Discussion
Anyone know the spec of SH's front coilovers? I need to know the make, closed length and the poundage for the front springs.
Reason being is that I bought the conversion kit and following a blast today one of the springs has fully compressed. I just need to know what size springs will work...
Reason being is that I bought the conversion kit and following a blast today one of the springs has fully compressed. I just need to know what size springs will work...
The shocks are GAZ, i would give them a call and ask what SH speced with them, i too also need new front springs with at least 100 pounds increase and about 2" shorter to allow the correct ride hight i want in the front of my SEAC.
I think they are about 350 pound springs 2.25" diamiter.
Cambelt
I think they are about 350 pound springs 2.25" diamiter.
Cambelt
I tried the SH setup on my car. Steve sent 350 pound/inch springs to start with but after a lot of experimentation he sent me some 450 lb/inch springs. The 350 lb/inch springs were coilbound. In the end I needed a lot of welding on the front suspension upper mounts which were rusted and I decided to revert back to the standard setup. hope that helps. (400SE by the way)
Lesliehedley said:
I tried the SH setup on my car. Steve sent 350 pound/inch springs to start with but after a lot of experimentation he sent me some 450 lb/inch springs. The 350 lb/inch springs were coilbound. In the end I needed a lot of welding on the front suspension upper mounts which were rusted and I decided to revert back to the standard setup. hope that helps. (400SE by the way)
just out of interest Lh, Questions??????????What length were the springs ?
Did you need to pre load them?
How much had they squashed to be coilbound? 3"---4" more ?
The fitment point of the coilovers on mine is about half way along the lower arm. 12" arm, 6.5" damper to chassis bolt. Some say measure from the lower arm pivot point to centre of ball joint, some say to the centre of the tyre patch. I used ball joint measurement as the wheel, tyre, brakes etc are all unsprung weight. (this has the potential to make a big difference) The angle of the spring (less than 90deg) also lessons its effect.
To hold the car up at this point,(solid, no sag at all) takes about 1350lbs, almost double the corner weight at the wheel.
I found this out with a 500lb spring, with no preload it compressed nearly 3" before holding up the car. So the only way your 450lb spring would work, is if it was preloaded on the damper about 2". So you would need a 11" spring compressed 2" to fit a 9" damper which then would give about 1" of sag when the car sits on it.
I kept getting told (IIRC) that wedge standard springs were circa 350lb, now that would be fine as long as it pre loaded 3" and allowing for sag.
Makes sense to me-----------------almost
To hold the car up at this point,(solid, no sag at all) takes about 1350lbs, almost double the corner weight at the wheel.
I found this out with a 500lb spring, with no preload it compressed nearly 3" before holding up the car. So the only way your 450lb spring would work, is if it was preloaded on the damper about 2". So you would need a 11" spring compressed 2" to fit a 9" damper which then would give about 1" of sag when the car sits on it.
I kept getting told (IIRC) that wedge standard springs were circa 350lb, now that would be fine as long as it pre loaded 3" and allowing for sag.
Makes sense to me-----------------almost
I imagine there's an element of rising rate at the spring .. the std spring is a large diameter so as the lower arm swings through its arc the effective point of contact of the spring moves along the arm .. ie imagine if the arm swung a long way upwards then the inner part of the spring would come away from the arm, so all the weight is taken further outboard on the lower arm .. this effect means the wheel rate changes advantageously compared to the apparent spring rate. When you have a coil over conversion located at one point on the lower arm you lose this useful rate change effect, meaning you need a higher rate spring than you might at first think.
Just a thought, but seems plausible.
FWIW on the tasmin race cars rates up to 1100lb/inch were being used and the need was still for a very stiff front ARB on most cars. I'm not surprised by the stories of mounts bending.
Just a thought, but seems plausible.
FWIW on the tasmin race cars rates up to 1100lb/inch were being used and the need was still for a very stiff front ARB on most cars. I'm not surprised by the stories of mounts bending.
spitfire4v8 said:
I imagine there's an element of rising rate at the spring .. the std spring is a large diameter so as the lower arm swings through its arc the effective point of contact of the spring moves along the arm .. ie imagine if the arm swung a long way upwards then the inner part of the spring would come away from the arm, so all the weight is taken further outboard on the lower arm .. this effect means the wheel rate changes advantageously compared to the apparent spring rate. When you have a coil over conversion located at one point on the lower arm you lose this useful rate change effect, meaning you need a higher rate spring than you might at first think.
Just a thought, but seems plausible.
FWIW on the tasmin race cars rates up to 1100lb/inch were being used and the need was still for a very stiff front ARB on most cars. I'm not surprised by the stories of mounts bending.
Don't think any of the racers run springs that hard, maybe 600-700 max I'll post up the info when I find it.Just a thought, but seems plausible.
FWIW on the tasmin race cars rates up to 1100lb/inch were being used and the need was still for a very stiff front ARB on most cars. I'm not surprised by the stories of mounts bending.
The men at GAZ reckon the front spring rates for wedges are quite strange for a car that is relatively light for its size. As a consequence the some of the wedge racers are running 1200lb on the front springs. I'm going to increase what I have from 675 to 700-725 om 8" springs just to get some decent rebound on my set up...
the SH coilovers are Gaz 1.9" units.
got a set of them on my mk2 granada with 9inch 650lb springs (which is too soft) if thats any help guys?
the top mounts on the tvr must be very flimsy, as ive had no trouble with the mounts or the lower arms on my granada. but then on my setup, im not relying on the coilover bump stops to limit travel
got a set of them on my mk2 granada with 9inch 650lb springs (which is too soft) if thats any help guys?
the top mounts on the tvr must be very flimsy, as ive had no trouble with the mounts or the lower arms on my granada. but then on my setup, im not relying on the coilover bump stops to limit travel
To safely fit coilover adj shocks you need to have a very strong bracket welded to the chassis at the top and the wishbones need ' redesigning ' . Took mine to Steve Gugleilmi's at Daventry , he redesigns suspensions for track cars so is experienced .
Edited by combine on Sunday 19th February 19:16
combine said:
Top safely fit coilover adj shocks you need to have a very strong bracket welded to the chassis at the top and the wishbones need ' redesigning ' . Took mine to Steve Gugleilmi's at Daventry , he redesigns suspensions for track cars so is experienced .
Hey Steve, any idea of the rating on the springs i had fom you? They are definately firmer than the ones i took of and the car sits a little higher on the front end now.Jimbo
combine said:
Jim , there's a lot to be said for having a well planted wedge , thats what I've been striving for . When you've got this much torque & power & acceleration you need the wedge to behave itself !
On the way home on Sunday i was a bit immature/naughty going through the Dartford Tunnel................planting it in second and it just span up and tried to turn itself round!!
I was ready for it so no worries but you are of course very right
Jimbo
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