Hey Paddock people,
With a dedicated track car, whats your alignment setting? My dad and I set ours up with what we thought is right. After about 10 track days I removed the RA1's and noticed the wear pattern isn't even. I can't remember if the front or the rears were more uneven. I flipped them around on the rims to get them to last longer.
Any help, as always, is much appreciated.

Shane

Shane,
When you say "uneven" that can be a whole gamut of things. As in, the inner wears faster than the outer, or vice versa. Any "cupping"? Show us some pics and tell us your current setup.

I think most people run a little extra camber over stock and about 1/8th toe out in the front to start until you get into slicks and a really stiff setup. There are a lot of other variables including but not limited to track layout, power of the car, how hard the driver actually drives it, etc. Track setups are way different than autocross setups too.

For RA1s I would start with -2.5 degrees front and -2.2 rear. Front toe straight ahead or maybe just a little bit of toe out. Rears should be toed in just a little bit. Then start taking tire temps and adjust from there.

Front camber 1.8 left 1.5 right
Front toe 0

Rear toe 1/8" in both sides
Rear camber - 1.75 left -1.5 right

George,
There's no cupping.
Here's my set-up.
front camber
left -1 right -1 1/8
rear camber
left -1 3/4 right -2
rear toe 1/4 in
I just want track setting, autocross isn't as important to me anymore. (although still super fun)
Woody,
I don't own that tire temp tool. (don't know what its called) I also don't think I can get the front to that much negative camber. I guess I could replace my ball joints with the de-cambered ones. With Matt's suggestion too, it looks like I should get them.
Matt,
Why is the left different from the right?
Something else to add.
I run RA1 205-50-15
front pressures (cold)
24psi
rear pressures (cold)
26psi
Shane

There's 360 degrees more right turns than left every lap...so a bit more camber on left side makes sense.....
I'm on 225/45/15 RA1's & usually start around 30 in order to work up to 37 or so....bleed them down a bit to 36 as soon as I get out of the car at the end of each session.....

No fancy reason - that is the most we can get on each side.

My car is behaving differently through Bishop Bend since the accident we had last year. Ill work on posted the video here in a few. The old alignment number are in this post. From those numbers I also added decambered ball joints. Suppose to add 3/4 more negative camber. I never got it on the alignment rack to prove that, but they certainly looked like they did.
We now have 2.3 negative camber in the front. (Rears are same as before) I have adjuster plates maxed out. Was awesome at Homestead at that setting.
Check out the steering wheel angle in the comparison video. First part is from before the crash, second part is after.
Guess I'm looking for any ideas here. Might have nothing to do with my camber?
I also changed my front bumper from a 916 to a stock looking set-up. I can't imagine that has anything to do with it.

https://www.youtube.com/watch?v=DGLmx5AEvwg

Shane, can you elaborate on how it's behaving differently? All I saw was a little less steering input in the second video going through Bishop's, which on paper is a good thing, as long as it's still in control.

What do the tires say? I.e., any difference in wear pattern from before? Have you tried getting tire temps with a pyrometer?

The car leaned on the right side tires before. Now, not so much. It was the only part of Sebring that felt different. I used to go flat out though that bend. I was lifting a bit. Not sure that I really had to. It just didn't fell normal to me.
As far as the tires go, the front are wearing more on the inside then the out. My concern there is that i'd like to see it more even. Especially for chump. Would love to see tires last 14 hours. (fyi. you drive first this time)
Donny just bought a pyrometer. I haven't got a chance to use it yet. There so busy with the Corvette that i hate to bother them for help. I'd love to see what that machine tells me.

Sounds like too much camber, especially from the wear. I just dont think these cars require that much camber until youre wearing slicks and move into really high spring rates. That's actually true with most cars. Until you have enough mechanical grip from the tire compound and weight transfer onto them, you are actually decreasing grip and increasing wear, especially on the inner edge. Tire temps would confirm this for sure. That might be why it feels darty/skaty, especially in a high speed sweeper like Bishops.

Also take a close look at the little triangles on the outer edge of the tire to see if you're scuffing all the way to them....if not, it's too much camber. Tire temp device-- pyrometer-- with a probe is really cheap if you don't go for the memory type unit....

Yeah, Longacre has one that's pretty straightforward, and I think it's like $100. I've been meaning to get my own, but since I'm not on the track all that much, it would just collect dust. The other trick is you need someone on your pit crew to check them because you want to get temps as soon as possible right after you pull into the pits. Too much to unbuckle, get out, and try to get accurate temps. However, for your purposes, it's more of a go-no-go. If you see radically higher temps on the inside (say 10-15 degrees higher than the middle/outside), then you know what's going on. Hell, in that case a Harbor Freight IR temp sensor might even be able to show that. John's suggestion to look at the triangles is a good one too. In that case though, keep in mind that your tire pressures have a big impact on rollover as well.

I'm not sure I could help here because our cars are soooo different but on Papa Smurf we have:
3 deg negative camber all around.
2 mm toe out front
2 mm toe in rear.

with these settings, the car feels like it's on rails, so I'm not changing a thing!!

John,
The tires already have been used so the triangles idea would be suspect. I could use some tire crayons to see how much rollover I have.
I need to use that Pyrometer. The guys I race with have the memory one, Just need someone in the pits so I can come off hot and have them checked. Hopefully I can get that done next weekend.

George,
Don't buy one, we can just borrow Donnys for set-up. I post up the numbers with tire pressures if it works out next weekend.
I still think I need to drive it again, I know I was pretty nervous after the hit.

Bob,
2mm toe out? Thats interesting. I'm at 1/8 toe in. I wonder if I screwed this up from the previous alignment. Looking now...

Front toe in makes the car squirrelly at high speed...

Yup, use crayons where the triangles are to set a new reference mark.

I think 2mm out is probably overkill for your car, given the way Bob's is setup. But 1/8th toe-in is a lot, even for a street car. I'm pretty sure mine is setup at zero on the front and 1/16th in on the back. You'll gain toe slightly at speed anyways, given the tolerances on most suspensions, especially ours, so the most you'd probably ever need is 1/16th out on the front.

Also - the more caster you run, the more camber you'll gain with the turning of the wheels as well. Most of us I believe run the caster as far back as it'll go, and then you'll likely have all you need, and can get rid of some of the static camber.

Hope you don't mind me entering your thread; I've never raced a 914 but raced 3 series BMWs for several years.
I'm confused by your comments above. You said you never got the car on the rack to check camber, but yet you quote -2.3 F camber. Are you using a portable camber gauge?
Also, how is it behaving differently? Understeering? oversteering? Feel sluggish or loose? I think the tire temps are useful only for setting camber, nothing else. The temps should be within 10 degrees of each other across the inner, middle, and outer tread.
RE correct toe and caster settings, that's probably based on how the car feels. IE is it understeering on corner entry or oversteering? Understeering on corner exit or oversteering? I tend to see the front end as contributing to corner entry and the rear end as corner exit, so if you want the car to behave a certain way on entry or exit, you set up the front or rear appropriately.

Sorry, I'm not familiar with the track in question, but my comment about the change in steering wheel angle is this may indicate the car is either pushing or oversteering more than before. If you now lift off the gas where you used to be flat out, maybe the increased negative front camber is causing more front grip, making the rear end seem a bit looser? Just a wild guess based on knowing very little about the track or your driving style.



Do you know something I don't? I've always heard the opposite. Front toe in makes the car more stable at high speed due to drag pulling the tires backwards. BUT racecars usually run slight front toe out to help with initial turn in

I've got a related question.

Setting camber and caster on the front axle, just loosening the three M10 bolts and then trying to move the top mount it pretty hard. Do you use anything to leverage it inwards/backwards or how do you do it?

A big ass screwdriver.

Raising the front wheels off the ground and a BF rubber mallet works too...

Doing an alignment on mine this afternoon and hopefully geting Close to the following for my 95% street and 5% slalom/autocross usage:

Front
Camber: -1,5
Toe in: 1 mm on each side
Caster: 5,5-6 somewhere

Rear:
Camber: -1
Toe in: 1 mm om each side.

Those cambers are very aggressive for a street car and will result in rapid tire wear on the inside shoulder.
Even 3/4 degree all around will result in significantly shortened tire life.

And here I thought I was being a bit conservative. I've got two sets of tires to alternate between and I probably wont drive more then 2000 miles over one season from April to September so I'll start with this and see what happens.

The added caster I dialed in yesterday really helped the front end feel less twitchy and sensitive to bad roadsurfaces.

Racer Chris really knows his damn stuff. Everytime I post and he posts afterwards I question whether I was giving the right information, lol.

Mats - the other thing I noticed, at least on my car, was that when maxing out the caster, I could get another millimeter or two by leaving the bolts all the way loose. There is a "lip" that you can push the bottom caster/camber plate over, that normally one wouldn't be able to do unless they're all the way loose. I think it could be ground down too, but I didn't have to do that. It's been awhile, so I may not remember this correctly.

I know you can also elongate the holes to gain even more caster/camber, to a point. But I'm sure that's clearly not necessary for your purposes. As I told Shane, it seems to me that most people probably think they need more camber than they actually do anyways.

Thanks for the tip George.

Just back from the alignment shop and I cant seem to get toe in on the left rear wheel. Right side is at 2 degrees toe in but the right side is at 2 degrees toe out despite that I have elongated the holes in the outer trailing arm bracket as much as possible.

I did check the mounting hole dimensions according to the underpan picture here on the World and it seemed spot on. Starting to suspect I have a bent trailing arm...
Does anyone have good dimensons to check it for straightness?

If it turns out you need a new one, I'll send you one for the cost of shipping.

Does the console (the 'mount' where the elongated holes are) hit up against the chassis? Is that's what's stopping you from getting more toe in? That's what was wrong with ours, we had to grind down on the console until we could move it enough...both sides. Did it at the track.

I've got Chris's outer brackets on the car and I've filed the mouthing holes up around 5 mm, might get another mm in there but then the round part will start to hit the body. Then again that is solvable by reducing the camber to make the mount sit lower. But then I start running into interference between my 195/55 tires and the inner lip of the fender.

I'll borrow a fender roller this weekend and see if I can gain more clearance....

Is there a GT stiffening kit on the chassis? If so, the piece which goes on the back side of the outer console will cause the same trouble you're experiencing.

I just completed an alignment on a 95% street/5% autocross car. We ended up with 0.5 deg front/0.6 deg rear, and about 1mm toe in all 4 corners.
Stock front A/S bar, although I'm recommending to the owner that he purchase a 19mm adjustable bar.
205/55 tires on Fuchs alloys and no issues with fender clearance.
I went through my test curves on a local road, comfortably - as fast as I dare drive a customer car through there.

Yes I have your full stiffening kit with the rod braces on the car.

My kit doesn't have the surface mounted plates that the GT kit has so that's not part of your problem.
It may be that you have a bent trailing arm.
The angle between pivot and axle in the horizontal plane is 12.5 degrees IIRC.
There is also a built in camber of 1.5 degrees.
There are no other measurements that I know of, although I think I've seen a picture of a go-no go fixture used to verify a trailing arm.

I'm thinking I might need to take down both rear trailing arms and put a suitable diameter pipe thru the pivot axis on both together and then measure the angle to the hub plane and see if there is a difference.

Didnt want to spam this thread with more questions so I started my own...

http://www.914world.com/bbs2/index.php?sho...=309230&st=

Let me try and clear up what you asked me about.
I didn't put the car back on the alignment rack after added the de-cambered ball joints. Elephant Racing says the add 3/4 more negative camber. It was measured prior to adding them. I tracked it after the addition and like how it handled. I never measured what was accomplished with the new ball joints.
It looks like you comments are on point. I agree the car was pushing slightly. It was just to different. I fixed it now.

All better now. Turned my fastest lap this weekend on some beat tires.
FYI, My alignment was not correct. My Dad left me to get it right and I messed it up. Now I'm 1/8 in. Huge difference.


https://www.youtube.com/watch?v=dFnQIlb23ZQ