For those running a BERGMAN 911 Fan...what are your impressions?

[rick m]

I have toyed with installing a BERGMAN type fan shroud on my Bay Window bus project.  The motor will be a 90.5 x 84 and have 48 dells.  I am running a hydralic cam (mild) in it with 40x35.5 valves.  Are any of you running a 911 type fan with a 2 liter or larger motor in your buses?

Would be interested in some feedback.  Keep in mind that in Arizona we get 110 degree days in the summer.

Rick M

[kingsburgphil]

I too had a clean sheet as to cooling options. But I failed to find anything I would trust on my motor.
Ultimately I converted to E85 and a basic baja bug style cooling system.  Cooling is no longer an issue
.
Ambient air temp was 109f in Fresno last week, not quite as toasty as Phoenix.

[pupjoint]

i come from a place where it is 80-110 all year round and humid.

i know of 4 friends using his setup. all of them run it because they want the 911 fan look, best price they could get when compare to csp kit, which also uses a replica fan.

3 of them have modified engines, 1 turbo, 2 stroker motors and 1 on a stock 1600. all blocked off the stock cooler ports, remove the oil relief piston near the pulley, full flow pump, to filter and returns to the case through the oil relief.

so far no complaints, fits ok and they drive everywhere. thats just from my observation and i have never done any sort of testing like what jake did.

[Torben Alstrup]

Hello.
Porsche fan system on a type 1 engine with type 1 heads is a bad solution. Period.

Reason is that the type one simply do not have the cooling surface and "free" area to handle the amount of air that a Porsche fan delivers. Because of that you get a tendency to stall the fan in its own air, resulting in way too high hp draw, typically around 20 hp @ 6000 rpm. Because of the partially stall the air get less eficcient in what it is supposed to do and therefore cools less. Next there is the problem of the system cooling cyl. 1&3 better than 2&4 and also 1&2 more than 3&4. So for perfect or best possible cooling its a no go.

I´m sure you know this deep down. But THE best aftermarket cooling system you can get for a type 1 is still the DTM. If that is not an option, go find a fan shroud from a 75&later 1600 bus engine. (The one with a velocity ring) That´s the best you can do for your engine cooling wise, after the DTM.

T

[pupjoint]

Hello.
Porsche fan system on a type 1 engine with type 1 heads is a bad solution. Period.

Reason is that the type one simply do not have the cooling surface and "free" area to handle the amount of air that a Porsche fan delivers. Because of that you get a tendency to stall the fan in its own air, resulting in way too high hp draw, typically around 20 hp @ 6000 rpm. Because of the partially stall the air get less eficcient in what it is supposed to do and therefore cools less. Next there is the problem of the system cooling cyl. 1&3 better than 2&4 and also 1&2 more than 3&4. So for perfect or best possible cooling its a no go.

I´m sure you know this deep down. But THE best aftermarket cooling system you can get for a type 1 is still the DTM. If that is not an option, go find a fan shroud from a 75&later 1600 bus engine. (The one with a velocity ring) That´s the best you can do for your engine cooling wise, after the DTM.

T

torben, when you say the doghouse with velocity ring, it would be the FI shroud. that has the smaller duct inside the shroud.

would it better if i use a normal german carb doghouse weld in a velocity ring? the normal doghouse has a bigger air scoop inside.

i have tried both actually and both seems to work ok and i can't find any differences on my CHT, oil temp etc. both had the heater ducts sealed off.

i am now on a Scat 36hp doghouse with a ring welded on, dint like the aftermarket tin idea had no choice but to go this way since i needed the clearance for the injectors and i dint want to modify the body.

would appreciate your feedback on this.

sorry rickm to hijack your thread.

[Zach Gomulka]

I use the early doghouse shroud with the large oil cooler scoop and a velocity ring added. I also made the type 4 cooler conversion and use a Porsche 356/912 top pulley to push more air through the larger oil cooler area and keep the heads cooler. On my drive to California a couple weeks ago I couldn't get the oil temp past 180 even when pushing it 85mph up a long hill.

I still wouldn't drive it when it's over 100° outside though. I'll take my air conditioning, thanks

[Fasterbrit]

Hi Torben. I am very interested in any data you may have regarding the findings on a Porsche type fan arrangement on a Type One engine. There's always a big debate over this setup, but I have never seen any hard facts to back it up. I know Raby has spent much development on the Dtm system, but would love to see some data. Any you might have would be greatly appreciated
Cheers, Matt

[rick m]

All interesting posts.  I made my own dog house cooler on my past 67 bug. I took a 36 hp shroud and cut the back off. I then welded the guts (vanes) into the 36hp tin. My 2110 would not run over 205 degrees, even when 107 outside.  In 1997, when Don Bulitta and I drove our bugs on the BERG Memorial Cruise, it was 107 t- 110 going from Vegas through Mesquite, Nevada, on our way to Salt Lake City, Utah.  I know the stock tin will work...but I also had auxilliary cooling (cooler and fan), along with stock VW ported heads (Don by the late Dean Lowry).

I know that Don Pauter is running a 911 fan on his 3 liter Ghia, but he modified it internally to direct the air so all cylinders maximize the affects of the increased fan volume and air.  So I know the 911 fan can work if done right.  Competition Engineering has done a lot with the shroud too, building their own that directs the air better than some on the market.  I understand how the fan might cavitate, as I work with pump motors that do the same thing when trying to push too much water through a smaller pipe.  The combination is key.  We know that air volume will work if directed properly.

FAT has run these shrouds for years on their off road motors.  I don't thing Ron Fleming or Greg Aronson would do it if they thought it compromised their motor builds.  Ron has one on the new street car he now has.

My point is that the can work if installed right. I would be interested in hearing more opinions on this, as air volume will help cool the motor if directed properly. Also, how well the air can pass through and around the heads makes a big difference.  That is where most of the heat is being developed.

Rick M

[Henrik Hagen]

I use the early doghouse shroud with the large oil cooler scoop and a velocity ring added. I also made the type 4 cooler conversion and use a Porsche 356/912 top pulley to push more air through the larger oil cooler area and keep the heads cooler. On my drive to California a couple weeks ago I couldn't get the oil temp past 180 even when pushing it 85mph up a long hill.

I still wouldn't drive it when it's over 100° outside though. I'll take my air conditioning, thanks

How big is the diameter of the 356/912 top pulley...  90 -95 mm

Is not there a risk of the fan running to fast and stalling when you drive with the porsche top pulley?

Is there not a upper limit to how much air you can push through the type 1 heads..

[Zach Gomulka]

I use the early doghouse shroud with the large oil cooler scoop and a velocity ring added. I also made the type 4 cooler conversion and use a Porsche 356/912 top pulley to push more air through the larger oil cooler area and keep the heads cooler. On my drive to California a couple weeks ago I couldn't get the oil temp past 180 even when pushing it 85mph up a long hill.

I still wouldn't drive it when it's over 100° outside though. I'll take my air conditioning, thanks

How big is the diameter of the 356/912 top pulley...  90 -95 mm

Is not there a risk of the fan running to fast and stalling when you drive with the porsche top pulley?

Is there not a upper limit to how much air you can push through the type 1 heads..

I'm not sure of the exact diameter. I believe the stock pulley ratio is 1.8:1. Remember, most aftermarket crank pulleys are slightly smaller than stock. The newer Berg pulleys are slightly larger.
I'm not sure what rpm the stock fan stalls at, but I'm sure it's under 3700 (normal cruising rpm) engine rpm's, even when over driving the fan with the small gen pulley.

[Bernard Newbury]

Hi Torben. I am very interested in any data you may have regarding the findings on a Porsche type fan arrangement on a Type One engine. There's always a big debate over this setup, but I have never seen any hard facts to back it up. I know Raby has spent much development on the Dtm system, but would love to see some data. Any you might have would be greatly appreciated
Cheers, Matt

Hi Matt I do not have any data but I used to have a Porsche style fan on the Ghia years ago and it would never cool properly. It was ok on local journeys like a couple of miles but as soon as it was more than a couple of miles, forget it. I tried a lot of things but in the end converted back to a stock T1 set up. One day it threw the fan belt and it felt like some nitrous had kicked in. Could'nt beleive it so I agree with Torben but only from experience.

[Torben Alstrup]

This hijack thing seems to happen every once in a while. But as long as good info is presented I´m sure Rick does´nt mind.

Pupjoint, you are correct, and then not. Reason is, that "we" on the eastern side of the pond, got the "carb version" of the fanshroud longer than you did. So, on the west bank you are correct that you would want the last versions of the carb shrouds and add a velocity ring to it. Clark Callis @ Awesome powdercoat sells them loose. Wheteher there is a difference and how much between the F.I. shrouds and the carb shrouds I´m not sure. I have not had a chance to compare them on a basis where I could gain decent experience from it.

Zack. You sort of hit the nail on the head, because you did exactly what is needed to take advantage of the type 4 cooler modification. - More air. On a stock fan ratio the type 4 cooler doesnt begin to pay off until the engine spins faster than approx. 3300 rpm. Increasing the fan ratio to approx 1,80 makes the cooler efficient at normal speeds too. - How much of a difference there really is in cooling done this way, I really dont know. In conventional set ups we are talking about 5 - 6 degrees C. @ 4000 rpm. But then the engine spins that much faster and naturally also creates more friction.

Matt. I´m sorry, I have not much info about this subject on paper. It is all info and experience that I have gained over the years, trying varius options on both my own and customers engines. And one of the "steady variables" over the years have been Porsche fan on type 1 engines equals problems. WRT the DTM, I think the results of Raby´s Huge cooling test might still be accessable on his website in one of the sub menu´s.
What I can say about the DTM is, that I have never EVER had problems keeping an engine warm between jet changes on the dyno, if i was a little slow or got hijacked by the phone, except the few times I have had the pleasure of tuning engines with these on. - Well, its not really a problem, but unusual to have to run the engine a couple of minutes at 25 -30 hp load to get oil temperature up to the sweet spot again.

Rick. I remember your set up because you did a write up somewhere about it. And it IS a very good way to do it. As for the 911 fan set ups you refer to, there is one major difference to a type 1 engine that i did´nt adress much in the initial post. That is "free area" When FAT does the 911 set up its about allways on a type 4 engine (I have never seen them do a type 1. But I dont live next door to them either)  The moment you talk type 4, you increase the cooling surface with approx. 30%. Then we are suddenly having a totally different picture. the same thing happens when Mr Pauter makes his 3 liter monster. Have you seen the space between the cooling fins on his heads ? A kid could almost squeeze himself through there. I do not know the specifics of the free area, but I´m quite sure if we took a measurement it would be close to a type 4.
Back to the type 4. Yes we can make the 911 system work on those. The conventional "BAS" style fan shrouds have all the known downsides. BUT, MSS and Rolf Klaus in conjunction with Remmele (I think) has done extensive testing and development wioth the 911 fan. - By using the newer 993 fan with straight inner air vanes and a rather weired looking fan shroud, they have managed to even out the amount of air to each cylinder/head and on top of that metered it so the fan draws less hp to cool the engine. I have only used one set of these sofar. But I can tell the difference easy by looking at the cylinder head temp gauge. The diference between left and right is less than 10 degrees C., versus the regular "BAS" style where it could easily be 35 degrees C.
The older 911 fan with angled inside vanes  can be improoved, absolutely. When we modify and install the inside vanes from some of the older 911´s (I´m not sure which model they actually come from, but they are on Ebay.de every once in a while) we can almost equal the air going to each side of the engine. But there is still a slight problem in nr 2 & 4 being a little too warm contra 1 & 3. It is MUCH better than running without it, but not as good as the newer solution.

Tiger. Yes there is a limit to what can be pushed though the cooling fins. That is actually the basics of why the 911 solution is a bad idea on type 1´s. Yes, if the 356 pulley is used on an engine that sees some rpm every once in a while, I would deinitely recommed to have a stock (NO Aftermarket) fan welded and balanced.

I hope I answered all loose ends.

T

[Zach Gomulka]

Clark Callis @ Awesome powdercoat sells them loose. Wheteher there is a difference and how much between the F.I. shrouds and the carb shrouds I´m not sure. I have not had a chance to compare them on a basis where I could gain decent experience from it.

I believe Jake Raby tested it and it was good for a 10°f reduction in CH temps. I definitely noticed a drop in my oil temp after switching to one.

[rick m]

Torben....I enjoy all the posts.  I like hearing differing views.  I have my own too...learned the hard way.  I still prefer the stock fan shroud (36 style) at it was actually pretty efficient.  The only challenge is it was designed for 36 HP,...not 150-200. I toyed around with the idea of milling off the flat sides of the barrels (between the cylinders as well as increasing the side of the bottom deflector tin...plus opening up the flow around the outer side of the top cylinder tin for more flow around the cylinders.  The challenge, I believe, is in moving air over the heads. They are the head sink and where the temps matter most...in my opinion.

I just tore my 2275 apart to do some mods.  I will be re-assembling the same exact motor combo (cam, etc.) to see how my mods worked.  I threw away the cool tin, which I have used successfully on smaller bore motors (90.5) and went back to the stock deflector between the cylinders.  With temps well over 100 here in Arizona, I will know right away if my mods worked well.

I appreciate all the feedback on the 911 style fans.  I do believe you can experience cavitation of the fan if there is not sufficient area for the air to move through the cylinders and heads.  So, there has to be more work to determine surface area of the motor, actual flow areas (volume that can get through) and the output of the fan in CFM.  It all matters.

I will post the results of my motor mods when the motor is back in.  Just freshened up the valve job yesterday and cleaned the case for re-assembly.  Need to do some ring gap work and then get ready to put the motor back together.

Rick M

[Fasterbrit]

Torben... Thanks for the heads up on Raby's data. I had a good look at his testing spreadsheets and his even airflow across the cylinders is impressive, and the individual cylinder temps are sustained at a very stable, cool number.

However... The oil temp figures are astronomical even on the final design. 280F peak with an average of 246F is way too high for a mineral oil and perhaps borderline for even fully synthetics as the oil will have lost viscosity and therefore is hydrodynamic lubrication qualities. With such a thin film of oil between moving components, wear rates would be sky high. I wouldn't want to bet on the the cam and lifter's ability to live under these oil temp conditions for very long...

Having said that, running an external oil cooler should combat the problem of oil temps. Combining the Dtm with sufficient oil cooling would therefore tick both boxes and make for a cool running engine. Regards, Matt

[Fasterbrit]

Sorry Rick, I appear to have gone off tangent and hijacked your thread somewhat. Back to the topic as I also have a Porsche fanshroud that I want to modify and install on an engine. I am sure that with the same approach as Raby took, it would be very beneficial to modify the Porsche fanshroud with internal vanes/foils. It is something I want to address, so will post any relevant info on here. Regards, Matt

[bugnut68]

Another factor to bear in mind when it comes to Bernie Bergmann is customer service... he has a pretty abysmal track record for making the pitch to sell the goods and then dropping you like a hot potato once your money is in his hands.  Plus a pretty questionable history of quality control.  All important factors to consider, IMO.

[rick m]

I have heard that about Bergmann too.  I fireman friend years back bought a complete motor from him and it took months to get it.  I know he was fit to be tied.  Communication and follow-up was pathetic.  I probably will not go that route anyway but always fun to discuss.

Rick M

[glenn]

My understanding is that Bernie sold the business a few years ago.

[Zach Gomulka]

My understanding is that Bernie sold the business a few years ago.

That's what I thought.

[rick m]

Hopefully, if the sale of Bergman's is true, the new owners will have a better understanding of what it means to deliver product on time and take care of their customers.

RM

[matberry]

Wouldn't running the Porshe fan at a slower rpm fix the air-flow/cavitation issues? I haven't measured for comparison, but as an idea, maybe running a power pulley would  be closer to stock Porsche fan speeds. Or a custom pulley could be made.

[glenn]

Hopefully, if the sale of Bergman's is true, the new owners will have a better understanding of what it means to deliver product on time and take care of their customers.

RM

Maybe, but i rather stick with vendors that I already know support their products.

As far as i'm concerned, the Bernie Bergmann bridge has been burned.

[bugnut68]

My understanding is that Bernie sold the business a few years ago.

He went back to Shawnee, Oklahoma, and at present, it appears he's moving it back to California.

http://www.bergmannvw.net/

[axam48ida]

I got one off a customers car for sale if anyone is interested?