I have a 1999 Porsche Boxster S with the tiptronic transmission that I am swapping the motor with a V12 from a 1989 BMW 750IL (M70) after a frame stretch. I plan to get the HP really up there (maybe 700 or even more...) but I need to know three things:

1. Is the Porsche tiptronic gear ratios compatible with the BMW V12 motor?
2. What is the max power the Porsche tiptronic transmission can handle? Basically do you think it can handle up to 700HP?
3. Any suggestions that can help with the engine swap...

Thanks

 

Stop while you still have any sanity. Also IBTL


Getting a BMW V12 to run without its transmission requires the use of stand alone engine management. As for a triptronic there is no chance. There are a number of companies that make adapter plates for the G50 for the kit car world but they are not cheap. Also getting the DK motors balanced on the old v12's is a major endeavor, plus no one really makes a stand alone for a 12 cylinder, most are doubling the signal on a v6 system and hoping for the best.

As for 700hp your dreaming on the V12, the motor is NOT made for that stress. Dinan is the only successful company that has done a good running turbo system on the older motors and it was nowhere close.

On the plus side if you actually do get it done, California would never let you drive it on the road

 

I say do it! That would be awesome to see.

 

Not to sound like a d*ck…. But if your capable of stretching a boxster (which unless you show us some pics is just talk at this point) you should be smart enough to do some simple math. But if your not then surely you would be resourceful enough to look up an automotive specific gear ratio calculator. Sorry to be a very negative Nancy but im just be a realist here. More car project ideas get talked about then actually done.

The boxster tiptronic is produced by ZF. It’s code/model is 5HP19

1st-3.67:1
2nd-2.00:1
3rd-1.41:1
4th-1.00:1
5th-0.74:1
reverse 4.10:1

Final drive 3.38:1

I don’t know bms’s that well but here is what I found. Produced by ZF. Code/model 4HP22

1st-2.73:1
2nd-1.56:1
3rd-1.00:1
4th-0.73:1
reverse 2.09:1

Final drive is 3.15:1

Gear ratio calculator site http://www.grimmjeeper.com/gears.html

Pin outs and some info on the Boxster trans
http://www.unofficialbmw.com/images/BMW_Automatic_ZF5HP19.pdf

Compare torque and HP over the rpm band and that will give you a general idea. If you have to change gearing for your project that’s big bucks. In fact what your doing would take serious cash to even get it to the point you could call half assed. To do it right would cost more then a new 997tt. You might be in luck as that tiptronic was fitted to lots of bmw's, so the bellhousing might not be too different. But the flexplate will. To machine that will cost alot..

Hope I helped and my apologies for being mean about it. But until you post up some pictures of a dissected boxster….

 

no, you can't and no you shouldn't.

 

Do you think the tip tranny will bolt up to my 3,000 hp jet helicopter engine?

 

The Boxster S first came out in 2000, so your 99 is a base Boxster. Porsche called their automatic transmission the "Tiptronic S", so I guess that's where the confusion lies.

Instead of having to stretch the car's frame and trying to figure out the engine electronics compatibility, why not just drop in a used 911 engine instead?

 

Just like everyone is probably thinking...I have to call BS on this one.

 

Why bother with all the headaches ?

 

yeah, gotta agree with most of the folks here. but remember the golden rule of cars: if you have more money than sense, you can make anything happen.

to the original poster: i admire what you're trying to make which is essentially a poor man's carrera gt. but what you'll end up spending in custom machined parts, reliable electronics and quality labor, you'll can pick up a used ferrari 430 and be a far happier man with a car that won't take two years to get on the road.

go for the body stretch, but stay within the your platform (porsche). use a cayenne turbo for the power plant. big power and legal swap in california since the engine will be from a newer model car.

 

Thanks for ALL the replies, no personal feeling hurt But just for more information to some, I personally know someone that had the swap done but used an Audi tiptronic (removed from a 2001 VW Passat), and no its not because he can not use the stock tiptronic, it was more because he bought the Boxster already with a bad tranny...

Unlike some info already gathered from this thread, some things that I do know is that:

1. The tranny should be easily bolted to the engine with a machined adapter plate, and reasonably cheap;

2. No aftermarket ecu is required if you know what you are doing, it can be run through the 3 ecu from the donor car using the donor engine harness

3. There is a turbo kit out there claiming to be able to get it up to even more than the 700 HP at a very reasonable price

http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT

4. The car is already stretched, which is really the easiest part of the project...

I already have a known option in the Audi tranny but my main concerns really were:

1. whether the gear ratios are similar enough to work smoothly (this was a deciding factor for the person going for the Audi tiptronic)

2. and whether the stock Boxster tiptronic would be considered to be a stronger tranny than the Audi tiptronic.

Honestly the 700HP is too much and only in theory, I actually aim for somewhere between 375 - 450 realistically. Any useful info is appreciated

 

I still say go for it. I would love to see the finished result. Definitely unique if you can pull it off

 

1. No its not going to be cheap, and you will have to machine all the interfaces.

2. Then every kit car builder ever is wrong. (Several V12 motors in GTO replica's and a few Daytona's). Plus you are adding boost and that means NO factory ECU will take that period. I have taken apart/fixed enough 850i's to know that.

3. That is a general turbo kit and it WILL NOT FIT, especially in a mid engine configuration. 400+ is reachable but only with stand alone engine management.

4. If the car really is stretched you have the space for a proven transmission why try to use a trip. The established route is so much easier. Specifically with the Audi box adapters that are out for this motor.

Offtopic what are you building that requires a v12 in the middle. I only know of a few kits out there that fit on a Boxster and require a stretch.

 

Pics or it's a troll post.

 

LOL @ a $525 turbo kit, sure that not for a 90's civic?