Dirt an ice require a softer suspension than pavement. When I was running my ZX2SR on ice, I ran stock springs and no sway bars. Much different than when I ran a track day.
Dirt an ice require a softer suspension than pavement. When I was running my ZX2SR on ice, I ran stock springs and no sway bars. Much different than when I ran a track day.
I read an article once about BMW suspension philosophy and it said they prefer running higher spring rates and smaller anti-sway bars when compared to other manufacturers.
My A2 VW GTI handled like a rock star with the Shine setup- Shine springs at all four corners, no front sway, and large rear sway. Luckily Shine has had the time and experience to find the optimum handling of the chassis and able to find the correct spring rates to compensate for no front sway
Didn't even notice the lack of front bar when on the road/freeway.
The E30 tuning community is turning this way as well. With the E30 M3 the factory race cars ran large sways, but now most of the aftermarket is supplying stiffer springs instead of bigger sways.
GRM DO A SHOOT-OUT WITH A COMMON RWD CAR!!
Smack35 wrote: 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
If anything, my car turns too well. I was catching mild oversteer at almost every corner entry. The only way I can cure this (if it needs to be cured at all) with sway bars is to run a front bar, right?
MrBenjamonkey wrote: If anything, my car turns too well. I was catching mild oversteer at almost every corner entry. The only way I can cure this (if it needs to be cured at all) with sway bars is to run a front bar, right?
It's kinda good that it is oversteering. I would learn to adapt with it. do most of your braking before the turn, and get on the gas early (but not 100%) and accelerate all the way through. If the oversteer is making you uncomfortable and starting to frustrate you, or it slides a lot every time it oversteers then there are a few options. If you have adjustable shocks, turn the front shock setting one or two clicks stiffer this is your best option. You could also stiffen the front spring. Maybe put a 600lb spring on the front and keep the 500lb spring on the rear. I wouldn't do this unless the oversteer is an aggravating problem. You can combine this with option number one, but if you do get the stiffer spring, I would back the shock down to its lowest setting. Option 3, add a front bar, but since your car handles better without one, then this isn't necessary. You can also raise the front end or lower the rear, but I like setting the car as low as possible, but make sure there isn't too much angle on the axle or they'll snap.
By the way, I'm really enjoying talking setup stuff.
Steven
"I should be faster than the diesel.......I hope, I think, probably Not!!!!!" Love the project and pulling kids into a race car! racing a Daewoo in Korea!! great looking track, "performancey all seasons." The whole everything is very cool IMO. Good luck and God's speed!
Smack35 wrote:MrBenjamonkey wrote: If anything, my car turns too well. I was catching mild oversteer at almost every corner entry. The only way I can cure this (if it needs to be cured at all) with sway bars is to run a front bar, right?It's kinda good that it is oversteering. I would learn to adapt with it. do most of your braking before the turn, and get on the gas early (but not 100%) and accelerate all the way through. If the oversteer is making you uncomfortable and starting to frustrate you, or it slides a lot every time it oversteers then there are a few options. If you have adjustable shocks, turn the front shock setting one or two clicks stiffer this is your best option. You could also stiffen the front spring. Maybe put a 600lb spring on the front and keep the 500lb spring on the rear. I wouldn't do this unless the oversteer is an aggravating problem. You can combine this with option number one, but if you do get the stiffer spring, I would back the shock down to its lowest setting. Option 3, add a front bar, but since your car handles better without one, then this isn't necessary. You can also raise the front end or lower the rear, but I like setting the car as low as possible, but make sure there isn't too much angle on the axle or they'll snap. By the way, I'm really enjoying talking setup stuff. Steven
It's a fascinating subject. I'm really jazzed up about setting this car correctly because it's the first time I've really had the opportunity to be flexible. All of my previous builds have been strictly limited by what I could find in the junkyard. Now with the better job and the general cheapness of everything in Korea, I can do stuff like get custom made coilovers.
Actually, the oversteer is a lot of fun. I don't know if it's fast, but the slides are gradual and very easy to catch. The only time I got close to spinning was a case of being WAY too aggressive and letting the rear hang WAY out before I tried to catch it.
The car's behavior was like this:
On the brakes the car was neutral to a little bit of understeer depending on how much of a flick I gave it. On trail throttle the car oversteers gently. Decreasing radius corners are a lot of fun because of this. Maintainance throttle produced nice four wheel drifts and full throttle produced mild understeer all the way until 4th gear when the engine was just too weak to cause much of an effect.
I don't have adjustable shocks, but I can play with the ride heights. As of now, the car is only a little bit lower than stock. I think that's why I don't need a bar to keep it flat. The theory, and my eyeballing the geometry, is that Nubiras have relatively high roll centers stock. I was thinking that I could lower the car to get the same effect as softening roll bars. Ie, lower the rear of the car and get more understeer (my car has that stink-bug ass in the air stance going on right now). Lower the front and get more oversteer.
I really think the best thing to do now is to work on increasing absolute grip. I could definitely get better tires and I think the car could use more camber on all four corners.
I'm probably going to f-up the balance soon anyway. The next engine is going to take the better part of 150 lbs off the nose.
Shaun wrote: "I should be faster than the diesel.......I hope, I think, probably Not!!!!!" Love the project and pulling kids into a race car! racing a Daewoo in Korea!! great looking track, "performancey all seasons." The whole everything is very cool IMO. Good luck and God's speed!
Yah man, this is a lot of fun. I can't believe they're paying me for this!
BTW, for lap times, I beat the following stuff:
Got toasted by a Hyundai I30, Audi S3, VW GTI and two other Mini Cooper Works.
If that's a MacStrut car, and i think it is, go ahead and lower it. Talking Geometry on a MacStrut car always brings that Colin Chapman quote to my head that goes something like this:
"To make a suspension work, don't let it work."
I'm sure my roll center is now 20 feet below the ground on my car, and it handles eleventy billion times better than it did at stock height with the same components.
I could be way off base here, and i'm pretty sure my car is quite different, but that's just been my experiences, and the few people that i've talked to in depth about setting up a MacStrut car pretty much just say to get your static numbers where you like them, and then cram a E36 M3load of tire under it, call it a day.
Something that Steve mentions in the threads on MR2OC that you want to consider is the relationship between the roll center and the center of gravity.
Several people noted a significant handling difference when using the same springs, but with and without roll center adjusters (ball joint spacers in the case of the MR2). If there is a relatively long distance between the two centers, then that will act as a moment arm and torque the chassis and induce excessive roll. If you can reduce that moment arm by playing with the roll center or the CG, then the roll will be reduced even without changing the springs. I suspect your high roll center is closer to your CG than you might think.
But there are other reasons you want a low CG. First is that it minimizes load transfer from tire to tire, allowing for faster cornering. Another is that when it's up so high, it makes it easier for the car to pole-vault over a bad bump in a turn.
Brotus7 wrote: Something that Steve mentions in the threads on MR2OC that you want to consider is the relationship between the roll center and the center of gravity. Several people noted a significant handling difference when using the same springs, but with and without roll center adjusters (ball joint spacers in the case of the MR2). If there is a relatively long distance between the two centers, then that will act as a moment arm and torque the chassis and induce excessive roll. If you can reduce that moment arm by playing with the roll center or the CG, then the roll will be reduced even without changing the springs. I suspect your high roll center is closer to your CG than you might think.
I'm almost positive this is what's keeping my car from rolling. Looking at pictures of the car cornering, I can tell that the roll center, especially in the back, is way up in the air. It might even be above the COG in the back because the car seems to do the stinkbug, ass in the air stance during cornering.
If my theory is correct, this means I can do some really easy balance adjustments just by playing with ride height.
I was thinking that when I stick the new engine in (and take about 150 lbs off the nose) I can recover my good balance by lowering the front ride height.
kb58 wrote: But there are other reasons you want a low CG. First is that it minimizes load transfer from tire to tire, allowing for faster cornering. Another is that when it's up so high, it makes it easier for the car to pole-vault over a bad bump in a turn.
Do you think this is too tall?
If you want a good example if really high roll centers, watch an old VW bug with swing axles go round a corner. It's truely a scary sight, as the outside tire starts rolling under as if the car's thinking about flipping over it. Newer cars have long since moved away from swing axles and the CGs are typically much more reasonable.
For the white car above, you asked if it's "too tall". Too tall for what, hard core racing? Probably. Anything other than that it'll be fine.
Rule of thumb. Understeer= soften the front/ stiffen the rear. Overs teer= stiffen the front/soften the rear. wheel widths and tire pressures can be experimented .
kb58 wrote: If you want a good example if really high roll centers, watch an old VW bug with swing axles go round a corner. It's truely a scary sight, as the outside tire starts rolling under as if the car's thinking about flipping over it. Newer cars have long since moved away from swing axles and the CGs are typically much more reasonable. For the white car above, you asked if it's "too tall". Too tall for what, hard core racing? Probably. Anything other than that it'll be fine.
Those are really high roll centers combined with the inherent crappyness of swing axles. The old Spitfires did that too.
Is there any disadvantage to aiming the roll center at the COG with a strut/multi-link arrangement?
You said the car might pole vault. That's why I posted the picture of my Nubira.
yeah that looks too tall in the rear, you probably half an inch or so to play with. BUT, if you're having this much fun with the oversteer, and if you can play with it the way you are there is no reason to mess with it. Lowering the rear will make the car handle better and it'll go faster, but then you may have a little less fun. I had my FV set up to be real twitchy for my first few races just because it was fun to slide it, once I started getting in better races, I made the rear a little more soft so I could handle it better and go faster. I
It's your choice, if you're having fun, keep it the same!
Steven
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