Home Alignment

[TT Oversteer]

Here's a link to my post on PP for those of you who want to venture over to the "Dark Side"

http://forums.pelicanparts.com/porsc...ent-setup.html

I tried this once before with marginal results. I learned a lot the first time and came up with some new ideas. This is the "new and improved" version that enabled me to get camber, caster and toe dialed in nearly perfectly.

[Ed Hughes]

Very nice. I like your setup. I wasn't quite as creative on the fixtures when I did mine. The point is that this isn't rocket science as they say, it just takes patience and some time. Again, nice job!

To all you fence sitters-try this sometime, you'll learn a lot about your suspension in the process. Don't be fooled by all of the digital readouts and lasers on the Hunter machines at alignment shops, it really is a simple process.

[rusnak]

I started messing with mine after Iceman's recent thread about fender vs. wheel rim clearance.

I re-aligned my rear suspension (a pain in the butt to get right) with string, 4 jackstands, some really long bubble levels, and a small step ladder and c-clamp.

In my case, the hardest part was to get the strings square (the two need to be parallel), and I measured the rim distance from string with a caliper/ depth gauge. I found that once your suspension is miles off, it is an iterative process to get it right. I also discovered the technique to get the rear suspension eccentric bolts to work. You have to loosen/tighten/loosen the eccentric bolt nuts in order to squeeze the springplate and trailing arm together, then the eccentric bolt will act upon the trailing arm the right way.

TT, I had the same concerns when I saw the cinder blocks as the others. I didn't quite understand the need for the center point. How did you check castor? That one eludes me.

I also used the Draco Harbor Freight toe measuring device that we discussed earlier this year. I shortened the process after a few frustrating hours by just setting the front toe at 0.00" with the steering wheel absolutely centered. Then I had a double reference to re-check the rear. The car tracks absolutely straight with nice handling. .75 degree neg camber. The rear was iterative no matter what, and when you make changes to the rear, you have to re-do the front. Also, lowering or raising the car will change the toe and camber settings.

[amjf088]

Hey TT,

Thanks!

Great pictures and informative description. When I get my suspension put back together I will be going through the whole alignment process.

Threads like yours really help. At first, I had planned on doing a "get it driveable" alignment in the garage and then taking it to a pro. Now, I don't see why I can't get the ultimate result on my own and bypass the shop entirely.

Thank you very much,
Allan

[TT Oversteer]

I didn't quite understand the need for the center point. How did you check castor? That one eludes me.

Rusnak, The center points are established to shoot a laser line between them which is effectively the longitudinal axis of the car. Most 911s have different track widths front and rear. If you just measure equal distance out from the hubs the strings will not be parallel to the longitudinal axis of the car and your toe settings will be wrong. You could also have a situation where the front and rear wheels on each side are parallel F to R but not parallel to the opposite set of front and rear wheels. The center points just give you an exact and permanent reference to measure from that is independant of wheel width or track width. Also, the distance from the hub to the strings will change with camber adjustments as you found in your "iterative" process. With the center line known and the strings set parallel to eachother the front and rear can be set independantly from eachother with just one adjustment. The beauty of the bar and string setup vs. jackstands is that the strings are set once and do not move relative to the car when making adjustments or rolling the car back and forth.

I checked caster with the same digital level I used for camber. Caster is just the angle of the strut relative to the vertical. I used an aluminum block resting on the front surface of the strut body with the level resting on top of it. Zero the digital level on the vertical then measure from the strut body (not the strut cover). You should read somewhere in the neighborhood of six degrees. This works because the longitudinal axis of the strut intersects the axis of the spindle. The car has to be on a level surface, obviously, for the angle measured to be accurate. The thing about caster is that most guys try to get as much as the stock strut mounts will allow for high speed stability, i.e. adjust the tops of the strut mounts as far toward the back of the car as possible. It's more important that the left and right caster be equal rather than a specific amount so if the absolute number you measure is a little off it's ok as long as both sides are the same.

[abe]

I would love to bring this topic to the 997 (we at the 997 group don't mind paying $700 for an oil change, but do our self alingment on a 911)....they probably laugh me out of the forum.
abe

[rusnak]

I see...that is why you have the car raised, to measure castor? I could never reach behind the front wheel on the ground. I have been happy with just getting them even with each other.

I think I understand what you are doing much better now. Very clever! I have to try it!!

One more question: would it work to have two plumbobs (one right, one left) to do the setup? Measure with a tape measure? I'm thinking left to right in an X pattern.

[TT Oversteer]

Originally Posted by rusnak

I see...that is why you have the car raised, to measure castor? I could never reach behind the front wheel on the ground. I have been happy with just getting them even with each other.

One more question: would it work to have two plumbobs (one right, one left) to do the setup? Measure with a tape measure? I'm thinking left to right in an X pattern.

The car is raised to allow adjustment of caster, camber and toe. I can slide under the car and adjust the tie rods and rear eccentrics with the weight on the car and suspension settled in its normal position.

I'm not sure I follow you on the two plumb bobs and X pattern.

[rusnak]

I had a meeting this morning at a Barnes and Noble, and I picked up last months Excellence magazine.

Guess what? There is an article on suspension alignment with the Smart Strings. I will read it when I have time later, but it looks very similar.

And another thing. Elephant Racing is making shock absorbers!! vonshocks or something.