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What Springs are you using?
Antnicuk - 29/10/08 at 01:25 AM

My stylus weighs about 650 - 700 kg's and i often have a passenger on track, i recently upgraded from the 180lbs springs to 250lbs springs on the rear but the back still squats a lot. If i go up in weight again i will have heavier springs in the back than the front i think! although i do want to go slightly heavier in the front anyway but once i have sourced a stronger anti roll bar. It doesnt seem to dive too much but there seems to be about 4 - 5 inches of travel on the back when on track. The car is road legal but wont get used much on the road. The shocks are AVO and the springs are 8 inch.

Also, how can i find out exactly what my springs are on the front, as i dont know, the marks have worn off, also, is there a cheaper way to test and tune the springs rather than keep buying springs, using them once and taking them off!

[Edited on 29-10-08 by Antnicuk]

blakep82 - 29/10/08 at 01:36 AM

maybe need to look at building some anti squat geomentry in there? don't ask me how lol something to do with the angle of your link bars on a live axle.
noooo idea about IRS. something to do with the angle of your wishbones i think

i know that doesn't help a huge amount, but read up on it on the net. its used a lot in drag racing

philw - 29/10/08 at 05:57 PM

quote:
Originally posted by Antnicuk
My stylus weighs about 650 - 700 kg's and i often have a passenger on track, i recently upgraded from the 180lbs springs to 250lbs springs on the rear but the back still squats a lot. If i go up in weight again i will have heavier springs in the back than the front i think! although i do want to go slightly heavier in the front anyway but once i have sourced a stronger anti roll bar. It doesnt seem to dive too much but there seems to be about 4 - 5 inches of travel on the back when on track. The car is road legal but wont get used much on the road. The shocks are AVO and the springs are 8 inch.

Also, how can i find out exactly what my springs are on the front, as i dont know, the marks have worn off, also, is there a cheaper way to test and tune the springs rather than keep buying springs, using them once and taking them off!

[Edited on 29-10-08 by Antnicuk]



What rear arms are you using? i thought you have the later convex ones, and what are the length of your rear shocks? 8" springs i have them on the front of mine and my rears are 15" with 10" 180lb springs but i'm going to put 205lbs on there as i've just had the fronts overhauled and stiffer springs fitted.

IIRCC there is a section on this on our site.

philw - 29/10/08 at 06:00 PM

quote:
Originally posted by blakep82
maybe need to look at building some anti squat geomentry in there?


It shouldn't squat mine doesn't (live axle) the rear is fantastic.

mr henderson - 29/10/08 at 07:05 PM

quote:
Originally posted by Antnicuk


Also, how can i find out exactly what my springs are on the front, as i dont know, the marks have worn off, also, is there a cheaper way to test and tune the springs rather than keep buying springs, using them once and taking them off!

[Edited on 29-10-08 by Antnicuk]


Take the springs off, measure their unfitted length, find a way of compressing one on to a bathroom scales (be safe). If you can compress if one inch, then read off the poundage. If less than an inch, then the result will be proportionate eg 100lbs at half inch = 200 lb in

John

Antnicuk - 29/10/08 at 08:48 PM

Hi Phil,

I have the convex rear arms but still have the original shocks i think although i have made newer shock mounting points on the convex arms directly above the originals which raised the mounting point of the shock as i couldnt get the car high enough, which i now can.

Would spring length effect how much the car squats?

I have 250 lb rears at the moment and the difference between the car being empty and being 2 up under hard acceleration is about 4 inches at the arch/tyre gap.

mr henderson - 29/10/08 at 09:44 PM

quote:
Originally posted by Antnicuk


Would spring length effect how much the car squats?



You can't separate spring length from poundage. To be able to hold a car at it's required static ride height a spring needs to be compressed by an amount equivalent to the load on it. The compression of a spring is a function of its free length and its poundage.

If a 10" 100lb spring is subjected to 200lbs load it will compress to 8". If a 9" 200lb spring it subjected to the same 200 lb load, it will also compress to 8".

John

Antnicuk - 29/10/08 at 10:33 PM

i think i understand that

so the answer is longer or shorter springs wont actually change the amount of travel if the rate is set accordingly.

philw - 30/10/08 at 05:12 AM

As you have altered the location of rear shock mounts, could you have altered the geometry of the rear suspension?

Antnicuk - 30/10/08 at 05:20 AM

the new mounts are in exactly the same as the old points but just an inch higher/taller on the lower arm so as far as geomitry is concerned its no difference to having a slightly longer shock body.

also the car was the same before i did it.

philw - 30/10/08 at 02:41 PM

quote:
Originally posted by Antnicuk
the new mounts are in exactly the same as the old points but just an inch higher/taller on the lower arm so as far as geomitry is concerned its no difference to having a slightly longer shock body.

also the car was the same before i did it.


Surely the the angle at which the shock pivots has changed?

Antnicuk - 30/10/08 at 04:26 PM

the new point is directly above the old one in the same plane and only an inch higher, any minute change in angle is so insignificant compared to the rather large tolerances used when building these chasiss. Even a Mazda RX7 is only built to 6mm tolerances

and the handling hasnt changed since i did it

[Edited on 30-10-08 by Antnicuk]