Opinion on Rear Percentage - Whats to much

[racefastnow]

We run a steel block, aluminum engine with about 56.5% rear percentage. I am wondering if this isnt to much. What would be some issues with to high of a rear number. Car gets in corner excellent, but just has no traction exiting. Had car for a few years now, nothing seems to help. Tried all sorts of lift bar changes, moving it on frame, on rear end, springs, moved every bar on it, changed bite from 20lbs to 200lbs. Car only works on black ice, if the track gets ripped up, the car wont pass a single car, but comes on like crazy if its black ice. always enters corner good, Tried slowing everything down, longer rods. It just doesnt dig and leave a rooster tail when its on the gas, seems to just flop over and have nothing. I can watch the better cars the rear wheel really digs and lifts the car up onto the rf, We have soft springs in front. Nothing seems to help.

[Matt49]

Rear percentage makes corner entry very comfortable because the car is mostly stable. My guess is that the driver is having to man-handle the car at mid corner to get it to turn and that is why you don't have any forward bite to get off the corner.
That's a guess based on what little we know about your setup. Scale numbers, ballast location, springs, bar locations, and shock information would be helpful.

[swingarm4life]

Agree with Matt. Another thing to look at is the chassis brand. Some chassis like more rear than others. Swing arm cars tend to like more rear. Even though that is pretty steep for rear percentage, you can get away with it and have a decent handling car depending on alot of other things (rear springs, shock valving, front springs, 5th coil rate and location, bar angles, etc.) Its kind of a different strokes for different folks deal, you'll see cars now with anywhere from 51.5-56.5 rear.

[racefastnow]

We have literally tried a 1000 combinations. It just doesnt dig. If the track is ripped up and packed down right before our race where the lap times are fast, our car will be a second off the pace. Than when it gets black ice where all the other cars slow down a second, our car will have the same lap time as it did in the mudd. Nothing seems to effect it. We have moved the motor, roll center in the front, softer and harder springs, more roll steer or less, 5th springs changed, moved location from 40 to 32 to back, bar angles, jbar angle. Its become very dissapointing as we always we believe its a matter of setup and can be changed without buying a new or different car.

[Matt49]

Then it sounds like you're down on power. When the track is fast, a 1990 Rayburn should have enough traction to be good even against today's cars.

[racefastnow]

The engine is good, its brand new and has been on a chassis dyno. the car just spins. Cant be in the throttle. and we tried bar angles and rear steer. one way makes it worse, and one small adjustment makes it go straight to the wall. Not sure if the traction is to instant where its loosing right away, or if it doesnt ever load the left rear correctly, this is why we tried a a different lift bar, we made it so it mounted on left on rear end and moved it 4 inches to the left on the frame. It felt like it dug better, but it wasnt any faster, Still had same problem. the left wheel doesnt dig and lift car. Acts like it just rolls over doing nothing.

[racefastnow]

Thats whats bothering us, when the track is fast and tack, it just spins, but when its black ice and most cars have a loose condition, were stuck to the ground and gone.

[phenom08]

Need to list what kind of car, springs, percentages, maybe something simple is off

[MasterSbilt_Racer]

Post video of your car. I almost promise you the driver is busting the car loose to get around the corner with traction in the track.

[Punisher88]

It isn't an old grt with the lr hitting the underslung bar is it? The older cars that bar needs to be dropped.

[swingarm4life]

Drive shaft isnt too long is it?

[racefastnow]

09 Warrior, drive shaft is right. we have it on a chain and nothing is binding or hitting. Its been doing this for 5 years. 200lr 225Rr. Bars are in standard holes from warrior setup. but we have moved them. Right now we lengthened the lr bars an inch moving the holes to keep the rear end square, has 56.5% Rear, have heard an open car run 54.5. this is a steel block aluminum head. The front end seems to work nice now. we changed the roll center a little and shocks and chained it up for travel. gets on rf nice on a bump. We have tried stiffer RF spring no bump, doesnt help with drive at all. Whats always bothered me is i really like the cars on caution when they rock them back and forth they get on the bars easy and the rear end rolls up easy. this doesnt seem to do that. Jbar 9inches and 20 or 22 in lenght i believe. 325 fifth coil at 38 to 34 usually

[racefastnow]

54.5 Left side%. with 140lb bite, we have had it with 20lbs to 200lbs. doesn help. went back to the standard lift bar with it moved 4 inches left on frame from standard

[Matt49]

What we do know now is that you've altered the front end geometry, you've changed 4-bar lengths in the rear-end, and you've moved the lift bar to a non-standard location (not even sure how you pulled that off without hitting the drive shaft).
Based on this and the previous posts, I think you have changed so many things on this car that you are simply out to lunch. Unless you have analyzed the camber curves and roll center migration with good software, you shouldn't be modifying the front end geometry on these cars. Put everything back the way it is supposed to be and put 54% rear in it and it will probably be fine. Put the lift bar back where it goes and 4-bars back at standard lengths.
My guess is that you had a baseline setup 5 years ago except the 56% rear which was making the car too tight on entry (which will make it loose on exit). Since then, you've changed everything except the most fundamental thing that would have fixed it.
I would start over completely with a totally baseline setup and go from there.

[Punisher88]

Is the rf lower pulled way ahead of the left front. If so I would put them even or left front ahead. I had my rf ahead and chased my rearend up the track for two years and put the lf ahead and now it steers better and leaves the corner amazing.