NotAMurasama

[QUOTE=Turn-R-Us,Jan 28 2008, 11:04 AM] no difference between stiffer springs and no bar ...and same springs and bar.

KeeblerElf

I'm pretty sure Turn-R-Us meant for the stiffer rear to cure understeer, since that's basically what a stiffer rear does. If one end of the car has more resistance to roll (via an anti-roll bar, springs, whatever) it will experience more weight transfer across its two wheels. Since tires are not linearly efficient, increasing the weight of one tire by 50% doesn't increase its cornering ability by 50% but decreasing the weight of the other tire by 50% roughly decreases its cornering ability by 50%. So the net result is the stiffer side loses more grip than the softer side.

Antonov

AutoX, HPDE, and DD. I have nothing to prove on the street. Aside from the occasional off/onramp, I drive really mellow. I really am looking to get as much seat time as possible, weather its karting, autox or hpde's. I am not setting my car up for autoX.

My thought was to completely pull the rear sway bar and compensate for the loss of roll resistance with higher spring rates in the rear. I was think of bumping the rates by about 150# to simulate the OEM rear bar. By removing the rear roll bar, I am effectively making the rear suspension even more independent thus tuning out inlifting. I really like the way the balance was before, and I don't want to spend even more money on a new front bar.

What do you guys think is a good about of spring to compensate for the rear roll bar?

INTJ

Nope. The sway bar allows for roll resistance without massive spring rates. There is no way it would benefit you to do that.

mikegarrison

I don't think I would say "there is no way it would benefit you to do that". A lot of people in this forum over the years have advocated removing the rear bar to help with inside rear wheel lift (among other things).

krazik

I'm going to a clutch type diff because with my extra power I'm not albe to over come it anymore. NA what I had worked very well.

Tires are usually RA1s or Hoosers. #'s are just an idea for stagger. You shouldn't use anyone's exact #'s here but will give you an idea how to change setup to get waht you want the car to do.

Tires: 275 x 4
Front:
-4 to -4.5
toe to taste
900 lbs front spring
saner 1.25" solid sway bar, on softest usually
Rear:
-3 to -3.5
toe to taste
1200 lbs rear spring
no rear sway bar

Brownergy

^nasty tasting toe

Can anyone elaborate on the ill effects of removing the rear sway but adding more spring? Is it just that the rear end is stiffer not allowing it to plant as well for acceleration out of the corner? ....... and also, what would be the negative effects if you later added a wing, would you need even more spring in the rear?

Sorry for the thread hi-jack and good luck euro!

krazik

In basic terms:

Sway bar reduces roll without significantly increasing wheel/spring rate. As expected when you remove it you get a lot more roll (sway) and you gain more grip from the additional compliance of the soft suspension. Then you have to increase spring rate to combat that roll and balance the grip. Increasing the spring rate makes that end stiff/less complaint causing the rear end to break traction sooner. So then you counter act the added oversteer by adding more front sway bar.

There is a handy cheat sheet that has been posted many times before that lists simple changes and their effect.

More front spring = less front grip
Less rear swaybar = more rear grip
Tire pressure +...
etc

Antonov

what's your theory?

krazik

Since many of us have done quite well w/o it.