dmoffitt

I'm getting an alignment done after my car leaves the paint shop - does anyone have the proper #s / settings that I should be at?

relevant info:

I've got the Bilstein Escort suspension, w/ camber plates up front, fabcar arms, the kokeln rear-subframe/t-bar delete, 89 rear trailing arms/hubs/etc. kokeln front sway, m030 rear.

so what #s should I give the shop re: an agressive autox / track alignment (the car will still be street-driven, but i'm willing to sacrifice a bit of tire-wear and smoother tracking / less tentancey to tramline a bit for the sake of turn in, holding in a corner, etc).... the shop is a very good shop, but they don't see many of these cars and haven't ever set one up for the track.

thanks!!

dmoffitt

based on the numbers found in David Floyd's thread, https://rennlist.com/forums/showthre...lignment+track I made an excel sheet, and averaged them... I came up w/ Front, -1.8 camber, between zero or 1/16 toe-in, around 3 for caster, rear -1.3 camber, and 0 to 1/16 for rear toe-in as well.

are those good #s to give them, for the above street/track/autox use?

jerome951

Last year had my alignment changed from a slightly aggressive street alignment to a track alignment after installing Charley arms.
Here is what I have:
Front: -2 degrees camber, 0 toe, I think around 3 degrees caster (get as much as you can keeping it even side-to-side)
Rear: -2.5 deg. camber, 1mm toe in

This is on an '89 951 with stock suspension except for Charley arms and sphericals on the front (no camber plates).

Car is surprisingly decent on the street. A little more darty than before, but I run 205 front tires on the street to counteract tramlining.

Huge difference on the track. The car now turns in without massive amounts of understeer and is well balanced. It lowered my lap times at WG by ~3-4 seconds. A small amount of that improvement was likely due to the new spherical caster block.

You may want to determine your front camber based on the tire you use on the track. Apparently Hoosiers and Kumhos need more negative camber than MPSCs and Toyos. I use Toyos, and still don't quite have even tread wear across the front (more on the outer shoulder, most likely due to camber change from no camber plates). I think Hoosier & Kumho recommend >-3 degrees, but that might not be manageable for a street-track car.

dmoffitt

Thx jerome... since i'll be running street tires for the first season of DE events (for the sake of having a lower 'limit' - i've unfortunately built a car that's way above my ability, and will likely be for years to come) that extreme amt. of negative needed for stickie shouldn't be a huge concern but i have heard that before.

i like cars with very eager turn-in, my rsx i had the front camber adjusted as well as toe and while it did feel a little more 'darty' than i think a lot of people would like, you could still drive it casually on the street w/o constantly worrying about it wanting to change lanes for you

so the 3 to 3.5 degrees of caster seems to be the magic number, and i think i'll start at -2 camber all around -- the only question/concern i have is, what to do about toe for the rear to combat what Ahmet and Danno speak of (braking) - i doubt i'll have problems w/ the rear coming loose w/ 335 tires, esp. on the street, but still, i want to go about doing this the right way. i'm thinking a tiny bit of toe-in might help bring the back around easier, with either zero or maybe a little (1/16 ish) toe-out i the front?

jerome951

With my alignment, it's definitely not a white-knuckle drive on the street.
I've heard that you want to little rear toe-in to combat wandering under braking. Going to some toe-out in front may make it too darty.

I only get rear wandering when I let the rear tire pressures get too high.

I'm concerned that the same camber setting front:rear may make the car oversteer unless you balance this with staggered tires (e.g. much wider rear than front). I use 235 front and 255 rear RA1s and my car is really well balanced in turns.

Heck, just go with something you feel may be too aggressive. If you don't like it on the street, you can always tame it a little. I don't think you'll be able to go too wild for track use.

Good luck.

RedlineMan

Hey -

These numbers are fairly good (with exceptions below) relative to what you have described as your equipment choice and experience in the subsequent thread.

With street tires, you will not create the cornering grip to utilize big negative. You should stay at or below your intended targets for all around use on street tires.

I would suggest you might go with very slight toe-in for the front. This will keep things stable, predictable, and comforting while you learn. Certainly do not go with toe-out for now. Go with 0 max if you must. This is about learning the car, and getting scared s%$#less is no way to learn!

DO NOT go 0 or negative on the rear toe. The farther you get toward 0 toe the less "stable" the rear end will become. For your novice purposes you should keep toe-in for the rear to keep it in line. The factory spec is 5/64ths total and works just fine. Only go to 0 or toe-out if you can handle a loose car at speed. In other words, DON'T!

Take what even caster you can get. 3-3.5 likely.

See you at the Glen this summer, eh?

JH - Central NY PCA Chief Instructor

keith

If you are solid on the rear (you should be with the Kokeln stuff) zero should be fine. The factory specs toe-in to compensate for bushing compliance, IMO. (i.e. toeing outwards when braking, etc)

I've run 1/16th toe out without any major issues, but feel that getting a max of zero is better.

Chris Prack

Keith, toe-in in the rear gives the rear suspension "bite" in a turn. John is completely correct in his explination but run what you like. I just won't do it on my car or a customers.........FWIW......

dmoffitt

I've got a hugely-offset tires size - 245F 335R so should I run more negative in the rear than the #s i posted above, such as -1.5 or even the same as front -1.8?

I think I'll set the front toe to zero or more likely toe-in 1/16 (or somewhere in between) - i can always make it more agressive later, as redline said, safe=easy to learn. rear, i'm probably going to keep it factory, if i feel i'm dragging the *** around i can always reduce it closer to zero to induce more oversteer (plus for minor / subtle tweaks, i've got the sways, i planned on setting the m030 rear to the middle point, and keeping the kokeln front piece as neutral as possible).

thx everyone for the suggestions!! keep 'em coming

Chris Prack

Typically less camber is required the wider the tire.

How much does your car weigh? A 335 IMO is too much tire for the weight of a 951. You are going to have a tough time getting heat into the tires to get much grip. I have never gone any wider than a 315 and that is only in one case. A 275 on a 10" wheel is probably better suited but again that's just my opinion.

dmoffitt

rears are 12" - my next set of tires will likely be 315, these were supposed to go on 13" wheels. oh well. it fills the wheel-well nicely

when it comes time to put something that needs a lot of heat to grip aka stickies, i'll worry about it more then, in the mean time i'll just experiment w/ the alignments etc...

thx for the suggestions, keep 'em coming!

RedlineMan

Hey;

A lot of people want to try a lot of different things. Some of it makes sense, some of it doesn't. If you drive to perhaps the 60th percentile, many of these items will not "cost" you anything. If you drive better/harder than that, you can run afoul of the tuner's old friend, Mr. Unforseen Outcomes. Perhaps if it is really bad, his brother, Unintended Consequences.

A classic example of this is going to a wider tire and getting LESS grip. This seems totally wacked until you look deeper. The car's weight, and more importantly the spring pressure generated, can only place so much downward force on a tire. If you increase the surface area of the contact patch, you also decrease the PSI of that patch. Less PSI often means LESS grip!

Yin & Yang, Grasshopper. Always Yin & Yang!

dmoffitt

well i'll just have to add yet more downforce. lightening the MASS of a car doesn't mean you can't add WEIGHT (in the mean time i'll just drive my hardest, which i doubt will even be CLOSE to 50% of the car's capabilities as of now). i've said before, this car was built to be a cool, fun street car, but that can get out on the track and teach me a few things. if i plan to be competative, i've already built myself into a corner class wise, so i'd be best off starting over or building a dif. car... *shrugs* not a huge concern right now. right now, i want my paint job to be done, tec-3 to be here/wired/tuned, and a few mechanicals (brakes!!) to be sorted, so i can just DRIVE. oh. and the snow could start melting in a few weeks too. that'd help!

Skip Wolfe

Hey dmoffitt,

You might want to drop Chris Cervelli a line. Since he will be slightly familiar with your car he might be able to recomend a setup thatt would take into account the specifics of the car. Just a thought.

dmoffitt

after the move to CO etc he's been kinda hard to get in touch w/, plus w/ changing shocks, and not like, pro-racing / club-racing the car, his settings would be quite different i'm sure. that IS a great suggestion as i'm sure he knows it in-and-out but i feel like i've bugged him quite a lot about tech stuff, more than i'm sure he expected when he sold the car, i feel like a pest