Anyone ever used this DTM cooling schroud for type 1? Will it really help to reduce the cylinder heat on bigger CC motors? Any issues in the speedsters? I am sure this has probably already been discussed.
http://vwparts.aircooled.net/R...TM-11001-p/11001.htm
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From what I have read Jake Raby did extensive testing and his shroud works exponentially better than what Germany's brightest engineers could come up with in the 1930s.
I'm not sure if the type 1 is available anymore.
I think I may be the only one, now that Jim D. has sold his speedster.
I was around when Jake did his supertest of all the available (at the time) shrouds, including the OG tin. The guy spent a freak-load of time and money on the tests, and used them to tweak and refine his DTM until it did better than OE tin (according to his reports).
Nobody ever saw the complete data. Bits and pieces of it were up on several sites for a few days, but then pulled down. There was a deal in the works for a VW magazine from England to buy the data to publish, but it fell apart. For a while Jake was telling people they would get the data if they bought a shroud, but I bought two and requested but never received anything.
It's odd, and one of the reasons I think the DTM never really took hold. I was deep on the front-end of the madness at the point he was developing the shroud, and saw (but did not record) the data he put up for those couple of days. It was enough to convince me to give it a try. Jake's stated reason for not producing data was that he had spent thousands, perhaps tens of thousands of dollars on acquiring the data, and he was not inclined to give it away. He was also very, very concerned about Chinese knock-offs of it-- I thought it was paranoia at the time, but over the years I've watched several knock-offs of Tiger's sidewinder come to market, so it doesn't seem like such a remote possibility any more.
My experience has been good. It cools the heads well and pretty evenly (I monitor all 4 cylinder temps). With a 2L motor, you'll need to supplement the oil cooling, but IMHO, it's silly not to do that anyhow. I think it does better than a 36 hp doghouse shroud (Scat or Empi-- there's very little difference), but it's not a huge thing. The cheap 36 hp shrouds are definitely more ruggedly built, and more difficult to adapt to a "bubble-top" AL case.
In short, I use them because I want every last possible bit of cooling I can get. I think these cars are starved for cooling air, and even if a DTM is only 5% better, that's 5% more than not running it. I like compression, and compression needs cooling.
Rusty S posted:From what I have read Jake Raby did extensive testing and his shroud works exponentially better than what Germany's sainted and infallible engineers could come up with in the 1930s.
I'm not sure if the type 1 is available anymore.
^ Fixed it for you, Rusty. 
LN Engineering bought the rights to the DTM, as well as Jake's "Type 4 Store" parts business recently. The Type 4 Store still sells Type 1 DTMs.
Can you add heater ports to the Type 1 DTM shroud? Is this direct plug&play replacement?
craig
It seems that all of them I've seen in Speedsters have the flex pipe across the top crushed or deformed by the right hood hinges. Not sure how that affects the flow from what it was designed to be.
Craig - You can't add the heater pipes as that would totally change the flow of air in the DTM.
WOLFGANG posted:It seems that all of them I've seen in Speedsters have the flex pipe across the top crushed or deformed by the right hood hinges. Not sure how that affects the flow from what it was designed to be.
Craig - You can't add the heater pipes as that would totally change the flow of air in the DTM.
That's a V1 Type 4 DTM. My Type 1 DTM clears just fine.
I see your hinges are flipped other way too which adds clearance. I had to install mine (CMC) like that too just to clear a stock '72 shroud.
Flipped over?
The DTM shroud at $625M is definitely not cheap. It looks well engineered.
Jake put down some data in Thesamba from a 67 mile drive in Nevada
crhemi (Bill) poboiinhawaii posted:Flipped over?
Right one moved to left side so they are further apart by maybe 3". Look at orange engine lid hinges vs Stan's.
Bill;
So the long leg of the L, sits on the furthest outside edge. Left is now right and right is now left. Look at the hinges in both pics, you'll go "Ah"
Got it.
Art, CMC, 1641cc posted:Bill;
So the long leg of the L, sits on the furthest outside edge. Left is now right and right is now left. Look at the hinges in both pics, you'll go "Ah"
The angel iron (aluminum piece) the hinge attaches to has been rotated.
We've used many, many DTM shrouds on Jake's motors over the years (TI and TIV) more than I can count, and never had a single DTM/heat issue.
Scott57 posted:Here's mine in my CMC.
That's an absolutely beautiful engine compartment 
And dust free! I almost had an orgasm when I saw those photos. Can you post or PM me other pictures of your car, it looks awesome. 
Wow what a nice looking engine compartment.
Wow Scott!
Very cool, would love to meet up with you and see your car. I'm in the Fairfax area and often go to Kattie's on early Saturday mornings, Dulless/Sterling and Fairfax Circle C&C's on Sunday. My buddy Syl from the Falls Church area also goes to these C&C's.
Pete
Gorgeous -- museum quality. Ever drive it??
First I've seen of a cable operated dual carb throttle, vs hex bar style linkage. I like it. How well does that work? easy to balance??
El Frazoo posted:First I've seen of a cable operated dual carb throttle, vs hex bar style linkage. I like it. How well does that work? easy to balance??
Um...
It's a sync-link linkage. Terry Nuckels and I keep talking about it. On and on and on we talk about it.
If you've somehow missed two or three years of evangelizing about it: you might take a look at the picture I put up 8 posts before Scott's.
I too am a fan of the Sync-Link, as well as the DTM!!
Dan - Your DTM looks different than the other T1 or even T4. I don't see the add on hose - is it a newer version? I'd love to see one in a carbon fiber weave.
The latest generation of DTMs don't have that hose going across the top.
Wolfgang...what Jack said 
Just for clarification's sake: there are 3 versions of the DTM:
V1 Type 4: uses a Type 4 oil cooler mounted in the shroud, and therefore has the heater hose.
V2 Type 4: has no cooler in the shroud. Assumes a remote cooler will be used.
Type 1: uses a Type 4 oil cooler in the shroud, and therefore has a heater hose.
All 3 remain available to purchase.
I have discovered a new ailment...........Engine Envy.
Robert M posted:I have discovered a new ailment...........Engine Envy.
Thats new? I came down with that the first time I saw a picture of a 671 blower on a big-block back in the '70s. A lot of the more imprudent decisions I've made since then have had their genesis in engine envy.
It's the fountainhead of the madness for me.
El Frazoo posted:Gorgeous -- museum quality. Ever drive it??
First I've seen of a cable operated dual carb throttle, vs hex bar style linkage. I like it. How well does that work? easy to balance??
Yep, it's a sync-link. It very sensitive and very accurate. After installing it uncovered that my throttle pedal spring needs replacing (I think). The old throttle set-up actually keep enough pull-force on my pedal to keep it up. I have a worn spring and the weight of the pedal now pulls the throttle a bit—keeping the rpm's at 2k unless I reach down and hold the pedal.
WOLFGANG posted:Dan - Your DTM looks different than the other T1 or even T4. I don't see the add on hose - is it a newer version? I'd love to see one in a carbon fiber weave.
It's the T1 version all fiberglass. There are different versions as Stan said above. Got mine a while back from the Type 4 Store.
mtflyr posted:Wow Scott!
Very cool, would love to meet up with you and see your car. I'm in the Fairfax area and often go to Kattie's on early Saturday mornings, Dulless/Sterling and Fairfax Circle C&C's on Sunday. My buddy Syl from the Falls Church area also goes to these C&C's.
Pete
Scott57 posted:Here's mine in my CMC.
Here is the before shot.
Stan.....I would be really interested in any data you have collected on your cylinder head temperatures as you drive out on the road. You said you can monitor all four and I would be very appreciative of that info. Using the DTM shroud of course. I'm with you, anything I can do to reduce heat (and heat is the enemy in this case) is a gain.......Bruce
Bruce--I know you will hear from Stan but here's my own experience. I have a medium-large Raby Type IV with the latest version of the DTM shroud plus a Seatrab oil cooler. No matter what the ambient temps are, and I mean from 40 to 105 degrees, and at any altitude, I never see any higher oil temp than 185 degrees and very low CHTs. ( I have wondered if my oil and CHT gauges are working!) I was always worried about high engine temps as I have been aware that heat is the enemy of an air cooled engine but heat is a non-issue now. I am really pleased with this engine and long ago I forgot about the cost. I know the DTM has a lot to do with my temps but feel that the Seatrab also plays a part----maybe a large part ---but whatever, this is a wonderful combo. I commonly run 75-80 and occasionally faster on long trips.
I envy the head temperature control of a Type 4, Jack. Such a better design.
Scott57 posted:mtflyr posted:Wow Scott!
Very cool, would love to meet up with you and see your car. I'm in the Fairfax area and often go to Kattie's on early Saturday mornings, Dulless/Sterling and Fairfax Circle C&C's on Sunday. My buddy Syl from the Falls Church area also goes to these C&C's.
Pete
Scott57 posted:Here's mine in my CMC.
Here is the before shot.
Scott;
What carbs are you running with the sync-link? I assume you love the sync-link like all the rest of the guys here? I can afford the sync -link, but not the carbs that match it. I've got kadrons 40/44 EIS
Art
I'm getting engine envy
Robert M posted:I have discovered a new ailment...........Engine Envy.
crhemi (Bill) poboiinhawaii posted:I'm getting engine envy
Guys, there is a cure for what ails you. I wonder if your medical plan would re-reimburse you? 
Stan......Did you not want to post what you found for cylinder head temps because Raby didn't either? I don't know if you had some proprietary agreement with him or not. That's Ok if there is some reason. Still, I am real curious about what you got for cyl. head temps. using the DTM shroud. It's a given that you have an entirely different engine configuration than I do but I'd like to compare them with what I get using an after market 36 hp shroud with no heater ports. Hands down...the external oil cooler does the job on the oil. Especially with the mocal oil filter bypass "sandwich" you recommended for warm-up............Bruce
aircooled posted:Stan......Did you not want to post what you found for cylinder head temps because Raby didn't either? I don't know if you had some proprietary agreement with him or not. That's Ok if there is some reason. Still, I am real curious about what you got for cyl. head temps. using the DTM shroud. It's a given that you have an entirely different engine configuration than I do but I'd like to compare them with what I get using an after market 36 hp shroud with no heater ports. Hands down...the external oil cooler does the job on the oil. Especially with the mocal oil filter bypass "sandwich" you recommended for warm-up............Bruce
Not at all, Bruce. I didn't reply because I don't roll quite like that. I use the tools I've got to do the best I can, but I'm a poor record-keeper.
I've had the 4-input head temp gauges with 4 different configurations:
1) a 2332 with welded 043 heads and 9.5:1 compression
2) a 2276 with the same heads and a weird cam (105* lobe centers)
3) a 9:1 2110 with a 120-ish cam
4) My present configuration (FK8, 10.6:1, twin plug)
Obviously, my present configuration runs the highest head temps. The thing with the DTM is the relatively consistent temps I see across all cylinders. Number 3 is always about 10* warmer, but the consistency is pretty amazing when you think how difficult it would be to get air to the 3-4 side of the engine.
I don't think I've ever seen head temps above 290-ish, which is pretty good with a 10.5+:1 engine in a speedster.
I'd love to compile "like to like" data comparing a 36 hp shroud with a DTM, but I just lack the will and time, so what I've got is "seat of the pants". The DTM works really well. I've got an Awesome Powdercoat 36 hp shroud with a Type 4 cooler and the flaps-- it does a good job, but I just want to get every last bit I can out of the cooling.
I'm sorry I didn't get this up sooner.
