How much can it handle?...
10-30-05, 02:57 PM
#1
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How much can it handle?...
How much power can a rear end from a 1981 rx7 handle? I have a "monster" im thinking about building, and thought about using a spare 7 rear axle I have laying around untill I can get a 12bolt shortened. Incase you are wondering this "monster" isnt a V8 powered 7....its a 57 triumph that im wanting to stuff a V8 in. I plan to change the front suspension and rear axle since parts for a triumph would be hard to find and high priced.
I have heard they can hold around 250hp.
I have heard they can hold around 250hp.
10-30-05, 10:24 PM
#3
FB+FC=F-ME
Man,this sure is getting asked a lot lately.....
It doesnt really matter how much HP you are making at the flywheel.Torque output and how you deliver it,is what kills a rearend or trans.
V-8s make lots of lowend torque.When you launch in 1st,your applying the maximum amount of torque to the rearend that can be made.At lower launch RPMs,the V-8 is pushing its max torque and 1st gear is giving maximum torque multiplication.This is when you break a R&P or twist an axle.Add sticky tires or drag slicks and it gets worse.
A high power rotary will tend to be more kind to a rearend.Radical N/A porting reduces lowend torque drastically.Turbo rotaries,while torquey, tend to have a bit of lag which also cuts lowend torque(except REW rotaries)You can be making LOTS of peak HP from a rotary and still have no problems with a stock rearend because they just dont have much displacement or grunt.Ive been doing it for almost 5 years with my 300HP 13BT.Vehicle weight also makes a difference.
A big cube V-8(compared to a rotary) can make short work of a stock RX-7 rearend,especially if you beat it.Thats not to say it might not hold up for a while,but itll be very stressed and its likely to already have 100K or more miles on it,being 20 years old.
It doesnt really matter how much HP you are making at the flywheel.Torque output and how you deliver it,is what kills a rearend or trans.
V-8s make lots of lowend torque.When you launch in 1st,your applying the maximum amount of torque to the rearend that can be made.At lower launch RPMs,the V-8 is pushing its max torque and 1st gear is giving maximum torque multiplication.This is when you break a R&P or twist an axle.Add sticky tires or drag slicks and it gets worse.
A high power rotary will tend to be more kind to a rearend.Radical N/A porting reduces lowend torque drastically.Turbo rotaries,while torquey, tend to have a bit of lag which also cuts lowend torque(except REW rotaries)You can be making LOTS of peak HP from a rotary and still have no problems with a stock rearend because they just dont have much displacement or grunt.Ive been doing it for almost 5 years with my 300HP 13BT.Vehicle weight also makes a difference.
A big cube V-8(compared to a rotary) can make short work of a stock RX-7 rearend,especially if you beat it.Thats not to say it might not hold up for a while,but itll be very stressed and its likely to already have 100K or more miles on it,being 20 years old.
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