Question about DIY alignment & corner balancing
 

I need to know how you are performing these measurements and making subsequent adjustments. Are the measurements performed when the car is at ground level and then jacked up to make a change and then remeasured at shop level? Or, do you set the car up on risers to allow access to the adjustment points and perform alignment measurements while elevated? Alignment shops have the advantage of a lift to allow easy access for these tasks but most DIYers don't have this luxury.

I ask this since I have just finished my development of a four corner chassis scale (more affordable than Intercomp and store-able on your bookshelf) and want to check with potential users to see how it would work in their world.

For a 911 and a 944, I'd guess that most do not use risers. You have to get the car up pretty high to make risers convenient enough to be worth it, and it is challenging to do that with a floor jack. With the car's weight on the suspension, you have to be high enough to easily access the adjusters to make small changes, and it is hard to do without quite a bit of elevation. Much easier for most without lifts to do the changes in droop.

One of my friends made really tall risers that can be used with a lift. He did not have an alignment rack (did not need one), but he did have a lift. These things were several feet high and impractical ti use without a lift. They are still used at a famous local Porsche shop. By the way, he knows his stuff, having developed what are likely the two most popular commercially-available alignment tools used at various levels of racing. He also spent quite some time leading the engineering efforts on a famous Porsche racing team...

Anyway, when I last did set up on my car, I used some borrowed roll-off levelers. They were tremendously helpful, but the amount of elevation wasn't nearly enough to adjust camber and toe. For this I just had to jack up the car.

I have experience with 944 and 911 cars, but I am pretty sure that many other models and makes are similar in that you need convenient access, and "alignment rack" elevation is the easiest way to get it.

Some good alignment tips in this thread from almost 10 yrs ago

http://forums.pelicanparts.com/porsche-911-technical-forum/97217-toe-adjust-techniquest.html

I don't have the luxury of "roll-offs" when I do my alignment stuff. So I jack up the car, make my adjustments, jounce the car best I can, and re-measure. That said, there's no substitute for rolling the car to settle the suspension. Jouncing has it's difficulties and you have to go around to each corner to jounce the car to try to settle all four corners.

Interesting note I hadn't recalled in Scruggs' booklet is he does the rear toe and camber with the suspension in full droop.

I do my own alignment and corner balancing, here's a couple tricks I use. I must say first I'm spoiled to have a lift in my garage though.

1) I have some sheets of flooring, you know the industrial type 1x1' square. Put two together with some grease between them and you have some cheap slip plates. These let you lower the car from the lift after say some height adjustments and recheck w/o rolling around. Tires will slip into position rather than grab on the flooring, etc.

2) I do roll the car (or drive it, even better) between all 'fine' adjustments.

3) I do occasionally drop the car tires onto some heavy duty stands (with the slip plates) so I can get under it - typically to adjust the sway bar preloads; I just need a rough idea where the suspension will sit. When I do this the lift is holding the other end (front/rear) and the unloaded lift arms are very close under the car... Safety third ya know.

HTH,
Chuck.H
'89 TurboLookTarga, 342k miles

Like I said, I do not believe most that do DIY align and corner balance have access to a lift. I think most rely floor jacks and adjust everything in droop.

If one owns or can borrow scales, fabbing up roll off platforms is pretty trivial. And you can buy used economy roll offs pretty cheap.

The process of course is immortalized in many threads, videos and periodicals like magazines and books. Interesting that Ray's booklet was/(is?) so popular amongst Porsche DIY folks. Also interesting to note that the developer of the commercial tools (SmartCamber and Strings) I mentioned above live(d) in the same area as Ray. Both PCA members and old friends.

The Puhn book is one age-old resource in book form.

In any case, if I were developing a DIY corner balance scale set-up as a "product for the masses," I'd optimize for a situation where my customer had to work in droop, raising and lowering the car between tries. That has to be the fat part of the curve.

I see you may live near Chico Mr. Abbott. If so, come on out to Thunderhill and visit with us some race weekend next year. You can conduct market research amongst us PRC racers. And the aforementioned alignment tool developer may be visiting and/or racing with us some time next year.

No risers at all. Just land the car on some sheet metal slip plates I have handy. No lift either... just a hand jack. I know that my car is so low that there is now way in hell to get under it on the ground.

In reality, I highly doubt that you can do any alignment adjustments while the car sits on the ground. Certainlly not any in the rear w/ a stock setup. Maybe toe in the front. Probably not ride height in the front though.

After it is all aligned I put it on risers and set the sway bar pre-load to 0.

If you can remove the rear quarters easily, like on my car, you can likely adjust camber and toe out back while the car is on the ground. But it would be awkward and difficult for small changes.

Changing the settings with the car on the suspension is possible with a rack, but again, challenging for small changes.

It is easy to remove pre-load on a lowered car resting on its suspension if you have access. I gain access by removing body panels. They don't weigh enough to make a difference.

Yah very time consuming. get it all close and then drive it around and recheck, re adjust and repeat. The first time I think I spent 7 hours. I would probably plan 4 now. The more bearings and less rubber the closer to "right on" matters.

Thank all of you for the replies; I figured it was a matter of weigh it & measure alignment, jack it up, adjust it, settle it and re-weigh/re-align.

Mike,

Thank you for the invite; I do live in Chico and have visited Thunderhill a few times, only 45 minutes from here. I got my copy of Puhn's book in 1979 and while it isn't quite up to date with more current designs it sure does cover a lot of ground and quite clearly; it is my go-to book for performance suspension discussions. I also have a copy of the Scruggs booklet, it provides a process to check corner balance by a driving test to see if the car pulls after alignment is completed.

I used to have some 2" tall Longacre ramps to drive up onto, but then we made some stands for use with a 2 post lift. Makes adjustments MUCH easier and more consistent.

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