I have a DTM fan shroud (from Jake) and I'm building a 2.6L nickies engine.

If I was to use my DTM in my 914, it would free up a huge space in front of the engine. Just imagine taking the away the stock fan shroud and cooler and how much room you now get.
I could mount an aux. cooler, mocal, put in a fan with a thermo switch and even put a plenem up to a GT lid.

Good idea? Bad? Would it cool almost as good as a front cooler, or just be a wasted effort?

I've always hated the idea of running lines and hacking in a front cooler on my cherry '74. I did get the DTM for my bug, but it will be a few years till I get to it.

Mark, I have contemplated the same for my 914, and will probably end up doing it with a modified DTM that I'm working with just for 914s..

The main thing is that the air must be kept away from the cooling fan, so an aluminum cavity with a charge air tube, from under the car, and a dirty air discrge external the engine bay would be trick..

Question:

Why has the DTM shroud been found to work better than 911 style shrouds? Porsche obviously went to the 911 style for a reason, is it just because they had 6 cylinders, and couldn't go "down the middle" any more?

Hi Thomas,

There is a "massive" amount of information on this on Jake's web sites. Also go to: www.shoptalkforums.com and perform a search. You will save Jake explaining all over again...

John www.ghiaspecialties.com

Jake can answer this better than me, but the 911 set-up pushes too much air on a /4, also it doesn't have directional vanes so the air doesn't go "down the middle" (hence DTM) of the cylinders. As well the DTM uses the widely available and way cheaper Type 1 fan and alternator.

A DTM is not a cheap kit, but price a 911 kit and a 911 fan

My DTM also looks like a piece of artwork.

Jake, what are you doing to modify the DTM? Will my DTM fit a 914? I know I lose the raintray.

Not this one again...

DAMN IT LISTEN! MORE AIR IS NOT THE ANSWER!! CORRECTLY POSITIONED AIR IS!

A 911 is a 911!!

The 911 engine is 40% LARGER in surface area than a Type IV.. The high volume low pressure air of the 911 system does well on a 911 engine, but not as well on the smaller more restrictive Type IV..

On a Type IV the engine is so short that it will not allow the pair of left directional vanes from the OEM 911 system to be used.. The airflow wants to follow the tangent of clockwise movement that the cooling fan creates as it turns, with nothing to divert this air to the left bank the right bank freezes and the left bank hurts badly.

I won't go into details here, as I am blue in the face with trying to overcome the "complex" that the 911 fan, with all its monsterous volume will perform magic on the cooling spectrum of your engine- BULLSHIT!

Here are the facts..

One of my F production customers, Mark peebles ran a 911 shroud for 5 years. He exploded 8 engines in that amount of time from HEAD FAILURES... He finally got tired of it and came to me..

I built his engine, and he ran it with the 911 shroud for a full season, and had no failures. He constantly called me and told me the heads were running 425 degrees all the time.. we had to detune the engine to keep it from melting.

Being in close contact with him, helped tremendously as I was able to back up my testing of 911 systems with his car, and compare notes from the dyno directly with the results of his car. On the dyno I made drive ratio changes, and etc and then told him to do the same... I prediucted the results based on what we saw on the dyno and the trends followed.

When the test work for the DTM began, it blew my mind. I had used these for 7 years but never directly compared one to the 911 shroud, yet alone 7 different 911 suystems.

When i saw what the differences were on the dyno, and saw all 4 cylinders run within 20 degrees of each other, instead of the 60-125 degrees apart readings with the 911 systems I decided to send my test shroud to Mark and have him install it in the race car...

He did, and made no other changes.... His head temps will now NEVER go over 350 degrees and they average 325 most of the time. This is down from an average of 400 degrees with the 911 style system, with the best drive ratio that i found (1.41:1)...

Since mark turns high RPM, and the TI fan is so efficient we have slowed the DTM fan speed on his car DOWN to 1.24;1 and it gives these readings. The stock DTM drive ratio is 1.58:1.

Another customer of mine, Crimson axe from the STF has a 201 BHP 2563 SuperHero that I built for him.. He drove from Baton Rouge LA to Orlando Florida about 6 weeks ago in 95 degree, hot humid southern air... His average speed was 85MPH, and his heads got over 300 degrees once in the entire trip, and he was cruising in 5th gear at that! This is FIFTY DEGRES COOLER than a stock 2.0 in a 914 as an average.... He is making double the stock power and running cooler.

He has dual CHT gauges, and each was within 15 degrees of each other the whole time.

The DTM took 12 years for Joe Locicero to create. he spent that long researching the airflow of the TI fan, and the hottest ponts of a Type IV engine and directed that airflow to those positions of the cylinders and heads. TheDTM incorporates vanes with airfoil characteristics, as well as deflectors to equal out the airflow on all 4 cylinders evenly for corerect expansion rates across the entire engine.

The 91 system is "Empty inside" and while that may work for a 911, it does not work for the engine that i have dedicated my ebtire life to figuring out detail, by detail everyday.....

The 911 system is good for one thing on a Type IV, and thats dragging 20HP off the engine, trying to force all that air through the cooling fins of an engine that it was not designed for....

Believe what you want, but after you spend 500 bucks in fuel, and almost wear out a 6,000 buck engine on the dyno, the differences are as as clear as night and day...

BTW, the temperature in my dyno cell averaged 160 degrees while the test were being conducted for 18 days.All weather was plotted as well as the inlet air temps of the fans being tested and even the air entering into the carburetors. I took head temps on all 4 cylinder simultaneously every 2.5 minutes and the test ran 40 minutes of duration with no changes being made to the test engines tune.

It was as perfect as I could make it! Cannot argue with facts.

I told ya Jake would have a better answer!!!

Now my question….

Jake, what are you doing to modify the DTM? Will my DTM fit a 914? I know I lose the raintray.

The whole top of the shroud changes, and the oil cooler cavity goes away....

When this happens ALL the shrouds internals change, as the air pressure differs enough to effect efficiency.

I need to make a new mold for doing this, if it fits nicely in mine..

Mark uses the DTM as is, with no mods, but his car is all chopped up..

Damn!

oh well....

Jake let me be the first in line when you complete the 914 dtm I will put it on my 2270.

Thanks
bernie

Cool. I have a wait list with many names on it already... to join it email info@aircooedtechnology.com and Kathy will add you.

When is the ETA?

Jake....you need to switch to decaf

too me it's a easy answer and if one does not "get it", they never will

the 911 fan was designed for a /6, it's been put on a Type IV and there are better options......, plain and simple, no need to try and justify the why and why nots.......no need to "defend" your reasoning, the idiots that come back and argue "well Porsche did this or that or it works on a 911, why won't it work on my 914" will always be clueless...it's like talking to wall

I am on the list


Bernie

I have now personally seen for myself what a DTM and set of Nickies can do for an engine on the dyno. While I was down visiting Jake's last week, I got my hand at tuning with the EMS a 2563. Aside from the gobs of torque, I noticed, much to my disbelief, what idle temps the engine was running. I was stunned to see the engine idling at 175-190 F, even with the dyno cell at over 100F! Head temperatures were amazing, and only when I had messed up the AFR, did the heads heat up to 300. On average, I'd have to say with a full load the engine got to maybe 290, but that's it. The DTM just makes the world of difference and helps to squeeze out every last drop of cooling capacity that the Nickies add. What more can you say about this proven cooling combo? I recommend the DTM to every one of my customers doing an upright conversion and try to instill the virtue of the DTM in each and every one!

And back to oil temperatures, I was very impressed how the DTM handled the oil temperatures on the 2563, even after the long sessions of pulling continuous high rpms for tuning the FI. Unless you're planning some crazy stuff, the oil cooling provided by the DTM is more than sufficient.

Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance

The engine that Charles was playing with made 199 lb/ft of torque...

It has 8mm more bore than stock, and still ran that cool on all 4 cylinders...

I just tested another Nickies engine today, it is a stock stroke with 102s.. it made 183 lb/ft of torque and a near flat curve as well... The customer was standing over my shoulder the whole time and saw the temps- he was amazed... the dyno cell was 140 today on top of that! Read here for some more on this one.. http://www.shoptalkforums.com/viewtopic.php?t=75566

nickie?

Nevermind....need to read better.

Thanks

Jake on my standard DTM is it just because of the cooler box?
(should be easy enough to relocate it )

Or is there more to it than that?

The wntire 10 oc clock, to 12 o clock top portion of the shroud goes away..

When you lose the resistance of the oil cooler and cavity all the pressures inside the shroud increase. That extra air has to go somewhere, and thats normally over the top of 1-2 cylinders...

This freezes 1-2 and creates a greater difference between the banks of cylinders- and the entire DTM concept is wasted.

Inside that shroud, there are very infinite settings and balances, when one thing is taken away, the entire engine notices it, and things happen...

Fitting a DTM with my new, big heads with different fins will require a re-do of the internals of the DTM as well, BUT the differences in power will be worth the hassles to create the jigs to make it work.

With an engine internally "Its all in the combo" inside the cooling system the same goes.

Only a 10 year old bump!

Mark, did you end up using your DTM kit or wait for the 914 unit or ?

Trying to get pricing for the different levels of kits , his Type IV store is not playing nice right now with my browser....

Personally unless it's a race car the stock T4 fan shroud in a 914 works just fine.

I ended up selling the DTM(s)
The big T4 nickies engine I ended up installing in my '67 bug.
For it I built a custom all steel hybrid shroud. A cross between a DTM, Joe Cali and stock fan shroud.

For the 914 it's a 3.0 /6, sort of close to RS spec, that I'm just finishing up and hoping to have on the road for the spring.

Jake is out of the parts business, he sold everything to Charles at LN Engineering.
http://type4store.com/conversion-cooling-systems.html

Mike,
Glad to see you are back into 914s again Reading this thread is bringing me back to when when I built my 2270 about eight years ago. Funny part about this thread is that I actually ended up with the first 914 DTM that Jake built as I built the engine with an external oil cooler only. Unfortunately the engine was never started and I ended up putting the car in storage after re-assembling the whole thing. Been gone from the states almost seven years. I should be back in Nor Cal by July and hopefully have the cars shipped back by Sept of this year. Looking forward to seeing some old faces at some 914 gatherings in the future.
Cheers,
Dominic

Hey Dominic....good to hear from you, I still the brand new aftermarket oil cooler I bought off of you years and years ago! Sitting in a cabinet unused....

Foley makes a cool horizontal fan

The only things are it's a bit spendy and the belt looks complex.
IMO this and the DTM, unless you are full race I don't really see the need.
Plus for a street car I'd want to keep the thermostat, it takes a bit of time to get my bug up to temp.