[Massive Type IV]

The fan was designed for the engine and the engine designed to work with the fan as a unit...

Sit down and look closely at a 547/587, 616 engine and the 911... Then look at the TI and TIV and compare them all to each other. Compare the thickness of the fins on the cylinders and heads, their placement and even their length...

I think Russ's 911 shroud works fine for what he does because the engine is more closely related to the 911 than a TIV or any other radial fan equipped engine. I would like to get some data from all 4 cylinders of russ' engine to see how they compare to what I have seen with the TIV head based engines and even what I have seen with my billet heads and the DTM. It might help shed some light on why some things occur.

VW didn't spend the huge money on equipping the engines with Aluminum cylinders and etc so they had to create a coling fan that had a ton of potential. This was way cheaper than putting more into the money into the engine internals that would generate less heat.... Thats my hypothesis on why that fan works so well on the TIV, the added surface area gets the heat into the cooling ai stream faster and the high pressure air is forced in ever nook and cranny to get that cooling air stream more powerful and effective.

In EVERY dyno test I ran my dyno cell ran hotter with DTM cooled engines than with any of the 911 systems, while the engines ran cooler... Proof that the air was being shed into the room at a much higher volume. These temps were as much as 30 degrees on the same day without variable weather between a DTM and two different 911 style shrouds...

Just an ironic thing that we noticed while plotting every damn temp we could!