986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Considering high HP rotary swap, need advise on transmission options...

rcracer_tx · 01-17-2011, 08:58 PM

Hello,

Ive been looking at doing a LN engineering/flat 6 innovations 4 liter swap, but after looking at dollar to HP ratio Ive decided that swapping the engine might be a better idea. I have been researching the parts and fabrication needed to do a swap and have hit a couple roadblocks that need to be addressed.

I am looking at putting a 13b or 20b rotary engine in the Boxster as its easy to work on, I know the platform well, and know a really good mechanic who has built 1000whp+ 20b's. I would be looking to make 500-600whp on a 13b rotary or 6-700whp on a 20b if it was turbo (Intercooler mounting nightmare + water/meth) and if it was N/A Peripheral port with Itb's 400-450whp.

Custom engine mounting isn't a problem as the mechanic has made several engine swap subframes in the past, so assuming all goes well I will need a new transaxle with a lsd and stout internals. The gearbox needs to be able to withstand 8-9k rpms, and a max of 500ft lbs. N/A Peripheral port would redline around 10-12k, so im not sure of any trans-axles that could handle the rpm's)

I'm not sure how to address the bellhousing to the Porsche trans-axle. Ive looked at kennedy engineering and their mounting kit that will mount the mazda rotary to any g50 variant transmission (911 turbo)

Is it feasible to put a g50 based transmission in this car if you made custom mounting brackets? I'm sure custom 300m axles could be made so i don't foresee that being an issue.Any advice would be greatly appreciated...

Thanks,

Brett

01-17-2011, 08:58 PM	#1
rcracer_tx Registered User Join Date: Dec 2006 Location: Texas Posts: 30	Considering high HP rotary swap, need advice on transmission options... Hello, Ive been looking at doing a LN engineering/flat 6 innovations 4 liter swap, but after looking at dollar to HP ratio Ive decided that swapping the engine might be a better idea. I have been researching the parts and fabrication needed to do a swap and have hit a couple roadblocks that need to be addressed. I am looking at putting a 13b or 20b rotary engine in the Boxster as its easy to work on, I know the platform well, and know a really good mechanic who has built 1000whp+ 20b's. I would be looking to make 500-600whp on a 13b rotary or 6-700whp on a 20b if it was turbo (Intercooler mounting nightmare + water/meth) and if it was N/A Peripheral port with Itb's 400-450whp. Custom engine mounting isn't a problem as the mechanic has made several engine swap subframes in the past, so assuming all goes well I will need a new transaxle with a lsd and stout internals. The gearbox needs to be able to withstand 8-9k rpms, and a max of 500ft lbs. N/A Peripheral port would redline around 10-12k, so im not sure of any trans-axles that could handle the rpm's) I'm not sure how to address the bellhousing to the Porsche trans-axle. Ive looked at kennedy engineering and their mounting kit that will mount the mazda rotary to any g50 variant transmission (911 turbo) Is it feasible to put a g50 based transmission in this car if you made custom mounting brackets? I'm sure custom 300m axles could be made so i don't foresee that being an issue.Any advice would be greatly appreciated... Thanks, Brett Last edited by rcracer_tx; 01-17-2011 at 10:26 PM.