@ALB posted:His words Danny- "And no internal vanes to route the air evenly over the four cylinders". It doesn't matter who made the shroud or what fan it's using; if there's no directional work inside the thing won't come close to even temps from cylinder to cylinder. I stand by what I said. Just look at all the work you did to make it work satisfactorily.
Actually, it DOES matter who made it. There are different shrouds, some are not shaped in a "cooling air flow" fashion. Bergmanns absolutely SUCK in this regard. Look at photos on the web, you'll see what I'm talking about. Al, it seems that you completely missed my point about a sealed plenum. Think about it for a minute.
It wasn't that much work. There is a factory part available for the P shroud, but only if it's modified a little. And it will only fit a real Porsche alternator and ring.
I stand by what I've said and done. The axial fan works on pressure, the regular VW fan works on flow.
The sled tins made a LARGE difference. TEN degrees cooler in all conditions. Why? I think because the air is forced to follow along the cylinder bottoms, thereby removing MORE heat than if the bottom of the cylinders is open.
The shroud Martin has looks really close to mine. The "wings" that he has that go under the stainless fan clamp are absent on mine, but the rest of the shape is the same.
Martin, I also used silicone to seal some areas that the foam weatherstrip wouldn't fit. AGain, pay special attention to the top and sides of the case, and your fan ring to shroud joint.
Here's the Porsche part I modified. There must be a reason the factory put it in there when they went to the 2.7 liter. The vanes go on the left, to turn the air opposite to it's natural direction on the 3-4 side:
