S14 Car Height

[floodo1]

So I was reading a Dave Coleman Q&A page and he said

On your hot dog-and-ramen budget, I'd recommend the Koni Sports (at around $560) and the stiffest, tallest lowering springs you can find. Eibach Pro-Kits (Sportlines are lower, so stay away)

Is it really the case that you should try to keep basically stock ride height? I mean this can't really be the case right?

I read on here that the car needs lowered 3-4" for good roll center location, and then someone else randomly on the intarweb said again that stockish height is good.

what gives?

[Def]

He was talking about "stock sized" springs, which are generally too soft for hard driving. To compensate you want the ones that don't lower the car much so you can get more suspension travel and spring force before you hit the bumpstops.

With a coilover suspension that you can get the rates up this is not applicable.

[Gearhead_42]

You can lower more... if you have the budget for the camber plate and RUCA replacements necessary to correct the alignment... but then you're operating the shocks outside their recommended travel range, and you start chasing in circles with the price increasing as you add coilovers, shorter shocks, etc.

Personally, I wouldn't lower more that 1.5" on "stock" type shocks.

[racepar1]

I'm sure he was referring to how soft most aftermarket stock style springs are. But he could have been referring to the roll center as well. As you lower your car the roll center of the suspension drops more than the center of gravity of the car (approximately 1.5-2x as much) this basically gives the weight of the car more leverage on the suspension resulting in more body roll and the need for stiffer springs to control it, which has negative effects on the handling of the car in other ways. I am not as much of a roll center whore as I used to be thanks to a conversation with wisass, but there is a happy median. Slamming your car is not good for performance unless you have adjustable LCA's to correct the roll center. On the other hand lowering it a reasonable amount will have more benefits than negative effects. If you want a basic understanding of basic and advanced suspension angles go to SCC magazine's website and read their "make it stick" articles. There is a lot of good basic info there.

[floodo1]

sorry guys, i think i should have phrased my question a bit better.
Firstly I have a really solid understanding of suspension, based mostly on R/C Car racing (road course sedan, and oval), imca asphalt car, and steve smith reading.

After reading what you guys posted I'm thinking that Coleman said not to lower your car much because the guy he was giving advice to didn't have much budget, which probably means no way of adjusting camber, and def not roll center or camber rise.

So I suppose my question should be, what about someone with a bit more budget. No aftermarket LCA's, but upper mounts, ruca's, tie-rods (spl with spacers), toe link. Given these mods how much should the car be lowered to maintain decent camber curves and roll center heights?

finally, as something of an aside, what is ideal? car really lowered, but lca's used to maintian something like stock cg v. roll center height?

[racepar1]

Ideal would be as low as possible with all the suspension angles corrected with adjustable arms and/or re-locating the pick-up points on the chasis and subframe. Lower center of gravity is always better as long as your suspension angles are all corrected and you still maintain full compression travel. Without correcting roll center I would say 2 inches or so is about as far as I would feel good with. Low enough to look aggressive, lower the center of gravity, and close the wheel gaps pretty well. But not so low that your control arms are pointed straight up and the roll center is like 4 feet below the ground. The main thing that you need to watch on out front macpherson strut type suspension is the angle between the LCA inner pivot point to the ball joint pivot point and the upper mount pivot point to the ball joint pivot point. Once this angle exceeds 90* the suspension starts gaining positive camber. The truth of the matter is that it is hard to give you an ideal number. I think my ride heighth is pretty much ideal, but I didn't measure how much I lowered it. I simply figured out where I wanted the front by looking at the compression travel and the angle of the control arm and then adjusted the rear from there to achieve the stance I wanted.

[ecugrad]

not so low that your control arms are pointed straight up

That's the non-engineering guy rule of thumb I have always gone by.

[@llan]

that SCC magazine's make it stick article is really easy to understand and helped alot.
thanks