rear axles/torque
02-28-07, 03:23 AM
#1
Savanna Rx-7
Thread Starter
rear axles/torque
I searched through about 30 threads, all dealing with rear axles, and snapping issues most of the threads simply said anything over 300ish and you have to worry.
so I ordered the bwaits moser axles so that I will not have ot worry about the axels for a while, but what about the actual rind and pinion? (also LSD) how much torque can they stand? I am not planning on doing 1/4 mile, as my preference runs toward road and circuit courses, however the turbine I am currently assembling has the potential to put me around 425ish (I know I started with a goal of 350 and got off track
) (bad Kenn chan no biscuit for you ! )
so am I going to need the grannies 8.8 like gonz, or if I stay away from slicks and the 1/4 mile should I be OK? anybody with experience (uhm direct freak you can answer at any time
kenn
so I ordered the bwaits moser axles so that I will not have ot worry about the axels for a while, but what about the actual rind and pinion? (also LSD) how much torque can they stand? I am not planning on doing 1/4 mile, as my preference runs toward road and circuit courses, however the turbine I am currently assembling has the potential to put me around 425ish (I know I started with a goal of 350 and got off track
) (bad Kenn chan no biscuit for you ! ) so am I going to need the grannies 8.8 like gonz, or if I stay away from slicks and the 1/4 mile should I be OK? anybody with experience (uhm direct freak you can answer at any time
kenn
02-28-07, 05:13 AM
#2
Have no idea what the Moser axles are rated at, Billy should be able to give you a general idea on those, but I think you will covered there. As far as the R&P and spider gears, your best option may be to purchase new ones and have them hardened, cryo-treated or something along that line. I don't know if the companies that provide this service recommend doing used ones or not.
It's a toss up. If this was a 1/4 mile build, I would definitely go with the Ford rear. Particulary for the extra strength and much cheaper gear sets. In your application, I would try and stay with the Mazda diff for the weight factor and research strengthening the rest of it. If, however, you find yourself changing gearsets for different tracks, it would be cheaper in the long run to go with the Ford.
I will be approaching the same crossroads soon. With the new parts Billy is coming out with, I can have TII brakes all around as a bolt in package. I like that idea, keep up the great work Billy.
On the other hand, I want to have the widebody be dual purpose, drag strip one day, twisties the next. Finding that balance may prove problematic having rearend and rear suspension that performs eaqually well at either track and of course, the occasional street challenge. 
It's a toss up. If this was a 1/4 mile build, I would definitely go with the Ford rear. Particulary for the extra strength and much cheaper gear sets. In your application, I would try and stay with the Mazda diff for the weight factor and research strengthening the rest of it. If, however, you find yourself changing gearsets for different tracks, it would be cheaper in the long run to go with the Ford.
I will be approaching the same crossroads soon. With the new parts Billy is coming out with, I can have TII brakes all around as a bolt in package. I like that idea, keep up the great work Billy.
On the other hand, I want to have the widebody be dual purpose, drag strip one day, twisties the next. Finding that balance may prove problematic having rearend and rear suspension that performs eaqually well at either track and of course, the occasional street challenge.
02-28-07, 08:02 AM
#3
Any FEA numbers posted would be highly an estimate since there is not a cost effective way to find out the heat treat figures on the stock axles.
What I can say is that these axles have allot going for them:
1) Manufactured by a very reputable company.
2) The diameter changes on the axles are nice and exaggerated over the stock axles. Not as many stress risers.
3) A great amount of metallurgy behind them.
BTW, kenn_chan, your axles are in. Email sent.
-billy
What I can say is that these axles have allot going for them:
1) Manufactured by a very reputable company.
2) The diameter changes on the axles are nice and exaggerated over the stock axles. Not as many stress risers.
3) A great amount of metallurgy behind them.
BTW, kenn_chan, your axles are in. Email sent.
-billy
02-28-07, 08:41 AM
#4
Rotary Enthusiast
iTrader: (1)
Join Date: Jul 2004
Location: Rocket City, Alabama
Posts: 1,035
Likes: 0
Received 2 Likes
on
2 Posts
For road racing, I have not had failures with the 1st gen Mazda ring and pinion. My PP produces about 200 ft-lbf torque. With my 2:1 road race 1st gear, then I have 400 ft-lbs going into the pinion gear. With 5.13 rear gears for short track, I have 2000 ft-lbs coming out the ring gear going to very sticky road race slicks.
I you are running a high torque turbo motor and a street tranny with low 1st gear, then you have the potential to get higher levels of torque to the rear axles (assuming your tires are sticky enough to hook up.)
I you are running a high torque turbo motor and a street tranny with low 1st gear, then you have the potential to get higher levels of torque to the rear axles (assuming your tires are sticky enough to hook up.)
02-28-07, 10:09 PM
#5
FB+FC=F-ME
I think youll probably be OK for a roadrace type application.
As mentioned,1st gear is the real killer,with more torque multiplication....and 1st isnt something your likely to be flogging much on a road course.Drag racing on the other hand,is all about that punishing 1st gear abuse.
For a road racer,Id just be very meticulous and setup a good,full inspected 3rd member,with the intent that it last a long time.Assume it will work,and get it as close to new as reasonably possible.That way if it does fail,youll know that the failure was just plain overloading,and not any past problems caused by a previous owners neglect/abuse.At that point,upgrading to a heavier,stronger rearend will be completely justified.
Check/replace all the bearings,set the lash,pattern and preloads with utmost care.You might wanna weld up the baffles a little taller inside the housing, to keep the oil from sloshing into the tubes during a long hard corner.We run sealed wheel bearings anyways,so theres no reason to let any of the oil leave the pumpkin.Run the best gear oil you can get.
Running a used,street driven rearend makes it impossible to eliminate the possibility that the first 100K miles of life were racked up on the same old oil,in less than ideal conditions,possibly riddled with abuse.I think thats a common cause of 3rd member failures on our cars.Even guys with near stock engines,will complain that the rearends are weak......but have they checked their oil lately?!
As mentioned,1st gear is the real killer,with more torque multiplication....and 1st isnt something your likely to be flogging much on a road course.Drag racing on the other hand,is all about that punishing 1st gear abuse.
For a road racer,Id just be very meticulous and setup a good,full inspected 3rd member,with the intent that it last a long time.Assume it will work,and get it as close to new as reasonably possible.That way if it does fail,youll know that the failure was just plain overloading,and not any past problems caused by a previous owners neglect/abuse.At that point,upgrading to a heavier,stronger rearend will be completely justified.
Check/replace all the bearings,set the lash,pattern and preloads with utmost care.You might wanna weld up the baffles a little taller inside the housing, to keep the oil from sloshing into the tubes during a long hard corner.We run sealed wheel bearings anyways,so theres no reason to let any of the oil leave the pumpkin.Run the best gear oil you can get.
Running a used,street driven rearend makes it impossible to eliminate the possibility that the first 100K miles of life were racked up on the same old oil,in less than ideal conditions,possibly riddled with abuse.I think thats a common cause of 3rd member failures on our cars.Even guys with near stock engines,will complain that the rearends are weak......but have they checked their oil lately?!
Thread
Thread Starter
Forum
Replies
Last Post