Input about alignments?

[SRD art]

For those that autoX, I am interested in what you all have experienced through setting up your own cars. I've read on different forums very varying opinions about alignments. My control arm instructions have an aggressive recommendation over stock however some people say to go way beyond that. For example one opinion may be .5-1.0 deg of negative camber while other folks are running up to 2.5-3.5 degrees negative. One may say 5-6 degrees of caster is good while others preach 8-9. Some say toe in and others toe out while how much toe varies.

I have two cars I'm building, both will have complete aftermarket Pro-touring suspensions, one will be mostly street duty and some autocross while the other will be mostly autocross with some street. Tire size and weight are different between the two, one will be around 3700 lbs race weight and on 275mm 300 TW street tires while the other will be around 3400 and 315mm Rival S's.

1. Should I anticipate changing the alignment a few times before it's right?

2. I don't have the means to go out and try several different alignments on each car to see what works best, where do I even start?

3. Is an alignment really individual to the car or it's a general rule for all cars?

4. With all other factors involved, how do you tell if the alignment specifically is right or not right? Tire heat? Handling? Tire wear? ... I.e. tire heat after an autoX run is xx so therefore should the alignment be changed or the shock valving adjustment or the spring rate or the sway bar, or... ?

Thanks for your insight. :D

[TheJDMan]

First off, are you planning to do your own alignments? If so I would start with your suspension manufacturers recommended settings and adjust from there to suit your driving needs. From my experience every car is different and the manufactures specs are simply a starting point to get you in the ballpark. Once in the ball park that is when the real tuning begins.

[dhutton]

Just hire Ron Sutton to advise you... :)

David Pozzi’s website is a good source of information.

pozziracing.com

Don

[groho]

Read as much as you can from Ron Sutton, much of it is here or http://www.ronsutton-racetechnology.com/news/article.php?storyid=50. It goes far beyond just "an alignment", its weight, roll, tire, weight transfer, maintaining as much tire grip as possible, and what it takes to make that happen at speed, go deep, ackermann steering, roll center, etc. Read about Lance Hamilton's "Barney", excellent example of improving handling and real-world autocross. I've made many suspension and basic alignment modifications based on Ron's principles and the difference between the start of last year, and the end of last year is absolute night&day. Being a newb running autocross and not scrubbing or mangling a set of 200 TW tires in my opinion speaks to the value of his techniques. . . .or. . . I need to drive harder!

[Cyclone03]

There was once a time when I would jump up and say more camber,more caster, toe out go go go...

Now I work on knowing what each setting does,how it effects the tire contact patch and how those changes effect both the "feel" and how I can drive the car.

I have an early Mustang so I dont have as many hard core Pro Touring companies serving up and racing what they sell as other companies do with GM platforms. That said working geometry,still works.

I have attended 2 of Ron Suttons work shops,I'm not as meticulous as I should be but I have a much clearer vision going into an event than I did 4 years ago when I turned my first autocross lap ever at a Goodguys event. You can grid walk all day and pick up things here and there but spending a full day learning is worth years of trail and error. Everything has been tried,nothing is really new,why not shave a few (hundred) of the errors off? I never graduated college but something I was told years ago still sticks in my head,"you dont know what you dont know".

I will share a set up secrete with you though,It's all about the outside front tire,but get that inside tire to help too and lap times just seem to melt away.

[GoodysGotaCuda]

Alignments are very much car-specific as well as tire specific.

Skidpad is a good way to help identify what direction you are going in with a consistent test and minimal driver input.

[David Pozzi]

It's best to rely on your chassis manufacturer for that info. Hopefully they can provide a proper setting. Alignment specs generally are similar but the worse your geometry is, the more neg camber or positive caster you may need. Some cars with stock suspension can't achieve much positive camber so you do what you can.
Some vendors make good parts, but don't autocross. For those you have to follow someone who is a successful autocrosser with similar car.

Generally you want a good amount of positive caster, you won't need as much neg camber if your caster is up there. If your spindle has 8 deg inclination, then you probably need to run 7 deg for starters. Then set camber at 1.5 deg or so and do tire temp readings to dial it in further. Your final camber could be 1.25, to 2.5 depending on starting caster and how much caster gain you have & how much roll. Many other factors play into this, but if you get very far away from these specs, start to question what you are doing.

If your tire sizes vary a lot front to rear, then the recommendations given will likely not work as well as intended. A significantly smaller front tire is going to create understeer that will be difficult to crutch with tuning. Generally you need more rear bar, may need more neg camber.

If you can't get specs from the MFR, then look for another MFR's recommendation for a similar application.

For toe, generally some toe out will help. You really need to know how much ackerman correction you have and how much bump steer. You could try 1/4" toe out to see if it helps in a tigher autox like Goodguys.
For shock tuning, if you can't get a recommendation, start in the middle of the adjustments, see how it works.

[pitts64]

I have SPC front uppers with the flats in the adjustment sleeves.

After installation and some wear in, I had it put on a Hunter Hawk Eye rack with a good tech and had it set to 5 Positive caster both sides, .5 negative camber and 1/32-1/32 toe in. It drifted to the right and was kind of boring.

I made my own adjustments based on feel, counting and charting the number of turns to each flat. Not sure were its at now but I added more caster to the right and added more negative camber. These two adjustments toed it out some since it's front steer. It's no longer boring and feels like I can throw it into any turn. Keep in mind my area is mostly twistys on steep hills, I might want it different if I lived in the flat lands..

[cornfedbill]

Ben,

I think I can guess whose parts you have on your car. I'm sure it's well engineered and very high quality.

All the suggestions above are good. I would get some shims, a cheap non-contact thermometer from Harbor Freight, a simple angle finder for camber and some way to measure toe - even if it is just a simple tape measure. Go to an event or track and keep meticulous records of performance, tire temps and the changes you make.

I would start with a lot of positive caster so you do not gain a lot of positive caster when turning. Put your angle finder on a good surface on the wheel or hub and turn from lock to lock. I bet at stock GM specs you will gain quite a bit of positive camber at full lock on the outside wheel. That is not good.

David and Ron are both experts. Listen to them. I would still start with at least one degree more caster than the kingpin inclination of your spindles. They are likely between about 8 and 9 degrees. So I would add a degree to that and start at 9 or 10 degrees of caster.

Toe out will help compensate for the effects of static camber. If you add negative camber the tires will try to turn in, just like leaning a bike or when you roll a tire across the garage. I found a quick reference once that had a rule of thumb for toe out versus camber. Just follow David Pozzi and Ron Sutton on this.

Remember that body roll will influence camber and weight transfer. If your springs and anti roll bars are stiff, you won't have a big problem, but if not, this will cause you to need excessive static negative camber to compensate.

Yes, each car is different. Even different drivers in the same car may prefer different settings.

Here's where I'm starting:

- Kingpin inclination is 8.75 according to David Pozzi. My measurements agree. So I am starting at 10 degrees of caster.
- Camber - because I do not plan to autocross much, but to run open road racing and track events, I will run 0.5 to 1.0 degrees of negative caster. I would run about 2.0 to start if it were an autocross car. Remember that excessive negative caster will turn in better, but will wear your tires when driving on the street in a straight line.
- Toe out - about 1/4" and will then check tire temps in a straight line to see how much they scrub.
- I am increasing the Ackerman angle of the steering arms but adding thin spacers between them and the uprights. I think you may have one piece spindles and do not have this option. It gives more toe in when turning, but not when driving straight.

I may be out in left field, but feel pretty confident that these settings will get me in started right.

Again, for autocross on tight tracks as opposed to open road racing you will want more negative caster and more toe out.

You may want to look into some basic tools so you can align the car yourself. You may find it possible to avoid paying for an alignment shop.

I'm excited to see the wagons back in action!