A flat six is also going to be shorter in length than a straight six.

But longer than a V-6 with two rods/journal and four main bearings.
This is the advantage of the V-8 (with five main bearings).

Best,
Grady

Personally, I view the american v-8 as one of the best engines out there. For its displacement, it is extremely compact. It can produce tons of power in a reliable fashion and is extremely simple. Hi-Tech is cool, but there is genius in simplicity.


I agree, Henry Ford got it right. Porsche thought Ford was a God after he visited the River Rouge Plant. Complexity is just the result of artificial racing displacement limits.

One of the big advantages of the 911 engine layout is the simplicity of design. There are ways of doing lots of the things in the 911 motor better but there is a BUNCH to be said about refining a design over decades.

A couple examples of how a design attributes could be improved:
- "Low center of gravity". Yes the flat six has a low center of gravity compared to a straight 6 but if you really wanted to go nuts with a low center of gravity you would change it to a 120° V6. That would allow you to put the crankcase closer to the ground but leave enough room at the heads for the headers.

- Air/oil cooling of the heads makes for a simple, tough and reliable engine... But the lack of concentrated heat exchange (like you get with water cooling) limits the ultimate power output along with reliability of the heads/valves in turbo motors and keeps the air cooled motor from getting 4 valves per cylinder.


One of my favorite engine related quotes is from Smokey Yunick: "An engine doesn't know what name is on the valve covers". The Porsche engine isn't magical but it is the rare case of engineering in a road car heavily tilted towards true racing needs and then refined for decades.

- Air/oil cooling of the heads makes for a simple, tough and reliable engine... But the lack of concentrated heat exchange (like you get with water cooling) limits the ultimate power output along with reliability of the heads/valves in turbo motors and keeps the air cooled motor from getting 4 valves per cylinder.


Water and four valves are better on paper, but only if you make use of their benefits. There is an interesting comparison of the air cooled, two valve 917 with the water cooled, 4 valve Ferrari 512S, in one of Colin Campbell's books. The Ferrari made 8% less power and the 917 won 24 out of 31 races. The Ferrari won once. For a sport car racing engine, 2 valves and air cooling were "good enough". I suspect things would have been different for GP tuned engines.

The important point about the advantages of the flat engine or air cooling is that neither were chosen for their "benefits". The choice was not made by Porsche and it was not made for technical reasons.