Non VW Cooling fan systems

don't know about which fan to use, but here's a link to some great photos from someone who built their own.

http://www.shoptalkforums.com/viewtopic.php?t=120663

Bruce!

Yes! You may not have to recreate the wheel here. Check this out - I love this and if there is any way that I can assist you I am in!

https://www.speedsterowners.com...y=376503989449286379

http://www.riechertmotorentech...ialgeblaese_typ1.htm

I wrote this guy in German and did not get a reply. I used a translator so who knows what was actually said. I want one of these in the worst way!

911 fan and alt.

I just sent another email. I mentioned our car club here and that we might be able to buy several at one time. There is a number but I have never called outside of the US before... and my mom never bothered to teach me the language!

https://www.google.com/url?sa=...vm=bv.87269000,d.cGU

Rusty, It's never to late!

I can't find this type of horizontal cooling system anywhere in the U.S. I went on this search before and had zero luck.

Here it is on youtube:

https://www.youtube.com/watch?v=8JVm5c3aIMI

I recall years ago Jake Raby did a study on aftermarket shrouds and alternate cooling systems.  I researched some because I liked the look of the 911 fan and shroud - the 911 fan/alternator was quite costly.  BLUF the stock OEM doghouse fan or his DTM for T1 cooled more efficiently with no hot cylinders.  I still like the 911 look but leery of creating new problems. Both VW and Raby have put alot of research into what cools best --- results are based on scientific tests not what looks cool.  I'd spent $ on a fire suppression system first.

SAMBA link below has good info on what performs best - mentioned BB system has 400 cfm less flow than a stock system - that's going to make a HOT engine even hotter - with resulting shortened life.

http://www.thesamba.com/vw/for...ewtopic.php?t=266611

Porsche changed from doghouse to the 911 fan for a reason. The folks that I know that run the 911 setup have zero cooling problems.

IMO if you are going to stray from period correct then this is the way to go!

https://www.speedsterowners.com...y=376503989449286379

It's beyond beautiful.

I can't stand it it looks so good.

...and sounds good!

https://www.youtube.com/watch?v=8JVm5c3aIMI

Rusty,

I think the 911 shroud looks really cool as well. I'm not as wild about the Riechert "Corvair" setup, but beauty is in the eye of the beholder, I suppose.

Regardless, to your original statement: Porsche designed a new cooling system along with everything else when they went from 4 cylinders to 6. The similarities between a push-rod flat 4 and an OHC flat 6 are that they are both air-cooled, horizontally opposed engines. Everything else is different. They designed a shroud to meet the requirements of the new engine, and it was a masterpiece. It also happened to look pretty freaking cool as well.

The 911 set-ups for push-rod flat 4s are pretty much back-yard adaptations. They have nothing at all inside to direct air, etc. They look cool for sure, but they have no engineering of any kind. Before Jake Raby was all cloak and dagger about it, he put some really interesting data up on the shoptalkforum back in '04 or '05. In short, the fan was really big and robbed a lot of horsepower to do a pretty spotty job of uniformly cooling all 4 cylinders. Flat 4s are much shorter than the 6s, and it made a lot of difference.

If I recall, he tested a Riechert shroud as well. It was better, but still not as good as OEM VW or a DTM.

I've run a 36 hp Scat shroud with all the flaps, etc., and I've run a couple of Raby DTMs. The DTM works. Not very many people like how it looks, but form follows function sometimes. I'd really like somebody to build a 911-style shroud for a flat 4 that works as good as a DTM or a VW shroud, too.

So far, I'm still waiting.

Right, on the 6-cyl 911, the fan sits several inches aft of the engine so at worst air has to make a 90 degree turn. On a VW 4-cyl, that porsche fan sits over top of the engine so to reach the rear cylinders, the air has to make a 180 degree turn. And it has to attempt that with no internal vanes in the shroud. And it's using a fan sized for 6 cylinders on only 4. There's also a difference in the fin densities between the engines that affect the airflow. End result is front cylinders get too much air, rears get too little.

I'm taking a shortcut for the down-draft cooling fan.

I'm going to buy this Porsche K-5 twin turbo for my VS (with down-draft system included). Now MAYBE I'll be able to keep up with Ted in SLO! 

Keep up with ME?! Heck no. Teby is the one who picked up a new stroker motor. He and the brothers Knuckle are the big dogs. I'm just a lowly ole CMC ridin' on 20's.

That motor looks like it came out of a helicopter. Are you sure it's not out of an Apache?

T

Yup Stan and Justin are right. It looks cool, but you can't really see the 911 fan in a Spyder. I have one, and it works OK. Got it in 2002, just before Jake figured out how bad they are. It's not quite a 180 for airflow to number 4, but close, like 135 degrees. Anyway, mine works OK like I said, but in stop and go traffic in the HOT summer, my head temps rise. Underway, 20mph or more is no problem. I'm making a sort of sled tin currently as my motor is out right now. Of course, they have to be reverse sled tins, to keep the hot air away from the fan intake. I'll let you know how it works. It is really difficult to seal the top half from the bottom in a Spyder so that method is kinda out. But if I can keep the hot air from recirculating, which is clearly what is happening, I might be improving things.

Maybe an electric blower fan duct right to the heads?

I'm going shopping for a Porsche style fan/alternator for this project. Pomona Swap meet and the Irwindale VW drags/swapmeet are coming up. What should i look for?

Question: Really, would a big electric fan work? I sort of doubt it but i guess it's worth asking at this point. I've seen them on drag cars but thought they were only temporary since the cars only run for minutes.

Another question...How would the belt tension be adjusted? Almost any movement of the four pulleys involved would cause belt misalignments.

I would think on that set up, shims to adjust belt just like stock.

Or this

Bruce, 

The guys on Samba have discussed electric fans for years, but the consensus is generally negative.  The VW fan style is much different from the generic electric puller fan that has replaced the mechanical rad fans most of us grew up with in American cars.  Stock doghouse cooler with welded high output fan, along with good engine tins, seems to be the preferred cooling method.  Google electric fan for air cooled VW, and it will take you to the Samba discussion.

The stock fan draws something on the order of 10 hp (dyno proven). This is why drag racers don't run fans. 10 hp is a lot. A 911 fan draws about 2x that. Slowing the fan down with a power pulley reduces the power consumption, but it also means the engine probably doesn't cool enough for a summer day.

So: 10 hp is apparently the minimal requirement, at least with the fan design that VW used. I work the the HVAC industry, and the design of the VW fan-wheel is actually pretty good.

So, lets assume we need 10 HP to drive a pretty good fan. I found a 10 hp single-phase fan motor on the web. It weighs about 130 lbs, and sells for about $1200. It draws 39a at its full-load rating.

Since volts x amps= watts, 39a at 230v is 8,970 watts, so a 9 KW generator like this one might do it:

This one's a steal at $900. It only has a 30a breaker, so it might not be enough. Regardless, it's rated for 9000 watts, and has a 15 hp motor on it-- because no motor or generator is 100% efficient. Every time you convert mechanical motor to electricity and back there is a loss. In this case the two together= about 50%. You'll need to find a place to strap it as well. Perhaps the luggage rack?

Obviously, I'm making light to illustrate a point: the stock fan moves a LOT of air. How much is anybody's guess, but you aren't going to keep up with the load with a couple of 1/10 hp squirrel-cage blowers from Grainger.

Sorry.

PS: Electric heat is pretty much the same deal. Like the electric cool fan, and the poor-man's supercharger (connecting the cooling fan to the top of the carbs), it's an idea that doesn't seem to ever go away.

Lol, you'd need a trailer hitch to drag that thing around.

Ok , I get it on the electric fan vs H.P. required.....Thanks Stan

Now, some of the dialog I've read says that the 911 fan is built for the 6 cyl. eng. and may be blowing too much air for a type-1, 4 cyl. thus causing unequal cooling of the 4 cyls. My guess is that there is a point where the the law of diminishing returns occurs and air flow is too much, creating turbulence, thus reducing cooling efficiency and costing H.P. as well. Am I on track here?   If i am, what about slowing down the fan to a more desirable cfm and saving some H.P. as well ?

Another thing that perplexes me is that the stock doghouse fan housing is off-center with the cylinders on both sides. I'm aware of the reasons for that but what about making a shroud and fan that's wide enough to get it centered ? Since it's bigger, maybe it could be run slower as well.

There are you guys out there who have much more background and knowledge than me on this stuff. I'd really like to hear from you. Also I realize that the only stupid question is the one that's never asked......Bruce

Slowing down the fan on a porsche-style shroud will only make the situation worse on the already air-starved rear cylinders.

If you made a purely wider shroud, you'd need to manufacture some combination of a new wider fan, new alternator stand, extended crank pulley, or a shorter alternator. Plus moving things rearward which could cause interference issues with the bodywork or engine installation difficulties. Beyond that, a wider fan is going to output an unneeded larger volume of air and use more HP to run. Sure you can spin it slower to match the stock fan output, but you aren't gaining anything over stock with the wider, slower fan.

If you want a centered shroud, get one of Jake Raby's DTM (Down the Middle) shrouds.

A DTM keeps the fan in the stock position, cheated over to the 1/2 side.

Unless I'm badly mistaken, this is because the air coming off the fan is being thrown in a CW motion (as viewed from the rear). Air is being thrown directly over the cylinders on the 1/2 side, so cooling them is never a problem.

The difficulty is in the 3/4 side-- as on that side of the shroud, the air coming off the fan is being thrown every direction but down. The directional vanes are all on that side, scooping air and redirecting it down over 3 and 4.

This takes a bigger plenum, and is why all shrouds that work well cheat the fan to the 1/2 side-- to give 3 and 4 a bigger plenum and a better chance at re-directing the air.

Now obviously, the entire shroud is under pressure, so the air is going to find it's way to the low pressure area regardless. But IMHO, fan rotation and "throw" cannot be discounted.

Thanks Stan....What is DTM and IMHO ?  Also wouldn't a horizontal cooling system solve these problems ?....Bruce

Jake Raby shroud DTM = Down The Middle

IMHO = In My Honest Opinion

Thanks Jim.....Now...What about my question about "corvair style" horizontal fan cooling systems. This is recognizing that it would cost more than the DTM...Bruce

The DTM, as the name suggests, directs air down the center of the cylinders on each side. Because the cylinders do not line up between the left and right of the engine, it's impossible for a stock "flat" shroud to do this. Just look at where the offset shroud holes in the stock upper cylinder tins are. The fan is moved to the 1/2 side because airflow on that side already benefits from the rotational direction of the fan so less shroud space over the cylinders is necessary. And as mentioned allows a bit more space on the 3/4 for redirecting the airflow. The third thing the DTM shroud does is use the air coming off the fan straight upwards on the 3/4 side and redirects that through a hose to the oil cooler. It's difficult to make air do a 180 so this repurposes that "wasted" air so it's not stolen from the air cooling the 3/4 side.

^ Yes sir.

To clarify for those unaware: it's fore and aft that the cylinders don't line up. The 1/2 side is about an inch or so further towards the pulley side (1 and 3 share a rod journal, as do 2 and 4-- something has to be further forward).

The DTM centers the air ducting fore and aft, but doesn't center the fan left to right equidistant between the cylinder banks for the reasons I pointed out and Justin elaborated. There is a shroud that does this, and it's pretty much useless.

The DTM really is a nice bit of kit, if not the prettiest thing in the world. As I said, I run one on the speedster. 

The primary disadvantage of the DTM is lack of heater hose outlets.

Ok you guys (Stan and justinh}....What I read here is that there's no info on what a horizontal fan shroud will do....Is that right ?.....Bruce

Sorry....I gotta stay focused....

No idea, Bruce-- but it's got to work better than the "normal" Bergman-style 911 fan.

I looks like there have been three different makers of a horizontal setup. Info may be retrieved from people in forums like this that have tried them and posted the results. Also, how well did this type of setup work on a Corvair?

As the 4 cylinder engine sizes and amount of HP they produce have sizably changed since there beginnings why not sacrifice a little horsepower to come up with something different and more effective? Well, aren't the 2 liter type 1 engines of today equal to that of the early 911s that required a change in cooling? I don't think the original shroud and fan is enough for today's 2 liter type 1 engines.

If you really want the best cooling for a 2+ liter type 4 engine, the best you can do (IMHO) is the original 411/412 cooling system.  It's a pancake system that looks similar to the red "Porsche" style system pictured way up above in one of Rusty's posts, except that the 411/412 version has a big-ass fan on the rear of the engine, unlike a Corvair that had a big fan on top of the engine.  

As far as the "911-style" cooling shrouds for a T-1 engine, I have never been impressed with their cooling abilities compared to stock VW shrouds and such, and cooling's what it's all about, right?

I have 2 914 T4 engines stored in Barn.  These are same engine as the VW 411/412 and '72+ bus but have higher HP/compression.  Both are 1975 - a 1.8L with dual bus single throat Solex 34 carbs and a 2L with 2 dual throat Holley-Webers.  I even found the needed bus flywheel.  I bought the Cali book on using a T1 shroud to convert to upright but never started on it (lots of welding needing).  As Gordon said the T4's flat pancake engine will fit in a Speedster - believe the rear 2x2" steel frame cross member has to be cut and moved back a couple inches for the cooling fan and its aluminum cast ducting (shroud) to fit. With the fan - the engine is a good 5" deeper than a T1.  Since exhaust would be directly below that intake fan - sealing there would be critical (stock oil cooler is there too).  I could see cutting out behind the license place and using ducting there to feed the fan. Here's photo I saved of a fellow SOC member's use of the flat engine - looks easy to service over an upright cooled engine. I like the Raby DTM - but it is costly and is tall where it just contacts the engine lid. Plus if it fits as designed - I'd rather spend the $ elsewhere.

Here's photo cooling fan on a T4-