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Don't oversize your rear sway bar

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Old 08-05-2016, 05:47 AM
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Default Don't oversize your rear sway bar

I have BMR springs and Bilstein HD shocks, with a weight of about 3200 with me in the car. When I wanted to make it more of a handling car from a drag car I had put in a 23mm rear bar from a 91 formula and a 32mm front sway bar from a 99 WS6 when I did the springs, and while it felt a ton better, god damn was it tail happy. I blamed it on the solid tubular poly LCAs and old 295/35/18 all around Goodyear eagle F1 supercar tires for a long time, so swapped to OZ Monte Carlo wheels and 275/40/17 Goodyear eagle F1 GS-D3 tires and it had a ton more grip, but still was tail happy and I was constantly fighting the steering wheel to keep it from walking out the rear end. I recently put back in the stock 19mm rear bar and it is now AMAZING at the difference. It rolls a little more but stays completely planted, getting a tiny bit of under steer that is easily corrected with throttle, but now I have complete confidence in the car that it won't shoot the rear end out and spin me off the road.

Lesson learned: a 23mm rear bar is WAY TOO BIG for a 32mm front bar. The 1LE cars had a 32/21 setup, and this may be a tiny better, but a stock 19 bar compliments a 32mm front bar much better.
Old 08-05-2016, 05:49 AM
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Old 08-05-2016, 08:27 AM
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Correct -- it is no coincidence that Strano's set is a 35mm front/22mm rear. I bet it was a handful with that bar on the rear.
Old 08-05-2016, 08:36 AM
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Gives me hope for my car. Right now it has slapper style traction bars which effectively lock up the rear suspension like an extremely heavy bar. Zero body roll but the *** end slides around with hardly any throttle on a tight autox course.

I'm ditching the traction bars and installing a pro touring adjustable rear sway bar which mounts to the body (unlike the stock bar which mounts to the lower control arms)
Old 08-05-2016, 09:24 AM
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yeah that would have maybe been ok with a 35mm up front, but probably still not ideal. Good thing you got it off of there!
Old 08-05-2016, 11:27 AM
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Mmm I've got a solid 23mm rear bar. Might as well be on ice when it's raining outside and you take a corner and you tap the throttle halfway through

I got a solid 35 front bar to try to counter the rear bar, now my front tires are worn like crazy on the outside edge because of all of the understeer. I don't have the best tire setup either though... Sure makes for a fun drive though! Understeer, understeer, understeer,thrott-OVERSTEER!!
Old 08-06-2016, 05:13 AM
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The 23 rear solid was paired with a 36 front solid on the 91 formulas, I don't know if a 35 front would be enough, again why Strano has 35 and 22 HOLLOW bars. I think the 19 is still a touch small for a 32 front, hence why 1LEs used a 21 solid rear with the 32 front, as I do get some under steer as the front tires give up as I take the left hand 90 degree turn into my work road at 50mph. I think a 21mm rear bar with slightly larger rear tires than front would be balanced, but I would love to try Stranos 35/22 hollow setup. I think if I went to a roto joint LCA it's going to get worse on oversteer, as the poly is helping act as more of a sway bar in the rear. There is substantially more body roll now, but I think it's more that it's hooking and planting rather than sliding and I'm getting more force to the tires than I ever have.
Old 08-06-2016, 08:00 AM
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3250 race weight???? Gut your interior and remove other stuff?
Old 08-06-2016, 11:25 AM
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Originally Posted by bufmatmuslepants
The 23 rear solid was paired with a 36 front solid on the 91 formulas, I don't know if a 35 front would be enough, again why Strano has 35 and 22 HOLLOW bars. I think the 19 is still a touch small for a 32 front, hence why 1LEs used a 21 solid rear with the 32 front, as I do get some under steer as the front tires give up as I take the left hand 90 degree turn into my work road at 50mph.
The 1LE cars that got a 32/21 setup had a higher front spring rate to compensate. Otherwise some of the 1LE cars got 35mm front/21mm rear bars, which is very well balanced.
I think a 21mm rear bar with slightly larger rear tires than front would be balanced, but I would love to try Stranos 35/22 hollow setup. I think if I went to a roto joint LCA it's going to get worse on oversteer, as the poly is helping act as more of a sway bar in the rear.
This is backwards. The Poly will act like a swaybar and add unwanted wheel rate (from binding) which can cause oversteer. The rotojoint will move freely like the suspension is supposed to and the rear will have more grip.
There is substantially more body roll now, but I think it's more that it's hooking and planting rather than sliding and I'm getting more force to the tires than I ever have.
Get stranos or UMI swaybar set and be done with it.
Old 08-08-2016, 05:34 PM
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Waiting for one of the suspension reps (or Sam) to pipe up on this.
Old 08-09-2016, 10:42 PM
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Sam has said it all years ago for those who cared to listen. Overbarring the rear will cause consistent oversteer, in some cases rendering the car barely controllable.



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