Dave951M

I'm in the process of testing an aluminum torque tube for the 944nz/Turbo. This test is being conducted in a 951 with over 350hp on the ground. Chief benefits are-

1) Uses readily available C4 clearance bearings
2) Weighs less (23lbs on the 944)
3) Easy to rebuild
4) Way less expensive than factory
5) Bling factor- who else has one
6) Number of bearings can be changed to suit
7) Length can be altered for changed weight distribution (track guys)

Here's a link to the 944 version-

<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=18;t=005616#000000" target="_blank">http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=18;t=005616#000000</a>

Is there an interest for a 928 version?

Stan.Shaw@Excell.Net

The forum is not allowing me to send you email. I might be interested, in the future, for a 928 race version. Please advise on cost.

reno928s

I am also interested. How much would it cost? Sal

BC

I would be interested as well.

If you are making this from scratch, then I assume that you can also determine the ID and OD of the tube? I read in the thread in your 944 area that you can control the amount of bearings included?

I assume that you are referring to the 928 5spd torque tube? The reason I ask is because there are MANY automatic 928s. I would not want to say whether they would be interested or not, but....

I am not sure if he has found a solution, but Mark Anderson of <a href="http://www.928intl.com" target="_blank"> 928 International</a> has always searched for ways to make the 928 lighter - 2inch lowering of engine for better CG, etc.
At one point he was looking for better solutions for the TT issue. I suggest you contact him.

Not that I would know the difference - but what aluminum are you using? Are you using stock carriers?

Donald

I'm interested in one for the GT.

PeteS

Since the torque tube on a 928 is a structural member, is the aluminum one as strong as a stock torue tube? In the one picture of the aluminum tube, I noticed that it has "OFF ROAD ONLY" stamped into it. Does that have to do with the structural strength of the aluminum tube as opposed to a stock one if driven on the street?

Dave951M

In answer to these questions, I have been speaking with Mark at 928 Intl, Devek and 928 Spec about this. That's why this thread is posted here as well. Before I haul off and start making something no one wants or has a use for I wanted to check with the 928 community. That tube is stamped with the ORO because that tube has no collision ears, not because of strength problems, call it a bit of CYA, just in case. That's not because it is weaker than the stocker, just the abscence of the ears could possibly be siezed upon by a legal beagle and well.... The stock I am using is 6061T6 3.5 dia, 1/4 wall. From my and others calculations, it is way overkill in the strength department. I make new carriers to fit the tube and locate them with screws. The screws are drilled and safety wired. To rebuild the tube or change bearings for whatever reason, just cut the wires, remove the screws and slide the driveshaft, with carriers, out one end. The carrier assemblies can be slid of the driveshaft easily at that time for bearing changes. As most Porsche manuals state, assembly is the reverse. The 944 version will be tested soon in a 951 hot rod with some highway testing as well. Depending on the results, production of that version will commence then, with a 928 version to follow shortly. I'm being told that the 84-on automatic is the one with the most issues, and the most common. That may be my starting point, but I'll look at others as well.

BC

While I understand your idea on the TTs for the 84 plus autos, I will have to say that people who have the five speeds are going to be the ones that will invest the money for more bearing support, as well as the lighter weight.

Tim murphy has a 928 that will soon put down 600rwhp. That would be a good test. While I understand that the strength issue is important on the tube, I believe that more importance can be placed on the shaft inside, as this is the piece that will wind up on wheel hop and sudden acceleration.

The tube in the 928 is not QUITE a structural member, as it is a link between two very massive hunks of metal. The engine (600lbs at least), which is sitting on two very small rubber mounts, is bolted to the tube, and the tube runs un supported to the transmission (200lbs or more), which is supported by a cross member - again - by two rubber mounts. Those points are the only four links holding a 928 drive train in the car. The TT WILL be twisted, but even more importantly, the TT will have bending stresses put onto it from each side.

PLease keep us informed.

BC

I should think that if this is going to be done that you may go over to the 928 email list and start a discussion there as well.

Maybe even pin this to the admin section up top on this board?

Cameron

I am interested for a '91 GT.

By the way, why was there no interest in the lightweight flywheel post?

.....Cameron
'91 Euro GT

BC

I did not see any lightweight flywheel post. I will have a choice of pretty much any flywheel I want within reason on my DTA (teeth wise) - so please do tell.

jpitman2

Anybody ever looked under a Miata? These have many similarities to a 928. The rear of the front mounted (IE NORMAL) gearbox is tied to the diff nose with a length of C channel - IIRC, 8-10mm thick, maybe 200mm deep vertically, two big bolts each end. The drive is a normal prop shaft enclosed on one side by the brace.
It strikes me that the 928 tube could be replaced by something similar, and a readily available prop shaft adapted to fit inside it. Maybe two lengths of C channel would be needed, but a normal prop shaft with a sliding spline would remove thrust bearing problems and tube bearing worries. As long as there was enough clearance at the bottom to remove the prop shaft, or to pull one brace out and get at the shaft, you would be way in front of the current setup, from a maintenance point of view.
??

jp 83 S, with a quiet TT

urnotthesameina928

Hey Dave sounds and looks like this tt will be a great improvement to our current unit. I currently need to eliminate my rattles with new motor mounts which should quiet my t-tube. Interest is in weight savings , price and maybe double the bearings to prevent all that rattling at idle my 86 auto does. It really is getting loud when I'm at a light.

vicente

The lightweight flywheel post:

<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=14;t=006849#000000" target="_blank">http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=14;t=006849#000000</a>

vicente

Dave: Im interested in an aluminium torque tube for my GTS if you develop it. Please, keep me informed.