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mif_slim
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Joined: 28 Sep 2004 Posts: 967 Location: sacramento
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Posted: Fri Dec 09, 2005 5:07 pm Post subject: Sway bar |
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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. _________________ IIVII II IF
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Tom Olsson Site Admin
Joined: 03 Nov 2004 Posts: 242 Location: Seattle, WA, US
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Posted: Fri Dec 09, 2005 5:17 pm Post subject: |
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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. _________________ 07 335i, 91 318is, 87 325is race car #55 Pro-3 |
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mif_slim
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Joined: 28 Sep 2004 Posts: 967 Location: sacramento
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Posted: Fri Dec 09, 2005 5:30 pm Post subject: |
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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. _________________ IIVII II IF
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Steve D
Joined: 09 Aug 2004 Posts: 102 Location: San Diego
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Posted: Fri Dec 09, 2005 5:37 pm Post subject: |
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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
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Joined: 28 Sep 2004 Posts: 967 Location: sacramento
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Posted: Fri Dec 09, 2005 5:48 pm Post subject: |
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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. _________________ IIVII II IF
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Tom Olsson Site Admin
Joined: 03 Nov 2004 Posts: 242 Location: Seattle, WA, US
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Posted: Mon Dec 12, 2005 10:52 am Post subject: |
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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. _________________ 07 335i, 91 318is, 87 325is race car #55 Pro-3 |
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mif_slim
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Joined: 28 Sep 2004 Posts: 967 Location: sacramento
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Posted: Mon Dec 12, 2005 5:44 pm Post subject: |
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Still thinking.. if the rear is stiffer it'll oversteer or understeer? _________________ IIVII II IF
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Steve D
Joined: 09 Aug 2004 Posts: 102 Location: San Diego
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Tom Olsson Site Admin
Joined: 03 Nov 2004 Posts: 242 Location: Seattle, WA, US
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Posted: Tue Dec 13, 2005 12:32 am Post subject: |
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Nice! Thanks for the articles, looks like I have it backwards. I've got some studying to do! _________________ 07 335i, 91 318is, 87 325is race car #55 Pro-3 |
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Tom Olsson Site Admin
Joined: 03 Nov 2004 Posts: 242 Location: Seattle, WA, US
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Posted: Tue Dec 13, 2005 2:04 pm Post subject: |
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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. _________________ 07 335i, 91 318is, 87 325is race car #55 Pro-3 |
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mif_slim
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Joined: 28 Sep 2004 Posts: 967 Location: sacramento
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Posted: Tue Dec 13, 2005 2:30 pm Post subject: |
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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](images/smiles/icon_biggrin.gif) _________________ IIVII II IF
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Tom Olsson Site Admin
Joined: 03 Nov 2004 Posts: 242 Location: Seattle, WA, US
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Posted: Tue Dec 13, 2005 2:55 pm Post subject: |
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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. _________________ 07 335i, 91 318is, 87 325is race car #55 Pro-3 |
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Steve D
Joined: 09 Aug 2004 Posts: 102 Location: San Diego
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Posted: Tue Dec 13, 2005 3:04 pm Post subject: |
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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](images/smiles/icon_biggrin.gif) |
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mif_slim
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Joined: 28 Sep 2004 Posts: 967 Location: sacramento
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Posted: Tue Dec 13, 2005 3:56 pm Post subject: |
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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 _________________ IIVII II IF
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