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Home String Alignment

255
273
Exp. Type
Time Attack
Exp. Level
Under 3 Years
SoCal
Hi everyone; alignment question for you all...

Long story short, I need a new alignment shop. I found a track-focused one the other night and they told me they actually only do string alignments rather than your typical alignment rack. After some research, it seems most racers and pro teams use the string method as well. I thought I'd look into this method and see if I can just do it myself at home as I know many do.
It looks fairly straight forward and doable...tedious, but doable. My question is: how would you adjust rear camber (on the S550, specifically) with the car on the floor? Would I need race ramps or similar to get some room under the car?
 
1,012
947
In the V6L
Hi everyone; alignment question for you all...

Long story short, I need a new alignment shop. I found a track-focused one the other night and they told me they actually only do string alignments rather than your typical alignment rack. After some research, it seems most racers and pro teams use the string method as well. I thought I'd look into this method and see if I can just do it myself at home as I know many do.
It looks fairly straight forward and doable...tedious, but doable. My question is: how would you adjust rear camber (on the S550, specifically) with the car on the floor? Would I need race ramps or similar to get some room under the car?
Dead easy. I've been using string for years and it's simple. Now, having said that, I don't adjust the way a shop does it. My adjustment process is to measure the settings and then put the car in the air and shift the adjustments by measured amounts. Then I go for a test drive and measure again. If it's not what I'm aiming for, I adjust again by a measured amount and repeat the test-drive and measure process until it's right. It's tedious, but you know exactly what you've got when you're done.

For the rear camber, I'd urge you to get a set of SPC camber arms. They're strong and easy to adjust with zero maintenance. The BMR UCA762's are also good, but you have to keep them greased. The reason to change the arms is that the stock adjuster was really only meant for setting the car up at the factory - it's brutal to reach, it's hard to adjust and it doesn't hold position very well after it's been loosened and tightened a few times.

On the question of "on the floor or ramps" the answer is that you have to be able to get under the car to do the toe adjustments, both front and rear. That matters because changing rear camber also changes toe - the rear knuckle pivots on an angled axis, so as you push the top of the wheel inward to increase negative camber, the front of the wheel pivots outward, giving you toe-out. You have to adjust both together from under the car. The easiest way to do that is with ramps.
 
3,803
3,745
Well some of those teams are also using $25K alignment plates, but in real life, strings do work pretty well.
The biggest issue, is to determine exactly what is center. After you do that, you can build a jig so that you can find it easier next time. On some cars, the factory establishes, or states, where center really is so the car can be teched, that is a huge help. Barring that, you'll need to put it on a lift.

porsche pic.jpg
 
255
273
Exp. Type
Time Attack
Exp. Level
Under 3 Years
SoCal
Dead easy. I've been using string for years and it's simple. Now, having said that, I don't adjust the way a shop does it. My adjustment process is to measure the settings and then put the car in the air and shift the adjustments by measured amounts. Then I go for a test drive and measure again. If it's not what I'm aiming for, I adjust again by a measured amount and repeat the test-drive and measure process until it's right. It's tedious, but you know exactly what you've got when you're done.

For the rear camber, I'd urge you to get a set of SPC camber arms. They're strong and easy to adjust with zero maintenance. The BMR UCA762's are also good, but you have to keep them greased. The reason to change the arms is that the stock adjuster was really only meant for setting the car up at the factory - it's brutal to reach, it's hard to adjust and it doesn't hold position very well after it's been loosened and tightened a few times.

On the question of "on the floor or ramps" the answer is that you have to be able to get under the car to do the toe adjustments, both front and rear. That matters because changing rear camber also changes toe - the rear knuckle pivots on an angled axis, so as you push the top of the wheel inward to increase negative camber, the front of the wheel pivots outward, giving you toe-out. You have to adjust both together from under the car. The easiest way to do that is with ramps.
Yeah the OEM rear slotted camber adjustment is a nightmare. I'll look into those SPC arms you mentioned.
Are there ramps you would recommend or maybe a few sheets of plywood gives enough room?
 
1,012
947
In the V6L
Yeah the OEM rear slotted camber adjustment is a nightmare. I'll look into those SPC arms you mentioned.
Are there ramps you would recommend or maybe a few sheets of plywood gives enough room?
One of the factors in how much space you need is that the factory toe adjusters have to be torqued to 129 ft-lbs, so you need room to swing a pretty big torque wrench. Another lifting option is to lift on the bottom of the lower arms with a pair of floor jacks, but it's tricky. The factory adjusters or the SPC's have to be adjusted with the suspension compressed at static ride height, hence the ramps. One advantage with the BMR rear upper arms and the BMR rear toe links is that the BMR adjustment points are separate from the mounting hardware so they can be adjusted with the suspension hanging at full droop.
 

xr7

TMO Addict?
439
448
Exp. Type
Autocross
Exp. Level
5-10 Years
Minnesota
I use the Smart String kit. You can jack up the car and roll it. Added advantage is you can tweak you alignment without going to the shop. Plus you don't have to explain to some noob why you want non-factory specs. Shops that deal with race car setups are few and far between here. When I was fleet manager I was sending all my vehicles to a shop that made springs, worked on everything from cars to class 8 truck and trailers. They weren't cheap but they always did what was needed and no BS. My second started sending the light duty stuff to the Ford dealer to same $30.00. Had two vehicles they couldn't fix. E-250 and a F-350. Took them to the other place, E-250 had a ton of tow out and the F-350 had a bad draglink joint. No more Ford dealer.
Probably get the pieces you need for doing alignments for less than $1000, if you do this for any length of time it will pay for itself.
Also nothing like rolling out on to the highway having done your own alignment and the car runs straight and true.
 
501
319
sfo
The biggest issue, is to determine exactly what is center. After you do that, you can build a jig so that you can find it easier next time.
I never understood why people make this so complicated. Strings are great but a throwback of a prior era. It still works but there are more simple and idiot proof ways. I also don't know how one could determine an exact car centerline. You can get close but a very small tiny error magnifys itself all the way to the last adjustment because the centerline is the start of the process. An error at the end would cause less damage.
 
1,012
947
In the V6L
I never understood why people make this so complicated. Strings are great but a throwback of a prior era. It still works but there are more simple and idiot proof ways. I also don't know how one could determine an exact car centerline. You can get close but a very small tiny error magnifys itself all the way to the last adjustment because the centerline is the start of the process. An error at the end would cause less damage.
With all respect, the position the chassis sits on the suspension isn't the issue. it's the angle of the four wheels relative to the centerline of the four wheels. That's what you're aligning to and it's easy to do - center the wheels between the strings and check the angles and the camber. If the chassis is off by half a degree, the wheels will never know the difference.
 
Few thoughts - I have SPC rear camber arms and am not a fan of them - the eccentric (final - because rough adjustment initially is done by calculating target camber and using lockout plates at inboard mounting location in specific orientation + plastic insert in the arm itself) adjustment bolt is hard to get to at ride height. I have not tried Steeda / BMR ones but at least visually they should be easier to adjust - those do not have lockout plates at inboard mount though.

Important thing about doing camber at home, on ramps or some other contraption - they need to be somewhat level. My garage floor in the bay where my car sits isn't.

Lastly - I have Quickjack - lowering the car on the ramps is pain in the ass since quickjack doesn't raise / lower truly vertical. And car on four Rhino oil change ramps doesn't leave much space underneath to work - Race Ramps have wheel cribs that would probably be useful.

If I had to do it, I would raise, adjust based on the calculation how much to adjust, lower, compress suspension and then do it again until satisfied. But - it was easier to find right person with an alignment rack.
 
501
319
sfo
strings seem antiquated to me. I get strings before the 1990's but since the 90's we have these great cheap compact consumer laser pointers that do not introduce error into our job. I see no reason to use a $500 string rig when you can do the same thing with a couple rulers and a $30 laser level from home depot? There is a lot of error that can be introduced with strings.
 
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82
50
Exp. Type
Autocross
Exp. Level
20+ Years
So Cal
Strings work for my cars. Use lasers if you want, but don't kid yourself about some increase in precision or accuracy. You can't get much closer than a light, fluorescent monofilament.

P. S. You center the strings with respect to the car by setting equal distances on each end of the car on the cross tubes and then setting equal distances side to side to something like a stub axle end or hub face on each axle. Once the string box is square, it's an easy job.
 
3,803
3,745
Here's the deal, I just spent a lot of last year with a Porsche cup team, earlier in the year they were DQ'd for a camber infraction by IMSA. So they went out and bought a state of the art $35K alignment setup with lasers and all sorts of star wars stuff on it. So they measure the car up, but they still have to take it to IMSA tech to make sure the machine that is going to tech the car reads the same, generally, it does not. You now have to you have 2 measurements, one, that you know is right because you set everything up, and one somebody else set up and is not as good as yours. So you have to adjust your known "good" numbers to whatever machine you will be teched on, because that is the machine that really counts. This goes on forever, with a lot of teams who are trying to get the most out of the rules, then you hit a curb during the race, and it doesn't matter anyway.
FWIW this song and dance goes on with the tires as well, we must start the car on 18.8psi in the rear tires, (the fronts also have a requirement but they are never an issue so I don't remember what it is) This is because only 1 warm up lap is allowed, and guys are spinning the 16.5 psi tires off the bead, since that looks bad on TV, Michellin mandates 18.8. Problem is, when warm, that takes the tire out of its performance envelope, so you have a rear tire running 32plus psi, rising,, and losing traction by the minute, while the fronts are operating within their performance envelope so the car goes loose 1/4 the way through the race. This is why, in Porsche cup. the race is usually over in the first 5 laps, you are either in the lead group, when your tires go away, or you've been blocked by somebody so that when you finally pass them, you no have any tires and are no longer in contact with the lead group.
All this could easily be remedied, but Porsche, in their ultimate teutonic reasoning, has decided that cup rules have to be universal across the globe, and for whatever reasoning, the europeans don't want to change, therefore we must handicap ourselves in north america, and warm tires by placing them behind the engine exhaust, placing them near heaters, warming the engine with the tires on the car, or whatever methods of cheating ( because tire warming is strictly forbidden) you can slide by the rules, up to and including letting air out of the tires after they were teched on the grid. All of which I've observed, but none of which I have partaken in.
I will stop here, as this rant could go on for pages, needless to say, I won't miss P cup.
 
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3,803
3,745
Sorry for the canard... back to the OP's original point.
The thing is, before I went off the rails
Get the car aligned at a performance alignment shop
then find a level area, in your garage, you can use some tiles to level the area if needed. you will also need to locate the center of the car, which as mentioned can be more complicated than it looks.
Once you do that, then "string" the car, and don't forget to add driver weight. Normally monofilament fishing line is used (without the rod of course) so it can be just reeled back when you're done. if you use a cross bar, you can notch it to hold the line.
Take your measurements from the line to the tires, write them down, so you can duplicate them.
 

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