Aircooled VW South Africa

Just wait till the Chinese start making a knock off of the DTM shroud for $150.

Yeah, it'll suck, won't fit worth a damn and won't even cool as good as an old 36hp fan shroud but people will buy it, people will bitch and moan and the Chinese will be laughing all the way to the bank.

After our extensive testing of Type I cooling systems in the winter of 2004, where we tested 14 different stock and aftermarket cooling systems, we had basically given up all hope on the Type I DTM. The system had given us very disappointing results in its ability to control head temperatures on all 4 cylinders of the engine. when an off the shelf, aftermarket chrome 36HP style shroud beat the Type I DTM in direct testing I gave up on any hopes of making it a marketable system. We did continue and finished our cooling system comparisons and attained valuable data that NO ONE else has concerning the hidden truths about cooling systems that are on the market today.

It seemed that no matter what we did to the internals of the system, nothing helped it to cool better. We tried more cooling vanes, less cooling vanes, differently placed deflectors, different drive ratios and fans. We even tried drilling holes in pertinent areas of the shroud in hopes to make it actually work as well as the Type IV DTM!

As a member of many online forums, I shared my testing results and disappointments with the Type I DTM with the world. Almost immediately following the announcement that the Type I DTM was to become a part of history my inbox filled with emails and the forums were buzzing with individuals urging me to somehow make the system work. Not being an engineer, or cooling system expert I was not sure I could make it a reality. the testing had taught Brent and I that without a few key ingredients any cooling system would not function correctly, and one of those ingredients was air pressure- then I had an idea!

The Type I DTM did have a very strong edge over the other systems, and that was it incorporated a Type 4 oil cooler and shoved alot of airflow into it in Joe's design. Knowing that I decided to take a break from the system for a few weeks and come back to the DTM after I finished a large project for a customer that had a timeline. I did research and talked to many people outside the VW industry about cooling systems and basic airflow. Each of them had a different idea, but almost all them told me that the system could be made to work if the pressures inside the shrouds upper plenums could be raised high enough to overcome the static that creates turbulance.

Then one night I called Mr. Bob Hoover, a VW veteran that was good friends with Joe Locicero, the inventor of my DTM systems. Mr. Hoover is a wealth of knowledge and said that he knew the problem and that he and Joe had discussed it in the past. He went on the explain to me that the stock cooling system used an "Eipper 320 series" AIRFOIL in its design!! Then it hit me, and I felt really dumb that being from an aircraft background I had never experimented with a vane shaped like an airfoil to speed up the air as it made its way through the shroud. It was very odd that I had talked to several engineers that were experts, but Mr. Hoover brought up something that they never did. When I asked one of them about it he said "its not the key, there are more important issues to overcome".

As time and testing would tell, the airfoil was the key and Mr. Hoover was right! It was no wonder that adding regular old "vanes" to the shroud produced worse results in the early testing- they simply CAUSED problems and created more resistance, and kept more air from going to the left bank cylinders. By adding airfoils the air is literally sucked over the leading edge of the airfoil, and sped up over the trailing edge of the airfoil, while helping to build plemum pressure. This pressure allows the air to be more easily directed by deflectors and less detailed types of vanes to the hottest parts of the heads! That area, by far is the exhaust ports!