My Handling issues , figured it out after Summit Point
As some of you have seen, I've been struggling with my Citation's handling since we modified the suspension after my Watkins Glen wreck in 2018, especially since we switched to the SCCA FC-spec Hoosier bias tires. We've been continually trying different spring rates, ride heights, damper settings, swaybar motion ratios in the rear, etc., etc., and some things got better, but others got worse.
At Summit Point, which I usually like, I threw a lot of changes at the car, none of which helped much, and some (before race 2) that made it worse. My times and race results throughout the weekend sucked.
I pride myself on getting my car working properly, but have been getting VERY frustrated with the lack of improvement. The situation was very confusing, and it was getting so bad that I, for the 1st time on the drive home, thought maybe it was my driving that was the issue and considered no longer driving in competition.
Monday, the day after Summit Point, I began seriously looking for design or mechanical causes and I finally identified the issue. There is an error in the front suspension geometry that hit me like a ton of bricks. It was so obvious that we (Steve Lathrop and I) should have never let it happen.
Luckily, it should be pretty easy to correct. So, again, we are looking forward to next season with FRP !!
Results of the bellcrank modification
It was a resounding success. The pervasive understeer, heavy steering, and overall low grip issues are totally gone.
We now have to bring the rear handling up to match the front. It's nice to be working on a different issue.
More to come as the season progresses.
Handling presentation covering a lot of stuff:
Short update after M-O FRP weekend
Race results, etc., were not good because I thought I could use the Rd Atlanta tires for a 2nd weekend. That was a bad decision. With the new, extremely smooth, non-abrasive, M-O pavement these tires didn't work well past the 1st race, which was pretty good, finishing 6th and lopping ~2.5 seconds off my qualifying time.
So, in the 2nd race, which was the 6th or 7th heat cycle on these tires, I had VERY little grip which resulted in falling off the pace. Others' opinions were that new vs used tires was worth 2+ seconds per lap.
However, over all, the car worked well with a new larger new rear master cylinder and the revised front bellcranks. A few tweaks on the rear brought the car into a good performance window that, IMO, only needs a tiny bit of fine tuning.
I'm looking forward to the rest of the season, and hope to improve our qualifying and race results.
OTOH, the 50-YO Chevy Van tow vehicle now needs a new water pump, because the current one (~180 K miles on it) developed a leak at the seal during the drive down to M-O. So using the van for long trips is out until that is repaired. That makes attending the Lime Rock race weekend questionable.
More joys of working on a 50-YO V8 van
Quote:
Originally Posted by
DaveW
...I saw that the fuel pump was dripping slightly (apparently leaking from the vent holes), so its diaphragm is on its way out....Luckily, compared to the WP replacement, this will be a relatively easy job.
Or so I thought...:(
Being able to see and get at the FP fasteners (on the upper side of the FP) required removing right half of the (sectioned) fan shroud and the alternator. The next issue will be holding the FP pushrod up in place while the FP goes in. I tried the G30 shop manual's suggestion of "heavy grease", but that didn't work at all. So I will attempt to hold it up with a "retrieval-claw tool" (the manual's alternate suggestion) when I get back at it tomorrow.
Back to the original subject
Quote:
Originally Posted by
jcolley
Dave,
I've been talking with Steve and put my name in for a set of the front bellcranks. Is there anything else changed out for the installation? Seems like the anti-roll bar pushrods *might* need to be modified, but not certain. Any changes to pushrod length?
Quote:
Originally Posted by
DaveW
The swaybar links will need to be ~1 " longer to compensate for the new location. I used the original links and threaded on a through-threaded extension using a 1" threaded stud (red Loctite) to hold them together. Pushrod and damper mounting should remain the same.
I installed the "new" correct geometry (swaybar motion ratio in tune with the rest of the suspension) front bellcranks today in place of the ones I had modified, which were much closer to the proper configuration than originally, but not completely correct. It'll be interesting to see if these make a noticeable improvement over the modified ones.
Our next outing will be at PIRC the weekend of June 6-9.