Body Roll! Pics

BurningRubber · Jul 26, 2010

A shot from the autocross at Mustang Week. I didn't know I was driving a truck around the course until I saw these shots...

Roush springs, J&M adjustable LCA's, Tokico shocks out back, have the front struts waiting to go in as soon as I can bust my old ones off, and Bullitt bolt-on subframe connectors...

I need some different springs and a stiffer swaybar out back. I'd like the front to sit lower but then I'm looking at CC plates, which would probably be a good investment anyway.

sneaky98gt · Jul 26, 2010

Pretty cool pics despite the body roll. I'll bet mine is worse...I'm sitting on a bone stock, 100k mile worn out suspension. It rolls like a mother...

I'm hoping to go to an auto-x track at least once before Christmas. The drag strip club at State supposedly goes a couple times a year, but I didn't get involved this past year until after they went. I look forward to trying it.

sneaky98gt · Jul 26, 2010

BurningRubber · Jul 26, 2010

sneaky98gt said:
Pretty cool pics despite the body roll. I'll bet mine is worse...I'm sitting on a bone stock, 100k mile worn out suspension. It rolls like a mother...

I'm hoping to go to an auto-x track at least once before Christmas. The drag strip club at State supposedly goes a couple times a year, but I didn't get involved this past year until after they went. I look forward to trying it.

Man auto-x is a blast! I looped my car going around the outside corner sometime during the night. I was trying to see how far I could push it, and I found out...

Thanks, I like the pics too even though it's rolling like a SOB, lol.

40oz · Jul 27, 2010

That's hardly enough body roll to comment on

Unless you have wider rear tires and experience understeer when you get on the throttle, a stiffer rear bar won't do anything but make the rear looser and hamper your ability to put power down around a curve. Stiffer springs will only make your car a PITA over every bump and expansion joint and decrease your car's ability to soak up road imperfections without losing traction.

Body roll isn't inherently bad for handling, it is mostly a driver/passenger comfort issue. Stickier tires will increase body roll as the tires can hold the same line at a higher speed. If body roll was inherently detrimental, stickier tires would decrease cornering ability and make for slower lap times.

Here's an image of the body roll on a normal street car, for rational comparison:
http://corvetteidaho.com/hib/assurance/images/553.05.jpg

You can eliminate body roll completely with stiffer springs, but you will also eliminate your suspension's ability to absorb road flaws without upsetting the car. And the last thing you want going around a corner is your car bouncing around. Unless you are bottoming out your shocks going over expansion joints and railroad tracks, your springs are probably stiff enough. And unless you experience understeer whenever you try to get on the gas going around a corner, your rear way bar is fine.

A stiffer sway bar on the rear will make the rear step out sooner when you apply power around a curve. If you have wider rear tires, a stiffer rear bar is a decent idea, but I'd look for one with adjustable end links so you can control how much rear lateral traction you give up to gain front lateral traction. Because a stiffer sway bar will reduce lateral traction at that axle but increase lateral traction at the other. In a FWD car, a stiffer rear bar is a benefit as it allows the you to rotate the car instead of just understeering off the road. In a high-torque RWD Mustang, a stiffer rear bar will enhance the tendency of the rear to step out. It can be a good thing if you have more rubber out back than in front, but it's a bad thing if you aren't having issues getting the front to bite on turn-in.

The goal of "zero body roll" is best left for open wheel race car designers.

IOW, it looks good as it is. Don't buy parts to make your car look better in pictures unless that's your only goal.

BurningRubber · Jul 27, 2010

Wow, awesome info 40oz, thanks...:thumb:

The feeling of the car rolling doesn't bother me at all. It actually doesn't feel how it looks like it may feel inside the car, if that makes sense.

I mentioned a stiffer rear sway bar because I am running a staggered wheel/tire setup and the front end plows pretty hard when it's pushed through a corner. I'd rather have the rear step out than experience severe understeer.

No doubt my tires (or lack of real good tires) play a part, but I think a stiffer rear sway would help as well.

40oz · Jul 27, 2010

BurningRubber said:
Wow, awesome info 40oz, thanks...:thumb:

The feeling of the car rolling doesn't bother me at all. It actually doesn't feel how it looks like it may feel inside the car, if that makes sense.

I mentioned a stiffer rear sway bar because I am running a staggered wheel/tire setup and the front end plows pretty hard when it's pushed through a corner. I'd rather have the rear step out than experience severe understeer.

No doubt my tires (or lack of real good tires) play a part, but I think a stiffer rear sway would help as well.

I'm with you on the understeer issue.

There are a few things to try first that are free.

First, front tire pressure is really important. You don't want the tire to be rolling over when you turn. Before buying anything, add pressure to the front tires and see if that helps. Too much pressure will start increasing understeer again, but often you need more pressure in the fronts than rears to keep the tire planted across the tread width. You can start with increasing it to 5 pounds over the factory suggestion. I move in two pound increments up or down from there until I know which direction I want to go.

You can also play with rear tire pressure the same way. I spent last summer running 37 psi front and rear, but 38 psi made the car skittish if the corner had any bumps or divots - turned quick, but felt like you had little connection to the pavement unless it was perfect. Ultimately I took it back down to 35 front, 32 rear because it almost felt like I was riding on basketballs Hard to believe that a single psi made that much difference, but honestly it did. However, at some point you tire of splitting hairs and pick a comfortable pressure and call it a day for daily driving. But if your wider rear tires are doing their job but overpowering the front tires, you could benefit from technically too much pressure in them until you can address the issue with a sway bar.

Second, make sure you are using the brake prior to turn-in. A quick stab is all that is required to transfer the weight to the front and make the tires bite. It's really easy to do it right, just a quick stab of the brakes and turn the wheel and the front will either hook and yank the front that way or you'll hear the tires squeal as they roll over/slip. ~35 mph is a good test speed. Done properly, you don't lose much speed but the traction difference is huge. Apologies if you already do this. It took me a while to figure it out for myself.

I actually want to feel the suspension compress when I do this as it means the tires are grabbing.

You should be able to get on the gas pretty quick without losing traction (not slamming the gas to the floor, just pouring on the power). If the front starts to slip when you apply the gas, you definitely want a stiffer rear bar.

You want an adjustable rear sway bar. The advantage is you can tune it to what you need rather than just bolting on a piece and hoping it makes things better. A number of companies make adjustable bars, you just want on with more adjustability rather than less. The Steeda one looks better than the H&R piece in that respect, for example, but ideally someone who has tried each can offer input.

I use a cloverleaf near here for higher speed "testing," as it is consistent and safe during low traffic periods. I use city streets and empty parking lots for lower speed testing. You can learn quite a lot without breaking the speed limit. Quite honestly, the stock configuration is quite good with proper techique. To really make it better you need to pick your mods with care rather than just buying a package from a vendor and calling it a day.

Just like drag racing, better tires are the best performance mod. But if you can get the car to drive the way you like, better tires just make it perform better. Putting stickier tires on a sketchy suspension won't fix anything. You'll appreciate the better tires more when the car's behavior is sorted out to your liking.

Deleted member 38176 · Jul 27, 2010

Good God your rear tires look like steam rollers in the first pic!

*EDIT* nevermind, part of the toppled cone looked like part of the tire lol

BurningRubber · Jul 27, 2010

40oz said:
I'm with you on the understeer issue.

There are a few things to try first that are free.

First, front tire pressure is really important. You don't want the tire to be rolling over when you turn. Before buying anything, add pressure to the front tires and see if that helps. Too much pressure will start increasing understeer again, but often you need more pressure in the fronts than rears to keep the tire planted across the tread width. You can start with increasing it to 5 pounds over the factory suggestion. I move in two pound increments up or down from there until I know which direction I want to go.

You can also play with rear tire pressure the same way. I spent last summer running 37 psi front and rear, but 38 psi made the car skittish if the corner had any bumps or divots - turned quick, but felt like you had little connection to the pavement unless it was perfect. Ultimately I took it back down to 35 front, 32 rear because it almost felt like I was riding on basketballs Hard to believe that a single psi made that much difference, but honestly it did. However, at some point you tire of splitting hairs and pick a comfortable pressure and call it a day for daily driving. But if your wider rear tires are doing their job but overpowering the front tires, you could benefit from technically too much pressure in them until you can address the issue with a sway bar.

Second, make sure you are using the brake prior to turn-in. A quick stab is all that is required to transfer the weight to the front and make the tires bite. It's really easy to do it right, just a quick stab of the brakes and turn the wheel and the front will either hook and yank the front that way or you'll hear the tires squeal as they roll over/slip. ~35 mph is a good test speed. Done properly, you don't lose much speed but the traction difference is huge. Apologies if you already do this. It took me a while to figure it out for myself.

I actually want to feel the suspension compress when I do this as it means the tires are grabbing.

You should be able to get on the gas pretty quick without losing traction (not slamming the gas to the floor, just pouring on the power). If the front starts to slip when you apply the gas, you definitely want a stiffer rear bar.

You want an adjustable rear sway bar. The advantage is you can tune it to what you need rather than just bolting on a piece and hoping it makes things better. A number of companies make adjustable bars, you just want on with more adjustability rather than less. The Steeda one looks better than the H&R piece in that respect, for example, but ideally someone who has tried each can offer input.

I use a cloverleaf near here for higher speed "testing," as it is consistent and safe during low traffic periods. I use city streets and empty parking lots for lower speed testing. You can learn quite a lot without breaking the speed limit. Quite honestly, the stock configuration is quite good with proper techique. To really make it better you need to pick your mods with care rather than just buying a package from a vendor and calling it a day.

Just like drag racing, better tires are the best performance mod. But if you can get the car to drive the way you like, better tires just make it perform better. Putting stickier tires on a sketchy suspension won't fix anything. You'll appreciate the better tires more when the car's behavior is sorted out to your liking.

Yes, big mistake I made last year was running the front tire PSI too low. I upped it by about 5-6 lbs this year and it did help a lot! Before the car would just plow the front end anywhere, this year it still understeered but the feeling of the tires rolling over in the front was much, much less.

The rears are at 32psi I think. I didn't mess with their pressure as I didn't think it affected performance like the front, but thank you for shedding some light on them as well.

The course was fairly low-speed, but the braking was done prior to turn in, in most cases. You can feel a HUGE difference between getting on the brakes ahead of time, transferring weight, and hitting a turn as opposed to trying to brake hard through a corner.

I was able to start powering out of the corners pretty well, despite it being wet. The rear tires actually work pretty well in the wet given the surface isn't slicked up with oil (like a wet highway). Getting sideways wasn't an issue until I pushed it on a wide corner.

I'll look into an adjustable swaybar when the time comes to upgrade. The SCCA does a few local autocrosses year-round, and I'd really like to get into doing them. Their courses are much, much faster and wider, but I think the speed cancels out the extra width of the course.

Thanks again for taking time to write all that up. That's what makes this site awesome...

Nightfire said:
Good God your rear tires look like steam rollers in the first pic!

*EDIT* nevermind, part of the toppled cone looked like part of the tire lol

Hahaha, yeah that cone sure does make them look enormous.

Dark04GT · Jul 27, 2010

The goal of "zero body roll" is best left for open wheel race car designers.

Agreed. The stang looks good and has a healthy/normal amount of body roll in those pics. Every car has some roll, means you are having fun.

02SatinGT · Jul 30, 2010

Your body roll actually doesn't look too bad. My M3 even gets roll and it has a way better set up then the modified Mcpherson set up the stangs have. 40oz gave you some good info. To add to it, there's more too it then having a good car or suspension. It's also about driving technique, which 40oz touched on. Just to give an example, I've seen a guy with a Kia Rio on an auto x course out do Porsches, Skylines and WRX's just by being a better driver.

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