Flat fan from an upright - how'd he do that?

[juicersr]

Some engineering whiz got really creative and built a corvair style flat fan out of the standard cooling fan.

http://backup.trinityhome.org/~harakiri/car/

Looks ridiculously simple from the photo, with a couple of pulleys that appear to 'turn' the belt 90degrees, after fabricating a horizontal support for the fan itself. Guy swears reliability. Anyone here do this or know of this set-up?

[RarlyL8]

I would think a belt system to be a no-brainer. Simply copy the Corvair.
The (expensive) 934 setup is gear driven and has the bearings oriented in the correct plane.

[911pcars]

The 935 parts suffers from a mechanical loss due to the drive gearing. No biggie when the engine outputs 600+ HP.

The Corvair setup has been talked about for years. I had yet to see one on a 911. This is my first. The right angle belt drive is less problematic than you think. The factory version had a fixed idler pulley, and once stretched, the belt would tend to oscillate as fan/engine speed changed and it would flip off the pulley. Not sure of the volume capacity of the Corvair fan, but it was certainly light - magnesium; lighter than the 911 version.

The aftermarket solved the thrown belt syndrome by a $10 kit that spring-loaded the idler pulley. A byproduct is that changing the fan belt was quite easy - no tools required. There might have been some drive loss from less belt friction, but it wasn't noticeable on a 164 cu. in Corvair engine which is coincidentally 2.7 liters

If I were to design this from the bleachers, I'd make sure to separate the alternator mass from the fan assy. i.e. mount it on a separate drive bracket and drive belt.

There would be additional work in fabricating a matching upper air shroud.

Sherwood

[Elombard]

Wow very cool. I would like to see more details

[TRE Cup]

a buddy of mine had a 140 hp monza in high school. Even with the spring tensioner and special Crown Corvair belt, one had to be careful when downshifting fast .
And the car felt like it got a 25 hp shot of nitrous everytime the belt flew off !

Another "trick"mod that did not work was the single Carter 4 bbl AFB carb on a shiny four tube manifold (not that dissimilar to the cis tubes and air box) . On cooler nights when we would hit it hard up on mulholland, it would ice up : Tubes would be freezing cold !!

[tcar]

Most people installed the Corvair belt too tight. Had to be somewhat loose or it would pop off.

Had to be much looser than common sense would dictate.

Very, very common mistake that caused this happening over and over again.

[911pcars]

"...And the car felt like it got a 25 hp shot of nitrous everytime the belt flew off !"

Yes. Common practice when "street tuning". Remove the drive belt for the 1/4 mi. "tuning" run against the other guy. Probably not a good idea for the long run however.

Sherwood

[Wayne 962]

Can't say I've seen that before. I'd be curious if anyone was making a kit...

-Wayne

[rouxroux]

Originally Posted by TRE Cup

a buddy of mine had a 140 hp monza in high school. Even with the spring tensioner and special Crown Corvair belt, one had to be careful when downshifting fast .
And the car felt like it got a 25 hp shot of nitrous everytime the belt flew off !

Another "trick"mod that did not work was the single Carter 4 bbl AFB carb on a shiny four tube manifold (not that dissimilar to the cis tubes and air box) . On cooler nights when we would hit it hard up on mulholland, it would ice up : Tubes would be freezing cold !!

The spring tensioner was truly a POS...As has been stated before here, the best prevention is to keep the belt "loose". (Trust me, if you had a 65 or earlier A/C'ed car and flipped a belt, you'd know what a hassle it was to take the AC condensor off the top of the engine and flip it over on the pass. side rear fender while you changed belts)! I actually got so mad one day while on the side of the road in the rain that I took a box cutter and cut my freon lines (don't tell Manbearpig) and chunked the condensor...Never ran AC again on that car!

The IECO tube manifold (they also made a 2-tube version for the 110 and smaller engines) was OK if you ducted carb heat from the "flip-over" cover by the oil cooler. I fabbed some shrouding to aim that warm air upwards after being left stranded after runs on Monte Sano mountain in Huntsville, Alabama.

(Oh, and SOME folk might also remember the "other" use for Corvair mag fans as well)!

[burgermeister]

Same use as mag tensile test specimens from the materials lab at the engineering school?

[cnielsen]

The carbs appear to be mounted backwards to simplify the linkage...interesting.

[TRE Cup]

Besides trying to make glass , lighting the fans up in the sand at the beach , they fans were also used as wheel center brake heat extractors ala 935

there was a guy in australia working on a aftermarket version of flat fan conversion for the 911. Dunno whatever happened with it. It was posted on this board too

[911pcars]

Originally Posted by TRE Cup

Besides trying to make glass , lighting the fans up in the sand at the beach , they fans were also used as wheel center brake heat extractors ala 935

there was a guy in australia working on a aftermarket version of flat fan conversion for the 911. Dunno whatever happened with it. It was posted on this board too

Yep. this stuff.




Sherwood

[safe]

Spezialmotorer in Sweden http://www.spezialmotorer.com/ makes a flatfan setup. Probably not cheap....

[juicersr]

Originally Posted by safe

Spezialmotorer in Sweden http://www.spezialmotorer.com/ makes a flatfan setup. Probably not cheap....

How about $20,000 The factory 'Special wishes' dept will make you one for 'only' $10-15,000 last i heard.

The previously mentioned guy in australia, Michael at http://www.promotive.com.au/ is still plugging away on his kit.

[911pcars]

To read about progress on the fan, go to www.promotive.com.au/

Then click on the link, "Parts for Sale", then the link for Horizontal Cooling Fan kit.

Sherwood

[afterburn 549]

I think this thread lost my interest when going into mega bucks..would be nice to see if there was a way to do this economically.
Can we persue that avenue ?

[safe]

Originally Posted by afterburn 549

I think this thread lost my interest when going into mega bucks..would be nice to see if there was a way to do this economically.
Can we persue that avenue ?

Spezialmotorer claims that a flatfan is a must over 700hp, so in reality its probably overkill for most of us.....
A bigger oilcooler is probaby a better investment over any flatfan setup, expensive or cheap.
Unless you want the cool look, because it is pretty cool looking!