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vwfye
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Joined: April 15, 2000
Posts: 7661
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 Posted: Wed Aug 26, 2015 12:49 pm Post subject: Type 3 fans and belt |
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Anyone know how much hp they bleed vs how much the stock t1 fan and belt bleed?
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1980s Sand Dragster "The Plunger"
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KTPhil 
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Joined: April 06, 2006
Posts: 34003
Location: Conejo Valley, CA
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| Posted: Wed Aug 26, 2015 1:05 pm Post subject: |
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| I can't quantify it but the belt is very lightly loaded on the Type 3 design, since it is only running the generator, not the fan. |
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vwfye
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Joined: April 15, 2000
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| Posted: Wed Aug 26, 2015 1:13 pm Post subject: |
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I figured the swing of the T3 fan also draws vs the T1 though...
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64 No'back Speedster "Pearl"
1980s Sand Dragster "The Plunger"
LME "Little Giant Killer 3" |
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KTPhil
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Joined: April 06, 2006
Posts: 34003
Location: Conejo Valley, CA
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| Posted: Wed Aug 26, 2015 1:24 pm Post subject: |
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| Type 3 fan probably takes a little more hp because it flows far more air. |
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Yabbadubbadoo
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Joined: May 21, 2012
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| Posted: Wed Aug 26, 2015 10:10 pm Post subject: |
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Type 3 fan rpm ratio is 1:1 with engine speed but the Type 1 spins the fan faster than engine rpm. That's gotta mean something in favor of the Type 3 don't you think?.
An engine builder reminded me of that when I was discussing welding the blades of the Type 3 fan. He said he's never done it to a type 3 because they don't spin as fast as a type 1 fan. I don't know how much merit there is to that observation but I'm sure he would have told me to weld it up if he'd spun the blades off a type 3 fan down the drag strip which he regularly build motors for.
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mackaymanx
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Joined: October 12, 2006
Posts: 479
Location: Australia
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| Posted: Wed Aug 26, 2015 11:15 pm Post subject: |
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| You have to remember that the Type 3 fan has a lot larger diameter, so the peripheral speed may in fact be as high as those attained on a Type 1 fan. |
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daos
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Joined: January 01, 2017
Posts: 309
Location: Stockholm, SWE
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| Posted: Wed Nov 24, 2021 4:03 am Post subject: Re: Type 3 fans and belt |
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| don't forget the type 3 is driving two fans, not just one. outer fan draws air in (and runs the generator), inner fan pushes it out for engine cooling. |
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VWporscheGT3
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Joined: September 01, 2006
Posts: 2076
Location: Gardnerville, NV
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| Posted: Wed Nov 24, 2021 7:56 am Post subject: Re: Type 3 fans and belt |
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| daos wrote: |
| don't forget the type 3 is driving two fans, not just one. outer fan draws air in (and runs the generator), inner fan pushes it out for engine cooling. |
lots of threads on this, technically it doesn't act as a fan, to not interupt flow and the draw from the main fain you can think of the outer fans blades as mainly directional vanes... it does not aid in flow other than minimizing obstruction. dont have a lot of time this morning otherwise i would grab some of those threads
I hope I didnt come across as snotty... that was not my intent. |
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Erik G
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Joined: October 16, 2002
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daos
Samba Member
Joined: January 01, 2017
Posts: 309
Location: Stockholm, SWE
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| Posted: Wed Nov 24, 2021 10:56 am Post subject: Re: Type 3 fans and belt |
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| VWporscheGT3 wrote: |
| daos wrote: |
| don't forget the type 3 is driving two fans, not just one. outer fan draws air in (and runs the generator), inner fan pushes it out for engine cooling. |
lots of threads on this, technically it doesn't act as a fan, to not interupt flow and the draw from the main fain you can think of the outer fans blades as mainly directional vanes... it does not aid in flow other than minimizing obstruction. dont have a lot of time this morning otherwise i would grab some of those threads
I hope I didnt come across as snotty... that was not my intent. |
you didn't.
however - the primary fan is basically a propeller, the blades are angled in order to draw air in. so it is doing work, it's drawing in air and air has mass, the fan has to move that mass. that equals load and has a parasitic effect, there's no way it's doing no work, otherwise it wouldn't be there. there is no need for it to direct air immediately in front of the second fan, that makes no sense. the air is 'directed' by the path it has to take - and it only has one possible path.
the second fan has vanes which move the air outward, i'd say it is not doing the main work of pulling the air in. naturally, it also uses a certain amount of power.
thanks for the tip about the threads, i'll look them up. didn't realise there were any. although - of course there are, there are threads on pretty much everything here.
Last edited by daos on Wed Nov 24, 2021 11:00 am; edited 1 time in total |
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daos
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Joined: January 01, 2017
Posts: 309
Location: Stockholm, SWE
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| Posted: Wed Nov 24, 2021 10:56 am Post subject: Re: Type 3 fans and belt |
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| Erik G wrote: |
6 year old thread!  |
not any more  |
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VWporscheGT3
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Joined: September 01, 2006
Posts: 2076
Location: Gardnerville, NV
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| Posted: Wed Nov 24, 2021 11:01 am Post subject: Re: Type 3 fans and belt |
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| daos wrote: |
| VWporscheGT3 wrote: |
| daos wrote: |
| don't forget the type 3 is driving two fans, not just one. outer fan draws air in (and runs the generator), inner fan pushes it out for engine cooling. |
lots of threads on this, technically it doesn't act as a fan, to not interupt flow and the draw from the main fain you can think of the outer fans blades as mainly directional vanes... it does not aid in flow other than minimizing obstruction. dont have a lot of time this morning otherwise i would grab some of those threads
I hope I didnt come across as snotty... that was not my intent. |
you didn't.
however - the primary fan is basically a propeller, the blades are angled in order to draw air in. so it is doing work, it's drawing in air and air has mass, the fan has to move that mass. that equals load and has a parasitic effect, there's no way it's doing no work, otherwise it wouldn't be there. there is no need for it to direct air immediately in front of the second fan, that makes no sense. the air is 'directed' by the path it has to take - and it only has one possible path.
the second fan has vanes (more like an impeller) which move the air outward, it is not doing the main work of pulling the air in. naturally, it also uses a certain amount of power.
thanks for the tip about the threads, i'll look them up. didn't realise there were any. although - of course there are, there are threads on pretty much everything here. |
I see your logic , but, if the main fan is drawing more air volume than the little fan can produce it negates the work load of the pulley "Fan" and then will only act as a ..for lack of a better term , a director of flow. which is the way it was explained in one of those threads..I will have to see if i can find that at lunch today.
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gt1953
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Joined: May 08, 2002
Posts: 13848
Location: White Mountains Arizona
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| Posted: Wed Nov 24, 2021 9:21 pm Post subject: Re: Type 3 fans and belt |
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The pulley fan, does it assist in drawing air in for the stock carb/fuel inj set up. Just wondering as it only makes a little sense.
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daos
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Posts: 309
Location: Stockholm, SWE
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| Posted: Thu Nov 25, 2021 7:10 am Post subject: Re: Type 3 fans and belt |
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the air to carbs/injection is bled from the air ducts just before the main bellows. i would say the carbs/fi take what they need from the air the fans are drawing in, the rest continues to the fans. so technically, yes, the fans assist the intake air since without the fans little to no air would come in through the body louvres. vw clearly considered this and designed the system to move enough air to cover both intake and cooling.
don't have any volumetric data for the engine airflow, might be able to dig it up in my bentley over the weekend. |
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ataraxia
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Joined: March 19, 2010
Posts: 4504
Location: Illinois
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| Posted: Thu Nov 25, 2021 9:16 am Post subject: Re: Type 3 fans and belt |
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| Erik G wrote: |
| 6 year old thread! |
Strange corpse to dig up and debate, for sure. |
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