spring rate recommendation for an S-10

[jerome]

I am ordering springs for my 82 S10. It will be 3000 lbs (rough guess) with a aluminum head sbc, fuel cell at back of the bed. I will be using spring adjusters up front with 5.5" x 9.5" springs. Front has tall ATS spindle. Out back will be a satchell link with bars approximately 30" longitudinally. Both sets of springs will be vertically mounted. Rears will be 2.5" x 12". I am looking for good street performance and ride, with maybe a couple roadrace or autocross days per year. I will be running this front bar:



Questions:
1. What rates front and rear? I've read ballpark i should be looking at 600 front, 150 rear. Is any brand better than the other? I was looking at the tru-coil cheap purple ones from speedway motors. and adjuster from either coleman, speedway, or afco.

2. How much does spring rate affect ride?

3. Is a rear bar necessary? I understand that the front bar cant be done away with without having a ridiculous spring rate, and inability to conform to road conditions. Rear bar is just one more thing i would have to fabricate.

4. Where can I get the rubber or poly spring pads? I cant find the ones I need. Do I really need them? I hear they help reduce NVH. If I do, I need 5.5" diameter, and with the angle molded in for the spring.


Thanks for putting up with the questions,
Jerome

[MonzaRacer]

Well basicly your S10 frontend if still S10 is the same thing as a Malibu, Monte Carlo, G bodies in general.

[Norm Peterson]

I'm running 640f/165r with the OE 32mm front bar and 22mm LCA-mounted rear bar in a 1979 Malibu. Ride-wise, I find it acceptable just about anywhere, but it's a bit soft for serious auto-X.

Properly matching front and rear spring rates will give you a "flat ride", which can be accomplished knowing the weight distribution, unsprung weights, wheelbase, and typical speeds driven. The above springs work well enough with G-body motion ratios at ~3450 lbs, ~53% front weight, 108" wheelbase, and ~55 mph, which is a bit on the high side for most anything but on a road course (and too low for open-road competitions). I suspect that 600/150 in your S10 will flat-ride at a slightly lower speed, maybe high 30's mph. It appears to be better overall to aim for a "flat ride" speed that's toward the low end of your sustained speeds, as this doesn't deteriorate very fast once you go above it, and it doesn't mean much at, say, 20 mph.

Satchell rear suspension linkages tend to have lower roll center heights than converging/triangulated 4-link arrangements (such as in the A/G-body), so once you've settled on a rear spring rate for ride considerations, you may need to add a rear bar in order to get the rear lateral load transfer up to where it needs to be for handling balance.


Norm

[HILROD]

The only thing I can add is if the v8 is in front of the stock firewall, it is farther forward than it would be in any other g-body, making it have more front bias. That would tell me it would need more front spring than other g's. I've used 3rd gen Camaro IROC front springs. They are cheap and should give you a good starting point. If they are too soft, it's not a lot wasted.

[Randy67]

If you go for 3rd gen F-body springs, go for the 85-86 IROC springs, these were the stiffest GM put on the cars. TRW lists a replacement front spring at 700 lbs. Should be able to find them in junkyards pretty easy. Later IROCs and Trans Am GTA would be a good choice as well.

[jerome]

Thanks for the info guys. I wont be able to drive the s10 for a long while so i wont be able to try the camaro springs, I'm just going to get the 650lb springs I think.

Norm, where can I read more about this "flat ride" speed. I've never heard the term before.

Jerome

[Norm Peterson]

Fred Puhn's book has it, although I'm not sure if they call it that. It's in the section where he discusses suspension frequency.

And you can do a search for it here either under that term, or perhaps 'pitch'. I know I've got some plots still active, but don't remember the title of the thread they appear in.


Norm

[HectorM52]

Moog Springs
Part Number 5662
Inside Diameter 4.085
End Type 1 Square
End Type 2 Tangential
Bar Diameter 0.750
Install Height 10.75
Load in Pounds 1690.0
Spring Rate 748.0
Free Height 13.01

Just thought I'd throw this out there for anyone interested. Its from the Moog website.

[HectorM52]

TRW Springs
Part Number CS5662
Inside Diameter 4.085
End Type 1 Square
End Type 2 Tangential
Bar Diameter 0.750
Install Height 10.75
Load in Pounds 1690.0
Spring Rate 748.0
Free Height 13.01

[73-TYPE-LT-LS1]

You may find this thread usefull. I created a spreadsheet to help figure out spring rates..

https://www.pro-touring.com/forum/showthread.php?t=36116