Technical How much hp/tq can torque tube setup handle

I was just trying to get some input from guys with experience running higher HP while retaining torque tube setup, what’s the most power they’ve run without breaking ?
What’s the ballpark horsepower range where you really need to convert to open drive ?

 

When you start throwing hp at the rear end the torque tube part of the factory design in not the weak link , the axles and the keys are.

 

I think an Outlaw sprint car is about 900 hp, and they use a torque tube.

 

I’m at around 350 horsepower, is there a torque tube closed drive setup that could handle this or should I do an open drive conversion ?

 

Yeah , I am thinking I’m gonna go to s stronger rear than my existing early banjo .

 

They make an axle upgrade to slip in axles. What are your plans? Tire sizes? Dropping the clutch at high rpm? What car? Weight? Driveshaft length? So many questions. All play a part. Like said above, the closed torque tube can be pretty stout.

 

https://www.hotrodworks.com/ Talk to these guys. They may be able to help you.

 

What kind? 30s Chevs were notorious for breaking axles with the stock 80HP six. Forties Fords could handle up to 150HP without too much trouble especially if you avoided drag racing starts. Some big cars like Buick were even stronger.
As others have pointed out there are custom made torque tube setups and quick changes that will handle anything you can throw at them, for a price.

 

Paging @HotRodWorks

 

I had a Buick powered 47 Chev, in which I ran a Buick transmission, and torque tube rear end. I abused the crap out of it, and never had a lick of a problem.
Bob

 

And the traditional way to do this was using Mercury axles. I will see if I can dig up the old article that I posted 15 or more years ago.

 

Here is one thread discussing axles. https://www.jalopyjournal.com/forum/threads/banjo-rear-with-late-model-axles.380478/#post-4128302

 

What trans?

 

Sure do.

 

Back in the 60's a buddy had a 39 Ford with stock drive train and a hot flathead. Never had a problem. Then he sold the flattie and installed a nailhead out of a 54 Buick, probably a 264. The first thing to go was the 39 trans. There was a guy in town that would machine and install later gears in the 39 case which fixed that problem. That moved the weak spot to the rear axle. Broken keys, split hubs, broken axles and then he sold the car.

 

Trans is a tremec t170 converted to work with closed drive setup . Went that route to avoid having to change rear suspension .

 

What car are you talking about? We are all assuming Ford banjo, but there are others. What car are you building?

 

1932 Ford , original banjo housing with aftermarket slide in axles .Stock torque tube setup that was shortened to fit .

 

Depends on the traction. spinning forgives, hooking up doesn't.

 

I’m running firestone bias ply 750x16 rears .
Not that big of a contact pattern on them , don’t seem like tires that are ever gonna hook really well

 

The banjo is not the first thing that will break in the drive line with a torque tube. It’s the trans. Yeah you might shear an axle key or break an axle. But I can almost guarantee, you will blow up the trans. Before you blow up the rear. Even the best built 39 top loader trans will not stand up to a heavy foot and lots of power. I’m very gentle on my 39 trans with a 283 in front of it for that reason. If you want a traditional set up with a torque tube, track down a 37 lasalle trans and convert it to torque tube. That one will hold up. Much stronger than the ford trans.

 

Keep in mind the 32 rear isnt much more than a model A rear.Later years have much more metal for internal support near the pinion.Henry had 65 HP in mind when he designed it.As he upped the HP he strengthened the center section.

 

Blown Arduns like to break stuff!


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no clutch dump and it pulled the rear of torque tube off the rear end . It was way beyond what the torque tube was ever meant for so I can’t be surprised or mad at the results .
I have a feeling open drive and a stout rear end may be in my future.

 

That looks like an early style banjo rear with the round coupler , basically a model A design. The later 32 rear and newer have a scallop looking coupler and are stronger.


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It appears that the torque tube bolts were not tightened before the first test drive. That joint will not pull apart like that if the bolts are torqued properly. The bolts are now extra loose and the weight of the car is on the spring behind the rear axle pushing the front of the banjo up. That is why the top is gapped more than the bottom.

 

I know how much mine couldn't handle...

 

Is that an original or aftermarket?

 

Ohio George Montgomery ran the torque tube rear in his gasser and had good success. I did a read up on it about a year ago when I was gathering parts for my 34 chassis with Cadillac 365. It’s worth looking up.

Scott


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Axle key's were my problem. HRP