Swapping engine fan on 3.0 SC to larger version - issues

[Flojo]

Hello,
maybe you can give me advise… I want to swap an engine fan I could get.

My SC has the 226mm diameter 11blade type 930.106.101.0 R
I could get the 245mm diameter 11blade type 901.106.101.5 R

Idea behind it: more air shoveled, more cooling.

Can I make it fit?

Guess I need a longer fanbelt and a different shroud?
Or is this just not gonna work?

Regards, Flo

[SWS911]

From what I remember those '78-'79 fans have a different pulley ratio and with the smaller diameter fan create quite the venturi effect. I think they changed it in '80 to decrease the "noise", but don't nail me to the cross on that one. I think they are better made and more desirable than the later fans/housings. Worth more too! If it were mine, I would have Mark Motshagen refinish it and KEEP it!

[Flojo]

To get it right, you say the smaller/SC one is "better" than the earlier/larger one?

[SWS911]

I think it's the one to have, period! Since you live in Deutschland, I wouldn't think cooling would be too much of an issue. It ain't South Texas by any means.

[Trackrash]

You will need the housing as well, not just the fan. Then the alternator will need to fit the fan housing. So you probably need the entire package. Keep in mind that the older alternators have less power. The Carrera housings tend to crack, so IMO, your best bet is a fan and housing from an '80-'83.

The outer pulley half can be changed to the older style as well. Depending on what combination you end up with you may have to use a custom length fan belt.

I have a '71 fan/housing/ alternator on my '78 SC motor, but it is in my '71 car. I tried two different crank pulleys, but didn't notice any difference in running temps.

Bottom line is if the motor isn't running hot, why change it?

[3rd_gear_Ted]

parasitic HP loss is greater with the bigger fan

[Flojo]

Originally Posted by Trackrash

You will need the housing as well, not just the fan. Then the alternator will need to fit the fan housing.

I know. I was offered the whole unit, fully refurbished (rebuilt and ceramic plated)

But ok, I guess I keep mine and refurbish it (again/*).

Thank you all for info.

(* I refurbed mine back in 2012, beadblasted it and heat-painted it, but it gets brittle now after time. so now again blasting and ceramic coating this time)

[shoooo32]

The smaller fan cars (78-79) have different pulleys as mentioned above. It only gets weird when you buy a 226mm fan car with a 245mm fan pulley on it. I shopped for months trying to get the right belt until I figured out what happened and bought the correct pulley!

[Trackrash]

Originally Posted by shoooo32

The smaller fan cars (78-79) have different pulleys as mentioned above. It only gets weird when you buy a 226mm fan car with a 245mm fan pulley on it. I shopped for months trying to get the right belt until I figured out what happened and bought the correct pulley!

Yes, it should be mentioned that when Porsche used the 226 fan they spun it faster than the larger fans. Thus the smaller pulley on that fan.

There is a thread here that shows all the fans and pulleys. 993 fan on a Carrera?