Looking For Suggestions

[bananahammack00]

I have an older (08) 4/4 Chevelle stub J-Car. The chassis builder has sold his equipment and refuses to answer his phone so I have no help. It was built for the softer Wissota tires and I have recently converted over to IMCA and need some forward drive help.The Baseline set-up is as follows:Springs600lf, 750rf, 225s rear. 3" Rear Stagger, 1" in front, 53% left and 56-57% rear w/o driver and 50# of bite w/o driver. Wheel offsets were 3" in the front and 4" on the rear. Car has been way too tight into and thru the middle of the corner so I have slowly (too make sure I didn't over adjust) started to change springs and j-bar/pull bars and have come to the following:Springs550lf, 600rf, 250LR, 225RR. 53% left and 58% rear. 1" stagger in front and 2-2.5" in the rear with 1/2" RR trail. There is a 2" offset on LF, 3" on RF/RR and 4" LR. Pull bar is a quickcar outlaw biscuit bar with new bushings @20° angle and 1/8" of preload. It is shifted to the left on the quick change as far as it can and parallel to the frame at ride height. J bar at 5° angle uphill to LR @ ride height and even with QC pinion. Shocks are run of the mill 50series QA1 refreshed at the beginning of the year. 5-6 LF; 4-6 RF; 9-1 lR; and 3-4 RRBar angles:LRT 24° LRT @ full drop (4.5") 43°; LRL 5°; RRT 7°; RRL 7°.The car is finally rolling into and thru the center of the corner, but has NO forward drive. I have slowly been adding until it develops a throttle push (recommended by the local builders), but the concern I have with that is I'm at 150# w/o driver and still not enough drive off. The 750lb drop to 600 on the RF made the car more driveable, but didn't loosen me up enough so I continued changing stuff with the Jbar adjustment finally making the biggest improvement. My question is should I continue putting bite in it until I get the throttle push or should I go back to the stiffer RF and hope I don't lose the gains I've made in freeing the car up on entry? I've read that 120# of bite is too high for 4/4 and I'm closing in on 200#. Another issue I'm having recently w/ raising the LRB and moving the Pull bar and angle, the LF tire is pulling 2-4" off the track and still lacking the forward drive.Let me know what you guys think or have any other suggestions I'm all ears. My slow improvements are taking too long and need some additional opinions.BH00

[let-r-eat]

How much drop from ride height on the LR?

Bar angles on LR at full drop along with bar lengths?

[bananahammack00]

4.5" drop on the LR, 43° LRT bar angle. Bar Lengths are LT 17 1/4, LB 15 1/4, RRT 17 3/4, and RRB 15 3/4. These bar lengths are what the chassis builder originally told me to use.

[let-r-eat]

Have you checked the index on the cage at full drop? Index the cage into the spring 4 or 5 degrees. Be careful your lower isn't hitting the cage when doing so.

[bananahammack00]

It appears the LRL link is 25° at full drop. Are you saying to index the cage 4-5°@ ride height or full drop? I'm close to 12° into the spring @ full drop.

[stock car driver]

12 is real low at full hike up. I'd set it 20 when jacked up in front of the Lr tire to start.

[mod71m]

If your right upper bar only has 7 degrees in it then it doesn't have near enough angle. It needs 15 to 18 degrees in it. Also I would add LR drop until you get 48 degrees in the left upper when you put a jack in front of the LR tire, your 24 degrees at ride height is fine. Get your pull bar closer to center also. Typically no more than 1" from the center of the brackets (assuming you have a centered pinion rear end). I angle the front of the pull bar toward the right front about 1"

[dkibel]

What advantage is there to angling your pull bar the right front? Dont you want your pull bar to be connecting (ideally) at your center of mass to be more efficient? I feel like if you start shifting away from the center of mass it will change the characteristics of the weight transfer under throttle. Just a question.

[let-r-eat]

20* + at full drop. That's usually 5 or so at ride height. The 12* at full drop isn't enough as SCD has mentioned above.

[bananahammack00]

Thanks all for the advice. Raced Friday and got to the point where bite wasn't the answer. Completely reset the car and went back to 600lf and 750rf with 225s across the rear. Surprisingly the car was still free enough on entrance and finished top 5...

[mod71m]

Having the pull bar angled toward the right front tire will make the pull bar constantly loose length as the car hikes up (think of this as if you viewed the car from the side. The center to center length would be shorter as the pull bar gets more angle in it toward the right front when hiked up). This reduces the amount of pinion angle change from ride height to hiked up. Anything to minimize the amount of pinion angle change is a good thing for the U joint. Another theory is that the pull bar will stay loaded better with it angled to the right (I'm not sure I completely agree, but that's another thing you will hear).

The point that the pull bar is lifting the chassis is good to be centered or right of center. The right side of the car gains weight dynamically during corning so it's a good thing to be lifting the car toward the right side.