BoxsterLS376 introduction - LS3 conversion :)

[FauxDiablo]

Originally Posted by Qmulus

Well, that is an Audi V8 along with an automatic, not a Chevy LSx. Audi V8s are pretty short, and will bolt up to the Boxster transmission with the right flywheel, so you may not have the same issues with the firewall that you do with the Chevy LSx.

Integration of the Audi engine with the Porsche electronics is actually pretty easy. Likely even easier than the Chevy, even with the GM Performance engine harness and ECU. I just so happen the proper engine ECU for V8 with manual transmission and no immobilizer sitting on my desk as I type this. You just have to make sure to get the right engine. You would want the 40 valve 4.2 from an '02-'03 A6, S6, A8 or S8 with the Bosch ME 7.1.1 ECU. The S cars will have a bit more hp. Those engines are also pretty light and I would bet you could use the AC compressor and power steering pump as is on the Audi engine, with just some adaptation needed on the lines. Those engines are getting cheap ($2k complete, sometimes less) with everything.

The down side is that the Chevy engine will be easier to make a lot of hp with. With the Audi V8, you will get maybe 350hp, and not much more no matter what you do. Both engines are reliable, but the Chevy would be cheaper to keep with parts available anywhere. I would say that the 40 valve V8 is probably one of the best engines Audi ever made, but if things do go south, you are looking at Porsche-like prices to fix it. The Audi engine will be a bit higher rev'ing and may match the stock Boxster gearing a bit better than the LSx. Hmmm, another interesting option.

FWIW...Audi V8 starter is on the passenger side, under the motor mount. Stock Boxster starter is on top of the stock motor, which means the starter opening for the Audi engine needs to be on the side, where it is not on a Boxster...gonna have to use an Audi transmission with that v8 Ccnversion...and aside from O1E manual trans, you might as well use the Audi automatic.

[Qmulus]

Originally Posted by FauxDiablo

FWIW...Audi V8 starter is on the passenger side, under the motor mount. Stock Boxster starter is on top of the stock motor, which means the starter opening for the Audi engine needs to be on the side, where it is not on a Boxster...gonna have to use an Audi transmission with that v8 Ccnversion...and aside from O1E manual trans, you might as well use the Audi automatic.

After looking into it more, I think that there more issues. I think you could modify the bell housing on the 6 speed to work with the Audi starter or just use the VW/Audi/Boxster five speed. Personally, I would never do an automatic.

The height of the Audi V8 for one would pose a problem, or more precisely the distance from the crank to the top of the engine. Although total engine height is very close, the M96 has the crankshaft much higher vs. the Audi engine. This MIGHT be a good thing if it would be possible to lower the transmission on the Boxster a few inches. While the Audi V8 is short, it makes up for it by being pretty tall and wide. The width at the bottom is not an issue with a Boxster, but the top end may be.

There just doesn't seem to be very many good engine swap options for Boxsters with the M96 that is fairly short lengthwise, short in height and very wide.

While I don't know much about them, I wonder if a tweaked Subaru 3.6 (EZ36D) would be a viable option <ducking> The design of that engine is much more like the later Porsche engines with a single front mounted timing chain, closed deck block, 4 valve/cylinder, variable intake and exhaust timing, mounts in the right place, etc. I bet it would even sound right. You can find them for $2k or less. That might make an awesome lemons Boxster...