The fuel cell did hurt my center of gravity. Now tires rub on hard corners.

[CAMAROBOY69]

Just as I suspected, installing the fuel cell above the exhaust like I did hurt my COG. The last time I was out I actually had some tire rub for the first time on the track. It wasnt horrible but it did rub. Keep in mind I have bone stock shocks up front. However I did install QA1 adjustable shocks in the rear. Thank god because without those I would have had more rubbing. I set them to 6 and that worked real well on the track. The front driver fender lip rubs and the rear inside of the wheel well rubs all when I corner hard to the right. After watching the videos I dont think the car rubs at all turning left. Also since Heather is only about 110lb it hardly rubs with her in the car on the track.
Until I get new shocks for the front I will probably roll the fender lip. The only reason the fuel cell is higher is because of how I ran my exhaust. So to get the look I wanted I had to sacrifice some COG. Eventually if I ever had the money I would have a tank made to go around my exhaust. Kinda like an upside down U shaped tank.

[Norm Peterson]

I'd guess that you were right on the edge before, as I doubt that your sprung mass CG raised by more than 0.5" or that the roll moment increased by more than about 3% or 4%. But that's probably enough to turn "occasional light contact" into something more frequent and firmer.

Norm

[zbugger]

Adam, what's the rest of your susupension? Bushings, swaybars, etc.... I remember you just cut your stock coils, but I don't remember the rest of the setup.

[CAMAROBOY69]

Adam, what's the rest of your susupension? Bushings, swaybars, etc.... I remember you just cut your stock coils, but I don't remember the rest of the setup.
The suspension is still bone stock. The bushings in the leaf springs are the only thing new and they are only rubber. I know if I threw new poly or delum bushings in the entire car that would help a lot. The car has almost no body roll at all. Very very little. If I just got some better shocks for the front that would help a lot. Right now all our effort and money is going towards Heathers 67 Mustang to prepare her car for the June 30th road track event at Grattan. My camaro will be out there July 28th. That is an incredible track. Very advanced.

[zbugger]

Well, I was just thinking heavier duty rear shackles and a big front sway bar would help you out better. Even putting poly bushings and endlinks on your front bar should help you out a bit. You don't have to reinvent your car. Little things like that will shock you.

[sinned]

Adam, you can't tell anything about what degree of body roll you are experiencing from the view behind the wheel, only a chase cam would show body roll. Using your tire clearance isn't a valid method either, as you roll the tire will tuck inside the fender so your clearance increases.

[Norm Peterson]

The front seat really is a poor viewpoint from which to estimate roll. Nothing about the periphery of the windshield or any other vehicle reference is flat and horizontal. The real amount of roll that is going on is at least double what you think, and nearly that if you're very careful in interpreting an in-car video and have a good external horizontal reference. I'd swear that my very lightly modded STS car only rolls a couple of degrees or a little bit more. In-car videos might lead me to suspect about 3. But external head-on pics and a roll stiffness evaluation agree fairly well at nearly 6* (only one degree of which is due to tire deflection).

The best estimate of roll that I work up from the videos is about 2* once the car is headed more toward the camera. But that's after the amount of roll has started to decrease (you're past the point of tightest path curvature and peak lateral g), so I suspect that you're getting 2.5* or a bit more.

Evaluation of tire clearances under operating conditions is not a simple analysis, since when the wheels are steered it's all different from what it is when they are in the straight-ahead position. More in some places, less in others.

Better damping will help some, and may eliminate rubbing that occurs during transients (when roll overshoots its equilibrium position). But they won't prevent rubbing if the steady-state roll angle is too great for the available clearance.

Norm

[coony]

Adam, you can't tell anything about what degree of body roll you are experiencing from the view behind the wheel, only a chase cam would show body roll.

I totally agree with this post, everything rings true, and the car looks pretty low, I would definetly say he is riding on the bump stops, probably has almost no clearance while at ride height at the bump stop.

[mustanggirl1967]

he isnt scared at all to drive that car trust me. He beats the hell out of that car everytime he drives it..

[TonyL]

stands to reason then that the car has no real "roll" with the suspension less than an inch off the bump stops. what you may be experiancing is what is left of the suspension jacking around. the rear end may actually be moving left to right causing the rubbing. the higher CG may help sling the weight around adding to this, as well as the beating the car is taking on the bushings.

In other words "slop" may be your issue.

I speak from experiance here. I too used to roll a 70 ekly that was ON the bumpstops the whole time. It battered all the bushings until the car was falling apart. Could be happening to you.

[Hidro]

How much higher is your fuel cell than the stock gas tank location?

Just curious...

Thanks,

[David Pozzi]

Please take the advice to heart, your car is probably rolling more than you think, I also think, but appears to be pretty well within nomal limits. If you turn the shocks up in an attempt to control the stock springs, you can easily over-dampen the car. The QA1's get VERY stiff when you turn them up.

Dennis said in his first comment: "Adam, I would bet with a decent front-end overhaul and some good spring/shocks your tire rub issue would go away."

If you are getting very flat cornering with totally stock suspension, I'm wondering how it's possible, except for super stiff shocks which would reduce roll in short duration corners.

How much bumpstop clearance do you have? Do you still have a stock front anti-roll bar?
David

[gearbanger]

There are some people that have the attitude that there is the best way and then everything else "sucks". That is not correct. Camaroboy didn't say anything about his setup being the best or any of that crap. All he said was that he mounted his fuel cell higher and that caused enough exra roll that he has a tire rub now. Probably so.

[chicane67]

Alrighty. What we are discussing here is weather body roll can be affected by placing a fuel cell higher than the tank was in a car that practically (per Camaroboy69) is riding on the bumpstops already.

Yes. Sure it can effect the CG. Once you place (any) weight it will have an effect, but is its placement bad or good ?? That is the real question. Since the weight was placed higher than, for a lack of better words, the stock location..... it does place the CG some what higher and the effect it has is lengthening the rear 'lever arm' of the CG. This would pretty much effect roll couple distrobution between the front and rear suspension systems independantly.

Now, how much of an effect can this have when your only quarter of an inch off the bump stops (which I am sure it is not) ?? Well, its only gonna move (roll) right up until it gets to the bumpstops. Then you induce bump oversteer.... and possibly worse.

From that point, the car becomes a danger, not only to the driver, but to the rest of the general populous..... road course or not. Its a good thing that the track is a 'controlled environment'.... but it doesnt say very much about the guys in 'tech'.

[gearbanger]

I don't now camaros, but it doesn't look low enough to be on the bump stops to me. How does everyone know that it is?

[6'9"Witha69]

When I first lowered the front of my Camaro w/ Hotchkis 2" drop springs and factory control arms, the frame rode on the LCA bump stops. I had to cut off the top of the pad to allow any real suspension travel.

[David Pozzi]

Just the fact that camaroboy69 is a beginner means each time he drives the car he will likely push it harder and problems will show up. Things like antiroll bar binding or rear spring binding in roll, not to mention the bumpstops or shocks.
I've instructed at autocross schools and ridden in many muscle cars that were lowered too much to handle well. I'm not saying that is the case here, - just that it's a common issue.
I've also ridden with a lot of new drivers, but that's another story...

Adam, there is help and advice here for the taking, but it takes a thicker skin than you have at your age.
Keep having fun with your car, you'll learn a lot.
David

[MrQuick]

There's some good advice here and its up to you to try or to keep an open mind to them. There is probably about 150 years of experience in this thread alone...well page now that im here.

I know your trying the lowbuck approach here but after time something is going to give. Last time I checked a stock set of bushings will last 3-30 good runs at the track. I know you wouldn't trust your motor mounts to that kind of punishment. ....hey ive been cenc..muummyuyu j/k

[TonyL]

All righty then.

I've broomed all off topic and unhelpful comments from the thread.

Please continue. ON TOPIC. any disrepectful remarks will be dealt with.

If you're post was deleted and or edited, sorry. Don't take it as an attack. It needed to be done. the tech advice was too valuable.