banditzed

iTrader: (3)

Hi,
I searched and couldn't find what fan CFM rating would be needed to cool a Ls1? It's in a 76 Datsun 280Z and there's not enough room to run the dual F-body fans on my rad. Planning on using a single 16 or 18" with a custom shroud. I also want to trigger it through the PCM and with my Vintage Air trinary switch. Any suggestions? I plan on having Speartech modify my '01 harness.
Thanks, Martin

Novas Forever

Do you have enough room for a 2 speed fan from a 3.8 Taurus? They move a tremendous amount of air, are 2 speed, and can be bought right. Check 'em out.

danglerb

Taurus 3.8 fan is about 16" and Mark VIII fan is a monster 18", but the shroud on the Mark is like 22" wide and kind of part of the fan. It wasn't obvious to me anyway how I might cut down without making it flimsy.

banditzed

iTrader: (3)

Thanks for the replys. I'd read about the Taurus two speed but also heard it draws major amperage. I was looking at the flex-a-lite Black Magic 180. 3300 CFM and draws 18 amps. Is that enough CFM?
Thanks, Martin

bczee

iTrader: (12)

I am running two SPAL Fans and I think they draw around 2900 CFM's together. With a 180 Deg T-Stat.. It has not gone above 200 deg in traffic.. (but I is only spring right now, waiting to see how it handles 90-100+)

Oscar Will

I use a SPAL 16" puller fan, I think it is around 2300 cfm, does a superb job.

ChiScouter

What size radiator are you using?

I think cfm and amp draw are directly related, I doubt that any manufacturer has a secret way of drawing more air on less amps

Rodder

iTrader: (2)

fan blade design, shrouding, and motor efficiency can all change the Amps to CFM ratio.

leonpiper69

iTrader: (3)

but still ... the more air it moves the more work (energy) required to do the job.

is it newton 2nd law of motion that says "energy can neither be created nor destroyed, it can only change state".

its kinda like how with a specific drag coefficient and weight you require x number of horspower to reach y number of mph. air is always going to have a given drag, we can't modify the air (i dont think).


as far as motor efficiency a shaded pole motor has very little torque vs. a split capacitor motor, but a split capacitor motor uses a lot more energy and thus can do more work.

and if you have a fan that is designed poorly and does not move as much air, there will be less drag on it, thereby drawing less amps.

so cfm vs. amp draw are directly related.

and yes the efficency of motors today vs. the archaic motors of the say the 1950's has greatly improved, but todays motors are basically the same as far as materials=efficiency the only major diff being for example a spal motor may have more windings, drawing more current to move more air.

a10beav

The '97 and newer Dodge Viper fan pulls about 4000cfm in high speed. The whole thing is about the same size as the F-body or Vettes, but you could cut the shroud down. A new fan is about $200 but you might get lucky and find a wrecked car.

banditzed

iTrader: (3)

Thanks for the replys. ChiScouter, I'm using a Northern Pro 26 x 19 3 inch thick 2 core aluminum rad. Fin area is 21 3/4 x 18 1/2. Does anyone know what CFM the F-body dual fans are?
Thanks, Martin