Constantine

An original 944 TT by itself weighs about 70 lbs.

An aluminum copy of a 944 TT would not work since it would not be strong enough as stated above.

It would need to have a much larger diameter to keep from twisting and bending under load. Some attempts of aluminum 944 TTs have been made already and heard about one in a race 944. Had many problems.

GM Corvette aluminum TTs are much larger in diameter and very robust. Some C7 TTs were also made of aluminum bellhousing ends and carbon fiber for the middle tube section. These were done for weight reduction as well as harmonic attenuation since the c-fiber does well in that category. Have some in the work shop.

Cheers.

orig944

Aluminum is stronger than steel for the same weight. This is why airplanes are made of aluminum rather than steel. An aluminum 924/944/968 torque tube able to take the same torque as the factory design would weigh less, plain and simple. The reason Porsche used steel is that it cost less for material and fabrication. The same reason the body is steel, rather than aluminum. Yes, the aluminum would have to be thicker to support the same stress as steel, but for the same structural strength, the aluminum version would be lighter.

Constantine

In order to swap out the OE 944 TT with one from aluminum, the structure would have to be much larger and would not be an easy fit into the 944 chassis.

Porsche used a steel tube and grafted an aluminum bellhousing for the transmission interface for strength and packaging in the 924/944/968. The steel TT also helps with reducing drive line harmonics/NVH traveling down stream from the engine.

It is interesting that many focus on the TT as a place to cut weight. The better places would be the top surfaces of the 944 replacing the steel panels with c-fiber, thinner glass and so on.

MorganWright

Thanks. I did not know Corvette used aluminum for torque tubes.

You live and learn.

I can't fit into a corvette so I don't drive them.

Tiger03447

GM and Ford both changed over to aluminum driveshafts in the 90’s. Yes they had to be a larger diameter than the steel ones to be able to resist the torque. Wall thickness would be more as well, presumably as I never saw one cut apart. U joints were always problematic in the early ones, with some of them requiring two different sized bearings in the same U-joint. 3 joint shafts were a hassle as well. The local driveline shops were full of them as more and more problems arose. This was mainly in the truck lines rather than the cars, as they were primarily going to front wheel drive.

Tony5

There's quite a few threads floating around the internet where people fabricated aluminum torque tubes to original dimensions, saved 20ish pounds and went on to live happily ever after. One guy was evem selling them for a while.

jeyjey

FWIW, Aston Martin uses an aluminium torque tube (with a carbon fibre drive shaft) on its VH platform cars (DB9, V8 Vantage, Rapide, etc.).