June 10, 2008 - Testing results.
The influx of hot air seems to have succumbed to my patching and the car no longer smells like exhaust fumes. So that's good.
The car is much happier with the 4.10 rear end. I've always liked this gearing combination. The stiffer mounts in the differential have cut down on shifter movement and the car shifts very nicely now. So that's an improvement. There should theoretically be an increase in NVH from the new mounts but it's rather hard to tell in this car!
I took the car out to the track again for a few laps, just to see if the rear end was hooking up any differently. And the answer is nope. Maybe a little bit better, but I can still spin up that right inside wheel if I am being aggressive. It takes a turn that's tighter than any that would be used on the street - aka, that would be found in the Targa - but I'm starting to obsess about this a little bit again. On the theory that the car is rolling too much and the rear sway bar just can't deal with this much articulation, I stiffened up the low-speed compression. While the car get a bit happier in transitions (I need to spend more time with this adjustment, as I should be able to really make it pivot nicely) it didn't make a significant difference.
I do really have to thank the guys at the Grand Junction Motor Speedway for working with me and letting me drop in once in a while. When I left today, they were surprised that I'd only taken a half dozen laps!
I'm probably going to swap all the control arms out. The bushings seem to need lubrication again. That's odd, because I've run these sorts of bushings for years in the past without any noise. But that dirt road really seems to have done a number on them and they sound terrible. So the arms have to come out at least partially, so why not experiment? I will check to make sure it's not dry sway bar bushings, which I don't think were very well lubricated on installation. Remember, I installed them at the track and didn't spend a lot of time greasing. Hmm.
edit - I did check, and it is the ungreased front sway bar bushings. Duh. The control arms are fine.
One reason to swap out the arms is because I've managed to accumulate a set of 1999-05 control arms. The rears have only 1700 miles on them so they have nice fresh bushings, while the fronts are higher mileage. The later arms are more heavily reinforced for more strength.
Third, I'm also hoping it'll let me get a little more camber up front, which will allow me to run a smaller (or no) rear bar, which will help with the rear traction.
First, I'll check the cornerweights to see if the right rear is out of whack. The traction problem is not as bad with a passenger, and of course I'll have a passenger during the race! I can tell when I'm going to have problems with the traction, as it's all due to the weight on the right rear wheel. Actually, it's the weight on the right rear and the antics I get up to in order to provoke it.
tags: interchange, drivetrain |
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