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Old 05-10-2019, 09:20 PM   #1
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Roll?

Nice pic of a tight left, abut 35-40 mph... But what I see is a lot of roll and unloading of the rear. Should I be looking at coils & struts or sway bars to correct? Right now all parts are stock. Probably a combination of both, but the unloading of the rear has me thinking sway bar.

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Old 05-10-2019, 11:13 PM   #2
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Truth be told, it doesn't look like much roll at all to me, especially for an autocross.

What is your car doing, understeering or oversteering? That is what you should be concerned about. If it's balanced, don't worry too much about how much your car is rolling in the turns, unless it is rolling so far that the car is unsettled.

Trying to tune your suspension by looking at a picture of your car probably isn't the best approach, in my humble opinion.
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Old 05-11-2019, 08:02 AM   #3
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I was getting a little oversteer before I dropped the rear tire pressure to 29lbs, tightened it up nicely. Very well balanced at that point and my times dropped over 4 seconds!

And I will agree with you, looking at a pic isn't the best way to tune a suspension if it's working, it just looked like a lot of loading.
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Old 05-12-2019, 12:28 PM   #4
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Here is a picture of me going through a 70 mph sweeper at Pacific Raceways, not the kind of turn you are likely to encounter at an autocross. Notice how much the car is leaning - maybe even more than your car in the picture you posted.

The car is really well balanced, so whatever lean there is doesn't really matter.

That said, I did put slightly stiffer sway bars on last week. They are ROW M030 sways, so they are a matched set. The reason I'm going with those is because I'm going to be using track tires now, and the loading will be a bit more than with the street tires, meaning it will lean even more. I don't want to chew up the edges of the tires, so hello stiffer sways.
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Old 05-12-2019, 12:42 PM   #5
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Nice. I'm thinking of going to the 030 bars as well when I move to the track only tires. I will probably be going to a matched set of tires, probably a 225-235 sidewall, 200 compound.
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Old 05-13-2019, 07:28 AM   #6
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You call that roll? I'll show you roll:


Or watch a well driven current gen Miata at full toot. Tons of body roll, yet the cars manage to be super fast at autocross.

Roll isn't necessarily a bad thing, means your car (and the driver) is generating grip. Inside tires aren't doing much of anything anyways, as long as you're not roasting the inside rear on corner exit.

Stiffer speeds rate of weight transfer, and creates less total roll which may keep a tire in better camber range, but it's not always better.
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Old 05-13-2019, 03:35 PM   #7
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That's not roll, that's stiff! I like!
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Old 05-13-2019, 04:54 PM   #8
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I agree, roll isn't your biggest problem. The first and foremost parameter to worry about is camber. The stock suspension (even M030) is hugely camber limited. Lack of camber is the primary reason the outer portion of the tire will wear (although roll contributes to running out of camber).

With the right suspension components and settings, its easy to get more than sufficient roll stiffness...

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Old 05-13-2019, 06:05 PM   #9
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Right now I'm set up for ROW settings, and I like them. (That's a great pic btw, your car is working!). I just want a tighter feel, more seat of the pants.
When I put a set H&R springs on my Audi, the change was immediate and I loved it, but I don't track that car, I just drive it. Maybe I'm getting overboard...
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Old 05-13-2019, 08:33 PM   #10
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Quote:
Originally Posted by mgfranz View Post
Right now I'm set up for ROW settings, and I like them. (That's a great pic btw, your car is working!). I just want a tighter feel, more seat of the pants.
When I put a set H&R springs on my Audi, the change was immediate and I loved it, but I don't track that car, I just drive it. Maybe I'm getting overboard...
No, you're on the right track (haha!). If you have camber under control then reducing roll will help you to balance the car better and it will also help a bit with camber so its all upside. Carry on!
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