142 guy
Member
- Joined
- May 31, 2014
- Location
- Saskatchewan, Canada
This probably has way more detail than you want.
https://www.collectionscanada.gc.ca/obj/s4/f2/dsk2/tape17/PQDD_0011/MQ39983.pdf
Its primarily the development of a mathematical model describing a beam axle with panhard rod system. The model also includes spring rates, damping rates and lots of other stuff. The interesting part is around page 48 where the author starts getting into the effect of lateral forces (going around corners) and the load transfers that occurs across the vehicle centerline just because of the panhard geometry.
So the short of it is that the panhard geometry can contribute to a difference in left - right side loading that might make your problem worse. That is not to imply that it is the sole cause of your problem.
Since the vehicle seems to like the left hand turns, perhaps you should switch to stock car racing? From my extremely limited knowledge the stock car dudes treat the panhard rod angle as a desirable component of chassis tuning. If you insist on turning left and right, the geometry lesson in the paper says the longer the panhard rod and the smaller the mounting angle, the less the difference between left and right hand turns. The Watts linkage does seem to be the go to solution for turning right and left at high speed if you have a fair amount of suspension travel (I have never bothered to check the linkage motions to confirm that it really does eliminate the panhard rod problems). If you have limited suspension travel and can get the rod angle small and the rod long enough the panhard rod's undesirable behaviour might not be significant.
I can't remember what the 240 was like; but, on my 140 optimizing the panhard geometry to minimize left - right differences did not seem to be uppermost on Volvo's design file.
https://www.collectionscanada.gc.ca/obj/s4/f2/dsk2/tape17/PQDD_0011/MQ39983.pdf
Its primarily the development of a mathematical model describing a beam axle with panhard rod system. The model also includes spring rates, damping rates and lots of other stuff. The interesting part is around page 48 where the author starts getting into the effect of lateral forces (going around corners) and the load transfers that occurs across the vehicle centerline just because of the panhard geometry.
So the short of it is that the panhard geometry can contribute to a difference in left - right side loading that might make your problem worse. That is not to imply that it is the sole cause of your problem.
Since the vehicle seems to like the left hand turns, perhaps you should switch to stock car racing? From my extremely limited knowledge the stock car dudes treat the panhard rod angle as a desirable component of chassis tuning. If you insist on turning left and right, the geometry lesson in the paper says the longer the panhard rod and the smaller the mounting angle, the less the difference between left and right hand turns. The Watts linkage does seem to be the go to solution for turning right and left at high speed if you have a fair amount of suspension travel (I have never bothered to check the linkage motions to confirm that it really does eliminate the panhard rod problems). If you have limited suspension travel and can get the rod angle small and the rod long enough the panhard rod's undesirable behaviour might not be significant.
I can't remember what the 240 was like; but, on my 140 optimizing the panhard geometry to minimize left - right differences did not seem to be uppermost on Volvo's design file.