Indexing Torsion Bars: 101 Projects book is completely wrong. >:|
 

So I installed new torsion bars (21/27) and sway away adjustable spring plates this weekend.

In the front, the 101 Projects book says that you should let the front suspension do a 100% full droop, and install the torsion bar key/adjuster part so that it's near the top of the subframe/adjustment area. This resulted in the dumbest stance ever, with the front of my car resembling a Baja 911 with about 4" of wheel gap. I took them back out, jacked up the A-arms, and reinstalled with the a-arms almost horizontal. This worked a lot closer, might need to try one more time. Is there a writeup on this?

In back, I installed 27mm torsion bars. According to the instructions that came with my Sway Away torsion bars, it said that I should set them to 17 degrees from horizontal. I did that, and when I put the car on the ground it completely bottomed out to the poitn where it was not even driveable. I tried adjusting the spring plate adjustment screw but even when it was 'raised' all the way, it wasn't even close to driveable.

I'm frustrated because I was following the directions here and both of them were 100% wrong. Other than trial/error, is there a better way to do this?

17 degrees is way to shallow....search and read up as others have done this exact mod. I did my suspension refresh years ago and nailed it on the first try but I spent hours planning and analyzing my data input.

http://forums.pelicanparts.com/porsche-911-technical-forum/473648-spring-plate-torsion-bar-installation-indexing.html

Yeah, shame on me for following the directions that came with the product. I should have searched the internet instead of reading the paper that said 17 degrees. :\

are you sure your car was level? all the measurements are going to be relative.

yep, man up, reindex them again and quit your bawling. you never get them right the 1st time.

consider it a learning experience.

Will do. I just think I could have done a better job guessing on my own than following these worthless directions.

Were you installing beefier T bars? The fronts are easy the rears..ugh. the 101 projects is with stock bars which will require a completely different angle.

I just did a full rebuild on suspension and I had to remove and re-index 3 times in the rear to get it where I thought it needed to be....Now I think I might have to re-index to raise the rear a bit. Its so odd because I swear I am back where I started? Maybe I had some binding in there or something. Its a long process.

I think after installing ER bushings and high priced racing shocks and struts front and rear it took me 8 hours on my back to:

- rough Ride Height
- rake
- closer on the ride height
- Tri Pod corner balance
- had to re-do the rake a bit

All this with ballast in drivers seat to mimic driver weight.

Then I had to set up the strings and adjust the camber and toe - at least a few hours there.

Its exhausting but satisfying, the car drives brilliantly but if I had the money I would probably pay some one with a lift and more experience.

I went through this whole exercise last summer. After replacing the whole suspension front and rear I was tired and tired of being on the floor in my garage. My car looked like a 4x4 :). I took it down to one of our local race shops and they did the full final ride height, corner balance and alignment. It was worth every penny to have that last bit of fiddly work done by a professional.

the spring plate angle calculator should get you in the ball park. set the adjustment on the spring plates dead center and then you can fine tune it up or down with the adjustment. the adjustment if centered when indexing gets you about a 1/2" either way.

Just did mine (front) with those instructions without issue. You do need to crank down on the bolt a little but not a lot. Did you try backing out the adjustment.

I've used the Will Ferch calculator several times, and it was pretty much dead on.

Bummer is this is not a tinker toy procedure.

Multiple iterations are required.

The guy in the engine bay on the cover of the first version of Bruce Anderson's 911 Performance Handbook beat my bee-otch ass to death about how I effed the rear spline indexing.

I scrambled on the phone enough to pull myself out of a deep hole and he allowed me to do it again in my garage.

Then he aligned. He still said it was not perfect but he adjusted things around the indexing.

Get the thing level before starting.

http://forums.pelicanparts.com/uploa...1524527894.jpg

You can buy a digital angle level for a few bucks. Well worth it instead of using analog gravity.

Did you move your car back and forth to let the tires and suspension settle before you made the determination that it looked like a "baja 911"?

I'm using a digital level app on my phone, works great. Yes, I moved it back and forth, it was like 4" too high. I reindexed the caps and got them pretty close, then tweaked with the adjustment screws. In back, I pulled the swingarms apart (sway away 2 piece) and reindexed them 2 more times until it was pretty close.

Result:http://forums.pelicanparts.com/uploa...1525097161.JPG

Would be nice to go a bit lower but I rub if I go any lower during hard cornering. Still need to install the rear swaybar that might help reduce some roll so I can get it a little lower.

Yeah after I realized how much work it is I am skeptical that a shop would do it correctly. I guess after doing it a few dozen times and having the right equipment it would take some of the back and forth out of it.

The JPS Black and Gold paint scheme is one of my all-time favorites. Looks good.

Exactly!

Thanks! I love it too, and it was a perfect fit for my dirty 70s 911 w thick shag carpeting (and rich corinthian leather?)

You can see how much wheel gap I used to have in back from this photo:

https://i.imgur.com/HweDQzU.jpg