sirringo

My guess is the same reason why Dundon can get away with charging $30k for an intake and exhaust...and shops can charge $260/hr...Porsche tax *shrug*

widers911

Cost of parts alone are 40k (pre covid $$).

Vocan

Probably partially because there are only a handful of experienced, reputable shops most GT car owners would trust to do serious engine work and good shops aren't hurting for work at the moment.

Also because many engine builds use new OEM parts (usually 4.0 components) and Porsche parts prices are considerably higher than they were 10 years ago. I've casually discussed engine build prices with both Alex at Sharkwerks and Tom at TPC and both mentioned Porsche parts prices as a big factor in how much more it costs to do engine builds now than it used to.

changster123

I see, that makes sense. Maybe many owners can't accept aftermarket parts from Mahle/JE/Bryant etc. They are fantastic well engineered parts. Porsche titanium rods are awesome though! Porsche GT engines aren't big boost high HP appplications. NA engines are super easy relatively speaking, including the tuning.

madmurdock

Manthey can do a 4.1, 4.2 or even 4.3 cheaper than anyone in the US if you are willing to ship them your motor.

powdrhound

Chris Cervelli has built a 4.1 race Mezger for me. It's an absolute rocket. I'm probably going to have him do a 4.1 for my street 7.2GT3. He's built numerous Mezgers for me in the past including various gearboxes. Probably the best value in the US for engine and gearbox builds. The only guy I would ever use.

Hamhands

Just keep in mind anything over 4.0 requires modification to the crankcase, once you go over that you can't go back (not that anyone really would, but just know that you cant).

Igooz

are you talking about rod clearance for the longer stroke?

powdrhound

Anything over 4.0L required machining of the case due to the larger diameter piston liners. We run Mahle Motorsport 106mm pistons with a 76.4mm crank which gives a 4.05 displacement, commonly referred to as 4.1 although I round down and call it a 4.0. With an 80.1mm crank you’ll get 4.25L, commonly referred to as a 4.3. Both require machining of the case to clear the liners.

Wonderdan

which one is likely to have historical significance when this is a classic?

HarmonyJim

How is the redline affected by such a long stroke? Is it reduced significantly?

powdrhound

Porsche uses the 80.1mm crank in the 997GT3RS 4.0. I think the redline is the same as in the 3.8 RS which uses the 76.4mm crank. I recently had a conversation with my engine builder regarding using the 80.1 crank in my current engine in place of the 76.4 thus bumping the displacement from 4.05 to 4.25. If I'm not mistaken, I believe he said they ran the stress calculation on this and stated that the redline would be reduced marginally vs. the 76.4 crank due to the additional rod angle. I wanna say 300-400rpm but don't quote me on that. This is on a turbocharged application however where the stresses are much greater than an N/A motor.

ThePhanatic

Redline on the SW 4.1 I believe is 8800rpm.

SupraSaiyan

I recall Alex said the SW 4.1 had a slightly lower redline (maybe 8600rpm?) than the SW 3.9 which was 8800rpm.

RAudi Driver

I'd rather have the engine that revved higher. More exciting!