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Joe vw wrote:The best solution for even cooling would seem to be twin type1 style fans spinning in opposite directions in a partitioned fan housing with DTM offset. Driven by a serpentine belt using the backside to drive the left fan. Of coarse the left fan would have opposite pitch on the blades. Using a remote oil cooler or a cooler that robs a little from each fan.
Allright Jake, start building.
Already though about it, but it would never sell, it would cost a fortune.... Would be cool to make it work though...
I know we can make the DTM work better than stock, and I don't think anything is gonna beat stock otherwise!
Jake,
I bet I know what you're thinking! I've been thinking of several ideas regarding our conersation about reallocating the air from the greater pressure bank 1-2 side just like the VW engineers did. Rerouting this air to the other side via a piggybacked conduit over the exterior of the shroud and then directed onto the 3-4 bank with such and angle and location to induce a scavenging affect or to increase pressure right on top of the cylnders and head or both. Given that 1-2 are abouth the same temp and 3-4 are about the same temp. We know what the problem and so did VW. We can take it one more step and tackle the problems VW opted not to. Like I said before, VW did a great job but they never intended to cool anything greater than a low-compression 1600-cc stocker powerplant.
I tried opening your pic ZIP file but it did not transfer. Resend it to me so I can sketch something and send it back. I think we are both on the same page.
Why don't you run a test / show a graph for the stock Doghouse with the Flaps / Thermostat.
Hi Jake,
Joe's post left me a question:
Does the type 1 DTM have the stock flaps installed? If not, would it be possible to install those anyway, even if it is just in a fixed position without thermostat operation? Maybe it could help direct/distribute airflow a bit better.
Did you test the stock doghouse system with the flaps?
Thanks and good luck with the mods!
Walter
T4T: 2,4ltr Type 4 Turbo engine, 10.58 1/4 mi in a streetlegal 1303
"Mine isn't turbo'd to make a slow engine fast, but to make a fast engine insane" - Chip Birks
The stock shroud testing is happening today... We'll see if the flaps and lower control plenums make a difference.
Just last evening I was able to make contact with Mr. Bob Hoover. For those of you who don't know Mr. Hoover, he is a well very well versed older gentleman that knows more abouut the VW than anyone I have ever made contact with.... He and Joe used to talk when Joe was building the shrouds as they were near the same age and had about the same experiences in life. He was able to que me in on some things that I previously did not know about Joe's design work and testing.
Heck, Mr. Hoover even knew the correct name for the airfoils that VW used as vanes in the stock shroud- "Eipper 300 series"- it blew me away. He and I discussed the ways to correctly measure the pressures in each side of the shroud. It seems that an airspeed indicator with a relocateable pitot tube will do the trick.. Here is a excerpt from an email he wrote me..
" Depending on air density and fan speed, the pressure differential should be equal to between six and 9 inches of water. (Not a bunch; 6" H2O is about 3psi; 9" is about 4.4 [you'd better check that. I'm old; I fart a lot and forget things.])"
So it looks as if this is getting more complex everyday- Now I can see more and more the reasons why the 911 fan doesn't do what it should for these engines! we'll see tomorrow just what it can do!
BTW, the Editor from Ultra VW magazine has expressed interest in doing the coverage of the test work- They are from England, and have so far been the only "Fair" publication that was willing to talk to us!
Hi guys, I'm Paul Knight, editor of Ultra VW magazine (over in England).
I just wanted to let you know I've been watching these results and findings very closely and, having looked through the spreadsheet results and information so far, I have to say I've been really impressed with the thorough testing Jake has been doing. Much like Jake, I long to know what does and doesn't work so we've decided to get together and publish the results when the testing is completed and everything has been filed and finished. Jake has made the effort to push the boundaries and perform this immense testing procedure and I have to say I'm more than happy to publish the findings - it's all groundbreaking stuff for those interested in reliable long-term cooling systems.
Watch this space... I think it could make for some great reading!
Yep- Paul and I talked early this morning, and it looks like the truth will come out in ink for sure!
This will be good! Thanks Paul for your dedication and desire to inform the masses of the true facts concerning our engines. I can see plenty of "Aircooled Technology" in the future for Ultra VW!
Out of respect for Paul, and what he is helping me with I will not be posting any more graphs and particulars until the information makes its way into the publication. After that I will be adding it to my sites.
There is an old saying, "The devil knows what he knows not by being the devil but because of his age". Yup, old school guys can definitely teach us a lot. They are the foundation of what we know nowadays.
Nice!
Paul,
Ultra VW Magazine is a really fine new magazine, I bought all copies so far, but please, please publish some more type 4 conversions! and some German Lookers to boot if you can. (that would set your magazine even more apart from Volksworld)
And for those who know not of Bob Hoover, he used to be a regular denizen of the rec.autos.makers.vw.aircooled newsgroup and still drops in with the occasional perl. But he does not suffer fools for long. He is a regular with the folks who use VW engines in light aircraft. I subscribe to that list just to read Bobs posts.
I've been thinking of several ideas regarding our conersation about reallocating the air from the greater pressure bank 1-2 side just like the VW engineers did. Rerouting this air to the other side via a piggybacked conduit over the exterior of the shroud and then directed onto the 3-4 bank with such and angle and location to induce a scavenging affect or to increase pressure right on top of the cylnders and head or both. Given that 1-2 are abouth the same temp and 3-4 are about the same temp. We know what the problem and so did VW. We can take it one more step and tackle the problems VW opted not to. Like I said before, VW did a great job but they never intended to cool anything greater than a low-compression 1600-cc stocker powerplant. 
