KSeries2497
KSeries2497 None
12/14/09 4:59 p.m.

I have a 1995 Ford Probe GT which is essentially stock. I'm going to upgrade the rear stabilizer bar (11mm stock) to a unit from a 626 (16mm), in the hopes of improving the car's balance mid-corner. This, however, does absolutely nothing to improve turn-in, which is also one of my goals. Since camber plates are out of my price range, I can only adjust toe on any corner.

I know that I need more toe-out on one end or the other or both, but I'm not sure how much I need or where I need it.

Any help you guys could offer would be much appreciated.

93celicaGT2
93celicaGT2 SuperDork
12/14/09 5:02 p.m.

You'd be surprised.... that will probably improve turn in slightly.

I can't answer how much you'll need, unfortunately, i'm not real familiar with that chassis.

Welcome!

Oh and... 2/10.

KSeries2497
KSeries2497 New Reader
12/14/09 5:10 p.m.

H-h-h- .... HalfTrac?

Anyway, I was thinking about it today and really I'd like to improve both turn-in and mid-corner in proportion to each other, if that makes sense.

93celicaGT2
93celicaGT2 SuperDork
12/14/09 5:12 p.m.

Yeah, drewsifer is around here somewheres, as well.

KSeries2497
KSeries2497 New Reader
12/14/09 5:14 p.m.

Coolio. But do you think that the new component will improve turn-in as much as it will the outright balance, or should I play with alignment to get there?

SpeedTheory
SpeedTheory Reader
12/14/09 9:17 p.m.

Honestly, on FWD, a good baseline typically is 1/16 toe out per side up front, and straight out back. Can you get camber via camber bolts or shims? If you could take a picture of a front shock/strut, that'd help me know. Adding camber would be a good plan if that's possible. This going to be for autocrossing or track days?

93celicaGT2
93celicaGT2 SuperDork
12/15/09 8:38 a.m.
SpeedTheory wrote: Honestly, on FWD, a good baseline typically is 1/16 toe out per side up front, and straight out back. Can you get camber via camber bolts or shims? If you could take a picture of a front shock/strut, that'd help me know. Adding camber would be a good plan if that's possible. This going to be for autocrossing or track days?

This man speaks truth. I'd share my settings, but they won't help you. I run a ton more toe than that, but that's also because i run a bit more camber than most street cars.

SpeedTheory
SpeedTheory Reader
12/15/09 9:02 a.m.

Well, I've got to know what the use is for the car + some design info on the suspension before I can give him adequate advice. Adding a ton of toe out back will just give him problems coming out of corners if he's got high spring rates or big sway bars back there. I know guys running Mazda3s in H-Stock running 3/8 total toe out in the back, and quite a bit up front. But we're stuck with small rear bars & stock springs.

93celicaGT2
93celicaGT2 SuperDork
12/15/09 9:11 a.m.

It's a stock car that he's adding a bigger swaybar to, but not a HUGE swaybar or anything.

And it's probably for backroad enjoyment, he MIGHT hit an autocross or two.

iceracer
iceracer HalfDork
12/15/09 9:12 a.m.

On my ZX2SR I have tried toe out on the front and I have not seen any difference to O toe I usually run. Getting more camber AND caster works good. The nice thing about caster is that it adds camber in the right direction as you turn. Negative on the outside, positive on the inside. I think you need a bigger bar. My car had a 13mm rear bar,I now run a 19mm for DD and for competiton an adjustable 22mm bar.

93celicaGT2
93celicaGT2 SuperDork
12/15/09 9:16 a.m.

Mine had a 17mm stock rear bar... i think i'm running a 24 or 25mm whiteline now, can't remember the exact size. It's huge. It's probably a little TOO big. If that's possible.

For that matter, i've got a 25.4mm rsb on the MX6, too....

SpeedTheory
SpeedTheory Reader
12/15/09 9:17 a.m.

I'm not a fan of necessarily adding more camber and caster on an FWD application. While camber is good, the more you add, the poorer the car will be to accelerate/brake in a straight line.

Increasing caster means more camber increase on wheel turn, therefore you don't need as much static camber.

Get as much caster as you possibly can, then tune camber from there (if possible, again, I don't know what adjustments are and aren't possible on the given drivetrain).

KSeries2497
KSeries2497 New Reader
12/15/09 10:39 a.m.
SpeedTheory wrote: Honestly, on FWD, a good baseline typically is 1/16 toe out per side up front, and straight out back. Can you get camber via camber bolts or shims? If you could take a picture of a front shock/strut, that'd help me know. Adding camber would be a good plan if that's possible. This going to be for autocrossing or track days?

For starters, this car is entirely a street car, and all it does is gets flogged around backroads. I am willing to tolerate twitchiness, but I would like to avoid excessive tire wear (it is also a commuter/grocery getter).

And here's your photo. This is the right front suspension. It's all this rusty. (Sorry about the hugeness.)

Clicky-clicky.

SpeedTheory
SpeedTheory Reader
12/15/09 10:46 a.m.

Photobucket / Imageshack are blocked at work. I'll take a look when I get home. In any case, max caster, 1-2 degrees of camber if you can get any up front, and 1/16 of toe out each side up front, zero toe out back. Minimum camber in back. Once I get a look at the picture, I may be able to suggest a way to get some camber.

KSeries2497
KSeries2497 New Reader
12/15/09 10:57 a.m.

Thanks, man.

93celicaGT2
93celicaGT2 SuperDork
12/15/09 12:08 p.m.
SpeedTheory wrote: Photobucket / Imageshack are blocked at work. I'll take a look when I get home. In any case, max caster, 1-2 degrees of camber if you can get any up front, and 1/16 of toe out each side up front, zero toe out back. Minimum camber in back. Once I get a look at the picture, I may be able to suggest a way to get some camber.

Nice. You just almost described my settings to a T.

I run 2 degrees camber front, 1.5 degrees rear, 3/16 toe front, 1/16 rear, and tons of caster.

It's a bit twitchy, but i like that. It's a handful on the highway, though.

SpeedTheory
SpeedTheory Reader
12/15/09 12:26 p.m.

Yeah, I'd encourage more if it wasn't a street car, but a "backroad" car with a lot of toe out could result in a hell of a lift-off oversteer situation that a less-experienced driver may not be ready for.

93celicaGT2
93celicaGT2 SuperDork
12/15/09 12:28 p.m.
SpeedTheory wrote: Yeah, I'd encourage more if it wasn't a street car, but a "backroad" car with a lot of toe out could result in a hell of a lift-off oversteer situation that a less-experienced driver may not be ready for.

Ding!

My car doesn't know the meaning of understeer. It oversteers on lift-off, it oversteers if you overcook a corner, it oversteers if you sneeze.

The plus side to that is that it's REALLY easy to rotate, and because it's a pretty progressive oversteer, it's pretty forgiving. It'll oversteer and just scrub off the extra speed you overcooked the corner by.

SpeedTheory
SpeedTheory Reader
12/15/09 12:41 p.m.

Yeah...I'd love to work towards that kind of handling with my HS car. Right now, it's either great (25% of the time) or (75% of the time) lighting up the inside front. I need to do some shock valving/sway engineering on it. I'm trying to find someone with a stock Focus sway bar so I can at least see if the Focus bars will fit. Would give me more testing options. Also need to find some stock Mazda3 shocks so I can swap them over while I get the Konis revalved (all of them need more low-speed compression, which the fronts when revalved will let me drop down to a smaller front bar, hopefully I can minimize wheelspin)

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