Exactly! If the car is set up right, you don't need crazy stuff springs.
My car is lower now than usual, but it's typically pretty high, for just this reason. I just wish I had everything I need to figure out the optimal right height.

Interesting. I've played around with rake to try and mimic some more traditional race car set ups and found a higher rear definitely made it more unstable in the rear. That being said, I didn't adjust the camber to validate the adjustments.

Aaaalways do an alignment after any adjustments. Or do you just mean you didn't try a different setting?

Reducing rake to 13mm had a positive effect on my car's handling.

Hey kaj, yep I remember you telling me about the 13mm rake, kinda small for yard work... What I was trying to say was, after raising the rear by a few threads on the coil-overs, the rear end was just not as planted through the corner as it had been prior to changing it. This is where I should have checked out my rear camber settings to see how much they varied, because for all I know it was the camber that made the rear end unhappy, not the change in rake.

Gotcha. So you hadn't redone the alignment yet. Yeah. That could do it.
Adding rake to my car induces understeer (opposite of your experience), but I've always done alignments after any adjustment so I'm unsure what happens with camber.

continuing on with the 'camber rules all' idea.

raising the CG of the car by increasing ride height (but then readjusting the camber back to the initial setting) causes the car to roll more (more deg/g) which makes the front tires hit their positive camber performance limit at a lower lateral acceleration, thus more pushy.

without doing the math for my actual cg, roll center, etc i'm not completely certain, but the theory is sound.

i really would like to blueprint my suspension to see which numbers come up. i think it's time to start compiling all this info into a how-to/check list so i can get busy.

I just had NASIOC flashback to me talking about rake changing the car's balance and assuming that .4 of negative camber in the rear wasn't that big deal and having Marshall point out that it was

http://forums.nasioc.com/forums/show...highlight=rake

All this reminds me is that the more I learn, the more I realize I know nothing

Interesting, I bought my AST's brand new with the AST recommended 14k F 16k R springs for race rubber. Not a bad setup. I had a Whiteline 26mm FSB and OEM 22mm RSB on with them.

However, the rear end of the car seemed too stiff. Taking bigger rumble strips the rear end of the car would get tossed and do the skip-hop crap as I tried to drive off apex. But the front felt good.

So I rolled the dice on what i have read on here and ordered 14k R springs and installed a Whiteline 24mm RSB, so now I am 14k square on 275 A6/7 Hoosiers.

Wow, so much better. With the bigger RSB I softenend up the fronts and the rears as well. The car is very neutral. I really have to massively overcook a corner entry to get understeer. And going to throttle generates just a slight oversteer/rotation that is easily drivable.

Lots of other work done, 12 plate diff, ACD reflash, PSRS, Ciro Plates, Robi Sphericals. but the square setup is definitely working for me right now.

Interesting indeed.
switching from a 22mm stock rear bar to a 24mm aftermarket rear bar is a bigger increase in roll stiffness than softening from 16k to 14k springs. So overall a net increase in the rear roll stiffness with that change.

Actually effects of roll couple are more dramatic than just forcing yourself to run with slightly less/more camber. The two effects manifest themselves in handling deficiencies in completely different ways, so i don't think you know what you're talking about.

Except raising ride height also raises the roll center, and the roll center moves a lot on a strut suspension. Body roll is dictated by the COG's position relative to the roll center (since the roll center is the point on which the car rolls), not the ground, or the tire, or really anything else.


Changing a sway bar is different than changing spring rates in regards to chassis balance and tire grip. The stiffer springs although stiffer, still allow more independent wheel movement. The stiff sway bar limits independent wheel movement. But then he also softened the dampers front and rear. You also don't know what stiffness he set the whiteline bar at. But I can see how the setup changes brought the car to be more neutral. Especially with softening the dampers in front giving the front end more grip.

The 24mm RSB is on the middle setting, where I started. I like to drive a setup quite a bit before changing, then change one thing at a time and re-evaluate. Slow, but I do learn that way.

The AST 5100's are single's and the front is set at 7 clicks, rear at 3 clicks (from full soft, 12 clicks total adjustment).

Alignment is Camber 3.6 F, 2.1 R, 5.8 Degrees Caster, 0 toe F and R.

That depends on the bar and setting. Hotchkiss 24mm is hollow and about 10% softer than the Whiteline 24mm.

My numbers show that the difference in roll rate going from 16k to 14k with Hotchkiss will be lower in first two holes and higher in last hole. 24mm whiteline moves that to lower in first hole and higher in last two holes. That is my numbers can be trusted...

Either way, its about the same in roll rates. with a range of adjustment.

I wish more of us would add this type of information when having suspension conversations.