Pogoing on the bars/shock LR

[johnny v]

Is there a simple explanation on what causes the pogoing effect when a car gets up on the bars exiting the corner?

[AH55]

Have you dynoed the shocks? A buddy of mine had that same problem in a 4 bar LM and he ended up having two junk shocks in the rear.

[johnny v]

we had the LR dyno'ed.... came out ok, 7-2 gas shock...Pulled a 3-5 off RR and put on a 4-4, same deal, no change.....I just can't remember where I read some stuff on this issue.... it was something about on a slightly rough track , with full hike, and its almost off the spring, the shock is pretty much out of the equation...and your riding on them stiff old bars....

[powerslide]

we had the LR dyno'ed.... came out ok, 7-2 gas shock...Pulled a 3-5 off RR and put on a 4-4, same deal, no change.....I just can't remember where I read some stuff on this issue.... it was something about on a slightly rough track , with full hike, and its almost off the spring, the shock is pretty much out of the equation...and your riding on them stiff old bars....

Is the shock the stop on your suspension?

[21 racer]

if track is rough and its on the bars that is what it is going to do, no suspension just riding on the bars

[johnny v]

Is the shock the stop on your suspension?

No Sir.. we are on a chain with a rubber top stop cushion.

[Dirtrunner35]

On a rough track put a j-bar on it with less angle. When your sliding in on a rough track, think about the angle of the short bar or j-bar, the axle tries to go farther under the chassis, making the chassis pogo, IMHO.

[powerslide]

rubber top stop cushion.

you have your answer

[johnny v]

you have your answer

Really? A 2" tall rubber bushing cushion at the end of the chain will make a car Pogo?

And a solid Chain will not? I just figured the rubber bushing would just give you a slower stop instead of a jerk or pop..... I guess your going to have to explain that one to this Old dog..... thanks johnny

[HEAVY DUTY]

The rubber creates a spring effect that pulls the rear back up and then it compresses and does it again. A solid chain just stops it and doesnt try to pull it back.

[Dirtrunner35]

I have a rubber stop on mine and it does do it on a slick track, now a rougher track it will when sliding over the rough stuff but not driving through it. It's the shorty bar or j-bar at alot of angle that makes it pogo. Make it more level and try it for your self.

[racehard24]

Dirtrunner, did you mean to say it doesn't do it when its smooth but will cause it to pogo when rough? The biscuits shouldn't cause it to pogo when smooth. Also isn't the theory of the biscuit to help from snapping. I don't see how this could cause the pogo.

[Dirtrunner35]

Sorry, you are correct, it doesn't do it with a rubber on smooth.

[28m]

I cant see a 2inch rubber biscuit making it pogo. I have "the" max hole on my upper left bar. If I go up one hole, it is a jumping jack. The other major cause is too much j-bar angle.

[texas racer]

I have a rubber biscuit on my l/r chain it will not pogo on the bars if I am smooth on the accel pedal. But if I am not it will pogo bad. As long as I am still getting forward bite I do not worry about it to much.

[BigBlueFord]

Really? A 2" tall rubber bushing cushion at the end of the chain will make a car Pogo?

And a solid Chain will not? I just figured the rubber bushing would just give you a slower stop instead of a jerk or pop..... I guess your going to have to explain that one to this Old dog..... thanks johnny

I don't think the rubber bushing by itself is making the car pogo. Bushing is like a spring. If you think about it all the other springs on the car have a damper (shock) associated with them. I think whats happening is the bars and j-bar are hiking the car up, the bisquit gets compressed and then rebounds pulling the car back down, bars hike it up again, bisquit rebounds again, etc. etc. With nothing to dampen the oscillation it keeps going until you come down off the bars enuf to not compress the bushing.

We just run a chain. We don't have a pogoing problem.

Rex

[John H]

Too much panhard angle for the track!

[powerslide]

I cant see a 2inch rubber biscuit making it pogo. I have "the" max hole on my upper left bar. If I go up one hole, it is a jumping jack. The other major cause is too much j-bar angle.

to each his own. This is why you see so many diff chassis brands and motor builders everyone has an opinion of whats right or wrong.