I had brought up the question of body roll last year. As I stated then, my car feels like it handles fine. I know I'm more softly sprung than my competitors (I use H&R Race springs, which happen to be progressive), but I'm not far off the pace of those with identical cars and much more experience than me, so I don't think I'm losing much time over this issue. It brings me back to my question "Is body roll always bad"?

These photos are from WGI. I think that the springs are compressing to the limit of the softer rate (of the progressive spring) and then taking a set. Opinions?

compared to this (non-turning)


Here is the beginning of the chute (I think perspective makes it look worse than it is here):



[Modified by Civic44, 5:37 PM 2/13/2003]

 

I would think by 'rolling' the car's weight from one side to the other would limit traction and stability. That body roll you have pictured does look a bit much for a road racer. Do you have a swaybar mounted?

 

I don't have sway bars. But rather than invest in them, I would prefer better shocks and/or springs.

 

yeah, your car rolls a lot. is it bad? provided you have enough static negative camber, or you are gaining enough camber as the car rolls, only in transition would the roll be bad. a car that rolls more would theoretically take a longer time to set, thus being slower in transitions. however, a car that rolls less won't require as much static negative camber, giving you more rubber on the road in a straight line and as such better braking/acceleration grip. generally speaking, less roll is better, but like anything, limiting body roll past a certain point starts to have less of an effect, even a negative effect.

nate

 

thats nothin.....

 

Further down the chute:

It doesn't look as bad in this pic (but it's further down the chute).

 

now is that truly body roll? or is that the plastic shell sliding to-and-fro on the frame?

nate

ps rj, what's the latest on the car story?

 

thats tupperware flex right there homeboy. Even with all the body flex the car is very easy to drive. Roll bar helped that out some.......

Car should be emerging from the hack (err body) shop this week with the frame un-tweaked, new hood/fenders/headlight assys/bumper cover/etc. I havent driven the car in nearly two months. Ready for VIR? Probably. I may be driving an Integra at VIR anyways.

 

it's easy to drive cause it doesn't have enough horses to get you in trouble. i drove an s2k last year and had it sideways all over the place, purely because it had so much more power.

nate-who would crap his pants if he had to drive a z06.

200th hi-jacked thread. am i h-t's most wanted yet.....?

 

z06..... hmmm........... actually the C5's handle very well. A friend of mine described it as similar to a miata in that it was light on its feet (err tires) and responded very quickly and had very good brakes - just with about 8 times more grip and HP. The last RWD car i autocrossed was a 100 whp RX7, and it was sideways everywhere - Dorifto!!!

 

In regards to spring rates, to a certain extent, they only need to be stiff enough to keep you off the bumpstops. If you aren't bottoming, you're stiff enough.

What shocks are you using? Since your rates a on the soft side, you probably don't need anything too fancy.

And KISS. I think people get in over their heads with fancy multi-adjustable suspensions. If you can't set it up, you'd probably be better off with a non-adjustable setup.

Just for reference sake, compare the fast lap times of MARRS SRX-7s (street springs, Tokico Blues, and a front swaybar) to MARRS ITA RX-7s. Currently, the fastest SRX-7s typically turn laps in the 1:33s and 1:34s. The record is in the 1:32s. The fastest ITA RX-7s turn laps in the 1:31s. The record is in the 1:29s. The ITA cars have tri-link rears, adjustable shocks, coilovers, roll-center spacers, weigh 300lbs less, and have 25 more hp to the ground. All that, and most days they can only get a 2.5 second advantage.

But the real story is in the performance of the upper-mid-pack cars. The top SRX-7s are pretty darn close. The top ITA RX-7s are all over the map. Some days, the SRX-7s could give the ITA RX-7s a good run and beat most of them. And I attribute that to the KISS priciple - the Spec cars are almost idiot proof.

 

What was the point of what I just said?

If you're happy running where you are - and you're still making noticable improvements as a driver - I vote for not messing with your setup too much.

If you think your car is maxed out. Or you just have to gain an extra couple tenths per lap. Or you just have a hankering to tinker. Then by all means, stiffen up the car a bit.

BTW - my car hits the bump stops at turn 8 at Summit Point. Turn 8 being the righthand, uphill sweeper before the bridge. It ain't fun, but not much I can do about it given our rules (maybe it's time for me to start messing with spring spacers and stiffer bumpstops? )

 

this is an old-school rule of thumb imo. back in the old days, tires weren't very good and required some relatively high pressures to work at all. the general tuning theory back then was a spring stiff enough to keep you off your bumpstops then use swaybars to minimize roll and balance the chassis. this is also the approach used on cars that have purpose built suspension layouts, with bump steer and camber curves optimized to a much higher level then street cars.

what a lot of people are doing now for chassis setups (and what carol smith promotes now) is to use a spring stiff enough to minimize unwanted suspension geometry changes. less bump travel as a car rolls will reduce the amount of bump steer you get and so on. this setup theory also lets you use a significantly lighter sway bar and reduce the lateral weight transfer created by the swaybars themselves.

i do agree with the k.i.s.s. approach. the more things you can adjust, the more things you have the potential to screw up. and like rr98itr pointed out, it is very difficult to change one thing and not effect several others. the end result is a change that may have improved the car, but not in the way you thought it would.

nate-who got his shocks revalved but didn't opt for the DA conversion

 

I raced my CRX with relatively low spring rates (325f/250r) and was very happy with it. I had tons of body roll, but it handled well, and I was comfortable with it. I never had problems keeping up with other, uber-stiffly sprung, CRXs through the bends. My Civic has higher spring rates, and I'm nowhere near as comfortable with it in the turns.

I for one do not agree with the theory that stiffer is better. Well, not with cars at least. If you are comfortable, and not losing time to the other cars through the turns, leave it alone.


Matt

 

a softer sprung car is easier to drive for a newer driver.

like i said, provided you can still use your tires well, a softer car won't be any slower once it takes a set. it will be slower transitioning from straight line to .9 g's cornering though. this is a good thing for a n00b who whips the wheel back and forth, not so good for someone who wants the car to respond immediately.

nate

 

Hey .RJ, do those things even have any steel in them? How come the shop didn't just "super glue" it back together like the REVELL snap-tite ones?

And what's with the open sunroof??? Got an ejection seat in that thing or what?

Just Kidding: Seriously though, I gotta give ya some props for racing a Saturn ...I don't see that everyday...to many wusses behind the wheel of those things. Long live mobile tupperware.

 

It is rather amusing to always be at the event as "that guy in the saturn". Dan Unkefer came to commend me in my flogging of the tupperware at VIR last october.