Ride height to low hinder you handeling?

[SA E30]

In terms of pure grip, the point at which your strut axis is perpendicular to the control arm is the crossover in the camber curve derivative--the point at which your dynamic camber is maxed out, and you will begin to lose negative camber on compression instead of gain it. Generally you'll want to set the ride height a good margin north of that point.

But "handling" is not quite as simple as camber curves, you also have to take into account the tie rod geometry, bump steer (and toe steer especially) is never fun. Strut travel, etc are also obviously equally as important.

That's quite a generalization at the travel needed is dependent on spring rates. So if you are running stiffer springs you can theoretically run the car lower before as it takes more force to compress the springs and get to the point in which the strut starts gaining positive camber.

[87e30]

Question wasn't meant to be rude, it was a genuine question. Very interesting thread, thanks!

[E30Pedia]

H&R Cup Kit springs are not for the track. They are far too soft. Get some real suspension (coilovers), and then play with the heights.

Erik

Cup Kits are too soft, i agree, but sway bars help to take away the body roll. I have driven cars that are on really stiff springs, and it felt like i was riding a skateboard. The car was too bouncy. It felt very sketchy when driven fast over bumps.

Yes and No. It is one way to control body roll but you can also do it with springs.

The downside to sway bars they don't allow the wheels to act independently.

The downside to using springs is that it can make the car over sprung and jumpy on a not so smooth track.

So would Softer springs ( Between 300-350lbs front and 400-500lbs rear) and a thick sway bar be a good combo?

[Iain]

Ride over bumps also has a lot to do with dampers (shocks) and bushes.

IMO you never, ever look at suspension as individual pieces - when modifying suspension I always try to envisage how all the parts work together (tyres, bushes, springs, shocks, sways, even wheels if they're very heavy or very light).

[Massive Lee]

Swaybars are to balance front grip vs rear grip, allwoing to tune handling - understeer vs oversteer . Using swaybars to keep the car from rolling is totally inadequate. This would be the job of the springs. Whoever wants a soft ride should b a 1970s Cadillac...

[daniel]

i made the mistake of installing the cup kit on my first e30, and yes it is way too soft for how low it goes.

[z31maniac]

Cup Kits are too soft, i agree, but sway bars help to take away the body roll. I have driven cars that are on really stiff springs, and it felt like i was riding a skateboard. The car was too bouncy. It felt very sketchy when driven fast over bumps.

That's because of poor damping, not spring rates.

My E30 on 550/750 rode suprisingly well on 40 series 17" tires, because the damping was where it should be.

[JMil86]

Wow. There's a ghetto in Portland?

Yes, but only for Mexicans.

If your oilpan/frame/exhaust/spoiler/whatever are scraping the ground at all times thats when you know you are at ideal ride height.

[mnstepchildrider1]

A car that is heavily lowered needs to have its suspension geometry modified to account for the lowering: some type of roll center spacers for the control arms and steering arms, raising the subframe, etc.

The lower the car, the stiffer the suspension should be. And not all tracks are friendly with extra stiff suspension. You don't want your car to bounce on bumps.

BTW we are talking track stuff, right?

BIR in MN turn 1-2 your car will literally HOP if you suspension is to stiff :rofl:, i have seen a 944 hop towards the outside line:rofl:
I'm sure the driver was crapping himself and it wasnt fun for him but it was quite the site

[erik325i]

That's because of poor damping, not spring rates.

My E30 on 550/750 rode suprisingly well on 40 series 17" tires, because the damping was where it should be.

Agreed. You need to match the dampers with the spring rates. My previous e30 was running 450/750 springs and it rode smooth.

Erik

[ThreeTwentyFissel]

Interesting! So a coil-over sys is the best way to control ride height/handling/body roll/etc? I need to know more please, this is my starting point (Suspension).

[Kolia]

Good thread.

Its refreshing to hear knowledgeable comments on suspension selection.

Interesting! So a coil-over sys is the best way to control ride height/handling/body roll/etc? I need to know more please, this is my starting point (Suspension).

Unless you plan on adjusting your ride height for every track, you don't really need that option.

A major drawback of a full coilover on an e30 is that it doesn't use the OEM suspension mounts anymore. The body is simply not made to take the loads that way.

Plus, most racing class will not allow these kinds of conversion. You usually have to use the OEM mounts. That means that most serious racing bits aren't made using coilover. Also means that, by choosing a coilover that nobody races with, you don't have access to all the suspension setup knowledge of the race/track crowd.

People tend to think that lowering a car will improve performance by lowering the CG. That is unfortunately not the case. Lateral G improvement from a 50mm lower CG might be in the order of 0.02G. The big improvement in feel and response is usually from the camber and toe gain in a static state.

All the theory is great. But at the end of the day our options are limited by the chassis we have, our budget and the uses we have four our cars.

[karimMsalama]

coilovers + low = drift

[bataangpinoy]

um, whoever started tha whole coilover+low=drift theory should be shot. a drift car needs more than just new shocks and springs. at a minimum, the swaybars and all the suspension busings need to be upgraded or replaced.
a well balanced, well built suspension can do anything its tuned to do.

im so tired of hearing that coil+low only bullshit.

you dont need coils to drift, and you dont have to be in the dirt either. the car just needs to be built correctly.

/rant.



and having a car set too low will hinder the car's performance. aside from the shocks bottoming out, the roll centers need to be re-positioned and that is often very costly and time consuming venture. and as you go lower, the cars camber will increase causing the need to intall and use camber plates and some sort of camber kit for the rear.

[JGood]

Good thread.

Its refreshing to hear knowledgeable comments on suspension selection.




Unless you plan on adjusting your ride height for every track, you don't really need that option.

A major drawback of a full coilover on an e30 is that it doesn't use the OEM suspension mounts anymore. The body is simply not made to take the loads that way.

Plus, most racing class will not allow these kinds of conversion. You usually have to use the OEM mounts. That means that most serious racing bits aren't made using coilover. Also means that, by choosing a coilover that nobody races with, you don't have access to all the suspension setup knowledge of the race/track crowd.

People tend to think that lowering a car will improve performance by lowering the CG. That is unfortunately not the case. Lateral G improvement from a 50mm lower CG might be in the order of 0.02G. The big improvement in feel and response is usually from the camber and toe gain in a static state.

All the theory is great. But at the end of the day our options are limited by the chassis we have, our budget and the uses we have four our cars.

Most off-the-shelf coilover kits, such as what ground control offers, use coilover front struts, which don't change the mounting points, and a stock style shock and spring in rear, with adjustable spring perches - again, not changing the mounting points.

I'm not sure what racing classes you are referring to, but spece30 and maybe a few other stock-oriented classes are the only ones that require stock style spring/shock setups. There are many classes that allow for a coilover type suspension, and even moved/modified pickup locations (wouldn't be all that hard to reinforce the rear shock tower for a true rear coil-over).

Coil-overs allow for great adjustability in preloading and corner-balancing. The benefits are only worth it to those who take the time to set up their cars properly though. I have to laugh at people who buy coilovers thinking their car will now somehow handle better simply due to the fact that it's a coilover setup.