.

I get the idea most people, including QA1, don't really run the numbers.

The first two advantages that come to mind are adjustable ride height and more spring rate selection, in the aftermarket, at least.  There's also the fact that most aftermarket lower control arms designed for the stock style S10 spring look dangerous and/or immensely heavy to me.

I heard so much about the unpredictable ride height and ride quality changes with drop coils that I figured the coil overs were a good choice at the time. I have the same apprehensions about drop leafs which is why I'm still running blocks in the rear.

i'm amazed you are still running blocks in the rear.

the difference between having and then removing blocks (3") for me was huge for me.

the "sway" the rear end did with blocks was quite noticeable and affected my confidence significantly.

i highly recommend running no blocks or adding a panhard bar or equivalent

ZQ8 leaves and 1" blocks wouldn't be a bad choice either.  Plus the panhard!

What about wheel hop though?  I've heard a lot of people complain about it when moving to drop leafs and I don't want to introduce new problems while trying to solve something that isn't a big issue to me. 

I have no complaints with the blocks but again, this is the only vehicle I've ever raced so it may be that I just don't know what a good rear suspension feels like.  I've had the truck sideways at 60+ mph and it always felt predictable and easy to control.  I don't even run a rear sway bar.

The ZQ8 leafs wouldn't be low enough, even with a 1" block.  I'd need at least 4" of drop in the rear to get the ride height I want so I'd need 3" leafs plus a 1" block (do they make 4" leafs?).  With a pulled leaf and 3" blocks it still has too much rake for my tastes.