Alignment: Toe-in/out?

[Vipergrün]

Hello all, I am dorking with some alignment stuff trying to get my car to stop pulling right.

I am assumming that item A below is toe-in and item B it tow-out?

A search of the BBS indicates that 1/8" overall toe-OUT is good for track and 1/8" overall toe-IN is good for the street.

Please correct me if this is wrong.


/----------\ = toe-IN if front of car is ^


\----------/ = toe-OUT if font of car is ^


I have 1/2" overall toe-IN according to measurements using the plumbbob and conduit trick. Need to fix that and the pulling.

Also, how do you guys go about finding the center line of the car so you can square things up and get accurate results.

Thanks!

[TimT]

1/2in OUCH!!

On track cars we use 0-1/8 in toes out. street cars we align to whatever the database in the Hunter machine tells us.

If you get the alignment straightened out and the car still pulls check the corner balance. We had a '87 carrera and the alignment was dead on, yet the car still pulled to the right. We checked the corner balance and the RF was seeing 900 lbs!!

We set the corner weights, then rechecked the alignment this car now tracks straight as an arrow.. no hands!!

[Mike M]

Brad...I chased a pull to the right for a long time.Had many alignments and nothing helped.Finally replaced rear bushings and torsion bars and
voila,problem solved.As far as toe is concerned,for a street car I would set it to spec,otherwise the car may feel very darty.
Just my 2 cents...

[Vipergrün]

Thanks Tim!

So, I checked the front ride height. The left front is 1/4" lower than the right front. Although I do not have access to scales, I assum that raising the left will *add* more weight to the left by increasing resistance on the torsion bar? Unfortunately, I imagine this will probably affect the right rear as well.

Thanks for your input.

[RoninLB]

I'm w/Tim on this one...........Ron

[snowman]

THis ain't magic folks. There are 3 things that can make a car pull. Toe, camber and caster.

Alll three can be acurately measured. The toe is most important, it is a major wear factor. Next the camber. It must be the same from side to side, usually 0 degrees to minus 1 degrees, with a difference of no more than 0,25 degrees. The caster must not be differen't by more than 0.5 degrees. and should be about 6 or 7 degrees. If all these are correct the car will NOT pull.

[snowman]

PS use about 1/8 inch toe in PERIOD. NO matter what the use.

[RoninLB]

Originally posted by snowman

If all these are correct the car will NOT pull.

I don't think you should bet on it..

[masraum]

If all these are correct the car will NOT pull.

Assuming all of the parts are in good working order (tie rod ends, bushings, bearings, tires, etc.... And assuming the tires are properly inflated. As little as 5 pounds difference in pressure from side to side can make a car pull.

I don't actually think toe will make our cars pull, right? It may cause horrible tire wear or dartiness, but pulling?

[jluetjen]

PS use about 1/8 inch toe in PERIOD. NO matter what the use.

I can't agree with the above statement. I'm with Tim on this one. Factory specs for street use. Straight ahead to slight toe out for track use. It makes a big difference in trying to get the car to turn in. Unless there is a lot of flex in the suspension design, toed-in cars on the track generally push pretty bad. Basically they're too stable.

[Vipergrün]

Interesting comments John. One of my complaints was that the car pushed thru the corners at a recent track event. Now I guess I know why! The car was just aligned and it appears those idiots dialed in 1/2 inch total toe!! Otherwise, inflation, bushings, torsion bars, camber, etc are all in order. Time to bring her in to a reputable shop!

[snowman]

Sounds to me like your all are talking about setting the sway bar, not he the toe. Get a copy of a book on "how to make your car handle". Tire pressure and toe are MINOR settings compared to MAJOR settings like the sway bar.

[Vipergrün]

Hey Snowman, I don't get it! I don't have an ajustable sway bar, so how do I know if it's set incorrectly? I was under the impression that if I remove/unbolt the swaybar during other mods everything should be ok. Can you please elaborate?

Thanks

[snowman]

You really need to get an aftermarket, adjustable sway bar. For both front and rear. You can get the info from almost anywhere as to increasing oversteer or understeer. By adjusting the sway bar you can increase the oversteer or decrease it. or make it understeer as in the stock case. To much to talk about in a forum, you need to get a book. I can suggest one if you want.

[jluetjen]

BB80SC;
Initially I wouldn't wonder too far from the factory settings, especially since right now it doesn't sound like you have a clear idea what the issue is except that you don't like the handling. In spite of everyone's attempts to "improve the handling" of a 911 by changing the settings, the reality is that the factory really does have a good set-up for most real world situations. Unless you have a clear strategy (The car has corner entry understeer at turn 3 at NHIS which I'm going to try to resolve by changing X, Y and Z without hurting my exit speed on turn 10), I'd strongly recommend going through the factory's settings one by one and confirm that they are set correctly. To do it right I'd recommend:

Confirm bushing integrety
Confirm what is actually on the car for T-Bars and sway bars
Condition(s) of the shocks
Tire pressures
Ride Height
Corner Weight
tire pressures (again)
Alignment

If you methodically work through them, chances are you will find at least one or two places where something has deteriorated or else someone has tried to "improve" the handling by changing something.

Since you're doing track events, here are some thoughts on how to analyse your handling, I've found that this approach works for me.

1) Until you are consistantly within the same 1/2 second, don't worry about the lap times or handling, work on being smooth and consistant with your driving. If your times are consistant to the same 1/2 second or better yet within 1 or 2 tenths...

2) Understand what is happening
* Break the corners down by speed and trend, such as
Slow corner, deaccelerating
slow corner, constant throttle
slow corner, accelerating
fast corner, deaccelerating
etc.

* Be aware of the car's handling in each phase of the corner:
Entry
Mid-corner
Exit

Watch your tires (or better yet get a pyrometer). Where are they wearing the fastest? Chaulk the sidewalls, how far over on the shoulder of the tire are you riding?

3) Come up with a plan
Each facit of the cars set-up can affect different situations and/or issues. I'd hesitate to say that some are major and some are minor. The objective is to find the best compromise for the driver, the track and the situation.

4) Confirm the results, either by the stopwatch (were you more consistant? faster?) or by seat of the pants (I used to take that corner at 4000 RPM, now I can take it at 4500 RPM!)

Toe for example...
(FYI Toe settings interact with ackermann and bump steer)
* Toe in can make a car track straight and not wonder. This is nice for street use. It can also make a car sluggesh on turn-in which can be a real pain on the track. This isn't "understeer" so much as "corner entry understeer". Once the car has taken a set in a corner, toe has a small impact on the handling. It also has very little impact on corner exit, especially in a 911 where the front end is so lightly loaded when accelerating hard. A car that has corner entry understeer may cause a driver to pitch the car into a corner or trail-brake to get the car to turn-in. A driver will doesn't understand this may mis-diagnose the problem as mid-corner oversteer as they try to recover from the drastic measures taken going into the corner. I once had this problem in a Spec Renault which made for a very frustrating race.

Alternatively, slight toe out can make a car wander on a crowned road. On a race track though toe out will help a car to turn-in decisively which gives the driver a lot of confidence. Ackermann can also help to do the same in certain situations.

Set-up can be a real rubics cube, and at least intially it may make sense to try to keep it simple and "do no harm".

[dad911]

Originally posted by snowman
PS use about 1/8 inch toe in PERIOD. NO matter what the use.

Sorry Snowman, I disagree also. Slight toe-in for street, toe out for track. In addition, the initial post is about an excessive amount of toe (1/2") and the car is pulling? Am I missing something, but how does an adjustable swaybar correct that?

Brad has a 23 year old car with at minimum alignment issues. With that age bushings & bearings and alignment should be checked. A 1980 SC as shipped from the factory is a fairly neutral car.

Originally posted by BB80SC
Also, how do you guys go about finding the center line of the car so you can square things up and get accurate results.

I have used parallel lines/strings with jack stands, measured equal distant from wheels. You can check camber with a digital level, or a plumb bob & trigonometry. Be sure pavement is level.
Brad, you may want to read pages 2 & 3 of this post :Toe Adjust Techniquest

[Vipergrün]

Whew, John, that's some heavy reading

Thanks for the link Alan. I have already downloaded that booklet, it's a great help.

Snoman, while I appreciate your recommendations, I find that adding yet another component to the equation when solving a problem can actually make things worse.....and empty the wallet

About 90% of my suspension-related stuff, t-bars, bushings, shocks, et, have been replaced or upgraded. I am simply trying to track down the pull to the right AND get the toe dialed in.

On a side note, do any of you have recommendations to verify the correct geometry of the struts? I still have a suspicion that the right side may be out of whack from an accident, even tho the shop says *no*.

Thanks!!

[TimT]

If you dont know the required angle between the spindle and the strut tube. Compare the struts , if the angle between the spindle and the strut is the same on each side of the car, then you can eliminate a bent strut from the alignment puzzle.

[kwikt 911]

Check your rear toe. If anything run 0 in the rear for street use.


Kevin
72 911T/E Toed out fronts toed in rears, only auto-Xed

[snowman]

I think John pretty much nailed it all.

On the subject of vereifying the geometry of the struts you have already done so in the alignment. The SAI and Included angles tell all. Yours, about 11 degrees each are correct for the car, therefore you have no damage to worry about. The total angle is about 21 degrees and you are right there.