Carl Fausett

For those that have been asking, to convert a 928 equipped with automatic trans to a manual trans 928. you need all the parts in this picture, PLUS a good used 928 transaxle.

If using our 6-speed kit to convert from a 928 automatic to a Chevy 6-speed trans, you do not need the Porsche trans or any of the items I have put a yellow X over. You can see it reduces the number of 928 parts you have to acquire to do the swap by quite a bit.

Our 6-speed conversion kit isn't ready to order just yet, but it's coming along.

Mrmerlin

Goodluck with your new trans kit.

FWIW there should also be a 5 speed tachometer included in the picture with this auto to 5/6 speed swap, and the jumper for the CE panel.

It would be interesting to see what you have for a foam air block off pad as there will be considerable air sucked through the shifter opening with a window down if some type of pad isnt not used

Carl Fausett

My gear chart in post #26 was incorrect. Here it is, corrected.

Note this chart compares C5 and C5 Z06 transaxles to 928 G28.13 only, as found in 1987-88 cars.

The gear ratios shown would be different for G28.10, G28.15, etc.

Carl Fausett

Just posting a few pics of the latest progress on our 6-speed kit. These pics show the C5 ZO6 transaxle properly located in the car. Next week we will be designing the compliant rear mounts for the transaxle to hold it where it is shown now.

I will be using a rubber or polyurethane rear mount - not sure which just yet. I have a couple designs in mind and have not landed on which one will go into production yet. I want to avoid solid-mounting the transaxle if I can.

You can just see the Porsche CV joint peaking out from behind the cross-member. The stock (but modified) Porsche cross-member is being used to locate the springs and suspension mounting points.

PS: I am also designing the kit to allow the use of the more common C5 transaxle too.

Carl Fausett

This picture shows how much room is left behind the transaxle, between it and the fuel tank.

Carl Fausett

This picture was taken level with the bottom of the rocker panels. It is only intended to show that we have the 6-speed tucked well up under the belly pan. The rocker panels and the belly pan are actually lower than the trans.

Koenig-Specials 928

Great update Carl.
Subscribed.

Carl Fausett

Had a very good meeting with the firm we have selected to make our splined clutch input shaft. I am supposed to have the splined shaft to fit to the car in about 3 weeks. We have been able to maintain the Porsche stub-shaft design with our 6-speed kit, so you can service the clutch without removing the engine or transmission. It also makes installation of the kit a lot easier.

As to the cross-member: I plan on a "photo day" here in about a 7-10 days so I can post pics of our cross-member design. Center link is 4130 Chrome Moly tubing, we have two solid or polyurethane trans mounts (your choice) , one on each side of the T56. The outer sections of the OEM cross-member are being used so you know that location of each rear suspension mounting point are exact and OEM.

More info when I have it - next time I hope with pics.

Mongo

I neglected to ask this earlier, but is that new torque tube 'fatter' than the factory one? It certainly looks that way in the pictures.

Carl Fausett

Yes, it is. We are using the Corvette TT, it is aluminum, and it has a larger OD than the steel 928 TT. It's also lighter.

As you can see, it fits. No hammering to the belly pan. The heat shield mounts (yellow arrows) had to be folded up to insert it, then they can be folded back down to mount the heat shields.

Tom in Austin

Cool stuff, keep it coming!

Carl Fausett

Here are some progress pics for you.

I think they are fairly self-explanatory, this batch is all about our rear cross-member and transmission mounts for the 6-speed transmission. Transaxle shown here is the C5 ZO6 transaxle. I am designing this kit to fit the non-ZO6 trans as well.

I have designed the kit to use for either polyurethane mounts for street-driven cars without roll cages , and solid mounts for racers and cars with roll cages.

Rather than make our own cross-member - we were concerned that it would be hard to position each suspension mounting point and angle of the Weissach rear links correctly - so I have opted to buy stock rear cross-members from 928 Intl and modify them. Then I know without question that all the suspension mounting points and angles are correct. There will be no alignment issues this way.

Each cross-member gets cleaned and bead-blasted, sectioned, then milled in a jig we have made to square it up to the transaxle.
From there we will be installing steel threaded inserts into the ends, but first we have the webbing in that area completely filled with aluminum by a professional welder. Then the full-circle threaded inserts are installed.

In addition to these two bolts on each side of the cross-member, we made our mount reach around and capture the factory cross-member-to-body mount as well. So we have 3 bolts on a side, two M14 fasteners into the cross-member and a M12 into the body.

The center section of our cross-member is made from mandrel bent 4130 Chrome Moly tubing. It is stronger than the aluminum section we removed.

Please note that all these pictures are of raw, unpainted parts. The finished parts the customer receives will be powder-coated.

I have a meeting this afternoon about the design for the clutch stub shaft. At present, I have been able to retain the sliding coupler system in the 928 clutch, so clutch service as well as installation of this kit will be much easier. As anyone who has had to pull an engine or remove a transmission just to replace a clutch knows, the 928 system is pretty slick and we want to retain it. Looks like we will be able to.

More news and pics as it progresses.

Carl

Ducman82

Well done. i like that approach.

Mongo

That crossmember is a real nifty design. Seats the transmission real cozy in the back.

Lizard928

Nicely done Carl, it is a good approach, and looks to be nice and robust.

It is also most appreciated that you have chosen to share the pictures with all of us.