Calling all structural reinforcement experts.
 

Ill get right to the point. If I were to cut the center section of the torsion tube in an '84 911 to accomodate a G50 transmission. What kind of reinforcements should be done to keep the car from falling apart?

I think it would be easier to locate a late model rear suspension then to do that.

Didn't Jack Olsen have to cut up his tube to move his engine forward?

Yes.

I elected not to cut the entire center out, to keep as much strenght as possible. I welded in circular caps to close off the tube at each side, then added in horizontal plates connecting the two block-offs. Then covered the face of that with a flat square plate.

Then I tied the torsion tube to the center tunnel with steel strap. After that, Dave recommended tying in diagonal braces that went through the rear panel and triangulated the tube to the inner rockers on each side.

I took pictures of it all while I went along with Dave's camera, but I don't know what he did with the pics. Hopefully they are saved on his computer. But he may not want to share them.

Exactly what I was looking for thanks Tyson. Hopefully some pictures can find their way to this thread.

So would cutting out the seats be required for a project like this or is there enough room to work with?

http://forums.pelicanparts.com/uploa...ndWhistles.jpg

http://forums.pelicanparts.com/uploa...orcement02.jpg

http://forums.pelicanparts.com/uploa...orcement01.jpg

http://forums.pelicanparts.com/uploads/99RearSeat.jpg

This picture shows you the amount we were able to move the drivetrain forward. Look at the relationship between the rear bumper and the exhaust tail pipe.

http://forums.pelicanparts.com/uploa...1070694510.jpg

Would shortened G50 that Patrick offers save the one from doing such reinforcements or those are still necessary? Thanks.

The shortened bellhousing G-50 means you won't have to notch the torsion tube, and can still run torsion bars.

The downside is that the engine will still sit about 1/2-3/4" farther back in the chassis for the trans to clear the tube. Not such a big deal unless you are racing on the track. The '78 and newer 930 has the engine sitting 1.5" farther backthan a 911, so I guess it's not the end of the world, but not the most gracefull solution.


BTW, thanks for posting the pics Jack! Those in-progress shots bring back a lot of memories. I can almost feel the slag burns just looking at them. ;)

Thank you Jack. Those are exactly the pictures I needed. I was confusing the hell out of my welder, trying to explain what needs to be done. Now I can just show him.

Anyway, about all of the shortening the box questions. That was my original plan. But since the clutch and flywheel assembly have to be all custom and modified, seemed like a big hassle that I dont want to deal with every clutch job. With the method Im doing, Im using all stock parts. No future problems.

Tyson, thanks for the explanation. But in this case, what would be the most "GRACEFUL" solution to convert car to G50, as I'm seriously looking on doing this?

BTW: sorry don't mean to hijack this thread...

Sorry to but in, since you asked Tyson, but in your case, shortening the box would be the best. You dont have to worry about a DME like I do.

So, if I used a short bellhousing G50 and did the Tyson/Olsen mod, would I basically end up with a mid-engine car?

Just got a new welder, can't drive (ACL), looking for something to do...

I was thinking - buy a g-50 car - change out the regular g-50 for a shortened bell housing - how many inches would that net?

Thom, I plan to do something along those lines someday.

To answer the "most graceful" question, that would be welding in a G-50 torsion tube.

I bought one on E-bay, and may someday install it in my '69, and use a shortened bell housing G-50. That way you end up with factory driveline angles, but the engine is about 1" forward.

You guys crack me up.

Yeah, Thom should do stand-up. He's got the gift!

What if you go coilovers and use shortened box? Do you end up with the same results: factory angles and engine forward?

Yes. You could even cheat it forward a little more without trouble.

Just keep in mind the engine opening. You may need to modify the engine sheetmetal, and alter the throttle linkage.

Tyson, thanks a lot!

The way to strengthen any tube is to re-tube do a partial then cut out what you don't want.