| Re: anti-squat with an IRS |
Subject: Re: anti-squat with an IRS by CFI-EFI on 2009/2/27 1:32:34 Quote:
What are you referring to as "uprights"? The knuckles? They "see" ALL the engine torque. In answer to "can an IRS have anti squat", I say yes. The quoted redrose is largely wrong. The comparison of the "C" beam to a torque tube is only partially valid. Regardless there still is (and always will be) a reaction for every action. With a Hotchkiss suspension the "action" is the tires clawing to grasp the pavement. The "reaction" is the banjo housing twisting in the opposite direction of the rear tires. With IRS, whether the diff is bolted to the chassis, like a C3 or there is a "C" beam like a C4, the "reaction" is mostly limited to the knuckles, because they are detached from the differential. The pinion rising on a Hotchkiss suspension is more the axle housing rotating backward in reaction to the torque at the tire patch than anything else. If not, the spindly, flexible, "C" beam of a C4 couldn't come close to controlling the forces. The reactive forces are controlled by the dog bones instead of a pinion snubber and slapper bars. Anti lift can easily be designed into the geometry of the dog bones. I think the engine torque, mostly being referred to here, is the engine rotational torque and the reaction, thereof, which is controlled by motor mounts and the batwing. In the illustration, the instant center should be where a line drawn through the dog bones intersect. That probably is where the point labeled "IC" came from but the line extending through the lower dog bone is omitted from the drawing, probably to keep the drawing from becoming too "busy". Also, I think it is interesting to note that, as drawn, the center of gravity is forward of the midpoint of the wheelbase. RACE ON!!! |
