Fan ratio for an SC?

[GaryR]

Anyone know what a stock SC fan drive ratio is? I'm guessing around 1.5:1 but i'm sure someone here knows the accurate number.

[Bob Kontak]

The 78 US 930-04 / US California 06 / Euro SC 03 all had 1.81 to 1.

Direct from the little Tech Spec book.

[Bill Verburg]

Originally Posted by GaryR

Anyone know what a stock SC fan drive ratio is? I'm guessing around 1.5:1 but i'm sure someone here knows the accurate number.

'78 SC 930/13 or /15, fan ratio is1.8

How's the car?

[GaryR]

Originally Posted by Bill Verburg

'78 SC 930/13 or /15, fan ratio is1.8

How's the car?

Figured it would be you answering that Bill..
Few hours on the celette, new hood, bumper, lights, headers, some bondo and paint, and she will be like new!

[Joe Bob]

What....Bob is invisible? Funny looking, yes....

[KTL]

Originally Posted by Joe Bob

What....Bob is invisible? Funny looking, yes....

Some of us still like you.

More light reading to beat the subject to death.

Engine Fan Drive Ratio

Do a search Gary, you lazy..........

[Grady Clay]

Gary,

The ’78-’79 911SC ratio is speced 1.81:1 with the largest (134 mm) crank pulley and a ~84 mm fan split-pulley.
However, it has the smaller 226 mm fan.
With the small fan, the air flow is specified as 1380 liters/second at 6000 rpm crankshaft speed.
Best cooling is using this pulley arrangement with the (earlier & later) 245 mm fan.
This is speced as 1500 l/s @ 6000 rpm with a 127 mm crank pulley.
Using the (~80 mm) fan hub from a 5-blade fan on the 245 mm fan and your 134 mm crank pulley, you can increase the ratio a bit more than 1.8:1 and get air flow in the (perhaps) 1700 l/s range.

These are very desirable combinations for a street 911 where one needs increased cooling of the engine machinery (cylinders & heads) at driving speeds.
For track use, your small fan (even at the earlier 1.3:1 ratio) and the Rubbermaid Solution is ideal.
This almost does away with the need for a front cooler.

Best,
Grady