Wednesday, July 25, 2012
Front Suspension Overhaul - Alignment
I took the car to Don this morning for an alignment and got some interesting results. The caster is now identical side to side, which hints that the strut or strut mount was bent and replacement of those components fixed the problem. Toe is also exactly where I want it. However, the right side camber is now out farther out of spec at +0.12 degrees (yes, 0.12 degrees positive). Since the maximum camber is -0.35 degrees, this is nearly a half-degree out of spec. For comparison, check out the prior results.
Don and I discussed several possible solutions. He gave the stock camber bolts a big thumbs down and said they simply don't hold their setting reliably. No surprise, I said, given that they're not an eccentric bolt. I then volunteered shims, but changed my mind, thinking that they would require more trial and error than I cared to perform. The last choice was, predictably, camber plates.
Don held both TCKline and Vorshlag plates in high regard, though he said from his perspective as a mechanic the biggest problem with most camber plates is the fact that they tend to bind up after being installed for some time and are therefore hard to adjust after the initial installation. The one plate he has found to NOT exhibit this problem? Vorshlag. Like all plates based on spherical bearings, however, he admitted the Vorshlag plates will produce noise and vibration that may be noticeable, if not objectionable, on the street. Not really news to me, but good to hear it confirmed. Since I knew I was not in a position to solve this problem today we continued with the alignment.
The E36 up on Don's lift just prior to the alignment.
The shot I couldn't get with the car on jackstands. Behold the front suspension, overhauled.
The alignment results. Some things are better than last time, and right side camber is worse.
When I asked Don to adjust the front end for zero toe he warned me knowingly, "You don't want that. Zero toe will cause the front end to wander all over the place. We do that for track cars, but you'll absolutely hate it on the street." When I hinted that excessive tire wear was the justification he rebutted "it's necessary to sacrifice some tire wear to produce the centering force." I relented, thinking that I just replaced the entire front end to avoid erratic handling at speed so I didn't want to intentionally produce that effect. In the end we settled for 0.11 degrees toe-in on each side (0.22 degrees total toe-in), or roughly half the prior amount and factory spec.
By the time he snugged up all the adjustment bolts to secure the car's new alignment settings and completed the short test drive nearly two hours had passed. I gave him $175 for a job well done and headed home.
After about 75 miles of stop and go, straight-line high speed, and sweeping high speed turns I can report a few things:
- In general, the front end is more planted and stable than it has been in a long time. The random wandering is gone. Characteristically, it's still an E36 but reacts a little more like the E46 now. And given how very different the cars feel I think that says something.
- I definitely feel more feedback in the wheel as I traverse bumps and I attribute that mostly to the use of M3 arms and solid bushings. This is not something I feel in the E46 despite its sharper steering but it's nothing objectionable however. The car is talking to me more loudly than before and I'm listening. It feels great.
- I do notice a slightly reduced centering force, particularly at 80+MPH, so Don was right. 0.10 degrees toe-in per side (0.20 total) is probably the minimum I'd recommend for street cars. Rest assured, that if you're considering 0.20 total toe in, the vehicle is completely stable and I don't need to tweak the wheel or anything like that -- it's just that the car is more eager to turn.
- I haven't done enough hard cornering to properly judge the impact of the X-brace but one decreasing radius off ramp on the GSP I took tonight put a smile on my face. Something is definitely different here, but I don't think it's fair at this point to attribute it to any one particular thing, including the X-brace. All I can say is that it hasn't hurt handling, that's for sure.
- As I turn the wheel for normal slow-speed turns the steering wheel feels smoother. And that annoying steering wheel squeal? GONE. At this point I'll attribute both characteristics to the new steering column bearings.
With the project complete I've put the E46 to bed once again and will return to the salt mine tomorrow with my old faithful E36.
This was clearly my largest and most complicated project to date. While the rear suspension overhaul was complex in its own right, in retrospect I view it largely as a grunt labor project. The front end overhaul, on the other hand, was more of an engineering effort. I had to carefully evaluate and select parts to achieve my goals, engineer proper solutions to fix unanticipated problems, and even make my own tools.
Adding to the challenge (and time) to finish the project was my first use of video to help tell the story. Because video is hard to shoot and edit I have long resisted using it but just I have posted pictures where they nicely substituted for the proverbial 1000 words, I decided to use video in cases where I felt it could replace 1000 pictures. All of the videos in this project were raw from the camera and that's because I couldn't justify the time to do it any other way.
My original parts estimate was $2500 but over the course of the last six months I bought $3500 in parts and supplies. I outsourced $750 in labor and bought roughly $400 in tools. I did not keep accurate time records but I estimate I spent a good 50-60 hours screwing around in the garage over the past two months. It's fair to say a pro would have taken less time to do this work but it's also fair to say few people, pros included, would have bothered to do many of the things I did. So I'll just call this 30 hours or $3000 labor saved.
The next major project will be the "lower" interior overhaul, which will involve replacement of the carpet and leather on the front seats and arm rest in the center console. I also plan to have the A and C pillars covered in matching leather since I was never able to find a suitable cloth replacement.
Mileage: 222675, Labor: $175 [Project Total Estimates: Parts: $3500, Labor: $750, Tools $400, Labor Saved: $3000]