vlad01 wrote:Asymmetric axles as in one is a LOT thicker than the other, changing the resonance between the 2 wheels causing destructive interference and canceling it out.
Ok,
vlad01 wrote:In live axles setup the chassis and ultimately the engine mounts make up part of the main load loop to the final road traction so they do play an important roll in tramp. Issues that allow tramp from the mounts is like you said broken ones, poor design from factory, aging rubber and in typical hydro mounts lost fluid. In IRS cars because the diff is fixed to the subframe the main load loops via the subframe back to the diff, not all the way through the chassis via the engine mounts, that in turn is a smaller independent load loop not effecting the main one much.
You give engine mounts to much credit. Regardless of how the diff is mounted, i.e live axles or IRS, the engine mounts have the same purpose and overall effect on the drivetrain. They are there to keep the engine steady thus reducing loss of torque at the engine itself. If a mount has deteriorated once the mount has either compressed or stretched fully the transfer of torque to the drivetrain returns to normal. This is almost instantaneous.
1st thing to check when you have axle tramp with an IRS is the rear suspension frame mounts diff mounts. If your diff mounts have seen better days you are much more likely to have problems.
With regards to the "load loop" load is spread through contact points or mounts. A live axle has 6 mounts for leaf springs (4 spring ends and 2 shocks) or many more for coil springs depending on configuration (e.g. torque bar, watts link, panhard bar, upper control arms, lower control arms, shocks). An IRS has alot more depending on the configuration. This helps an IRS to spread the torque load more effectively through the rear portion of the vehicle. The monocoque design then helps to spread it further. 2 cars that are exactly the same except for rear suspension (i.e. live or IRS) have the exact same "load loop". The difference is the number of points that load is spread through into the monocoque. Monocoque design spreads the load throughout the car, unlike a separate chassis which the vast majority of the load is applied to the chassis.
vlad01 wrote:This is the reason why live axle cars twist the chassis and stand on the rear right wheel and IRS cars just squat at the rear and barely twist the chassis at all.
Any street car that can "stand on the right rear wheel" has either way to much power or a poorly designed monocoque frame or suspension or it is purposefully built to drag race and even then it hasn't been sorted out very well. What you are trying to allude to with regards to IRS happens because of better design. I have given 1 example above but I'll give you another here. Take 2 cars that are equal in every way expect for the rear suspension. Both are 4 link with a watts link but 1 is straight 4 link and the other is triangulated. The straight 4 link car will move, i.e. try to "stand on the right rear", more than the triangulated 4 link. Why? because the triangulated 4 link spreads the torque through the monocoque more efficiently than the straight 4 link. IRS are more efficient than live axle simple because they spread the torque more efficiently and that is because they have more contacts points and better design. The only way you'll mount an engine better is to have more mounts or mount it solidly.
