Auto cross Allignment-, how are you set up and how do you like it? Options

[ottox914]

Up here in the frozen north, its getting, well, closer to frozen, which means wrench time. Now that we have a "motorsports" forum, I was wondering, what allignment do the rest of the auto crossing 914's use, why, and how does it work?

Not like it matters to this thread alot, but got the rears pulled to clear the 7" keizers and 205 50 710's, and found some good values for wot throttle response across the rev range for the SDS, and had a total blast at our last event of the season yesterday...

[Joe Ricard]

Well there was (or is) a wise old man that told me how to set up my car to go fast in tight Autocross courses.
Pretty much worked exactly like he said.

1/8" total toe out front
1/16 total toe in rear
as much caster as you can get keeping them equal.
Camber is tire dependant. Hoosier A3S05 liked -2 degrees. Tune with pyrometer.

Attitude of car or "rake" 1/4 lower by the front lift donuts.

[Brad Roberts]

What he said.. except for this:

Camber is tire dependant. Hoosier A3S05 liked -2 degrees. Tune with pyrometer.

This is driver dependant. Some people need -1.5 and some need -4. Yes some tires work better with more or less but it all comes down to how hard the owner of said tires pushes them.

Carrera Cup cars show up over here after being driven by a pro driver with -5.0-5.5. Very FEW people in the states can drive that car on our tracks.

1/8 toe out in the front works if you have new plastic bushings or bronze.. or roller.. the only time I use zero is if the stock bushings are in place. It will toe out this much on the stock worn out rubber crap..LOL

B

[Aaron Cox]

Well there was (or is) a wise old man that told me how to set up my car to go fast in tight Autocross courses.
Pretty much worked exactly like he said.

1/8" total toe out front
1/16 total toe in rear
as much caster as you can get keeping them equal.
Camber is tire dependant. Hoosier A3S05 liked -2 degrees. Tune with pyrometer.

Attitude of car or "rake" 1/4 lower by the front lift donuts.

(toe out in front - makes it "twitchier" no?
that makes it great for AX

i street my car too... but my specs
are 1 1/8 or 1/16 toe in front (cant remember)
1/16 toe in rear
-1.6 Camber front
-2.0 - 2.1 camber rear
max caster up front (being equal)

a little toe in upfront makes it a bit more stable in a straight line (good on the street)

oh yeah.. and my AO32R apparently like lots of camber

[Brad Roberts]

Correct on the toe out. Great for turn in, not so good on the street. The car will follow EVERY groove it encounters.

I have found I dont need to run toe in in the front with 914's. They always turn in well if the cross weights are good. I also dont like to scrub all 4 tires as the car goes straight. The 4cyl cars have a hard enough time dragging the two rears with toe in!!


B

[jhadler]

I agree on the toe in and toe out numbers most folks have mentioned.

Keep in mind that what's good for dodging cones is not always good for the track. Brad's comment about draggin tires is valid on the big track, where every fraction of a pony is valuable. Reduce the rolling resisitance as much as you reasonably can without sacrificing lateral grip.

I run around 1/16" toe out in front and around 1/16" toe in at the rear. As much caster as I can while keeping the camber equal. I don't remember the camber numbers though, something like -1.25 F, -1.5 R.

-Josh2

[nebreitling]

all those toe numbers sound like good AX baselines. camber is something that I never had enough of in the front, but often had a bit too much of in the rear. At -3.5 front, I was still looking at decambered balljoints.

It's hard to get too much caster on a stock 914.

all of this is dependent on your setup and driving style. experiment often.

[Brad Roberts]

Nathan's post proves my theory.

Everyones needs are different. What works for one person may not work for another.

Take these numbers and "start" somewhere. Adjust accordingly.

Running on the same Hoosiers Nathan ran on.. I use -3.0 to -3.25 in the front. he may push the front tires harder than I do.

I cannot emphasize how important individual alignments are. I learned this ages and ages ago with Pro drivers. I got tired of "generic" alignment shops throwing whatever the "last guy" had on the car. I was performing "out of the box" alignments at age 18 when I had access to a the "latest" Bear ACE equipment (Sears/Park Mall/Arlington TX..lol)


B

[Joe Ricard]

Yup camber is driver dependant. rim size also affect the profile of the tire.
225/45-15 A3S05 on an 8 inch rim makes for pretty square sidewall 35 PSI makes for great grip and very quick response.

Driving style is a biggy. I am more twitchy and prefer to slide the car a bit to change direction rather than turn and "hang on" the turn leaning on the tire that is just scrubbing speed.
Hey it's what I have been taught and it is pretty competative in a fairly big fish pond.
Yes Aaron toe out makes the car a handfull on the road. I usually drive 80-90 MPH going home from and event with both hands on the wheel 100% concentration.

PS. now I run bias ply slicks and this is a totally different animal.

[J P Stein]

Golly, must be even slower than I thought....I only run -.5 camber at both ends.
You must be right again, Brad (IMG:style_emoticons/default/biggrin.gif)

[nebreitling]

has anyone done anything with redesigning the front end to create significant positive ackerman in an AX-914? if you're running super wide/sticky tires (enough to get into scrub radius issues), i think it would be a major benefit. you could run the static toe straight up and get good positive ackerman to swing the car around the tight stuff.

(maybe i'm thinking too much about karts here....)

[J P Stein]

has anyone done anything with redesigning the front end to create significant positive ackerman in an AX-914? if you're running super wide/sticky tires (enough to get into scrub radius issues), i think it would be a major benefit. you could run the static toe straight up and get good positive ackerman to swing the car around the tight stuff.

(maybe i'm thinking too much about karts here....)

Yes, Porsche did....by divorcing the strut tube from the ball joint & spindle.
They're still all attached (thank God (IMG:style_emoticons/default/biggrin.gif) ) but the strut has been moved inboard thus allowing more backspace on the wheel to get rid of scrub radius problems.

The 914 setup is hopeless, me thinks. Adapting a post 89 strut setup to a 914 A arm
would be a possibility....and prolly the best bet. More backspace could then lead to a clearance issue to the inner fender at full lock. I haven't looked into the dimensional aspects of this. Got a late model strut assy laying around?

[ottox914]

What is anyones experience with rear camber? We seem to agree that front camber is driver specific, and that with tire "A" a different drivers might end up being faster with different settings. How about camber in the rear? My mind goes both ways on this, one thought is to match maximum front camber to the rear, perhaps to try to make both ends handle the same, this will maximse cornering grip. The other side of the coin is that with the limited power of our 4 cyl cars, keep the back tire flat on the ground, but as much power down as is availible.

Any thoughts on rear camber?

[nebreitling]

i was always happy with -2 to -2.5 in the rear...

[DanT]

On my mild little put put I have -2.5 front and -2.75 rear. Works nicely (IMG:style_emoticons/default/smile.gif)

[J P Stein]

We seem to agree that front camber is driver specific, and that with tire "A" a different drivers might end up being faster with different settings.

Well, Brad agrees with Brad (IMG:style_emoticons/default/biggrin.gif)
The actual fact is that some tires like more camber than others....front & rear may vary and someone like Nate will like more camber as he liked to run radically low pressures. Course he chewed up tires rather quickly, right Nate?
As for Euro cup cars....maybe. Also maybe they run on glass smooth F1 tracks & maybeuse stiffer springs & lower ride heights that can't be used on an American track.
They also run class spec tires and can fool with pressures....lota maybes.

I run Hoosier bias ply slicks and they don't like near the camber that radial R-spec tires like.
Like Joe said, tire temps across the face tell the tale. Tread wear (or wear dots) also
are a clue to both camber & pressures.

.

[nebreitling]

someone like Nate will like more camber as he liked to run radically low pressures. Course he chewed up tires rather quickly, right Nate?
.

righto. (IMG:style_emoticons/default/beerchug.gif) but i had similar experiences with other tires at other pressures. tires are a happy consumable, no biggie there.

[grantsfo]

On my mild little put put I have -2.5 front and -2.75 rear. Works nicely (IMG:style_emoticons/default/smile.gif)

Cough ...mild ....This link is for you Dan (IMG:style_emoticons/default/biggrin.gif) : Tribute to Dan's "put put"


Some of us with practical street cars who drive on the worst roads in the US could only get about -2 ...I tried going lower and kept bottoming out on the bumpy section of mountain road to my house.

[DanT]

(IMG:style_emoticons/default/chairfall.gif) (IMG:style_emoticons/default/chairfall.gif) (IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/av-943.gif)

That is tooooo funny Grant... Thanks for the sentiment.
Is it really that low? (IMG:style_emoticons/default/biggrin.gif) YES (IMG:style_emoticons/default/burnout.gif)

[Borderline]

has anyone done anything with redesigning the front end to create significant positive ackerman in an AX-914? if you're running super wide/sticky tires (enough to get into scrub radius issues), i think it would be a major benefit. you could run the static toe straight up and get good positive ackerman to swing the car around the tight stuff.

(maybe i'm thinking too much about karts here....)

I've been waiting for someone to use that word, "ackerman". Carroll Smith wrote a couple books back in the 80's on tuning and building race cars. At first he recommended zero ackerman. Then a couple books later he changed his mind and was recommending extra ackerman. I've spent the last 20 years or so playing with sailboats and have just got back into cars the last couple years. I was expecting everyone to be doing this and more. Seems like extra ackerman gives you the best of both worlds: Straight line speed and stability and then improved turn-in and possibly more cornering power. It's on my list of things to do. It's just way down there right now. I've got to get the thing painted and an engine back together over the winter.


Nathan: how's the karting going??