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Sway bar

 
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mif_slim



Joined: 28 Sep 2004
Posts: 967
Location: sacramento

PostPosted: Fri Dec 09, 2005 5:07 pm    Post subject: Sway bar Reply with quote

Hello, i just wanted to know what sway bar you guys set your sway's at? I got mines Full stiff up front and loose in the back. I was thinking if the back was stiffer would it be better for the e36's? I have UUC sway bars on mines. I wanted to make it medium stiff but I wouldnt know the diffrence.
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Tom Olsson
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Joined: 03 Nov 2004
Posts: 242
Location: Seattle, WA, US

PostPosted: Fri Dec 09, 2005 5:17 pm    Post subject: Reply with quote

Generally a stiffer rear sway will cause push or eliminate oversteer. My car (E30) will have an 19mm front set to medium, and the stock bar in the back, as I like the rear end a bit loose to rotate the car on turn-in.
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mif_slim



Joined: 28 Sep 2004
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Location: sacramento

PostPosted: Fri Dec 09, 2005 5:30 pm    Post subject: Reply with quote

yeah, it seems like when I switch the sway bar from stock to UUC sways.. my rear is more loose. I kind of like it but the autoX that i go to, the pavement is a diffrent pavement from the road. I wish it was the same but its not. We'll see, I only asked because going on a off ramp I tested out the UUC sway bar, I feel the tail alittle loose which is good for me but I dont want to push it yet until Im at autoX event to know where the slip point is at. I'll try to stiffen the rear or make it medium but now its at soft.
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Steve D



Joined: 09 Aug 2004
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Location: San Diego

PostPosted: Fri Dec 09, 2005 5:37 pm    Post subject: Reply with quote

I'd always thought that when you stiffen up a bar you increase traction at the other end of the car (ie bigger rear bars reduce weight transfer in the rear, causing relatively more weight transfer in the front, increasing front traction and thereby reducing understeer).

My e30 has the suspension techniques 22mm front bar (not adjustable) & 19mm rear bar, which is set at the stiffer of 2 settings. The 22/19mm bars are what are required for spec e30, btw.
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mif_slim



Joined: 28 Sep 2004
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Location: sacramento

PostPosted: Fri Dec 09, 2005 5:48 pm    Post subject: Reply with quote

Mines are 25.4mm front and 23.8mm in the rear compare to stock, stock is 22.5mm front 19mm rear (for M3) I know mines smaller then that. fron has three way adjustments and rears got 2.
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Tom Olsson
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PostPosted: Mon Dec 12, 2005 10:52 am    Post subject: Reply with quote

Quote:
I'd always thought that when you stiffen up a bar you increase traction at the other end of the car (ie bigger rear bars reduce weight transfer in the rear, causing relatively more weight transfer in the front, increasing front traction and thereby reducing understeer).


As I understand it, if you're car's understeering, you can dial that out by adding more front bar. Most car's naturally understeer, hence your set-up of 22 front, 19 rear. I think the point here is to add a bit of traction to the front to balance the natural stick of the rear.

But I have to admit I'm no expert at this, I'm just starting to get good enough (raced for 2 years) to start actually start thinking about what the suspension can do for me, and adjustments to go faster. The tracks up here are really rough, and the car tends to bounce on a really stiff suspension. I'm going to try softening it up a bit to get it to hook up in the rough stuff. I think the popular setup here is 650 front /800 rear on the springs, 22 front / 19 rear on the bars. I'm going to try 550/750 and 19/stock on the bars. Yes, I'm going to get more roll than the other guys, but let's see what happens.
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mif_slim



Joined: 28 Sep 2004
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PostPosted: Mon Dec 12, 2005 5:44 pm    Post subject: Reply with quote

Still thinking.. if the rear is stiffer it'll oversteer or understeer?
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Steve D



Joined: 09 Aug 2004
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PostPosted: Mon Dec 12, 2005 7:01 pm    Post subject: Reply with quote

Try these links:

http://rogerkrausracing.com/overundr.html

http://www.nsxprime.com/FAQ/Track/highperfdriving.htm

http://www.grmotorsports.com/news/012005/lean-less-the-inside-scoop-on-anti-roll-bars.php

The last one is long, but worth reading.
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Tom Olsson
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PostPosted: Tue Dec 13, 2005 12:32 am    Post subject: Reply with quote

Nice! Thanks for the articles, looks like I have it backwards. I've got some studying to do!
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Tom Olsson
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PostPosted: Tue Dec 13, 2005 2:04 pm    Post subject: Reply with quote

Boy did this thread open a can of worms. I talked to a couple of my mentors this morning, and I wasn't crazy. A few competitive people here in the NW are running a stiff front sway and the rear full soft or even disconnected. The thought is that a stiff setting will take grip away from the same axle. They run a soft rear sway (or none) to maximize grip to the drive wheels, and control turn-in with other adjustments (front camber or toe-in).

That said, this thread has certainly got me thinking, and I talked to my suppliers today to change my setup on the car I'm building to the standard 22F/19R, so at least I have adjustability in the rear, even if I choose full soft on the rear bar. Thanks for the conversation, this has been valuable to me as I build up the car.
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mif_slim



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PostPosted: Tue Dec 13, 2005 2:30 pm    Post subject: Reply with quote

yes, I had a few guys at my track events tell me about disconnecting the rear sways... what confused me was that some guy who just came the first day said that he had too much oversteer.. one of the guys told him to just take it off to lessen the oversteer.

Now, to my understanding so far... the stiffer the swaybars the more tires on the ground = more grip..but too stiff aint any good either...now with that said, if the rear sway is taken off wouldnt that mean that one tire will be off the ground and causing less traction = oversteer?... man this is getting intresting to me. Very Happy
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Tom Olsson
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PostPosted: Tue Dec 13, 2005 2:55 pm    Post subject: Reply with quote

More roll equals more weight transfer to the outside. More weight on a tire means more traction (as long as you don't exceed it's max "gription". If the weight transfer happens too fast, then the car instantly goes past the grip limit of the tire). In a corner, your traction is going to come from the outside tires due to centrifugal force pushing the car out, away from the apex.
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Steve D



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PostPosted: Tue Dec 13, 2005 3:04 pm    Post subject: Reply with quote

Tom, you're right - you aren't crazy (well, I guess I don't know you so I suppose you may be, but that's another discussion), the sway bars are but one part of the setup equation. Other adjustments made to springs/shocks/camber/toe/caster/even air pressure will effect the oversteer vs. understeering tendencies of a car. I'm far from an expert on this myself, but am willing to play one on occasion! Very Happy
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mif_slim



Joined: 28 Sep 2004
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Location: sacramento

PostPosted: Tue Dec 13, 2005 3:56 pm    Post subject: Reply with quote

Im going to try out the sway bars on soft for now.. once done that Im going to put it in hardest.. then after that .. no sway bars.. we'll see how it performs.. but that wont be til march.. dang.. I cant wait
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