Doing my own alignment

[Tori]

Hello fellow Pelicaneers....

Trying to get my car back into fighting trim since lowering. (25F/24.5R wheel well measurements)

I know i need to corner balance, and will be doing that hopefully next week. I Have a set of scales lined up, and after that i'll get serious about the alignment.

I work at a repair shop, and we have a very nice Hunter alignment rack that i can use. Our alignment tech doesn't know P-cars, and i feel with your guidance i'll be able to do a better job than a flat rate tech that quite honestly, has no desire to work on my car.

Clearly the rear was WTF (waythefuch) outta whack, and i could tell it from driving. I set it up tonite to get familiar with the machine, and what it takes to move things about.

Here are the before specs:



I didn't plan on doing anything with the front tonite as i need you're help with those adjustments. I've read a few posts already on that subject, but need to be more clear on what to do, and the exact process.

Time allowed me to only move the rear which was my goal, and read where i currently am, and see where i could get the rear.

Here is where i was able to end up. (i actually had the right rear matching the front, but while reattaching the sway bar, i ended up shoving the car over on the rack which skewed all the measurements. I got it back in place close enough to take this pic, but imagine the RR camber reading 1.0


I feel it's pretty good considering the car has been lowered.

What do you think from the numbers i'm providing ?

Any tips on doing the front ?

[brianlay]

Those ride heights are bordering on aggressive lowering but will work. Your should consider shimming the steering rack if you haven't already done it.
Depending on your intended use of the car I would recommend front camber more negative than stock, you may not be able to get more than -1.8.
I would aim for -2.0 rear camber. That gives a nice handling improvement without introducing excessive tire wear.
As I recall there is quite a bit of interaction between the rear toe and camber adjustments so you have to go back and forth a few times to get the correct result.

[Tori]

Hi Brian, thanks for the response and specs. I agree that it's borderline too low. I've not driven it much like this due to the alignment being as far outta whack, but i do notice i scrape in places i don't want to. And the other day when i had a 200+ lb. friend in the car, it was for sure too low. I am considering bringing it up .25" all the way around, maybe a full .50" I guess i'll see where the corner balancing takes me.

The car is just going to be a sunday driver. I've got a single track day planned at the end of the month, but have no plans on making that a habit. Mostly so i can learn to drive the car and find its limits in a safe environment.

I keep forgetting to see if the steering rack is spaced or not, i have always noticed a tad bit of bump steer, so if for sure needs them, or more of them.

[brianlay]

I forgot to ask about the torsion bar sizes. Lowering without increasing the bar sizes will increase the chances of bottoming out.

[Tori]

Originally Posted by brianlay

I forgot to ask about the torsion bar sizes. Lowering without increasing the bar sizes will increase the chances of bottoming out.

That i do not know. Car is bone stock AFAIK, so if that tells you anything ? 87 Coupe

I haven't felt it bottom out either.

[brianlay]

Probably stock, so be careful about going too low 25.5/25 is a good target.

Rack shim like this Porsche 911 (1974-1989) - Steering System - Page 2

should be fine.

[Luccia at Pelican Parts]

I think it's always good to learn how to do this. It's definitely on my list as I feel like I'm always changing suspension items and aligning my vehicle. It's convenient that you have one of those great racks to do the job. If anyone else wants to attempt to tackle their alignment, and doesn't have access to a rack like this, I suggest to check out Smart Racing alignment products. Anyways, good luck with the fronts and kudos for learning to alignment your own vehicle.

Porsche 911 - Smart Racing Products Alignment Tools

[bpu699]

Can someone clarify...

For the front wheels, + toe means the wheels are spread out at the front, ie, toe OUT, right?

But on the rear wheels, when the alignment machine reads + toe, the leading edde is pitched out?

Confused...

Does + toe for the front, not mean the same a + for the rear?

Eg. Your car has both front and rear wheels leading edge pointed in..

Is that + toe front and rear?

Is that _ toe front and rear?

Or is that - front, + rear?

[gomezoneill]

Originally Posted by bpu699

Can someone clarify...

For the front wheels, + toe means the wheels are spread out at the front, ie, toe OUT, right?

But on the rear wheels, when the alignment machine reads + toe, the leading edde is pitched out?

Confused...

Does + toe for the front, not mean the same a + for the rear?

Eg. Your car has both front and rear wheels leading edge pointed in..

Is that + toe front and rear?

Is that _ toe front and rear?

Or is that - front, + rear?

NO + toe means toe in both front and rear. - is toe out.

[KTL]

Some good DIY alignment discussion here, thanks to a guy named Ray Scruggs who put together a DIY book on it for 911s.

Toe Adjust Techniquest

How To Measure Toe In/OUt?

I know the fender heights have been thrown around A LOT on this forum and that's fine for street driving and appearance. But if you're going to track it and want a sharp handling car, you can't go with fender heights. Corner balance is the way to go.

Also, you should corner balance your car before aligning it. The corner balancing will mess up your alignment. It'll especially mess it up if your corner weights are way off to start.

The front end of these cars are VERY sensitive to ride height change. So if you have to crank on the front torsion bar adjuster screws quite a bit to set your weights, your toe will be messed up. I can guarantee you that. Especially if you corner weight it and then change direction by ignoring your weights and just going for equal fender heights side-to-side.

Unfortunately corner weighting is a bit compromised by your original sway bars. Since they have fixed length drop links (the front bar is awful in this regard), when you reconnect the sway bars they will be fighting your corner balance. To get your optimum corner balance you need sway bars with adjustable drop links. The rear bar is easy to swap out fixed links for adjustable spherical rod ends. The front? Nope you're stuck with that crappy setup! Sorry.......

[jpnovak]

Can you read individual toe settings on the rear? this is required for a good alignment. If you only have total to then there can be a situation where one side is toe-out and the other toe-in and car will crab down the road. This is bad for handling and tire wear.

I use strings for alignment and have my notes in mm dimensions rather than degrees. Yes, they can be converted using some rather simple trig but my setup ruler reads in mm.

I usually rough in alignment to get it very close in ride height, toe, camber and caster. Then I corner balance and then recheck the alignment. At this point there are only minor changes required and this does not disturb chassis balance.

Spend the time to get it right and you will be rewarded.

[Tori]

Okay, i revisited the alignment rack this past weekend. The goal this time was just to get familiar with moving the front end, and possibly curing my right hand pull.

Remember, this is just practice for me until i can get the scales and attempt corner balance.

I was of course able to adjust front toe, and played a bit with front camber. The spec. i got from a post here on the site was - 1.0 (negative) front camber. My left front was already at -1.1 and the right front was at -2.5 I was only able to get the right front to -2.1 before i ran out of adjustment.

I realize i can only get so much with the ride height i'm at, but if one side is good, shouldn't i expect the other to be able to get close that same spec ? I assume something must be bent or tweaked. Any thoughts on that ?
Can i slot the holes in the body to allow for more camber adjustment ?

[manbridge 74]

You might consider the factory method of measuring from center of t-bar to ground and center of wheel hub to ground. It's more accurate than the fender measurements.

Search the tripod method of corner balancing until you get some scales. I think you'll find you won't need to do any slotting of holes. You'd gain very little from it.

Unless you are going for looks make sure the tie rods are angled down slightly or at least level. Having them angle up results in an ill handling 911.

[Driven97]

Originally Posted by Tori

My left front was already at -1.1 and the right front was at -2.5 I was only able to get the right front to -2.1 before i ran out of adjustment.

That doesn't sound too good. Take a good look at the front pan. Does the machine measure caster? Is the caster way out of whack? That could cause a pull.

[brianlay]

in my experience getting even -2.0 on both sides is a challenge with stock parts. usually have to settle for slightly less.
With those numbers either
-something is seriously bent
-some non-standard parts are installed
-your measurement technique is incorrect

widening the slots probably won't help since it's usually strut mounting plate hitting the body that limits movement.

[Tori]

Originally Posted by brianlay

in my experience getting even -2.0 on both sides is a challenge with stock parts. usually have to settle for slightly less.
With those numbers either
-something is seriously bent
-some non-standard parts are installed
-your measurement technique is incorrect

widening the slots probably won't help since it's usually strut mounting plate hitting the body that limits movement.

I'm not trying for -2.0. Trying for -1.0

I took the bolts and upper square washers off, and it looks to me like the bolts are at the limit.

[Tori]

Originally Posted by Driven97

That doesn't sound too good. Take a good look at the front pan. Does the machine measure caster? Is the caster way out of whack? That could cause a pull.

Here is the measurements when i was done with it sunday night. You can see there is only a .20 difference in Caster, which isn't enough to cause a pull and if it did it would cause a pull to the left. Mine is pulling right.

[Tori]

Originally Posted by manbridge 74

You might consider the factory method of measuring from center of t-bar to ground and center of wheel hub to ground. It's more accurate than the fender measurements.

Search the tripod method of corner balancing until you get some scales. I think you'll find you won't need to do any slotting of holes. You'd gain very little from it.

Unless you are going for looks make sure the tie rods are angled down slightly or at least level. Having them angle up results in an ill handling 911.

Thanks for the response, but i don't see how the method of measuring has anything to do with anything. Feel free to tell me how i'm wrong, i'm up for learning, but i just don't see how that effects things. To me if you measure "the correct way" and come up with X measurement, how is that different from measuring the fender height ? I'm not going for factory heights, I want the car to look a certain way just like so many others here on the board.

I do know about the angle of the tie rods, and will deal with that by spacing the rack.
Thanks for the input on the slotting of the holes, it sounds like that won't get me much more adjustment.

[brianlay]

The fender height method assumes the axle height is close to 12 inches. That's about what you get with a normal wheel and tire combination. It also assumes the fenders have the same dimensions side to side, but that's rarely true on these cars. For precise height measurements, no matter what your target height, the factory method is the best way. Suppose you set the height exactly the same side to side using the torsion method and then measured the fender lips and they are slightly different. The factory spec for height difference side to side is 5 mm (.20in). How are you going to know where you are unless you "calibrate" the fenders?

Something isn't right with your camber measurement. The car should have no trouble being adjusted to 0 degrees. The negative camber limit, even with some height lowering , is close to -2.

It's hard to believe you can't get back to zero. Are you sure you calibrated the alignment system?

[Tom '74 911]

Originally Posted by Tori

I assume something must be bent or tweaked.... Can i slot the holes in the body to allow for more camber adjustment ?

If the LEAST amount of front camber you get get is -2.1, something is not right. You might have a bent a-arm, strut spindle, strut or the car could be bent.

I'd avoid slotting any holes as it sounds like your goal is just the stock settings. Most people doing the slotting are trying to gain more negative camber than -2.0 deg.. If you have to slot holes to achieve the stock settings, then again, something is not right!

If you've messed with the ride height and are dealing with the car wanting to pull to one side or the other, you are wasting your time trying to align anything until you do a corner balance. That needs to be done BEFORE the alignment as the alignment settings will likely change as the car is adjusted on the scales...

Corner balance first.
Alignment afterwards.

If the car still pulls or the alignment settings are wacky and/or not symmetrical side-to-side, then start looking into the possibility of bent suspension & body parts.

Tom