pp4rotor

hello all,

i tried searching to no avail, so i will ask, even thought it a dumb question.
how strong is the fb rear end? do the all motor guys that run in the 10's use the stock axle? what will be first to fail? how much are the moser shafts? will this rear end hold up to ~350 to 400 ft lbs?

thanks for your time

wwilliam54

v8 guys run 300ft/lbs with no prob on the stock 7"

but if you plan on useing slicks and have decent power, go ahwad with a ford 9"

pp4rotor

thank you so much!
you rock!

pp4rotor

thank you so much!
you rock!


hey, as a side note, how mych torque can the fb trans take and will it bolt up to the 13b form an fc with no problem?
SORRY for the newb question!!

mwatson184

Yes it will bolt up, it won't take much power to break though. It really depends on how hard you shift/drive. You can always swap a tII tranny in, it isn't too much work or fabrication, but kinda costly.

pp4rotor

so, aprox how much torque do you think the turbo ii can handle?

peejay

NOTE that the V8 gues running all that power are generally not running slicks, and they can launch "gently". Rotaries generally don't have enough torque to launch gently, so you end up dropping the clutch at stupid RPM, and running slicks so you don't break the tires free, and **** blows up.

The smoothcase (RX-7 N/A) transmission is a piece of crap. You could break one with a stock 12A. First to go is 3rd gear because it's the gear that is furthest away from any good bearing support, so the shafts/case flex causes the teeth to chew on each other. (This is generally a bad thing) Mazda then elected to make the transmission worse in '82-83ish by changing the center support bearing to a more failure-prone type, and going to a finer tooth pitch which is more sensitive to the gears going out of proper mesh. Mazda used the trans in all N/A RX-7s. All rotaries from '74 to present have the same bellhousing bolt pattern, although a Turbo flywheel won't fit in a smoothcase trans.

mwatson184

peejay loves n/a trannys!

pp4rotor

so... how much stronger is the turbo ii trans??

peejay

Almost all RWD transmissions have weak 3rd gears. It's simply because 4th gear is usually just connecting the input shaft directly to the output shaft. 3rd gear then is on the frontmost end of the outpur shaft, and that end of the shaft can flex around quite a bit because its only support is via a bearing where it spigots into the input shaft - so it's supported on a bearing that rides in a shaft that is supported by other bearings, and it's easy to get things cockeyed when you start applying heavy side loads (power).

But Mazda didn't *have* to have such shitty support for the input shaft bearing... it's just flapping in the breeze, relative to other trannies.

T2 trans is probably stronger than a Borg-Warner T5 trans. That's not saying much either (The T5 was originally designed for 4-cylinder Monzas)

Directfreak

iTrader: (2)

Plenty of people running 10 secs on them..
They just don't like High RPM shifts (>8,000 RPM)

peejay

That's because of the mass of the gears that the synchros are tring to accelerate/decelerate. It's very difficult to make a strong tranny that shifts nicely.

Of course, ve haff vays of making trans shift...

- Pete (Synchros? Who needs 'em?)