jbryan

Let's don't forget that Alois Ruf built many air cooled 3.6 and above motors that made over 550 HP. I know because I drove mine to over 36K miles with no problems. I believe the current owner of my former car has well over 60K on it now...no problems.

Robert Linton

Where they turbo or super charged?

doubleurx

Must be. I don't know of any RUF naturally aspirated motors. Maybe they're out there? I simply don't recall any NA motors.

Robert Linton

I cannot either. As such, I still think that if we can get approximately 500 HP from an NA, air cooled engine that's not bad.

997s07

At what RPM? That would be amazing.

Robert Linton

Hoping for 8000 to 8500 but might be 9000.

jbryan

To answer your question about Ruf, they were air cooled turbo's.

sccchiii

RUF had NA air-cooled engines back in late 70's....stroked from original specs if my memory serves me correctly. Obviously not 500Hp back then and not sure what more recent versions have in HP dept but they have definitely have made non turbo cars

Texas RS

Mine runs on pump or race gas, just the flip of a switch.

Texas RS

Texas RS

997s07

So will you be using titanium internals? How bad will the low end torque suffer? I am amazed that an air cooled engine can do this naturally aspirated. Learning a lot here.

Robert Linton

Yes, titanium rods, hollow stem titanium valves and other materials.

Robert Linton

Yes, titanium rods, hollow stem titanium valves and parts made from other materials such as aluminum MMC.

Robert Linton

Good news. Latest dyno run of Cartridge 4 liter, 2-valve, normally aspirated, air cooled engine on street gasoline and with a catalytic converter produced 455 HP and 453 Nm of torque.