Fan Club (horizontal type), Archive pics from '05 Options

[Maltese Falcon]

In 2005, "Excellence" magazine showcased my bi-turbo, black 9146 gt-tribute car. My good friend Marco G. of @TLG_auto (North Hollywood, Ca.) was a contributing photographer/ writer for the magazine...as well as a 1st Class air-cooled Porsche tech. Pete Stout was at the helm of "Excellence", and the car must have been one of the few 914s to ruffle the feathers of the status quo 911 readership. We always knew that Pete had a love for the 914 (IMG:style_emoticons/default/wub.gif) Here's a splash of pics given to me by Marco just after the article hit.

[Johny Blackstain]

Just wondering what powers the flat fan? Obviously it's not belt driven so it's either electric or shaft & gears. Oh yea, I want one (IMG:style_emoticons/default/biggrin.gif)

[Maltese Falcon]

Just wondering what powers the flat fan? Obviously it's not belt driven so it's either electric or shaft & gears. Oh yea, I want one (IMG:style_emoticons/default/biggrin.gif)

You had it right there !
The fan is serpentine-belt driven via the front of the crankshaft. 917's take this drive from the center of the crankshaft via internal gears...right up the middle to the top of engine.
Back to the 6 cyl type; continuing from the front crank pulley, there is another upper pulley (and tensioner pulley) located higher (and parallel) to the crank pulley. Its steel axel sits in a magnesium housing that is nestled (strapped & bolted) into the upper portion of the 911 engine case (curved contour area) of the normal front fan. This casting also houses an internal axel (lubricated with engine oil pressure. This axel has a bevel gear-set which meshes and directs the final drive (90°) upwards...which is what spins the fan. The Porsche part number for the latest (last design) is 911/78 which delivered the most cfm cooling air delivery, which is the unit that you see here.
I'll dig up the factory cfm specs and post later. YES it does rob BHP off of the crankshaft...but minimal and we can run more boost to compensate.

[Johny Blackstain]

You had it right there !
The fan is serpentine-belt driven via the front of the crankshaft. 917's take this drive from the center of the crankshaft via internal gears...right up the middle to the top of engine.
Back to the 6 cyl type; continuing from the front crank pulley, there is another upper pulley (and tensioner pulley) located higher (and parallel) to the crank pulley. Its steel axel sits in a magnesium housing that is nestled (strapped & bolted) into the upper portion of the 911 engine case (curved contour area) of the normal front fan. This casting also houses an internal axel (lubricated with engine oil pressure. This axel has a bevel gear-set which meshes and directs the final drive (90°) upwards...which is what spins the fan. The Porsche part number for the latest (last design) is 935/78 which delivered the most cfm cooling air delivery, which is the unit that you see here.
I'll dig up the factory cfm specs and post later. YES it does rob BHP off of the crankshaft...but minimal and we can run more boost to compensate.

Cool & thanks for the info. Been in love with the flat fan ever since I saw LeMans for the 1st time. I had no idea it was belt driven in the six since Porsche did a much better job of concealing the belt than Chevy did. Probably easier to change the belt in the Corvair though (IMG:style_emoticons/default/biggrin.gif)

[Maltese Falcon]

You had it right there !
The fan is serpentine-belt driven via the front of the crankshaft. 917's take this drive from the center of the crankshaft via internal gears...right up the middle to the top of engine.
Back to the 6 cyl type; continuing from the front crank pulley, there is another upper pulley (and tensioner pulley) located higher (and parallel) to the crank pulley. Its steel axel sits in a magnesium housing that is nestled (strapped & bolted) into the upper portion of the 911 engine case (curved contour area) of the normal front fan. This casting also houses an internal axel (lubricated with engine oil pressure. This axel has a bevel gear-set which meshes and directs the final drive (90°) upwards...which is what spins the fan. The Porsche part number for the latest (last design) is 935/78 which delivered the most cfm cooling air delivery, which is the unit that you see here.
I'll dig up the factory cfm specs and post later. YES it does rob BHP off of the crankshaft...but minimal and we can run more boost to compensate.

Cool & thanks for the info. Been in love with the flat fan ever since I saw LeMans for the 1st time. I had no idea it was belt driven in the six since Porsche did a much better job of concealing the belt than Chevy did. Probably easier to change the belt in the Corvair though (IMG:style_emoticons/default/biggrin.gif)

For street use Corvair was a great flat fan design, even uses oil galley lubrication. Problem with "Bending " the V-belt into a different direction = belt slip & dropping a belt if used in spirited competition.
Ask me how I know ¿¿ For short 20 min autocross runs, my Corvair pals squirt wd-40 all around the v-belt and pulleys ...keeps them happy for a short while. Porsche uses a Guibo up on top of the fan, which counters abrupt fan oscillations from upshifts/ downshifts.
The 1st iterations of RSR flat-fans used v-belts, 2nd gens all had the serpentine, and the tensioner.