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RHough
Samba Member
Joined: May 12, 2013
Posts: 299
Location: Canada
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 Posted: Sat Oct 25, 2014 6:59 pm Post subject: |
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| Juanito84 wrote: |
| RHough wrote: |
| It would take massive wattage....and even more important...massive amps....to produce that torque and static pressure with an electric fan. Ray |
Power = Voltage × Current. If it really does take 10hp (7457W or 690A = 7457W ÷ 13.5V ÷ 80%) to turn the fan you could use a higher voltage system for just the fan which would result in lower amperage. For an example, a 48V system would reduce 690A to 173A.
Then again, how much air do you really need? Lowering the fan RPMs really cuts down on power needed to turn it. For an example a stock pulley with the engine running at X RPMs needs X amount of power to turn the fan as shown below:
RPM - HP
1000 - 0.06
1500 - 0.2
2000 - 0.5
2500 - 0.9
3000 - 1.6
3500 - 2.6
4000 - 3.8
4500 - 5.5
5000 - 7.5
5500 - 10.0
6000 - 13.0
6500 - 16.5
7000 - 20.6
7500 - 25.3
8000 - 30.8 |
The demand in watts does not change. Reducing the amperage by increasing the voltage would allow you to run smaller gauge wire in the system but the HP requirement remains the same.
There is no free lunch.
I have not looked for data that shows the VW fan delivers more air than required. I know that at high RPM (high fan load) the belt slips and that limits maximum fan RPM to some fraction of the theoretical drive ratio.
*If* you could determine that the fan at belt slip is all the engine ever needs and you found that there was a need for higher flow at some lower engine RPM you could engineer a way to over speed the fan at that condition and under speed at RPM the max needed point. In effect a variable displacement cooling pump.
The best fuel economy is found at moderately heavy loads at low RPM ... the stock fan would be turning too slowly to cool the engine if you ran gearing that tall. |
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modok
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Joined: October 30, 2009
Posts: 26790
Location: Colorado Springs
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| Posted: Sat Oct 25, 2014 7:15 pm Post subject: |
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IMO 2-4 HP for the fan is realistic. That is still a lot.
Five years ago it was simple enough to say it's impractical.
Have you seen how cheap you can get brushless motors and speed controls, and lithium batteries now from china?? It is almost practical 
I think you could do it with 24 volts, but more would be even better.
BTW, once we have the 24 volt system and bank of batteries in place you would call it overcomplicated, or...... just right to add electric supercharger too. |
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Juanito84
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Joined: March 17, 2012
Posts: 2436
Location: Colorado Mountains
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| Posted: Sat Oct 25, 2014 8:12 pm Post subject: |
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| RHough wrote: |
| The best fuel economy is found at moderately heavy loads at low RPM ... the stock fan would be turning too slowly to cool the engine if you ran gearing that tall. |
Which is why I'm interested in this idea. The ability to fully control the fan electrically would allow you to run whatever gears, RPMs and load you want.
Yes, watts would not change. If top fan speed requires 10hp or 7457W it won't change with volts or amps, although higher voltages and lower amperages tend to increase efficiency and the need for giant cables.
| modok wrote: |
| I think you could do it with 24 volts |
You could convert the whole car to 24 volts by changing the relays to 24V and then run lights of the same wattage (head light with head light, blinker with blinker, etc.) in series. But then when one head light burns out both will turn off!
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If a water cooled engine cools its water with air, isn't it just an overcomplicated air cooled engine? |
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RHough
Samba Member
Joined: May 12, 2013
Posts: 299
Location: Canada
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| Posted: Sat Oct 25, 2014 8:55 pm Post subject: |
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| Juanito84 wrote: |
| RHough wrote: |
| The best fuel economy is found at moderately heavy loads at low RPM ... the stock fan would be turning too slowly to cool the engine if you ran gearing that tall. |
Which is why I'm interested in this idea. The ability to fully control the fan electrically would allow you to run whatever gears, RPMs and load you want.
Yes, watts would not change. If top fan speed requires 10hp or 7457W it won't change with volts or amps, although higher voltages and lower amperages tend to increase efficiency and the need for giant cables.
| modok wrote: |
| I think you could do it with 24 volts |
You could convert the whole car to 24 volts by changing the relays to 24V and then run lights of the same wattage (head light with head light, blinker with blinker, etc.) in series. But then when one head light burns out both will turn off! |
I think a practical solution would be to put a transmission between the alternator and the fan. A two speed planetary might be all it would take. Gear it for mild overspeed at low RPM to provide better heating and cooling at low RPM and use an electric clutch to engage the underspeed gear at higher RPM. The same circuitry used for AC compressor cut-out could probably be made to work as a control circuit.
The fan and shroud provide enough cooling for most situations if long liife on big displacement engines reported here is a good measure. The challenge would be to match the cooling performance using less HP. |
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DubStyle
SBS Hit Squad
Joined: July 26, 2003
Posts: 6250
Location: SBS headquarters: Missery
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| Posted: Mon Oct 27, 2014 3:45 am Post subject: |
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The intent of my thread was to generate conversation about this idea. I see a lot of good data/information. I'm glad there are people willing to think outside the shroud. :p I remember a discussion with a fellow VW enthusiast about pressure vs CFM. Thanks for the input folks... open and free discussion is GREAT!
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Juanito84
Samba Member
Joined: March 17, 2012
Posts: 2436
Location: Colorado Mountains
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| Posted: Mon Oct 27, 2014 5:21 am Post subject: |
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| RHough wrote: |
| I think a practical solution would be to put a transmission between the alternator and the fan. A two speed planetary might be all it would take. |
I think the most practical solutions would be 1, for short bursts of speed as in drag racing using an AC clutch drive on the alternator like Eric Allred says he can make, or 2, for fuel mileage us an adjustable ring type thermostat, kind of like the ones used in the old pre 60's Beetles. With idea #2 blocking the fan inlet will create a vacuum there and lower airdrag just like a clogged vacuum cleaner blower speeds up and actually uses less electricity.
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If a water cooled engine cools its water with air, isn't it just an overcomplicated air cooled engine? |
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modok
Samba Member
Joined: October 30, 2009
Posts: 26790
Location: Colorado Springs
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| Posted: Mon Oct 27, 2014 4:50 pm Post subject: |
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I'd like to have a variable speed belt drive for the fan, it's actually doable. You know all the little mopeds are variable belt drive and they handle about the same HP as our fan uses, or a bit more.
Centrifugal supercharger tho.........there's a application for electric. Not so simple to GEAR something to turn 30,000 rpm, and switch it on and off. For what a pro-charger costs........it's doable!! And the OEMs are doing it, already appearing on some of the fancy stuff. |
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58 Plastic Tub
Samba Member
Joined: September 03, 2007
Posts: 419
Location: Nowhere, USA
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| Posted: Mon Oct 27, 2014 6:42 pm Post subject: |
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| theKbStockpiler wrote: |
| Has anyone used the oil injector idea with a vw to any success? |
Yes.
I have two engines set up this way, along with thermal coatings in the combustion chamber/exhaust port, and a DTM. Why? Because I'm greedy, and I want to run all the compression my fuel will allow. The bigger of the two (2276) is a twin plug engine as well.
As far as electric fans on the street? It's a lot like electric heat-- it just seems like it ought to work, but the numbers get out of whack pretty quickly.
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"A single point in isolation is a reference point. Two points is a line. Three points is a trend. Trends don't lie." |
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auslander
Samba Member
Joined: January 07, 2003
Posts: 1831
Location: Heart Of Dixie
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| Posted: Tue Oct 28, 2014 11:19 am Post subject: |
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Shit I just noticed I didn't post the pic, lol.
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Zombie
Wandering...Have you found what your looking for?
66 POS Bus
69 Class 11 Beetle
71 Cat-Look Beetle
64 Old Skool Baja
74 "Swamp" Thing
!!! F**k Cancer !!!
Time's Tide will Smother You
"You can't throw a rock in Long Beach without hitting a tweaker" Steve Tucci |
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DubStyle
SBS Hit Squad
Joined: July 26, 2003
Posts: 6250
Location: SBS headquarters: Missery
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| Posted: Thu Oct 30, 2014 6:37 am Post subject: |
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| auslander wrote: |
Shit I just noticed I didn't post the pic, lol.
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Qué es esto Senior? Is this your engine bay? It can't be, you had dual Carbs your engine.
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SBS #1
SBS #1 on FB
"The original & best lowered Split Bus website/club" |
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VWporscheGT3
Samba Member
Joined: September 01, 2006
Posts: 2076
Location: Gardnerville, NV
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| Posted: Thu Oct 30, 2014 7:37 am Post subject: |
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I would be Interested to see a completely redesigned cylinder head, with a exhaust chamber cooling port, alot like the Harley-Davidson XR1200 head shown below
the port is on the left, that is sealed off by the head gasket, but the inlet is on the intake manifold surface, and it exits out the opposite side of the pipe. just like most oil mods though it would require a dry sump pump with significant volume to cope.
combine that with the type 4 style lay out , it may (or may not) be fairly effective in cooling the head under extreme conditions
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Schnell, SCHNELL!
I like being wrong, Because, it is another opportunity to learn. If you stop learning from your mistakes than what is the point?
If you have any questions about Forged ICON 4032 VW pistons just shoot me a line. |
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theKbStockpiler
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Joined: July 07, 2012
Posts: 2316
Location: Rust Belt
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Steve Arndt
Samba Member
Joined: August 01, 2005
Posts: 1780
Location: Boise, Idaho
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| Posted: Thu Oct 30, 2014 11:02 am Post subject: |
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| That is about the worst possible chamber shape possible on that HD head. |
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VWporscheGT3
Samba Member
Joined: September 01, 2006
Posts: 2076
Location: Gardnerville, NV
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| Posted: Thu Oct 30, 2014 11:05 am Post subject: |
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I can tell you first hand... finest "sportish" motorcycle Harley davidson has ever built, most of its "advancements" though were basically stuff leftover that Buell wanted to use on his XB motors but never got the chance. But the XR is a fantastic all around motorcycle
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Schnell, SCHNELL!
I like being wrong, Because, it is another opportunity to learn. If you stop learning from your mistakes than what is the point?
If you have any questions about Forged ICON 4032 VW pistons just shoot me a line. |
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auslander
Samba Member
Joined: January 07, 2003
Posts: 1831
Location: Heart Of Dixie
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| Posted: Thu Oct 30, 2014 11:15 am Post subject: |
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[quote="DubStyle"]
| auslander wrote: |
Shit I just noticed I didn't post the pic, lol.
Qué es esto Senior? Is this your engine bay? It can't be, you had dual Carbs your engine. |
Not mine, It's a closed pull through setup to bring fresh air into the bay. These type of fans would be ideal to the squirrel setup. Fab something from the fans to the cylinder tins???
_________________
Zombie
Wandering...Have you found what your looking for?
66 POS Bus
69 Class 11 Beetle
71 Cat-Look Beetle
64 Old Skool Baja
74 "Swamp" Thing
!!! F**k Cancer !!!
Time's Tide will Smother You
"You can't throw a rock in Long Beach without hitting a tweaker" Steve Tucci |
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SBD
Samba Member
Joined: October 24, 2012
Posts: 3269
Location: SOUTH DAKOTA
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| Posted: Sat Nov 08, 2014 6:48 pm Post subject: |
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"Additional oil flow is directed across the cylinder heads, as well as through passages in the exhaust valve and port, to cool those critical areas." 
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| mark tucker wrote: |
| I wouldent waste $ or thyme on building a small motor. build it big so it dosent have to work hard.remember it's only as fast as your foot alows it to be unless you build a small turd then it just stinks as it squishes up through your toes when you step on it. |
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Air Cooleds Only
Samba Member
Joined: October 18, 2009
Posts: 157
Location: Prescott, AZ
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| Posted: Sat Nov 08, 2014 7:15 pm Post subject: |
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| Eaallred wrote: |
| theDrew wrote: |
| I wonder if you could rig something w/ an old AC magnetic clutch |
We did this while I worked at Aircooled.Net. I managed to make a functioning prototype for John C's car before I left. It worked just fine, the thing is making it only re-engage at low rpms. I can imagine it would blow the fan apart if you engaged it at any decent rpms. I believe John still has it on his 63 bug, but the car has been in hibernation while he has taken the time to raise his kids.
I designed the new alternator cover plate, and adapter hub to fit the clutch while there. The rest was bolt-on. John had a bunch of adapters made, but I heard they needed one small mod to work, I am unsure what that was. I kinda screwed it up a bit I guess.
I designed it all once, I could do it again I reckon. If there were an interest in it, i'd invest in making a handful of kits this winter when the HVAC season is slow. They wouldn't be a cheap $100 item though. |
Another idea I've been thinking about with this setup was to use it in place of a stock thermostat as well. It would be slick, however I wasn't aware of the possibility of exploding a fan if engaged at a higher than idle rpm.
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 Air Cooleds Only |
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[email protected]
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Joined: August 03, 2002
Posts: 12785
Location: Salt Lake City, Utah
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| Posted: Sat Nov 08, 2014 8:06 pm Post subject: |
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Do you guys realize that if you block the airflow to/from the fan, the power the cooling fan draws drops to almost nothing? Like the stock thermostat/flaps system, which worked fine.
How much power it takes to drive the fan depends on how much air it's moving. The stock system works fine. Acceleration and blowing up fans is a separate issue entirely.
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Juanito84
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Joined: March 17, 2012
Posts: 2436
Location: Colorado Mountains
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| Posted: Sat Nov 08, 2014 9:01 pm Post subject: |
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| [email protected] wrote: |
Do you guys realize that if you block the airflow to/from the fan, the power the cooling fan draws drops to almost nothing? Like the stock thermostat/flaps system, which worked fine.
How much power it takes to drive the fan depends on how much air it's moving. The stock system works fine. Acceleration and blowing up fans is a separate issue entirely. |
Exactly! Take a vacuum cleaner for an example. With no clogs the motor RPMs are lower and the amps are higher. But get a clog and RPMs increase and amps drop. In other words blocking air flow lowers power consumption. The same is true with the VW AC engine fan.
I do wonder, however, on which is better to block air flow. Before or after the fan?
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If a water cooled engine cools its water with air, isn't it just an overcomplicated air cooled engine? |
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RHough
Samba Member
Joined: May 12, 2013
Posts: 299
Location: Canada
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| Posted: Sat Nov 08, 2014 9:10 pm Post subject: |
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| Juanito84 wrote: |
| [email protected] wrote: |
Do you guys realize that if you block the airflow to/from the fan, the power the cooling fan draws drops to almost nothing? Like the stock thermostat/flaps system, which worked fine.
How much power it takes to drive the fan depends on how much air it's moving. The stock system works fine. Acceleration and blowing up fans is a separate issue entirely. |
Exactly! Take a vacuum cleaner for an example. With no clogs the motor RPMs are lower and the amps are higher. But get a clog and RPMs increase and amps drop. In other words blocking air flow lowers power consumption. The same is true with the VW AC engine fan.
I do wonder, however, on which is better to block air flow. Before or after the fan? |
After ... so when it fails it won't take out the fan ...  |
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