Any aftermarket highperf. fans available?

[movin]

Is there a high performance fan available?
Looking for more airflow and lighter weight.
How about titanium? Carbon Fiber? I have the eleven blade fan on a 3.2, no cooling problems, just want a cool looking, better performing fan that doesn't corrode.

[This message has been edited by movin (edited 07-07-2001).]

[movin]

Maybe it's too much to ask for!

[This message has been edited by movin (edited 07-07-2001).]

[This message has been edited by movin (edited 07-07-2001).]

[emcon5]

The fan is already made of Magnesium, which is not exactly known for being heavy.

If the corrosion bugs you, get it powdercoated.

Tom

[M.T.W]

Anyone know if a 993 engine fan will fit on '86 Carrera?

[dtw]

You must adapt the larger fan housing as well. This means you must modify the fiberglass shroud to fit the larger housing. Some just buy the new shroud. My wrench upgraded a 3.0 to that fan but he just grafted on a fiberglass patch to his shroud.

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Dave
1972 911T (E motor) RSR replica project
http://members.nbci.com/dtwinters/garage/

[Roland Kunz]

Hello

Porsche made high performance fans for racing. The low is they will not contain the alternator.

The best way is to get a early 11 blade 911 fan with the 650 Watt Bosch alternator or switch to the 964/993 set up.

Grüsse

[RarlyL8]

What about running a different pulley - so the fan runs faster?

[Roland Kunz]

Hello

Well each fan has a maxium delivery curve. If you speed them up they will need more power but will not move more air, This is the reason why prop planes are slower then jets.

The secret to high volume is not the speed it is the gap beetween the ring and the blades and the endtips of the blades.

The smaller the gap the better and any broken away tip will start turbolence and lower the more effective laminar stream.
In other words; Chaos slows down. I just look at my desk ( Close to final entrophie ) and yes thats true.

Grüsse

[movin]

Roland,
How about a total redesign. I'm sure fan/propellor technology has advanced quit a bit since 15 to 20 years ago. Just look at the advances in submarine screw design.

[Ted Stringer]

Roland, How hard would it be to fit a 964/993 fan and housing to a '84 3.2? I need to replace my fan (chipped blade done by PO) and the housing is cracked. Also do I need to get a 964/993 alternator to do this or will mine fit? I understood that the 964/993 fans were driven from a separate belt than the alternator. Can they be made to run from the same belt?

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Ted Stringer
nuke3@juno.com
'84 911 Targa aka pocketrocket

[Bill Verburg]

*The M64 3.6 liter fan running at 1.6 x crankspeed flows 1010 liters/sec @ 6100 rpm.

*The A series SC(1980) with the larger 245mm fan, running at 1.68 x crankspeed flows 1500 liters/sec @ 6000 rpm

*The 78-79 SC with the smaller 226mm fan running at 1.8 x crankspeed flows 1380 liters/sec @ 6000 rpm

*there is some confusion as to the units in my source literature

[This message has been edited by Bill Verburg (edited 10-25-2001).]

[Jon Green]

Bill,

Really useful data, the first time I've ever seen this.

Do you happen to know the flow rate for the 5 blade fan 245mm with 1.8:1 pulley @6000 rpm?

Thanks,
Jon

[Bill Verburg]

Facts; the 5 bladed fan 245mm, runs at 1.8 x crankspeed, is more efficient at moving air than 11 blade, is noisier than 11 blade, is made of magnesium.

Anecdotally; I had a 5 blade oem on my '76 Carrera 3.0, it made a wonderful deep bass moan at wot. When I updated to an 11 blade 245 mm fan at 1.8 x crankspeed the moan was gone, the cooling did not measurably improve. From this I infer that it is moving roughly the same amount of air as the A series.

[Roland Kunz]

Hello

@movin

I think there is no really need for that and therfore is no marked.
Lets say your new design will lower the effectivity by 10% then this would be the amount from 3-4 HP.
On the other side how much engenieering will have to be investet and how much units can be sold ? And for what price ?

More effective would be to develop a automatic drive that allways keep the fan at the optimal speed and can be clutched out for a short time under full WOT and then jumps progressivly back in. The fan with alternator will pull up to 40 HP power.

Porsche used that clutch trick on there fromula 1 cars in he 60´s.

I once worked on the idear to add a clutch and drive the fan via the alternator but couln´t find someone who jumped in on that and I never had the resources and time to go for it. The cluch was the easyiest part but to modify the alternator............


@Ted Stringer

The 964 has two belts with different drive ratios.

Basically Porsche needed to add a beefier alternator. That unit was a big larger and so the fan had to become a larger hub giving shorter blades. Now the fan also should be less noisy. So with two seperate drives each unit could be optimized without crossings or compromisses. The 964 unit does flow a much lower amount as Porsche had deletet the oilcooler and the heating freshairduct will not restrict the flow. The fan will not have enough flow for a normal 3,2 application and so you have to overdrive it into the power suking high speed.

No benefits. The largest benefit would be to underpulley the alternator and use a smaller unit with has less drag. Just short the old 911 had 650 W while the 964 has 1600 W. In other words the old unit delivers 0,9 HP at full load and will suck some 2-2,5 HP from the engine. The 964 unit will deliver 2,2 HP and suck some 5 HP from the engine.

The question is do you need the 1600 W ? A 3,2 engine has a 1250 W alternator and if you will save electric power you can live with a smaller unit. Especially if you drive on higher engine revs you also can underdrive the pulley and built in a optimized alternator for that.

To add the 964/993 system into a 3,2 you need to change your engine mount to a modified 964 unit, the pulley and have to delete the AC ( no space on the pulley or body). An much simpler way would be to modify the rear valance to the 964 cutout and implant a 964/993 engine.

This makes sense.

Grüsse

[Bill Verburg]

The 12 blade(submarine screw type) draws 8.3 hp at 6100 rpm

[movin]

I understand the costs of R&Ding a totally new design, and to be sure, the market has to be ascertained before taking up such a venture. One consideration, I and others want, is an improvent in appearance. Egad, that thing becomes damn ugly in time. It's an eyesore that greets anyone you show your engine to.

[M.T.W]

Grusse/BillV
Uhh.....thanks. i think.
So......in plain english, sounds like the answer is "NO". The 993 fan WON'T fit in 3.2 engine. (without major mods).
Well, MOVIN, looks like we gotta find another way to make our engines look 'cool'.

[Ted Stringer]

Thanks for straightening me out guys.

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Ted Stringer
nuke3@juno.com
'84 911 Targa aka pocketrocket