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This project started because my track car was burning more oil than normal. Fred Gear at Porsche Birmingham does my track set up and anything needed with my car. We thought it was valve guides and decided to add some power while we were in there. I spoke with a couple of companies here in the US and also contacted Colin at Ninemeister in UK. I decided to go with his 9m 993+2 kit that consisted of billet aluminum heads, cams, light weight flywheel and some other things. As my builder got into the engine he found a lot of wear on the cylinders and rings, so I figured while we were in there we may as well do a 3.8 build. I wanted to maximize my horsepower and torque but still wanted a reliable engine. After many discussions with Colin at Ninemeister we decided to build a race engine.
After several recommendations for rennlisters, I sent the case off to Ollie's Machine Shop in Arizona to have 3.8 bore, machine cut O-rings, boat tailed the mains, shuffle pins, moon cut the cylinders and machined the case for the new GT3 oil pump. Several race shops told me that the slip fit cylinders would be fine but Ninemeister and a couple other race shops said the race engine would not last as long unless I did the machine fit which cost more money and time. I decided to go with the Mahle 109mm cylinders and the Mahle 102mm RSR pistons
Before and after Ollie's moon cut the cylinders
Correct Mahle 3.8 993 RSR piston. Originally the incorrect pistons with higher compression were sent to me. While discussing my upcoming tune and the project, Jeff Gamroth at Rothsport saved me on this one. He asked to see a photo and told me the pistons I had were the wrong pistons so my supplier replaced them.
Fantastic build. Are you sure the pistons are 103mm, and not 102mm? Mahle 3.8 are 102mm (making, IIRC, 3.746L displacement) the last I did one of these builds some years ago. But maybe they added a mm and are finally making a true 3.8 p/c? What compression are you running? And how are you handling engine management, are you flashing the ECU or going Motec? Congrats, will be a great motor. I've driven these. Lots of fun.
what is the build cost of this as you plan it? my guess $35k... lemme know if i am close
and what is the expected increase in hp and tq? debating a similar undertaking on a 964 motor
I'm in the automotive business and get discounts on some of these parts and labor but still almost double your guess. You can definitely do a build for less and certainly for more too but a lessor build may not be this extreme. I wanted the best parts and wanted to make sure it was going to hold up on the track and last a long time. I also have a Motec system and Rothsport intake I'm adding to this. I will post dyno results within the next 3 weeks after the tune.
Fantastic build. Are you sure the pistons are 103mm, and not 102mm? Mahle 3.8 are 102mm (making, IIRC, 3.746L displacement) the last I did one of these builds some years ago. But maybe they added a mm and are finally making a true 3.8 p/c? What compression are you running? And how are you handling engine management, are you flashing the ECU or going Motec? Congrats, will be a great motor. I've driven these. Lots of fun.
Thank you, I can't wait to get it on the track. You are right the pistons are 102mm, I've updated the post. My compression was about 11.8:1 Engine management will be Motec 84.
07-14-2018, 11:40 AM
993 3.8 RSR Engine Build
