Contact Aftermath, Getting Back to Where I Was

[Supercharged111]

As some may know, myself and Derek shared more than a near death experience on Friday's rainy practice session. My right front connected with his left front after his off in T5 in R3. My camber got pushed in a little and the caster all the way, so I was a deal or 2 off and just came into tech. For R4 I got symmetrical camber and reset toe, the car went .6 seconds faster too. Now I'm in my garage checking caster, because the car pulls to the left. Lo and behold tonight I find 3.8 on the left side and 4.8 on the right. I also find, via a possibly erroneous method, that the left wheelbase is 1/8" longer than the right. I dropped a plumb bob off the rear of the front tire and the front of the rear and measured that distance, with the straightness of the front wheels eyeballed. I'd really like a more scientific method than that, but can't seem to find one. Same with caster, I eyeballed the center and marked 15 degrees off of there either way to measure my caster. At this point, both caster bolts are maxxed but I'd hate to dumb the right side down to 3.8 just to make the car track straight. I'm kicking myself now that I never checked my caster before so my baseline now is on a possibly tweaked car. I've already hogged out the UCA mount holes on the left side and I still had to max out the lower adjustment slot to get 2.2 degrees of camber. I suppose I could loosen the k member and try pushing it to the right to decrease my lower camber adjustment in an attempt to gain some left caster? If all the frame goodies are OK and it turns out I bent a spindle, well, it seems to have made my caster better so to change or not to change is the question?

[Supercharged111]

After a couple days of derr, I'm going with plan A: align the car and run it. I just remembered the left side has camber to spare, so I can use some of that range to put more caster in the car via the hogged out UCA mounts. If it doesn't feel right, I'll get the frame pulled later in the year but for now, I'm leaving town for a couple months after the Pueblo race and don't really have a lot of time to horse around with it up until then. So hedge your bets that my car will suck and come on up to Pueblo for the weekend of the 4th.

[Pranav]

Have you not considered your spindles may need replacing? They bend easily. Mine got bent this past weekend, maxed it out and only have -1* of camber as opposed to 2.2* with room to spare on the LCA slot.

Sadly this is the third vehicle on which I've bent a spindle.

[Supercharged111]

Not dismissing that possibility, but have no idea how to check. If it's bent and gave me more caster, maybe the left side needs a good whack too.

[Pranav]

Probably a good idea to pick up one or two and check before jumping to conclusions, they make for good spares.

[Supercharged111]

Yeah, there are a couple V6 mullet-mobiles in the local pull and pray. Those cars are too slow to crash, so decent bet they're straight. I guess I have to expand what I consider to be consumable.

[Supercharged111]

Well I breathed a sigh of relief tonight. I can get all the caster I can stand out of the left side and all the camber I need to go with it. Going to replace the UCA bushings this weekend, they look pretty haggard. Then I'll just dial in caster up top and finish with camber on the bottom. I plan to simply match the right side's caster as the tire temps looked too good to be true after the final. I figured I'd use the lower caster bolt to match my wheelbases, then dial caster up top but as it turns out I mismarked the floor last night and my wheelbases are in fact the same. At this point, I theorize that, worst case, I have a bent spindle. Still need to inspect the right LCA for cracks before I give it a clean bill of health. What a relief! Now I can focus on what I believe to be an oil pickup that fell out.

[Supercharged111]

Another sigh of relief, check this out.




See that shiny stuff? Looks like the bushing shell got pushed out of the arm. I could totally see that accounting for an extra degree of caster on the right side which made me go .6 seconds faster post-impact. That's some solid data there. I just replaced the UCA bushings on the left side today because, prior to Hallett, I could push the arm quite a bit when bolted down tight. Those bushings were buggered up, but the right side wasn't like that. . . until after Hallett. I noticed on the left side that the replacement bushings slipped in pretty easily so I'll be tacking them and hopefully they don't push out from normal contact free racing. Also got the caster bearings replaced, those things were haggard. Once I weld the sleeves back in tomorrow, I'll see where the alignment sits and hopefully the car is straightish.

[Al Fernandez]

Havent bought them in many years, but back in the day you could buy solid delrin uca bushings that were offset drilled.

[Supercharged111]

Havent bought them in many years, but back in the day you could buy solid delrin uca bushings that were offset drilled.

I think Strano used to make adjustables too? I see Global West makes some nice upper arms with the Del-alum bushings with extra camber and caster added in. That'd be easier than monkeying around with caster up top, those short arms make it super sensitive to change. I ended up doing all new upper control arm bushings, they were all shot to hell. It's much tighter now but the bushing fitment wasn't all that tight so I plopped a couple of tack welds on each bushing in hopes that they'd stay put. That right upper arm was tweaked a smidge, the ends had to spread apart with a prybar to get it back on the mount but if those tack welds do their thing then it should be fine.



That plus the new caster bushings should hopefully make the car less twitchy under braking, it was noticeable in the final at Hallett. Watch me not go any faster now too.