Vehicle Stance?

[skyguy61]

Hey Sydneykid,

Would a Skyline or any car handle better if the stance of the car was level? most cars seems to be lower at the front,Id like to lower the rear of my car by 1/2 inch to 1 inch by cutting the rear springs cutting 1 coil off each spring only, would that be okay or would i lose too much spring rate?The car has stardard springs at the moment, I am going to upgrade the suspension in the future but right now im spending money in other areas, your advice would be appreciated. Cheers

[rgr34]

hey there your goin to get flamed on here for wanting to cut ur springs.....saying that i have cut springs on previous car which was shit daily....... have to say it worked out alrite the spring rate didnt seem to change much.....in fact it felt better than when i put kings springs in with the stock shocks..... this was on a vn commo..... id recommend u get proper springs/shocks for a skyline....... or reset the stock springs if you want to be cheap........

Edited June 14, 2007 by rgr34

[Sydneykid]

GTR's handle best around 355 mm front and 345 mm rear (centre of wheel to guard), GTST's around 350 mm front and 340 mm rear. This gives around 10 mm of rake, that's nose down as measured at the sills, just behind the front wheel and just in front of the rear wheel.

As for the reasoning behind that, I don't know how technical you want to go. The principle is to keep the roll couple (RC) somewhere close to standard while lowering the CoG (centre of gravity) and maintaining a reasonable CoR (roll centre). If you lower it too far, the CoR rapidly gets too low, sometimes below ground level. The CoG can't possibly go that low, so you end up with an enlarged RC. Without getting technically too deep, the problem becomes more complex with Skylines, as the front and rear CoR's each individually change dramatically with height, so you end up with disparate RC’s front and rear. This manifest itself as unpredictable understeer and/or oversteer, depending on roll, tyre slip angle plus power and steering input. Nasty things to drive, that bite.

That’s handling covered (in simple terms), ride comfort is another issue. Basically you end up with insufficient travel to soak up bumps and the thing crashes into the bump stops, eventually wearing them out. With no bump stops to protect them, it then smashes the shocks into pulp and the chassis cracking starts to appear.

Pretty simple this lowering stuff isn’t it?

cheers

[Basti]

SK i just got out of an exam. cut us plebs some slack will ya? my head hurts just reading that stuff. (im just kidding, seems to be a very helpful post as usual - just need sometime to figure out what some of those words mean)

[T04GTR]

yeah the norm is 10mm rake to the front