Electric fan, Push or Pull

Post by **dbrick** » Mon Feb 07, 2005 12:12 am

Anyone have any info about how much efficiency I would lose using the electric fan in front of the radiator? I machined a spacer to let me use an "American" style flex fan, so I could run both. I picked up a brand new 16" on ebay cheap. If anyone is interested, the guy who did mine will make the spacers for $20.00.

To fit the electric I either have to move the radiator 1-1 1/2 inches, or get out the grinder and cut the extra 15mm dia shaft sticking out of the waterpump flange. As far as I can see, it should pose no problem to cut it off, unless I'm missing something. To front mount, radiator brackets must move about an inch.

Any thoughts appreciated.

Post by **spl310** » Mon Feb 07, 2005 6:50 am

If someone has one handy that has the right springs in the right places, that would be a good thing to post a picture of....

Post by **dbrick** » Mon Feb 07, 2005 8:35 pm

HUH? were you thinking distributors maybe?

Post by **spl310** » Mon Feb 07, 2005 9:02 pm

Well, that was bizarre. I posted that to the distributor thread....

70MTroadster · Post by **70MTroadster** » Tue Feb 08, 2005 2:51 am

Dave, I just bought an electric fan from Summit Racing, a PermaCool. Their literature that came with the fan says that the fans are designed as pullers for 100% efficiency. The fans are reversible though for pushers and they say this drops efficiency to 80%.

Scott

SLOroadster · Post by **SLOroadster** » Thu Feb 10, 2005 3:28 am

What was the part # from Summit, and how much was it? I'm looking to ditch the 7 blade turbine soon.

Will

70MTroadster · Post by **70MTroadster** » Thu Feb 10, 2005 4:14 am

Will,

The one I bought was for my 510, which has a cross flow Rabbit aluminum radiator in it now. I got the 800 cfm PRM-19128 fan and mounted it the back of the radiator with the plastic ties they supply. It works great. It was $65.88 plus shipping. I have enough room to add another just like it if I need more cooling.

For my 70 Roadster, I've measured and would most likely go with the PRM-19008 12 inch fan at 1650 cfm rating, about $80. I'm running a plastic 4 blade fan now that I adapted from a 510 because I hate the dreaded "Datsun 7 blade Fan Sound".

I don't know where I saw it but a 2L engine supposedly takes about 1600 cfm to cool it.

Like so many have said, the fan eats more horsepower than you think. I was amazed at the improvement in performance on my 2L 510. Can't wait to electric fan the Roadster.

Scott

nomadtrash · Post by **nomadtrash** » Thu Feb 10, 2005 2:27 pm

I cut the shaft on my car and didn't have a problem. I also moved the radiator forwards about 3/4" by using longer bolts and some washers as spacers. You can't go too much more forwards because the radiator will hit the hood. I also used a Chevy water pump pulley that slowed the pump adn prevented cavitation at high rpms. If you aren't racing then the Chevy pulley might not be a good idea. I used a puller fan. The important thing about a fan is having a shroud. A fan without a shroud is far less effective.

Post by **dbrick** » Fri Feb 11, 2005 12:04 am

Did you use the original shroud with the fan inside? By the way, the 16" perma cool fits like it was made for the roadster radiator. It's rated at 2000 cfm puller 1600 pusher. In front of the radiator it slides into the bracket for the air scoop and clears the top tank by less than 1/4 inch, just need to move the radiator about 3/4" back to clear the radiator support bars. On the back side, the brackets line up with the bolt holes for the fan shroud.

nomadtrash · Post by **nomadtrash** » Fri Feb 11, 2005 12:11 am

Mine didn't have a shroud. The motor ran pretty hot. When I installed my new racing radiator I put a fan with a shroud on it. Now it won't even reach operating temp without a thermostat installed.