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I've been curious about whether or not a Porsche Tiptronic automatic trans. could be used in a GTM. Anyone ever done this?
 

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I've been curious about whether or not a Porsche Tiptronic automatic trans. could be used in a GTM. Anyone ever done this?
No. And you will not get a lot of help in this forum, unfortunately. You'll get a lot of: "Why?!" And "Evil!" And "Stickshifts rule!" Believe me, I, and others, have asked.

If you want to do this, issue's you'll have to face are: mating of the electronics, building new transmission mounts (requires welding skills), and getting an adapter to mate the engine to the transmission. The tiptronic is electronically controlled, and it depends on signals from the Engine Control Unit to function properly. The transmission mounts for the GTM are built for a Porsche manual gearbox from a 911, which must be inverted to actually work. You'll likely have to cut the mounts out and replace them yourself or hire someone to do it for you.

A better possibility for you is the Superlite Cars SLC. Though I too like the looks of the GTM better, Superlite Cars provides far more customization options and will build motor and transmission mounts to suit, even after you've bought the kit. That still leaves you with the issue of getting the electronics to mate up and building an adapter plate to tie engine and transmission together.

Other issues of note:
1.) The Tiptronic is torque/horsepower limited. They can be built up a little, but if you're looking at a 500hp LS7, you're not going to get there with a Tiptronic.
2.) You'll need your own shifter and linkage solution, though the Tiptronic does open the possibility of push-button shifting or wheel-mounted paddle-shifters.
3.) You're going to be blazing the trail. The build manual and the helpful hints on this website don't cover automatic transmissions. Unless you're very handy at figuring stuff out, this may be a bridge too far for you.

Hope that helps.
 

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The main issue that I see with auto transmissions of any type that are designed for a rear engined vehicle is that they typically don't like being inverted to suit the needs of a mid engined platform.
Now if you had one in mind that was already in the correct orientation that could handle the torque of a LS engine then go for it.
 

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Yes...what Dave mentions is going to be your biggest hurdle. Unless you can make the engine run backwards, you will have several reverse gears and one forward gear. The Porsche transaxles that we run have been inverted to remedy this situation, and AFAIK, it is fairly impossible to invert an automatic trans and have it work.
 

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You would have to use the transmission from the Cayman, which is mid-engine. The real problem is figuring out the codes for the electronic control. I have discussed this with one of the main Porsche guys in the country and he says that it is impossible to get any information from Porsche so you would have to reverse engineer the control and adapt it to work with the LS engine inputs. The other option would be to use an Audi automatic as they are front wheel drive with a longitudinal installation. Check with Scott at Advanced Automotion and see if he can give you any idea on a controller. I can do the adapter.
 

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I'm pretty sure the Cayman has the input shaft above the axle output. So you'd end up with bad half shaft angles, or the engine mounted way too high in the chassis, or both.
 

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Yes, the halfshaft angles would change due to the location of the out put flanges. I am not sure if that would be a problem though.
 

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Here becomes the real problem

So a lot of good points have been made here, but the most important on has been overlooked.

Yes you can use a Porsche Tip in the GTM, however not mated to anything other than a Porsche engine. The same Porsche engine that the tip came out of.

It is the electronics that really ruin this idea right now. The gearbox is electronically shifted and requires inputs from both the engine ecu as well as other ecu's in the car. There are no stand alone systems currently for the Porsche units.

We would love to come up with a solution for this, but as of yet, due to cost and lack of real interest, this has not happened. We are still thinking about the options for the LS however, and I hope to have a solution here at some point.

It is likely to be rather expensive I think, but who knows, until we come up with something it is tough to tell.

Erik Johnson
GBox LLC
(303) 440-8899 work
 

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Erik, that's right, I had forgotten that you were involved with attempting to see if it was a viable solution to use the Boxster trans, weren't you?
 

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I can get a controller for the Audi automatic that will work with the LS engine. That transmission is very similar to the Porsche unit.
 

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Both Getrag?
There's an early 5-speed automatic transaxle that was used both in the Porsche Cayman/Boxster and front-wheel-drive Audis. This was a ZF unit. I recall reading about/seeing a separate control box that could be used to interface between the 5HP19 and a non-Porsche/Audi engine.

The Dual-Clutch Transmission (Which is NOT a Tiptronic. It's actually called a "PDK" which is german for "dual-clutch") probably is out of the question, but the ZF automatic units are a little more in the realm of possibility. However, like I said in my post at the top, they are torque and horsepower limited. You're not going to be bolting one of these to the back of an LS-7, regardless of whether or not you get the electronics to work.
 
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