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Adding modern scoop for split bus engine bay cooling / pres.
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flemcadiddlehopper
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PostPosted: Mon Feb 13, 2012 9:00 pm    Post subject: Reply with quote

slow36hp wrote:
i wonder what effect the positive pressure in the engine compartment would have with the fan. i know the max a fan can produce is based off of zero pressure meaning you need a unrestricted flow. but at positive pressure are there really substancial flow improvements?


important to remember we are talking about inches of water pressure, not PSI. If all I do is maintain zero pressure while increasing air flow, then I would say my mission was accomplished. Also as mentioned previously by someone, all the extra air would just flow out the intake vents. To me again that sounds like an efficient addition to the cooling system, more cool air than the engine needs.

gordo.
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flemcadiddlehopper
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PostPosted: Mon Feb 13, 2012 8:52 pm    Post subject: Re: cooling air Reply with quote

Cptn. Calzone wrote:
No doubt about it a 2 litre engine will be needing more cooling and combustion air especially with dual Dells lets say and a header. The cooling system and air into the engine bay although ingenious is designed to cool a much smaller engine turning slower speeds and generating less heat. So more air in will be beneficial, provided it is not at the expense of tinware or seals.


Well said, Not to worry I understand the value of proper seals in the engine bay. You've hit the nail on the head with the cooling and combustion air.
With a set of big webers pulling for all there worth they can flow up to 1000cfms and a porsche style fan can flow as much as a possible 3000cfms. All this through those little side vent, and having to be sucked in, not forced in. Forced air induction is nothing new for the engine to breathe better, it only makes sense that it would help the cooling system work better too.

Thanks for all the input, even those who think it's a dumb idea help me think it through and plan better.

gordo.
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slow36hp
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PostPosted: Mon Feb 13, 2012 8:36 pm    Post subject: Reply with quote

i wonder what effect the positive pressure in the engine compartment would have with the fan. i know the max a fan can produce is based off of zero pressure meaning you need a unrestricted flow. but at positive pressure are there really substancial flow improvements?
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flemcadiddlehopper
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PostPosted: Mon Feb 13, 2012 8:22 pm    Post subject: Reply with quote

Derek Cobb wrote:
flemcadiddlehopper wrote:
I am just looking for ways to improve an existing system in ways that are more modern than what was designed.


I'm pretty sure gutter drain pipes had been around for many, many years back when the engineers designed your bus. Nothing modern there...


Rain gutters are the other guys.
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PostPosted: Mon Feb 13, 2012 6:43 pm    Post subject: cooling air Reply with quote

No doubt about it a 2 litre engine will be needing more cooling and combustion air especially with dual Dells lets say and a header. The cooling system and air into the engine bay although ingenious is designed to cool a much smaller engine turning slower speeds and generating less heat. So more air in will be beneficial, provided it is not at the expense of tinware or seals.
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Derek Cobb
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PostPosted: Mon Feb 13, 2012 3:07 pm    Post subject: Reply with quote

flemcadiddlehopper wrote:
I am just looking for ways to improve an existing system in ways that are more modern than what was designed.


I'm pretty sure gutter drain pipes had been around for many, many years back when the engineers designed your bus. Nothing modern there...
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Sambafraser
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PostPosted: Mon Feb 13, 2012 11:53 am    Post subject: Reply with quote

If cooling is your main aim this might be what you are looking for -

I think it looks like shit.

Like a Baptist Preacher Jake Raby is trying to convert heathens like us to run a Type4 and the Down the Middle fanshrouds. This fanshroud allows distribution of airflow to each cylinder, with 40% of air from the fan going to each cylinder bank and 20% to the oil cooler. The system is a direct bolt on fit for Type 1 engines and utilises the Type 4 oil cooler.
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PostPosted: Mon Feb 13, 2012 8:17 am    Post subject: Reply with quote

Sorry guys, uh I am not running hot and do not have an engine problem, I haven't even got my engine built yet. I am just looking for ways to improve an existing system in ways that are more modern than what was designed.

as far as the air flow through a pipe...your calculations may be correct for an existing fan in a house. But, stick your head in front of that fan for while....then drive a jeep (or landcruiser,your choice) at 70mph with the windshield down. Which one blows harder.
The pipe does limit the flow but pressure decides the volume.
Correct from the 150 psi point. The flow data is 3900 SCFM with a pressure drop of 7.5 psi. The air flow at 135 psi = 6.57 psi drop/7.5psi drop X 135 psi/150 psi = 0.7884. Extracting the square root yields 0.8879. Multiplying the 0.8879 X 3900 SCFM yields 3462.88 SCFM

Read more: How to Calculate Air Flow in a Pipe | eHow.com http://www.ehow.com/how_6524519_calculate-air-flow-pipe.html#ixzz1mH5lw4cO

I don't know ...more air in and more air out sounds good to me.

gordo.
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PostPosted: Mon Feb 13, 2012 6:03 am    Post subject: Reply with quote

Good real world science. A Bong! LOL!

I was a heating guy for many years. 4" pipe flows maybe 50-60 cfm.
Not much help for a badly tuned or too high compression engine.

My 2110 ran hot at freeway speeds, so I lowered the compression to 9 to 1, and it ran cool all day on the freeway.

Timing, compression and air/fuel ratio should be checked if your'e running hot.

Quoting Gene Berg, Looks like a "bandage on your knee for a sore on your elbow".
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PostPosted: Mon Feb 13, 2012 2:22 am    Post subject: Reply with quote

It isn't hotter, you are simply pushing the air out of the engine bay thru the vent. So the faster you go, as the scoop under the van is the same size will push the air out.
The same effect(although opposite pressure) is when you take your finger off the vent of a bong. The air will take the path of least resistance. Wink
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flemcadiddlehopper
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PostPosted: Mon Feb 13, 2012 12:23 am    Post subject: Reply with quote

Not sure why the air coming from the front of the bus would be any hotter than the air being pulled into the side vents?

The key elements of this idea is to create positive pressure in the engine compartment ( with cool air routed from front of bus ) and create negative pressure below and behind the engine (evacuating the hot air behind the bus).
There was once a famous Kiwi Engineer (John Britten) that didn't follow what others did. In his bike design he moved the radiator to below and behind the seat so the air behind the bike (low pressure area) would have expanded hot air and exhaust gasses taking up more space and raising the pressure behind the bike.
I can't see why this same principle won't work on my bus. Maybe I'll even get better mileage, be able to go faster and not be affected by cross winds. Ah, who am I kidding I'll be happy if it just looks cool and doesn't make things worse.

Gordo.
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PostPosted: Sun Feb 12, 2012 12:48 pm    Post subject: Reply with quote

Alot of research and testing was done over the years by VW in hot places.
The Aussie spec they used longer and then 2 vents high up. Like this
Image may have been reduced in size. Click image to view fullscreen.

The Bay windows then used this scooping and high up. High because the air has less dust/grime.
As for the question about water in the jar thing. Bear in mind one of the problems you will have with ramming air from under the car is that the air will probably be just pushing out the factory vent in the side as it has air rushing past it, where before it was drawing cool air. The faster you go the air sucks more air out. The system isn't sealed. So you could be making it hotter by sucking air where normally it would be under pressure.
Essentially running like a VW with a loose fitting cooling tinware.
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PostPosted: Sun Feb 12, 2012 11:07 am    Post subject: Reply with quote

One more thought on the subject.

I have (from the PO) louvres in my rear deck lid. They make the upper engine area exposed to the low pressure behind the bus at speed. If my deck lid louvres were vented through the rear bodywork and directed towards the lower engine cooling tin it would aid in pulling hot air from the engine.

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this way I could make those hideous things at least functional rather than dis-functional.

gordo.
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PostPosted: Sun Feb 12, 2012 8:25 am    Post subject: Reply with quote

Derek Cobb wrote:
I think you need to have your test rig out of the vehicle. All you are doing is comparing the air pressure inside the engine compartment with the air pressure inside the passenger compartment.
Your bottle needs to be in the ambiant air that the bus will be traveling through, and also out of the turbulent, moving air.


Good point. You might seal the bottle and run a 2nd small air hose back to a neutral location in the engine compartment to get the differential pressure in the engine compartment while keeping the bottle in the cabin where you can see it.
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slow36hp
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PostPosted: Sat Feb 11, 2012 11:07 am    Post subject: Reply with quote

if you were putting a h20 subaru or 911 in maybe this would make more sense.but i believe if i recall right you werent doing a motor swap. the big question is how hot is your car expected to run to need all this air? as is the doghouse could over cool and required a thermostat. but yes it would work to increase airflow through the engine bay. not doubting there is always room for improvement in designs and engineering there is however a point it all becomes overkill or fixing the effect and not the cause.
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PostPosted: Sat Feb 11, 2012 9:52 am    Post subject: Reply with quote

I know that there is not much interest in this subject, and most on this site can't see past the end all be all doghouse style cooling system. But , if we are now exposing the upper engine compartment to the high pressure air that's in front of the bus, could we not expose the lower portion of the engine cooling tin to the huge low pressure area behind the bus? This could be done in the same fashion as the modern rear diffusors mounted on modern race cars. If the diffusor guided the air flow from the lower tin as pressure behind the bus dropped it would essentially pull air from the engine.

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just a thought. Gordo.
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PostPosted: Thu Dec 22, 2011 7:46 pm    Post subject: Reply with quote

HotStreetVw wrote:
Surely the German's didn't expect to export the beetle/bus all around the world and only considered the temeratures of west Germany. The german engineers I've worked with are freakin bright and not that short sighted and I'm sure the ones that were lucky enough to develop the aircooled engine were as well.

Fluid flow is pretty complex, rain gutters aint.

flemcadiddlehopper wrote:
It is not so much that something is broken and needs to be fixed , more that there is room for improvements that were not in the original design ( for the temperatures of West Germany ).
Take a look at what the first bolt-on engine improvements are any small displacement engines (read: ricer)... a cold air intake. So keeping the engine compartment cool not only has a bonus in the power dept. but it will help any cooling issues that may arise.
I don't see a problem with having too much cool air...let the thermostat (bellows) do it's job. Also, If i am running a larger engine with a porsche style fan (please don't start any discussion on the fan stuff...there is already a two day read thread here somewhere) the engine is already drawing more air than the compartment was designed to flow. my van also has a louvered deck lid only worsening the air flow problem because the louveres now expose the upper engine compartment to the vaccuumous space behind the flying loaf of bread.

I plan to run my van only during the summers after restoration as I don't want to subject it to all the nasty road chemicals and grime, so I will not be needing the heater. It never put out enough heat to be of any help in a Canadian winter anyways.

thanks for the input, I still think it's not a bad idea. Especially since anything that is done can always be undone if it didn't work.

Gordo.



Really...?

I am a mechanic, and spend most of my days dealing with the short-sightedness of the engineers in the automotive trade.
The engineers may be exceptionally bright, but it is what fits the budget that ends up being produced. The VW was not a very expensive vehicle back in the day...so I am sure many ideas did not make it to production...As with todays vehicles they just have to make it off warranty...Even the cost of rain gutters added to every car would have been enough to spell disaster for a post war German car company.
I know of a Bus with a water cooled Porsche engine and rads under the bus. All the cooling air for the rads is flowed from a collector at the front of the bus that measures 2"x 30" and the fans only come on after an extended parked idle time.
I am still quite a ways away from building or testing this, as my Bus is just headed to the Body man for restoration. After that I will show what I've done. (no rain gutters in this fab.)

Gordo.
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PostPosted: Tue Dec 20, 2011 7:37 am    Post subject: Reply with quote

Surely the German's didn't expect to export the beetle/bus all around the world and only considered the temeratures of west Germany. The german engineers I've worked with are freakin bright and not that short sighted and I'm sure the ones that were lucky enough to develop the aircooled engine were as well.

Fluid flow is pretty complex, rain gutters aint.

flemcadiddlehopper wrote:
It is not so much that something is broken and needs to be fixed , more that there is room for improvements that were not in the original design ( for the temperatures of West Germany ).
Take a look at what the first bolt-on engine improvements are any small displacement engines (read: ricer)... a cold air intake. So keeping the engine compartment cool not only has a bonus in the power dept. but it will help any cooling issues that may arise.
I don't see a problem with having too much cool air...let the thermostat (bellows) do it's job. Also, If i am running a larger engine with a porsche style fan (please don't start any discussion on the fan stuff...there is already a two day read thread here somewhere) the engine is already drawing more air than the compartment was designed to flow. my van also has a louvered deck lid only worsening the air flow problem because the louveres now expose the upper engine compartment to the vaccuumous space behind the flying loaf of bread.

I plan to run my van only during the summers after restoration as I don't want to subject it to all the nasty road chemicals and grime, so I will not be needing the heater. It never put out enough heat to be of any help in a Canadian winter anyways.

thanks for the input, I still think it's not a bad idea. Especially since anything that is done can always be undone if it didn't work.

Gordo.

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flemcadiddlehopper
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PostPosted: Mon Dec 19, 2011 11:46 pm    Post subject: Reply with quote

I had thought of that too. If a valve was in place the air could be diverted to either the feet of the front of the bus , or to the feet of the rear of the bus. Although the airflow in the bus has never been a problem...the roof vent at pace will blow the hair back of the rear seat passengers, no problem.
If even 1/4 of that airflow was through the engine compartment, I would be attaching it directly to my carbs.

Gordo.
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PostPosted: Mon Dec 19, 2011 7:25 pm    Post subject: Re: ram air cooling ducts Reply with quote

flemcadiddlehopper wrote:
I am currently restoring my '67 11 window. I am wondering if anyone has used this cooling idea? Using the existing heater tube (for front heat) and a intake placed just below the front bumper to use the high pressure area at the front of the bus to force air into the engine compartment. A long thin intake (24" x 2") should help keep a fair amount of air moving through the compartment at 50mph.
Any thoughts would be appreciated.

Gordo.


I think it's a good idea if you don't want to use the tube for heat. You'd behead the old heater boxes and go into the front tin or firewall area, right? Your idea spawned an idea to force air into the cab area if you didn't want to go to the engine with it. A dual damper would be necessary.
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