suspension tuning help
 

My car is picking up the front inside wheel when I get on the power. I have twin tube tein flex at 4/5 from max rate with 580/400 springs, rb front hollow and solid rear bar with 1.7* front camber (max), 2.2* rear, 1/16 tow in rear, and 4* caster. Right now the rear is planted, but when I get on the gas the front washes out a bit...and I'd love to have a lot more toe in.

I have no bracing in the car so should I play wish suspension settings, weld up mounts for my rear triangle brace, get door bars, get a strut bar, change sway bars, or what?

SM cars were beating my ass with turn in and ultimate grip.

Any reason no bracing? Extra weight or just didn't feel like the costs were worth it? I don't drive a car on par with yours, but I like to think all of the bracing I've added really helped. I don't track mine, so again, not on the same level, but from spirited driving on the road, like high speed on ramps the car now vs. stock feels much less likely to kick the rear end out and the front feels more much planted and "point and go". I'm running FM frame rail braces, BF double hoop roll bar, shock tower brace, all of the factory R package bracing and FM sways. Only think I lack that I want is the BF frog arms that go under the fenders to strengthen the corner on the passenger tub to the suspension/shock mount area in the front. I think one of the best upgrades I could have made were bushings. Having known what I know now, I wouldn't have gone with OEM bushings all the way around, I would have done a harder after market bushing kit. Even the new stock bushings helped a good bit with the handling of the car. Felt about equal to adding stiffer sway bars.

Surely your good in the tire department. Everything else looks good to me.

I just haven't gotten around to it. I'm leaning toward door bars and the k-brace in the rear.

I want door bars so badly, but I know it wouldn't work too well with my car being my daily driver. I can see how they would help out a lot. Whats a K brace? Is that the brace that mounts on the diff housing and sub frame?

I would make some sub frame braces like OEM with some tubing with crushed ends, buy FM frame rail braces and door bars and be done with it (and the k brace, whatever it is).

reduce front roll stiffness or reduce front rebound damping to allow the wheel to drop.

Yea..you gotta soften the front up a little. I would go with reducing the roll stiffness.

At what height is your ride?

Find out first if your front outside is running out of droop travel, or your setup is such that all the weight is transferring off the inside front.

Picking up a front tire happens in some RWD cars, when you have roll and squat at the same time, with grippy tires.

Lack of droop is typically a problem with shocks with very short travel, or very uneven pavement, such as tight uphill hairpin turns on bumpy mountain roads. (I have seen a stock Corolla get momentarilyl stuck like this!)

If you're picking up a wheel by simply transferring all the weight off a front wheel, and if you have excess understeer, then simply reduce the front stiffness - either by adjusting your sways or reducing front spring rate. The latter however will increase front lift/droop under power and you may then run into problem #1.

If you're picking up a front wheel and the handling is fine, you can ignore it. If you're picking up a front wheel and the car only understeers when it picks up a front wheel, then fix it - you may need to soften the front to bring the tire down, and then decrease front camber to rebalance the car. This has the benefit of possibly reducing inner tire wear (which wears under braking).

y8s, the tire is probably in the air long enough that low-speed rebound damping isn't keeping it from coming down.

I have door bars in my daily driver. You get used to it, not that big a deal IMO.

you have a lot of oversteer with this setup, dont you?

Why bother with door bars? Just cage the bitch.



You need to figure out what the cause of the issue is before you try and solve it. Is it chassis flex? Suspension travel? Bind? ect?

EEEE bro that's sick la verga!

Me? No. With neutral and light throttle on corner exit it is balanced. With moderate throttle there is oversteer but it is controllable. No rear sway FTW.

I could stand for some heavier spring rates, but if you want "this" kind of flat turn in...... a cage, and bracing is your friend.

i was asking hustler about that. last time i checked 550 front / 300 rear / rb hollow front sway bar and no rear sway bar was just about as neutral as anyone would want.

I still question this no rear sway..... I have yet to run without one.
I thought all the AutoX'ers did this to get the car to rotate easier, which then becomes...well "not" nuetral.
I guess I should take mine off to see the difference.

I've been watching this as I just received my Tein Flex and FM sways. Debating on the rear and I think I will start with the Flex and FM front and leave the stock rear. Split the difference between no rear and stiffer rear.

Thoughts?

chassis flex

Yeah ultimately that is the answer. Just try it and see. It is easy to disconnect it and zip-tie it out of the way. If you like it, it is also easy to remove.

I've gone back and forth with rear sway through 3 different suspension setups (about to try fourth). Right now I have it on just for a level of protection for 6" rear...rather oversteer than blow it right now.

I think when I do Konis with stiffer springs next month I will finally take it off for good. It was surprising just how long the rear would stay glued when N/A without rear sway. With turbo oversteer always comes first, I'm just trying to find out now if the bar makes it more predictable or not.

Wouldn't removing the rear sway have the exact opposite effect on a Miata? Unless I miss understand your meaning of rotate. Take off that rear bar and the car is going to shift it's balance from oversteer to understeer. I noticed a significant difference when I went from the solid RB bar to the hollow, the car had much more tendency to push.

A car being neutral depends on a lot of factors, so in fact removing the rear bar could make the car more neutral, which would follow in a RWD. I personally like having front and rear bars.

Swaybars are good for fine tuning, not so much as a solution to a problem.

sway bars play pretty significant role in suspension so i dont know how you would use it for fine tuning. changing alignment, tire pressure, and adjusting shock settings is fine tuning in my opinion.

hustler: you should also check with more knowledgeable people about your alignment. you are running more camber in rear then front which is not exactly a good thing for miata with its dynamic rear camber (camber changes during turn) so you have barely enough grip in rear during turns. here is an example of dynamic miata camber on my previous car:

http://urbansoot.net/images/miata/CP3_0065_WEB.jpg

thats -2.2 degrees front and -1.8 degrees rear. see how in this picture rear camber is WAY more then -1.8? dynamic camber ;)


ps: look at inner rear wheel, not outer.

what's the range of settings on your tein flex? i would raise the shock settings. i would say rear only, but it might change to oversteer if you don't raise the front also. (or try them at the same level) by raising the rear shocks stiffness, it might help to keep from transferring as much weight to the rear under acceleration while cornering.

also wonder why your running more camber in rear than frt.? i run 1.7 frt. 1.2 rear

Are you worried at all about side impacts with the door bars? Thats the only thing keeping me from doing them. A side impact looks like it would ram that bar into your hip, probably shatter your pelvis and leg and what ever other damage in that area it could cause. I've never seen any in person though, so I can't really say anything about how you fit into the car with them.

I'm not sure about turbo miatas, but for spec miatas, a good alignment for r888s is about -2.7 front camber, 1/16 out front toe, -3.3 rear camber, and rear toe depends on the track. For RA-1s, same but -3.0 front camber and -3.5 rear camber.

Hustler, why are you only able to get -1.7 out of your front? Something isn't right there... either the guy who aligned your car doesn't know what they are doing, or you have a bent control arm or subframe, or a bad lower ball joint.

a local shop just finished building spec miata and they could only get -1.8 degrees up front too. doesnt go further. i guess it has something to do with bushings perhaps...

All it has to do with is one (or multiple) of the following:
Bent upper or lower control arm
Bent subframe
Bad lower ball joint

It's also possible it's bushings, but unlikely. Just as likely that it is because the entire car is tweaked.

If they built it and didn't address that issue, that's a shitty shop and I'd never bring my car there.

That's what's hard for me to decifer.... my car is so stiff now, that it already has a wee bit of understeer when setting for a turn, even with the over sized rear bar. I'll just have to do some testing I guess.

I does have something to with the bushings a bit..... we can usually get a bit more camber when upgrading to the polypro bushings.

You aren't allowed to in SM.... and any decent car out there has at least -2.5 camber on each side.

Yeah after reading up on it that seems to be the biggest debate point, especially on m.n. I think some modest padding on the part of the bar next to one's hip would take care of it. Some fixed back race seats would take care of it too since it is low relative to hip position (at the area near the seat back hinge); a race bucket would cover the bar.

Another problem, though only cosmetic, is there is some minor wear visible where my shoes sometimes scrape the bar getting in and out, and where the seat belt buckle gets caught between the bar and the door (sticking retractor). Also, it is entertaining watching passengers not used to the door bars get in and out of the car, especially larger passengers.

I'm also worried about the bar pushing the lower side bolsters of the seat up and making me sit crooked. I guess a narrow race seat would be ideal with door bars. Just doesn't look like any room down there for a 1 1/2'' bar (plus padding preferred). What seats are you running?

And its also not that the entire door caving in on a side impact is preferred either. I would imagine a side impact from an SUV would feel like a huge wave coming for you. Top edge of the front would be above the roof of our little cars, so it would pretty much crush the entire side. At least maybe the door bar would reduce intrusion, but your day would still suck balls.

He He..... Yeah, I know..... I've already made the decision in the build that this is no "spec" car anymore.

everything is straight on that car. all suspension components are brand new.

Right now I have the stock seats in the car and the bar does not push in the side bolsters, though it is a close fit. It basically just fits between the seat and the door panel. The seat will also no longer slide all the way forward, though I am 5'7", 30" inseam, and it is not an issue. I have been meaning to ask Hard Dog about aftermarket seats with the door bars.

Yeah either way a side impact that bad is going to be a big pain in the butt, and the side, and a big headache (puns intended). Though there is already a smaller bar for it incorporated into the door, side intrusion is an argument for the door bar. Though really an SUV bumper is so high it is going to be coming at you at chest or even head level.