Electric Fans

M4vr1k · Post by **M4vr1k** » Sun Oct 15, 2006 2:51 pm

Hi guys
After reading the article in the Technical section on the electric fans, and not learning anything new, i need to ask the question.
Currently i have 2 12" fans on the front of the radiator, yet the Z still heats up when idling or driving slowly, and the temperature creeps a bit high for comfort before the fans come on. The temp needle will normally sit about halfway up the guage when driving around, but the fans will not come on until the needle reaches the "M" in TEMP, which seems a bit high. I am replacing the current thermo fan switch with one of a slightly lower operating temperature shortly
Is anyone else running electric fans with more sucess? and secondly, what sort of temperature should the Z run at anyway. Halfway up the guage is about 125 farenheit, which is only about 50 celsius, and that seems really cold.
Any info would be appreciated
Zac

ForemanNZ · Post by **ForemanNZ** » Sun Oct 15, 2006 5:34 pm

I think the thermostat for the 300ZX opens at somewhere between 75 and 80 deg C. Try putting your fans behind your radiator and see if the cooling ability improves, as I'm sure you will get better cooling.

Most people overestimate their electric fans ability to cool their motor and underspec their fans - I have found some extreme fans that flow previously unheard of CFM ratings, as listed below. I have heard than the standard 300ZX fan is good for 6000cfm, but I wonder what RPM is required to reach that - I'm sure the CFM of these fans would be enough to cool the radiator enough, as their RPM is not affected by the engine RPM

Zirgo (http://www.zirgo.com/)
3985cfm single 16" http://www.thehoffmangroup.com/Zirgo/de ... emid=ZFU16
3000cfm single 14" http://www.thehoffmangroup.com/Zirgo/de ... emid=ZFU14
These are my favorite brand of fans. Nice thing about them is every fan can be changed from a puller to a pusher without buying anything extra. The fans are also just fans, no fancy looks.

Flex-a-lite (http://www.flex-a-lite.com/)
3300cfm single 16" http://www.flex-a-lite.com/auto/html/18 ... treme.html (looks like crap)
5500cfm dual 15" http://www.flex-a-lite.com/auto/html/mo ... ctric.html
2500cfm dual 12" http://www.flex-a-lite.com/auto/html/lo ... ctric.html

Be Cool (http://www.becool.com/)
will update shortly when the bloody pdf downloads!

M4vr1k · Post by **M4vr1k** » Sun Oct 15, 2006 7:24 pm

The fans i have on there are good quality Davies-Craig fans, they werent cheap. I have them mounted on the outside of the radiator, pushing air though, Do you think they might function better mounted behind and pulling air?

ForemanNZ · Post by **ForemanNZ** » Sun Oct 15, 2006 8:20 pm

Yep, because you may find the fans on the front are blocking air from getting though at speed

M4vr1k · Post by **M4vr1k** » Mon Oct 16, 2006 10:52 am

The issue isnt when i am at speed, its when the car is sitting still

nzeder · Post by **nzeder** » Mon Oct 16, 2006 11:40 am

Some fans are designed as pull others as push - do you know what you have?

M4vr1k · Post by **M4vr1k** » Mon Oct 16, 2006 1:05 pm

These fans can do both. Had that issue first, the fans were pulling air through the radiator, and out the front of the car. Made for a good exterior heater though...We solved that by swapping the polarity on the fans

ForemanNZ · Post by **ForemanNZ** » Mon Oct 16, 2006 1:14 pm

and did you turn the fan blades around? you may find the blades are curved and are specific to pulling air through

nzeder · Post by **nzeder** » Mon Oct 16, 2006 1:29 pm

Most electric fans are the pull type and are mounted behind the raditor ie

front of car ----> raditor -----> electric fan ----> engine (the fast bit) ----> spinning wheels (the fun bit)

I would check the blades as Zfetch states.

M4vr1k · Post by **M4vr1k** » Mon Oct 16, 2006 3:46 pm

ahhh, no, i didnt try that, ill whip them off tomorrow and see if they can be swapped over.
Unfortunately, wont be able to test the results for a few weeks, has been a holdup on the linkages for my new carbs, they have to come from England unfortunately.
Unless someone has a set of master linkages for Dellorto 40mm side draughts