I bet you have an opinion on these two items

[Al_C]

I don't think I posed these questions elsewhere. If I did, well, I guess I'm just repeating myself. Wouldn't be the first time. Here they are:

1. Accommodating the mid-shift option on a TKO600
2. Location of the battery.

Let's deal with the mid-shift first. I believe there will be interference with the cross-member in the transmission tunnel. I know some builders have just removed the tube; others have moved it and re-welded it. Unfortunately, I don't weld. Here's the "before":



When I put the mid-shift kit on the trans, it looks like it will interfere. Here's my possible solution:



Conceptually, it's the same solution a bunch of you have employed for the clutch interference. Here's the question: Am I nuts? Is it worth the effort, or shall I just cut out the interference and be done with it? Will that tube contribute to torsional strength or not?

OK, topic #2: battery. Other than to make more space in the trunk, what advantage is there to installing the battery in the engine bay?

OK, back to work. We have great weather in Chicagoland today and I can keep the garage open! Applying Thermo-Tec to the aluminum today.

[BEAR-AvHistory]

Never saw the need for a mid shifter. Have no issues with the battery in the trunk, like the rearward weight bias of the car. If I had to do it over again would have mounted it to the side to compensate for driver weight & torque.

[wareaglescott]

I like the forward battery tray. Made some of the electrical runs shorter and easier as well as freed up some trunk space. I am not going to be racing the car. Realistically I most likely will never drive the car beyond 80% of its capabilities so the weight distribution/ balance where not a consideration to my battery positioning. Those that can drive the car hard enough that they can tell a difference may have a valid point though on that.

[mikeinatlanta]

How do you plan on attaching your solution?

Battery, depends on use of car, size of battery, and current weight bias. Mine is behind Pax seat, but is a very small battery. With an all alloy motor and T5, I'm already too tail heavy. Also flatly do not have room anywhere up front.

[RR20AC]

I debated the same issue with the mid shifter. Adding a new brace or leaving it the way it is. Ultimately I left it cut wide enough that if I have to pull the tko600 I will cut the top panel a new oval going back so I have room to go back with the mid shifter on. My top cover is not removable as I have also installed the dash support. Others did comment that with the cover riveted and glued on there should not be a strength issue but Factory Five did answer my question of that with: "Make sure all the supports we put in are there".

[CraigS]

Everything I have ever seen says that backbone definitely contributes to chassis stiffness. The only question would be how much is it weakened by removing one diagonal. I would remove it and replace it. I don't think the battery placement is very important unless you are racing. I autocross a lot and doing corner weights tells me the rear is heavy. Also w/ just the driver in the car, it is heavy on the left. So I moved my battery to the right front. I don't think it made a difference I can feel but, if you will move it somewhere, that is the right direction to go. I do think it has a benefit electrically w/ the vastly reduced length of battery cable.

[karlos]

I think midshifters are the schnitz. That is to say, I like 'em.

If you have to cut the crossmember, then go ahead and do the repair. It'll at least put back some portion of the original capability. As you stated, it's the same relatively straightforward repair that many have done for the clutch pedal interference problem. Was hoping I wouldn't have to chop up my frame, but couldn't get the driveline angles to come in without doing so. Ended up with what you see below.

A piece of 1/2" X 1/2" bar stock will fit right inside the open end of the cut crossmember. Just need two small pieces in either end of the cut, another longer piece over the top, and a right angle drill to get into the tight corners. Not great, but better than leaving it open.

Hey FFR...how about moving that crossmember back about 1/2"?

[CraigS]

Karlos that is a nice technique for someone w/o a welder. Well done!

[Al_C]

Karlos' approach is exactly what I was thinking. Except, his interference is at the back; mine is on the front. Thanks for the input!

[mikeinatlanta]

Sorry if this upsets anyone.

The reality is that the bolt in solution pictured will do little to nothing beyond giving a visual impression. Triangulated structural pieces, when loaded, are loaded in tension and compression. A couple of small diameter clearance fit bolts installed through thin walled tubular structure will not carry any significant load in tension or compression, and therefore the bolted piece will not perform the structural duties of the weld in piece removed. IF the bolts were interference fit, and IF the tubes were solid you might be able to carry some load, but not in the way pictured.

IMO (you asked for them ): Better to remove the tube and leave unrepaired than installing a repair that is structurally unsound.

[karlos]

Sorry if this upsets anyone.

The reality is that the bolt in solution pictured will do little to nothing beyond giving a visual impression. Triangulated structural pieces, when loaded, are loaded in tension and compression. A couple of small diameter clearance fit bolts installed through thin walled tubular structure will not carry any significant load in tension or compression, and therefore the bolted piece will not perform the structural duties of the weld in piece removed. IF the bolts were interference fit, and IF the tubes were solid you might be able to carry some load, but not in the way pictured.

IMO (you asked for them ): Better to remove the tube and leave unrepaired than installing a repair that is structurally unsound.

Yep, agreed. But what you describe is not what was actually done. The bar stock is solid, not hollow, and there's a short piece inside the hollow tube at either end. Hard to see in the photo but there's a short section of solid bar inside the tube, flush with the cut end and extending to the white dashed line. So the four bolts pass through the original hollow crossmember, the solid bar inside the tube, and the solid bar on the outside. There's an inch of solid steel bar stock being clamped up there.

[mikeinatlanta]

Yep, agreed. But what you describe is not what was actually done. The bar stock is solid, not hollow, and there's a short piece inside the hollow tube at either end. Hard to see in the photo but there's a short section of solid bar inside the tube, flush with the cut end and extending to the white dashed line. So the four bolts pass through the original hollow crossmember, the solid bar inside the tube, and the solid bar on the outside. There's an inch of solid steel bar stock being clamped up there.

It's good that the thin wall tube is reinforced to prevent collapse, however, it does not correct the issue. You are essentially attempting to carry a pure shear load with noting but the friction of a clamping load to carry it, and there is absolutely no way two small clearance fit bolts would do the job. Not a chance that setup could carry the tension or compressive load of the original thin walled tube. Keep in mind that the original tube is there to add stiffness and to do so requires no movement. The bolt together joint would move under relatively light load and therefore provide essentially none of the stiffness that called for the tube in the first place.

EDIT: I would add that even welded the tube would no longer be sufficiently stiff to contribute to chassis stiffness. The fact that the tube is no longer straight means that you now get to deal with bending under compression or tension. Even if only a little, you will still thwart any contribution to overall chassis stiffness. If unable to weld in a replacement, I'd still cut out the tube, clean up the welds, touch up paint, and move on.

[karlos]

If unable to weld in a replacement, I'd still cut out the tube, clean up the welds, touch up paint, and move on.

Respectfully disagree...sort of. I looked at this type of repair previously when it came up as part of a cut-the-frame-or-notch-the-clutch-pedal thread. See post #34 here: http://thefactoryfiveforum.com/showt...780#post221780

The graphic shown below is a repost from that thread. It shows that stresses in the repair region itself are low. But when you step back across the reinforced area into the basic hollow tube section the stresses peak up due to the bending you referred to above. However, the repair is effective in restoring a portion of the original capability. About 70% of the original capability based on what I wrote in that old thread.

So I agree that the repair doesn't restore the full capability of the unmodified tube, and I clearly stated this in my first post. But I don't agree that it would be better to cut it and leave it completely disconnected. I can't get back to the original strength but I can get most of the way there. Worth doing in my opinion. And I doubt that the chassis members are operating at anything close to 70% of their ultimate capability anyway.

[Al_C]

This is what I love about this group. Where else will you get analysis to this degree? I guess I have to read through this again, as we don't really have a consensus. Good food for thought, though!

[Mark Reynolds]

Battery forward and low, obviously. Mid-shift not needed, but if you have one just cut the tube out for clearance and don't worry about it. Mk1-2 had no backbone structure whatsoever.