Porsch engine vs VW engine

2 more cylinders, for a start. If you're talking about the oldest Porsche engines, like what the 356 used, the VERY first versions WERE VW engines and produced the same horsepower. However, the 4 cylinder engines in the 356 super 90, Carerra and other faster cars made from 70-110 (I think) HP because they used different induction (dual carbs, usually) different exhaust, higher compression ratios, bigger valves and different rocker arms and valve geometry.

If you're talking about the aircooled flat 6 the Porsche 911 uses, like I said, it has two more cylinders for a start. It has a balanced crank, chain driven cams in the head, better cooling for oil and air, some had dry sump lubrication, better exhaust, big valves, everything is precision made and balanced. There are tons more differences but I'm too lazy to look them all up and list them.

Porsche aircooled engine =/= VW aircooled engine unless it's the four cylinder type 1 in the 356 or the four cylinder type IV in the 914, and type IV VWs. Plus the type IV =/= type 1. Type IV is much stronger.

---------------------------------------------------------------------------------

Dear Mel,

Calling the Porsche and VW 'the same design' is stretching the point to the max. They both happen to be horizontally-opposed air-cooled four-bangers but that's about as much as you can say with regard to their 'same-ness' without the need for qualifiers.

You really need to take one apart to appreciate their differences. But beware... once you appreciate WHY they are different... why the exhaust valves have 10mm stems and their own rocker shaft and all the other 'unimportant' details -- you'll understand why VW heads are inherently limited to a maximum SUSTAINABLE output of 45bhp regardless of displacement.

-Bob Hoover

I have had and rebuilt the older 4 cyl. Porsches. The Super 90 produced 90 HP and had a redline of 5800 rpm; the SC had 105 HP and a redline of 5500. The 912 used basically the SC engine and it had 107 HP at

5800. All these engines were built more sturdily than the VW engines, which is why they cost more. They were designed for maximum usage for long times. The Super 90 actually had an oil pickup that swiveled, so that when centrifugal force threw the oil to one side of the engine, the oil pickup was there. It also had ballcheck valves in the valve covers to prevent leakage during hard cornering. Another tidbit, was that the Super 90 exhaust valves were sodium filled for better cooling. It is more than carburetors and exhaust systems.

The beetle engine was built for regular consumer use, whereas the Porsche engine was built to race standards. The are similar, but not the same, other than opposed 4 cylinders.

The 6 cylinders are another story altogether.

Fweem.

Dave

- David A. Tosi Facilities Manager Habitat Re-Store

3826 High Point Road Greensboro, NC 27407