I am curious as to how a QC rear reacts under hard launch conditions such as a drag race. I assume that the pinion being on the rear side of the ring gear would tend to "plant"the front of the car and unload the rear tires. How is that overcome?
It's on the rear. But it is turning in the opposite direction. The ring gear still turns the same and I think the torque would be the same. Never noticed any difference with mine.
Same rotation torque is countered by the housing mounts. The tooth forces would apply, to the exact location of pinion and ring mesh-zone however (fore & aft), which is relevant to your question.
The relevant forces don't change, the traction of the tires verses the opposite force trying to rotate the axle.
to answer your basic question- it works out the same in the end- yes it can lift the front and plant the rear like normal- if it does the opposite, check your shift linkage as you're in Reverse. The answer to the question you didn't ask- will it survive? Depends on weight of car, traction, and HP- they're tougher than people give them credit for (depending on type) but they're by no means indestructible. -rick
Guess I'm extra dense today. I always thought the pinion climbed the ring gear and that's what raised the front end in non QC cars. More liquor needed.
Sort of...that's what makes the housing rotate, and the housing is connected to the rest of the car. If the pinion is in front of the axle, then it needs to climb it. If the pinion is behind the axle, it needs to go downwards on the ring gear. The important thing is that it twists the housing relative to the axle shafts
I feel like my quickchange car doesn't lift the front end under hard launches, I felt the same way as the original poster does about it. Mine also has a locker in it and I cant get much wheel spin before it hooks up. It feels like it pushes the front end down but not unload the rear. Also when im cruiseing and stab the throttle it feels like it just goes forward, it doesn't feel like other cars ive driven. But I haven't driven any other model a's, so it could just be the short wheelbase or stiff suspension. It also felt like it shifted to the side when taking off and downshifting. I thought maybe it was from the spur gears, either way a panhard bar fixed that. I also agree with what squirrel is saying about the pinion climbing down the ring gear. that's what makes sense.
When I get on my roadster with a Halibrand six spline quick change the front end goes up and the rear tires start to make a funny noise which at times includes an odd smell similar to rubber burning. I discovered the above takes place when the pedal located all the way to the right is depressed to much. I did add a ring gear snubber to make sure the ring gear stays planted against the pinion gear. As a side note the rear radius rods are long they attach to the bottom of the frame way up by the front of the door. Leverage is a good thing.
Remember, most dragsters used V8 or Model A quickchanges up into the early 1960's and about the 180 MPH level...
A car rear will squat, lift, or remain neutral in height upon accelerating. The rear control arms project f'wd and either pass beneath the center of mass, thru it, or above it, is one explanation I've read. The result-behavior is not always easily intuited. There are threads that cover this one.
If you think of it as the pinion un-climbing the ring gear, then it forces the rear of the QC case down. Never thought of it that way before. As to the question of the wheelies, Yep, it will pull the front wheels just like those uncool rear ends. Strength? Jamie Frankland told me that they fall between a Dana 60 and a Ford 9", with the 9" being the stronger. (Don't shoot me, I'm just the messenger) By the way, Mark Williams agrees with the Ford being the tougher of the two. A Champ size QC can easily handle 800 HP in drag racing with an automatic but needs the cushion of the torque converter.
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