Coil-over spring rates

[dville_gt]

Currently running a 14" 150lb coil over spring on top of Strange 10-ways in the front. Car feels like it has NO suspension in the front. You will literally bend the fender trying to push or pull on it. I pulled the struts off to make sure they were working correctly and they are, and I checked the front control arms for any binding but they move freely.

What I did notice is the coil looks very compressed when the car is sitting on them. They measure 14" when off the car (DUH), and about 8" when the car is sitting on them. Brooks indicated that they shouldn't be compressed more then 5 inches. Additionally I had asked them about some pretty aggressive wear on the coil over sleeves and he mentioned this is also a sign of springs that are too light.







Ideally I'd like to put the car on some scales, but do not have access to 4 corner scales. Any idea on what spring rate to shoot for (obviously this will be a blind guess at best). Car has an iron block 370 ls motor with a front mounted t6, air conditioning, large radiator and intercooler, but tubular k and suspension. Probably pretty heavy on the front even still.

[Grape]

500 lb 8" spring will solve your problems. you need some barrel springs so they don't slinky and touch the adjuster sleeve. if you can get it to my shop you can use my scales........

[dville_gt]

500 lb 8" spring will solve your problems.

[Grape]

i really don't understand the stupid low spring rates for a 3000 lb street car. We run 150's on the front of a 2600lb paved latemodel when we are using bump stops and a 2" sway bar. car will go thru tech at the correct valance height, then as soon as you touch the brakes the nose never comes up

[CRASH]

I don't think he was being a smart ass, dude.

[dville_gt]

I don't know the logic either. I asked Wolfe a while back and they recommended 130-150lb 14" springs for this application (again, without knowing front axle weight). My front is rock hard though, cannot possibly be correct as it sits. Seems like that coil couldn't compress much at all before the coils literally touch each other.

[Mach1]

i really don't understand the stupid low spring rates for a 3000 lb street car. We run 150's on the front of a 2600lb paved latemodel when we are using bump stops and a 2" sway bar. car will go thru tech at the correct valance height, then as soon as you touch the brakes the nose never comes up

The car in question can only drive straight

[dville_gt]

I don't think he was being a smart ass, dude.

in that case whoops, i guess that makes some sense however as the fewer inches of spring you have the higher the spring rate would need to be. as i understand it the weight rating is how many lbs it takes to compress the spring 1". obviously if the entire spring is only 8" you couldn't have as much compression, but i just never see any mustang guys running such short springs so i figured he was being a smart ass.

[Grape]

I don't know the logic either. I asked Wolfe a while back and they recommended 130-150lb 14" springs for this application (again, without knowing front axle weight). My front is rock hard though, cannot possibly be correct as it sits. Seems like that coil couldn't compress much at all before the coils literally touch each other.

bolt it back together with no spring, and make sure the strut isnt bound up with the swing of the lower control arm. We use dummy penske's on the oval stuff with no spring installed just to make sure the shock mount doesn't create a bind in the shaft.

[Grape]

in that case whoops, i guess that makes some sense however as the fewer inches of spring you have the higher the spring rate would need to be. as i understand it the weight rating is how many lbs it takes to compress the spring 1". obviously if the entire spring is only 8" you couldn't have as much compression, but i just never see any mustang guys running such short springs so i figured he was being a smart ass.

short springs are lighter, we run the shortest we can...........

[dville_gt]

what are the odds that these springs are just weak and not holding up to their rating. 150lb spring compressed 6" is 900lb per spring or 1800lbs on the front axles. seems pretty high for a car i'd guess only weighs ~3000lb

[CRASH]

in that case whoops, i guess that makes some sense however as the fewer inches of spring you have the higher the spring rate would need to be. as i understand it the weight rating is how many lbs it takes to compress the spring 1". obviously if the entire spring is only 8" you couldn't have as much compression, but i just never see any mustang guys running such short springs so i figured he was being a smart ass.

Just thought I'd point out that it seemed to me like he was genuinely trying to help.

[dville_gt]

bolt it back together with no spring, and make sure the strut isnt bound up with the swing of the lower control arm. We use dummy penske's on the oval stuff with no spring installed just to make sure the shock mount doesn't create a bind in the shaft.

tried this yesterday. shock traveled through it's range without a problem.

[Grape]

what are the odds that these springs are just weak and not holding up to their rating. 150lb spring compressed 6" is 900lb per spring or 1800lbs on the front axles. seems pretty high for a car i'd guess only weighs ~3000lb

no matter what spring rate you put on the car, the amount of weight the springs are carrying will not change, stiffer spring just gets less displacement from free height to ride height. your car is probably 55% on the nose.......so should be 1650 on the nose, maybe more.

[dville_gt]

no matter what spring rate you put on the car, the amount of weight the springs are carrying will not change, stiffer spring just gets less displacement from free height to ride height. your car is probably 55% on the nose.......so should be 1650 on the nose, maybe more.

I knew the amount of weight on the front wouldn't change, but I am thinking that I am literally basically bottoming out these springs just sitting on them. That is why I cannot push down to further compress them at all.