Variable rate springs for Harrison

[macloft]

Hello Craig
The AVOs were set in the middle setting
The real problem I have is, to get the car at the right height to pass inspection (4 inches) i had to jack the back up until the rear shock was almost fully extended. So when I am driving the car and the shock rebounds over a bump the shock would fully extend and bang.
Certainly when the car was lowered I could get the setup to work right.
Maybe I got to short an AVO. I do not have an issue with the AVO itself or the spring I believe I have wrong length.
Cheers
Bruce

[400TT]

Bruce, know exactly what is wrong, performed the same mods but Warwick would have covered that with you.

I'm just giving you a heads up if you are changing shocks.

Haven't used AVO's for a very long time, so don't know how hard they are. But with the QA1's, don't get too carried away on the number of clicks you put into the shocks, start soft and work your way up, don't start half way. Hope that helps.

[muzzza]

I have 17" QA1 shocks on the rear of my Harrison, with 300lb 250 long springs. Have also fabricated spring mounts that bolt onto the chassis. ( front and back ) This means I can easily fabricate brackets to raise or lower the spring mounting point, and hence the car ride height.

This solves any spring / shock compromise settings. eg "winding up the spring pre-load to raise the car "

Unless you run a circuit car set up for zero droop, you will only need sufficient pre-load to keep the spring firmly in place when the suspension goes into full droop. When you pre-load a spring for no other reason than raising the car height....it is NOT THE THING TO DO. It also changes the the linear properties of the selected spring. QA1 shocks blow apart very easily with too much spring pre-load.

With too much pre-load and not enough droop, it is not too hard to lift a rear inside tyre and "Rotate"......when the tyre does make contact with the road surface again, the spring will not take up the loads progressively / smoothly as you have wound up too much pre-load. ( a 250lb spring acting like a 350lb spring )

I would stick with 17" shock ( easy to shorten shock or put in a droop limiter ) and 250 long spring.....possibly with a spacer under the top spring seat. 300 long spring may be a little too close to lower suspension arm, if you are running a skyline rear end. MUZZZA

[macloft]

Hello Muzza
Good comments. I would like to see some pictures of the top mount if possible. Thanks Bruce