Forums » Grassroots Motorsports » Suspension Without Swaybars 1 2

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  Oct. 28, 2010 7:56 p.m. MrBenjamonkey Reader

  I'm running the Daewoo right now with neither front nor rear swaybars. Just 500lb/inch coil overs. It doesn't have very much body roll. A little at the front, almost none at the rear.

  I did some digging around and I think the reason for this is that the car has a pretty high roll center, close the the COG. Or at least that's how I'm interpreting the lower control arms (4 wheel struts on Daewoos) that point up at about an 8 degree angle in the front and maybe 10 degrees in the back.

  This leads me to the question, is there anything wrong with a high roll center? Because the suspension is a true independent now, the car really deals well with bumpy corners without the sway bars. If I'm not getting much roll, is there any reason to lower the RC and put on anti-roll bars?

  Here's a video of the car cornering. (skip to 6:00 unless you want to see the incar stuff too)

  http://jaycut.com/content/5-october-2010-1755

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  Oct. 28, 2010 8:05 p.m. SVreX SuperDork

  Mathematically, if the suspension were identical in both cases, the lower COG and roll center would always corner better. Picture a double decker bus cornering hard, vs a go cart. One wants to tip over no matter what you do, the other would be nearly impossible to flip, even though it has no suspension.

  However, as you have pointed out, the suspension will not be identical. If you have to make suspension compromises to lower the COG, the car won't necessarily corner better.

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  Oct. 28, 2010 8:17 p.m. MrBenjamonkey Reader

  All of the tracks I have access to are pretty bumpy, so I don't want to go much lower. Would the car handle better if I were to lower the frame side mounting points (thus lowering RC) and then adding sway bars to tame the extra roll?

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  Oct. 29, 2010 8:44 a.m. ReverendDexter Dork

  I dunno... I don't have the math/physics to back it up, but it seems like the ideal would be a suspension that doesn't need swaybars to make up for the lack of roll stiffness. One less interaction to cause weirdness, less weight, and full advantage of the suspension's independence. Really, I can't see any downside.

  --There is no turd more polished than the Ford Mustang--

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  Oct. 29, 2010 9:26 a.m. DaveEstey Reader

  well the front end can get a little funny under heavy breaking but once you get used to it you should be good to go.

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  Oct. 29, 2010 9:59 a.m. SkinnyG Reader

  Herb Adams says running no sway bars would require spring that are way too stiff to compensate for the lack of bar.

  I'd suggest picking spring rates based on suspension frequency, lowering it until it bottoms out only occasionally on the worst bumps, then control body roll and balance with sway bars.

  Some choose springs as stiff as you can go without leaving the ground. Others choose springs as soft as you can get away with without bottoming out. Somewhere in between is probably balance.

  Lose 1000lbs - ask me how! www.gwellwood.com

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  Oct. 29, 2010 10:11 a.m. iceracer Dork

  Control arms angle up. which way ? If they angle up from chassis mount to ball joint, the roll center will be below ground level. Not good If the CG and roll center are the same level, in theory there would be no roll.

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  Oct. 29, 2010 10:16 a.m. MCarp22 Reader

  SkinnyG wrote: I'd suggest picking spring rates based on suspension frequency, lowering it until it bottoms out only occasionally on the worst bumps, then control body roll and balance with sway bars.

  my thoughts exactly.

  Mike Carpeter - 1991 Miata base

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  Oct. 29, 2010 10:21 a.m. Matt B HalfDork

  SkinnyG wrote: Herb Adams says running no sway bars would require spring that are way too stiff to compensate for the lack of bar.

  Not necessarily. It has already been done quite successfully by Steve Hoelscher, who has multiple national championships in DP. He was nice enough to do a write up on his methods for determining no-swaybar-setup spring rates based on vehicle weight, weight distribution, motion ratios, etc.

  Here are the write ups on MR2OC.com

  STS Setup with Xhead pt1

  STS Setup with Xhead pt2

  His advice has led to quite a few quick aw11s. It hasn't worked for everyone, or their particular track, but the majority seem to enjoy the setup. Obviously, super high rates don't play well with especially rough tracks or the street.

  Benjaminmonkey - kudos for trying out the path less traveled.

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  Oct. 29, 2010 10:24 a.m. kreb Dork

  . It doesn't have very much body roll. A little at the front, almost none at the rear.

  Correct me if I'm wrong, but shouldn't the body lean the same amount on either end? That is unless you've got some tasty frame flex going on!

  It is better to wear out than to rust out.

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  Oct. 29, 2010 9:41 p.m. SkinnyG Reader

  Matt B wrote: Not necessarily.......

  Not necessarily the right setup, or not necessarily Herb Adams?

  Knowledge is power. Arm yourself with the most knowledge from the most sources, test and try things, then form your own conclusions. Be prepared to have others disagree - and that's ok. Whoever gets the fastest time wins.

  Lose 1000lbs - ask me how! www.gwellwood.com

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  Oct. 30, 2010 4:30 a.m. MrBenjamonkey Reader

  iceracer wrote: Control arms angle up. which way ? If they angle up from chassis mount to ball joint, the roll center will be below ground level. Not good If the CG and roll center are the same level, in theory there would be no roll.

  They are lower at the ball joint than at the chassis. So if you look at the car head on the left side arms are angled like this "/" at about 7 degrees.
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  Oct. 30, 2010 4:31 a.m. MrBenjamonkey Reader

  kreb wrote:

  . It doesn't have very much body roll. A little at the front, almost none at the rear.

  Correct me if I'm wrong, but shouldn't the body lean the same amount on either end? That is unless you've got some tasty frame flex going on!

  What I meant to say was that the front suspension flexes a little and the rear cocks a wheel up before bending very much. That said, if I don't fix the rust ...

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  Oct. 30, 2010 4:41 a.m. MrBenjamonkey Reader

  Matt B wrote: Benjaminmonkey - kudos for trying out the path less traveled.

  Here is the part I where I would like to tell you the whole thing was planned and a result of my genius, but ...

  A combination of my incompetence, rust and epically stuck bolts meant that when I took the old struts out I broke all four swaybar links. I drove the car around with the new coilovers while I waited for the links to arrive and was pleasantly surprised, so I pulled both bars and did the track day without them. Actually, if anything the car was a little too tail happy during the track day.

  I have four brand new links ready to go, but I don't know if I'll ever use them.

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  Oct. 30, 2010 4:45 a.m. MrBenjamonkey Reader

  DaveEstey wrote: well the front end can get a little funny under heavy breaking but once you get used to it you should be good to go.

  Is that how you're running your Honda?

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  Oct. 31, 2010 5:45 p.m. DaveEstey Reader

  No sway in the front.

  I do run a (massive) sway in the back but I'm fairly certain I could take it out and still have a very nicely handling vehicle.

  Keep in mind it's a CRX though, short wheelbase makes life easy. I ran no front sway in my DC5 RSX and it had much better grip coming out of corners but was squirrelly on the brakes if you weren't straight.

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  Oct. 31, 2010 7:09 p.m. Jensenman SuperDork

  X 1/9's AFAIK never had sway bars and they handled very nicely. I see no reason that on super smooth pavement it couldn't be done, but the moment there's a bump... On rough surfaces, long travel and relatively soft springs are the way to go, on smooth hard surfaces short travel and stiff springs. Problem is, most places have a mix of the two, ergo the sway bar.

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  Oct. 31, 2010 8:20 p.m. MrBenjamonkey Reader

  I'm actually running middle of the road spring rates. The car is about 2500 lbs and my springs are 500 lb inch on four wheel stuts. It doesn't come anywhere near bouncing off the road on my very bumpy track and it doesn't have much body roll at all. Actually, I kill people in bumpy corners with this setup. I think this is because of the Daewoo's high roll centers.

  My question is, if you can eliminate roll and swaybars with high roll centers, why doesn't everybody make high roll centers.

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  Nov. 1, 2010 3:13 a.m. MrBenjamonkey Reader

  Matt B wrote: < Here are the write ups on MR2OC.com STS Setup with Xhead pt1 STS Setup with Xhead pt2

  I finally got okayed by the administrators and read this stuff. A lot sounds very familiar. I'm running much lower rates than he would suggest for the AW11, but he himself says AW11's have long virtual arms.

  The stuff the other people have been saying sounds eerily familiar. My car was running used all seasons at the last track day I did and the only guy I wasn't out cornering had a 500 lb lighter car on Hoosiers. When the Daewoo was stock it still didn't roll much, but it felt really heavy, it understeered horribly and I would get these weird sensations of relative stiffness shifting around. Sort of a nuetral - oversteer- massive push progression.

  Now the car just digs in and grips. The steering feels great and mid corner bumps simply don't bother it. I can't wait to try with some proper tires. Also, as they mention in the MR2 forum, my car was gentle on tires.
  

  If X Head's right about swaybars reducing mechanical grip, it might be interesting to experiment with no swaybars on all sorts of cars in conjunction with a higher RC to allow lower spring rates.

  I think I'm going to experiment with lower tire pressures and lowering the rear (making it relatively more rolly) next time out. All excited now.

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  Nov. 1, 2010 7:52 a.m. racerdave600 HalfDork

  I've driven both of Steve's X1/9 and MR2 without the sway bars, and the X1/69 before when it had bars and softer springs, and the difference is night and day. To this day, his X1/9 was the best autocross I've ever driven, bar none. You could do anything with it. The MR2 is also amazing, just in a different way.

  We've had a lot of discussion in the past about the no sway bar set up, and he thinks it would do even better in a "normal" front-rear application. Even though the spring rates seem very stiff, they do not feel that way when you drive it. it really is amazing.

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  Nov. 1, 2010 10:11 a.m. Matt B HalfDork

  SkinnyG wrote: Not necessarily the right setup, or not necessarily Herb Adams?

  With all due respect for Herb Adams, I don't believe his statement is true for all setups/situations. Implying that all cars MUST have swaybars because the spring rates will be OMFG too high in order to compensate just isn't true. Although, for a street car, he has a point.

  MrBenjamonkey wrote: If X Head's right about swaybars reducing mechanical grip, it might be interesting to experiment with no swaybars on all sorts of cars in conjunction with a higher RC to allow lower spring rates. I think I'm going to experiment with lower tire pressures and lowering the rear (making it relatively more rolly) next time out. All excited now.

  Awesome. Do it.

  racerdave600 wrote: I've driven both of Steve's X1/9 and MR2 without the sway bars, and the X1/69 before when it had bars and softer springs, and the difference is night and day. To this day, his X1/9 was the best autocross I've ever driven, bar none. You could do anything with it. The MR2 is also amazing, just in a different way.

  Lucky bastard.

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  Nov. 1, 2010 11:16 a.m. Jay_W HalfDork

  When I took the swaybars off my rally car, our stage times went down. Quite a bit down. Since swaybars work by lifting a wheel, they reduce traction (much more noticeably on dirt) and yes indeedy even in smooth corners the car had more grip. That said I still have swaybars on my street car and have no intention of taking em off just yet. But I'm seriously thinking about experimenting, next time I autocross it, with undoing the end links for one run and see what happens.

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  Dec. 15, 2010 7:43 p.m. MrBenjamonkey HalfDork

  I realize I'm necromancing but, Jay's post got me thinking. For handling in the dirt I was under the impression that tires behave differently.

  For example, on pavement if a tire that will generate 1000 pounds of grip with 1,000 pounds of load gets its load increased to 2000 pounds, it's new grip will be something like 1800 pounds. But, in the dirt the tires can sink into the surface somewhat. Theoretically, couldn't that mean that the 2000 lb load would result in 2200 lbs of grip in the dirt?

  I ask because back in high school I did a lot of unsanctioned rally cross on a dry lake bed against my friends' 4x4 monster truck thingies. Running a huge amount of front roll stiffness, very high front tire pressures and a soft rear seemed to make my car (80 Corolla) turn in better and put the power down better as well.

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  Dec. 15, 2010 7:55 p.m. Smack35 Reader

  Because it handles kerbs well, it may not handle up to its potential. I would put an adjustable sway bar on the back, start at the soft setting and work your way up. This will stiffen the rear end allowing the car to turn in better, but it won't affect the absorption of bumps. Don't put one on the front because that is just counter productive.

  For reference: my '89 Civic hatch has 450lb front springs, 650lb coilovers. The shocks are all the way soft up front and all the way stiff in the rear. I have no front sway bar with my rear bar set to the middle. My front end is pretty much slammed, and the back end is a little high.

  Just saw your video saying you have all season tires. This would play a big role, and since they do not offer the grip that the Hoosier's that I use offer, the lack of a sway bar allows the car to roll over (obviously) this means that the tires absorb the roll which is good. If you had the sway bar on there it would put more stress on the tire making it slide.

  Hope this helps, Good Luck,

  Steven

  To quote the late, great,Colonel Sanders : "I'm too drunk to tase this chicken."- Ricky Bobby

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  Dec. 15, 2010 9:28 p.m. kb58 Reader

  Another big variable is personal preference. If Michael Schumacher drives your car without bars, there's a good chance it'll get a faster laptime than you will, so what's that mean? That no bars are faster, or that he's a better driver, or that he likes cars with no bars, or that you like cars with bars, or a mix of all these?

  I didn't have bars on Kimini, the mid-engine Mini, and it was surprisingly neutral. Understeer, oversteer, either were there depending upon cornering attitude and throttle.

  Kimini, and now a mid-engine Seven, www.midlana.com

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