95ONE

ok. I will start with the basics. Main tube gets here on Tuesday. the collar (Sleeve) gets here Friday I hope. Here is what the Steel sleeve on the Trans bell housing looks like when cut out. Im sure you guys will find VERY interesting the large ballooned out pockets near bottom of sleeve that keep it in place.. It looks like this sleeve was heated up with the aluminum housing and then pressed out. Crazy. This thing would never let go. after it was heated and pressed out, the actual torque tube was dropped in this sleeved trans bell housing and welded to the sleeve collar. The piece in this picture weighs a full 5lbs. JUST this little piece. The pic below is the bare trans housing without the steel insert. Small pieces broke off when I pressed out the inner steel sleeve thinking it was straight and not "buldged." Luckily, the breaks were inconsequential. The sharp edges of the broken areas will be sanded down and welded removing fracture stress points. Note the splines on the Steel sleeve. More German engineering crazyness.

I'll post back pics of what I'm doing next week when the 6061 aluminum tube and sleeve get here. I'll explain what I mean in detail then.

blown 944

You are an American badass... Watch you weld...

Black51

What exactly is the purpose of the 'aluminum' torque tube build? Only curious, not calling you out. My guess though is for weight savings on the track... Maybe also power response. What about strength characteristics though? How do you propose that against the stock torque tube?

JDS968

I think you're confusing the torque tube with the driveshaft that spins inside it. The torque tube is a fixed piece that does not move other than shifting under acceleration/braking with the flexible motor/transaxle mounts (and not at all with solid mounts).

944er-teile.de

don't think thats correct - the complete torque of the engine has to be hold by the torque tube - the tranmission is able to swing around while adding rotation to its inlet and so the tube has to prevent it from turning...

gt37vgt

I briefly worked at hardy spicer where they did the first corvette forged aluminum torque tube .. awsome they start with a 8" tube and forge it down to 4" an d its perfect .. yeh stuff that cool has to go down under

JDS968

The torque tube is rigidly fastened, with no flex, to both the transaxle and the engine. The driveshaft spins between the two, inside the torque tube, transmitting the engine torque to the gearbox. The function of the torque tube is to spread the forward impulse that the CV axles impart on the transaxle between the transaxle and the engine, so that they can transmit that forward impulse through their mounts to the body.

To think of it a different way, imagine, just theoretically, that the transaxle were welded directly to the body, in a spot that was strong enough to absorb all of the forward impulse from the drive wheels. The torque tube would then be entirely unnecessary, and the driveshaft could spin bare (or covered by a splashguard or something) between the engine and transaxle. This is, of course, similar to how front engined, rear wheel drive vehicles operate when they are designed such that their rear suspensions transmit the forward impulse to the body, rather than their transmissions.

In the case of the transaxle Porsches, and in fact most realistic production cars for the street, a transaxle solidly mounted to the body will be unacceptable due to noise and vibration concerns, so the flexible transaxle mounts lead to this "swinging around"; however, that should be minimal with a mount that has not deteriorated.

944er-teile.de

perhaps my english is to bad to understand but my opinion is another: the transmission will not make any movement to front or rear as it got the balljoints that allow to disconnect this load to the transmission. The torque tube prevents the transmission to turn in the same direction as the driveshafts first. The second is that the tube will brace the transmission against the rotation and torque of the engine - it has to hold the transmission in place when the engine gets it's torque on the transaxle. It' a complete different situation compared to the fix rear axles with differantial in perhaps old Ford cars.

dillon410021

carbon fiber shaft would be cool and light also?

hp18racer

How much lighter do you expect your aluminum torque tube to be?

JohnKoaWood

OP, I want to see results...

Everyone else.. keep it going, I need the comedic relief every once in a while...

95ONE

Sid, we are our greatest fans.. I think the same of you in that you are not afraid to speak out from popular opinion, you say why not do it also-and make it work. Wish you were on here more...

Power response no. 20lbs lighter.. yes.. It is exceedingly difficult to drop weight any further than what I've done. And.. this is a fun challenge. I've weighed everything. know the weights of the tubes. the weight loss will be almost exactly 20lbs. (Before weights have been taken, and finished project will be weighed. Actual results will be revealed no matter what) I could have lost 30 with carbon fiber and titanium. but the extra 10lbs would have cost me $2k more.. Baller, yes, but um.. great example of the diminishing return theory.

All I can say is that the torque tube only takes a fraction of the torque load applied by the engine/wheels. Much of the flex it would see would be from the body. I have stiffened the tub considerably.

Not much cooler than that. I do what I can with what I've got though. I SERIOUSLY considered Carbon Fiber. 10xs the price. 10xs the work. that only gave me about a 7 lbs weight loss over Aluminum. It wasn't enough.

Yes, AND I will be mounting the transmission and the engine Almost completely solid. (very small dampening has been decided with delrin or extremely high durometer rubber to allow for high frequency vibration, hopefully to reduce fatigue)


Yes sir. I priced out just a titanium driveshaft and for me to build it was around $1250-$1500. It saved 5lbs. Too far out of my budget "guidelines."

As Stated earlier. It should be right at 20lbs. The torque tube assembly without driveshaft or bearings was 60lbs on my digital bathroom scale. I will weigh completed Aluminum one when I am done for confirmed weight loss.

I will post next week or a little after Some results and welding has been done. I have a few "Common" welders tricks to show you at that time also.

Duke

I'm gonna follow this build closely, thanks for sharing!

95ONE

.. I looked up 6061 strengths like yield and tensile. They seem to be as strong as the original tube which I am guessing is in the 1010 or 1020 classification. It cut extremely easy and was very soft (Original Torque tube) the only difference was the modulus of elasticity. It is (all class of Aluminum) around 1/3 that of the steel. Thickness will fix that. The Stock thickness of the steel tube seems to be .165 wall. using my digital calipers. I have a .250 wall pipe. This makes the pipe I have actually STRONGER/STIFFER than the original torque tube. I might actually turn it down on a lathe to a .185 wall thickness. I don't need anything near as stiff as the .250. EDIT: No time to make any others.

Here is a pic of the same spots that were broken off from the picture above, but this time the two knicks in the aluminum have been ground down for smoothness and weld-ability. The next pic shows the spots puddled in with filler rod. The cast housing is going to be taken to a friends machine shop to open up the hole about 1/8" it will cut and clean up the dirty and splined inside diameter for my intermediate pipe insert piece to butt smoothly against.. It will actually be a .003 interference fit (Heat up cast housing, let pipe sit outside in cold- slide tube in..housing cools, pipe warms, material binds together.) along with those old school welding tricks I was telling you about earlier. once again, I will detail those out when the time comes. Last pic is of the large tube that has already arrived. Short intermediate "sleeve" will be in on Monday.. crap, I just remembered i need to buy the delrin inserts for the bushings.. where do i get those again?

Pics are below.

Duke

Some serious work to get this done!

Do you have to run an intermediate sleeve between the tube and the housing?
Will you interferance fit the sleeve to the housing and then slide in the tube and weld it?

Have you thought about shortening the tube and drive shaft and move your engine rearwards?