My first day at the track is coming up (6 days to go!) so I'm trying to get things more dialed in, make sure I have the basics right and then I'll have a solid foundation to go from.
First thing with swing axle cars is controlling the rear suspension, and making sure that the outer tire doesn't jack during a turn. Jacking can lead to poor handling, or rolling the car! Negative camber helps for sure, and I'm at 3-deg negative in the rear right now. But the travel still needs to be limited. There's a couple ways to do it, and I decided to use limit straps. I took a bunch of measurements of the suspension movement and settled on 12" straps.
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Here's the droop without the straps. You can see the camber goes several degrees positive when the spring plate rests on the built in stop. I would NOT want the outer wheel doing that during a fast turn!
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Here's one of the straps installed
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And the new travel limit with the strap. I've got it limited to about 0-1 degree of positive camber, which still gives pleanty of travel, but should keep things in check.
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I like the idea of adjustability on things, so they can be fine tuned. I started playing with a design for adjustable limit strap mounts so I could dial in my suspension travel (more for the street, less for the track, for example). Enter my 3d printer. Rather than buy the hardware I needed, I just printed it so I could check the concept before spending a dime.
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Assembled
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And fit on the car for checking clearance. The upper mount location of the strap can be adjusted a total of 1" for fine tuning.
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As I feared though, the mount would hit the tire as I saw when I reinstalled the wheel and cycled the suspension. At least I hadn't bought anything or wasted time making the L bracket from steel. The printer is so handy for this type of concept testing. I've got an alternative mount in mind that should clear everything no problem. I'll mount up a printed version of it soon to check. Here's the tire hitting the original concept.
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My toe plates came in so I've started doing an alignment on the car. Man was it off! I was at about 5/8" toe in on the front, the spec is 1/16" to 1/8". All that toe was just wearing the tires fast and scrubbing speed! The right tierod needed to be shortened, the ends were bottomed out and the overall length was too long. So I cut about 1/2" out of it and ran a tap through it go get more threads. The tap is a 14x1.5.
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Tapped it far enough that I could bottom out the tierod end. That's the piece I cut off sitting on it.
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With the tierod shortened I was able to set the front toe in to 1/16", just where I wanted it.
I also checked the rear toe, it's got too much toe in as well, but not quite as bad. I'll try to adjust it as well before my track outting.
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And finally, last night I finally put on the front sway bar I had bought many years ago for the car. It's made for a 2-3" narrowed beam, and mine is 4" narrow. I had to cut about 1/2" off each end to compensate for the narrower beam. It was a huge PITA to install, those t-bolt clamps really don't want to conform around everything. Many a 4-letter word later and I finally got it on. Swing axle cars have very high rear roll resistance, so the front bar should really balance the car by adding front roll resistance.
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Other than possibly setting the rear toe and testing my rear limit strap adjustable mount concept that's probably it before hitting the track with it. I feel like the car should be at a pretty solid starting point with the recent changes I've made.
Beyond that, future plans are for offset link pin bushings so I can get the front camber to about 1-deg negative, it's at 0.5 deg positive now which is where they sit stock. Depending on how the back of the car behaves, it may get a sway bar or a camber compensator (which acts like the opposite of a sway bar, they actually reduce roll resistance).