clutch or flex fan

Posted By: 4spdana

clutch or flex fan - 03/17/13 06:03 PM

i've seen dyno results for using a clutch fan over a solid steel fan. but how does a flex fan stack up to a clutch?

i have a small block i turn 7500 that i run on the street and a little at the strip.

what would work best , or should i use electric fans on radiator ?

suggestions?

Attached picture 7629314-MoparGarage025.JPG

Attached picture 7629314-MoparGarage025.JPG

Posted By: therocks

Re: clutch or flex fan - 03/17/13 06:17 PM

Most will say a clutch fan or electric.Ive run stainless flex for at least 25 years.Never a problem.The one on my 440 sees hi RPMs all the time and is street strip.My kid runs one on his 413 also.Never any overheating problems and both have factory rads.Most people with overheating problems are after market rads and clutch or elec fans.A lot will say a flex requires HP to turn.My answer is if that is slowing you down you need more motor.Rocky

Posted By: 1_WILD_RT

Re: clutch or flex fan - 03/17/13 06:20 PM

Either a clutch fan or electric, I've seen the aftermath of a couple flex fans letting go... 7500 is twisting it up there, a clutch fan would probably only see 4500 or so, the flex would be directly driven & since the WP pulley is slightly smaller than the crank the fan may see 8-8500..

Lotta centrifugal force at that speed...

Oh, BTW the one car I was riding in when it lost a fan blade at 80mph the fan blade exited the RF inner fender & cut through the tire... Driver skill keep things from getting very ugly that day...

Posted By: 4spdana

Re: clutch or flex fan - 03/17/13 06:35 PM

what brand of flex fan you using?

Posted By: 340SIX

Re: clutch or flex fan - 03/17/13 07:12 PM

Quote:

Either a clutch fan or electric, I've seen the aftermath of a couple flex fans letting go... 7500 is twisting it up there, a clutch fan would probably only see 4500 or so, the flex would be directly driven & since the WP pulley is slightly smaller than the crank the fan may see 8-8500.. Lotta centrifugal force at that speed...

Oh, BTW the one car I was riding in when it lost a fan blade at 80mph the fan blade exited the RF inner fender & cut through the tire... Driver skill keep things from getting very ugly that day...

I like the great hole they make coming out Fiberglass hoods, kinda like a large toaster

Posted By: 360cuda

Re: clutch or flex fan - 03/17/13 07:16 PM

I used to be a firm believer in flex fans until I pulled a blade off one out of my battery...never again. That thing made a mess out of my Challenger

Posted By: 68LAR

Re: clutch or flex fan - 03/17/13 07:29 PM

Quote:

what brand of flex fan you using?

Most of my friends that run street/strip cars that use a flex fan are using the stainless steel Flex a lite 1300 series. They're good for 10,000 rpm and pull gobs of air. They are a little louder, but that comes with the territory. I use a Jag clutch unit with a 6 blade fan. It don't kick in until 180*, so with a 160* thermostat, most of the time it is freewheeling. My engine seldom gets above 165*.

Posted By: 4spdana

Re: clutch or flex fan - 03/17/13 07:44 PM

thanks....Sweet B-body.

is it really 440 ci ?

how is it so fast?

Posted By: 1968RR

Re: clutch or flex fan - 03/17/13 08:45 PM

Quote:

thanks....Sweet B-body.

is it really 440 ci ?

how is it so fast?

If I remember correctly, there was an article in a Mopar magazine (or was it Car Craft?) a few years ago about 68LAR's car. My '68 Road Runner is kind of like the twin to his GTX (color, hood, 440, etc.). His ride is really nice.
Also, I run a flex fan and I've never had any heating/cooling issues.

Posted By: Mr.Yuck

Re: clutch or flex fan - 03/17/13 10:21 PM

Grab a Summit 18.5" plastic fan. They work great and you won't cut your hands all up and you won't send a fan thru the rad. And the best thing is they are CHEAP.

Posted By: forphorty

Re: clutch or flex fan - 03/17/13 10:43 PM

http://www.network54.com/Forum/215655/message/1066184641/Car+Craft+Cooling+Fan+Dyno+Test

Posted By: 4spdana

Re: clutch or flex fan - 03/17/13 11:07 PM

thats what i was looking for...thanks.

and a summit plastic fan... never would of guessed it

thanks for all the info

Posted By: 68LAR

Re: clutch or flex fan - 03/17/13 11:20 PM

Quote:

Quote:
thanks....Sweet B-body.

is it really 440 ci ?

how is it so fast?

If I remember correctly, there was an article in a Mopar magazine (or was it Car Craft?) a few years ago about 68LAR's car. My '68 Road Runner is kind of like the twin to his GTX (color, hood, 440, etc.). His ride is really nice.
Also, I run a flex fan and I've never had any heating/cooling issues.

Thanks, I appreciate the compliments.
It was 2004 when my car was featured in MOPAR MUSCLE. Some things have changed since then. Back then I was running in the very low 12's with a .040" over 440. Over the years I've changed a few things. I currently run a 493 stroker. The rest of the car is basiclly the same as back in 2004 except for a new interior and some suspension and transmission upgrades. I feel blessed that the car runs so good, especially being a heavy stick car. Just like back then and since I bought the car, I've done all of my own work except for the machining part.

Posted By: RoadRunnerLuva

Re: clutch or flex fan - 03/18/13 11:07 PM

What about the MP "Viscous fan/clutch" kit...
what RPM's is this fan good to?
Is it a good setup for street/strip cars?
Anyone here use this fan kit?

Posted By: Mr.Yuck

Re: clutch or flex fan - 03/19/13 01:38 AM

Quote:

thanks....Sweet B-body.

is it really 440 ci ?

how is it so fast?

It's a 440.... I hope to be in the 11.teens-20's w/ a stock stroke, stock 6-pack this year... 3.91's driven to the track and back... vroom vroom.

Posted By: Mr.Yuck

Re: clutch or flex fan - 03/19/13 01:41 AM

Quote:

http://www.network54.com/Forum/215655/message/1066184641/Car+Craft+Cooling+Fan+Dyno+Test

50 hp from a fan???? really?

Posted By: forphorty

Re: clutch or flex fan - 03/19/13 03:14 AM

Quote:

Quote:

http://www.network54.com/Forum/215655/message/1066184641/Car+Craft+Cooling+Fan+Dyno+Test

50 hp from a fan???? really?

http://www.carnut.com/ramblin/dyno.html http://www.carcraft.com/techarticles/ccrp_0311_drivetrain_power_loss/viewall.html

Posted By: ahy

Re: clutch or flex fan - 03/19/13 03:26 AM

Quote:

What about the MP "Viscous fan/clutch" kit...
what RPM's is this fan good to?
Is it a good setup for street/strip cars?
Anyone here use this fan kit?

I'm running that kit on a 496B engine with AC. Works great. I have a backup 7 blade fan I've never needed. Agree as many have posted, the clutch fans seem to take high engine RPM without coming apart like (some at least) flex fans do. The thermal clutch cuts down on HP loss.

Posted By: therocks

Re: clutch or flex fan - 03/19/13 10:58 AM

I run Summits stainless 18 inch fan.Been on at least 15 years and still like new.The 440 sees over 7K all the time.Runs 180 all day long.Picked it up in their clearance for like 10 bucks.Rocky

Posted By: radiatorman

Re: clutch or flex fan - 03/19/13 01:58 PM

Look at a Hayden 3718. 34 years on mine.

Bob

Posted By: Mopar Mitch

Re: clutch or flex fan - 03/19/13 06:53 PM

Flex fans were banned from being used on autocross cars by the SCCA Solo group a few years ago. They claim too dangerous; I've raced with a couple different flex fans (thin and wide... wide gives better cooling a lot!) and never had a problem, but a clutch fan broke my water pump shaft a long time ago (30 years ago... so that's when I changed to the flex fan.. never any problem).. But, now the rules have changed to allow electric fans.. to be installed sooner or later on my car.