I'm not a big fan of high volume/flow pumps.  You want the flow rate to be slow enough to allow the coolant to actually dissipate heat as it passes through the rad which is what the stock pump was designed for. I'm also not a "fan" of flex fans or electric fans.  Yes, the mechanical fan will steal a little power but unless you are going for max performance (racing) I doubt you'll notice.  And, in my experience, the stock steel fixed blade fan on a thermal clutch is more reliable than any of the after market "improvements".  JMO
I have a stock pump (89 Standard 5.0, not reverse but that won't matter), a six blade steel fan that was on our factory AC 66, thermal (not RPM) clutch, good shroud, a 20" two row aluminum rad (1" tubes), a 194 degree stat, and a coil in the lower hose.  It has gotten up to a measured 225 degrees while setting in traffic with the AC on in Las Vegas at 120 ambient.  Any other time, including hour long fourth of July parades, it never goes above 200.
For what it's worth, we used essentially this same setup on the Falcon Project with exactly the same results...can't make it get hot.

Good luck Mark, hope to meet you at a Bash some day.

BB
 

Last edited by Bullet Bob (1/01/2019 8:51 AM)

The SPAL electric fan was one of the best modifications I've made to my car.  I built a double relay fan controller with a thermostatic switch.  With an old school three row copper/brass radiator its had no problem keeping the car cool, even in weather where the heat index was over 100 (at that temperature I might add it only ran about 5 degrees hotter than at any other time).  Its been on the car for two years and been 100% reliable.  I did a round trip from my house to Atlantic City back in September and it functioned flawlessly over that 150 mile excursion.

I get the simplicity of mechanical fans, I truly do, but every new vehicle has an electric fan now, and has for close on to two decades.  The reliability issues people may have had almost always stem from a cheap aftermarket electric fan.  A high quality fan, sized appropriately will have no trouble keeping your car cool, and being perfectly reliable. 

The big thing to be aware of with electric fans is there is no industry standard for how to measure fan flow.  Most companies do not test the fan against restriction, and this is why you'll see cheap fans rated at 3,000cfm.  Those numbers are pure BS, because the minute the fan has to operate against restriction the real numbers would be lucky to be half what they claim.  Last I checked a radiator is a restriction, so if you actually plan to use the fan you need to know real world numbers.  This led me to use the SPAL fan I did, because they realistically rate their fans.  Another dead giveaway is that it takes about 10 amps to move 1,000cfm, so if you see a fan rated at 3,000cfm that only draws 15 amps in operation you can be sure that's BS too.  My fan is rated a little shy of 3,000cfm, but draws over 30 amps at start up and mid 20s continuously, so I know its really moving the claimed air, even behind an actual radiator. 

Fixed fans rob a fair amount of HP, and are also on all the time.  I've found this results in over cooling in cold weather and the engine seemingly never wanting to get up to temperature.  Perpetually running an engine too cool results in accelerated engine wear.  This issue is why I went away from a fixed fan. 

Flex fans claim to skirt the HP drain by flattening out at higher speed to reduce parasitic drag.  IMO flex fans are ugly.  They don't look like they belong on a classic car, more like leftover aftermarket stuff from the '80s.  IMO they belong with over chromed out engine compartments and braided stainless hoses everywhere. 

Clutch fans can eliminate the HP drain, except when in operation, but clutch fans add another component that can fail (I've had two clutches fail over the years), so the idea that its more simple and therefore more reliable isn't really accurate in my experience. 

Nahh .... he's hanging out on Beemer boards, working out how to modify them.
I really like my 95 mustang e-fan, controlled by the ecu, pulls around 70A at start-up on high speed, so no surprise that it was introduced along with a 3G alternator.
It only fits because of the short water pump used on the 94-95.
If I was using v-belts, I woulda used a clutch and fan.

Last edited by 50vert (1/01/2019 4:41 PM)

I use a Hayden fan clutch from Rockauto. It’s been reliable so far.

I have two electric set ups that both work very well. One is like TKO mentioned with the Spal fan and a simple temp switch with relay so the fan gets full power. The second is a fan set up from a 95 Mustang GT which is two speed and I trigger it with an aftermarket control with thermocouple in the top of radiator tank near fill neck. I have override switches in both circuits bout have not used either. The one with the 95GT fan is on the car that I have the removable top on the radiator support which also has a large opening cut out. I think it is 29 inches.  

Hmmmm....sounds a lot like how mine and the Falcon Project are set up, with the same results.  Did you include a spring in the lower rad hose?  I'd think with that hi-flow pump you might want one.

BB

Checking for collapsing lower hose is easy to do. Get the engine up to temp to get the thermostat open, stand where you can see the lower hose, then have someone wing the throttle. The sudden increase in rpm spins the water pump faster which sucks more water from the radiator. If the lower hose is prone to collapse it will during this test. There is a reason the inlet of the water pump is called “the suction”. A trip to the parts store for an aftermarket stainless steel radiator hose internal spring will stop collapse.

mark1965 wrote:

and any thoughts on them vs flex fans.

Flex fans are not a good option IMHO.  Engine masters did a shoot out (was free on youtube but now you have to subscribe to motor trend) where they did dyno pulls comparing no fan (as the control) a clutched fan, a light plastic fan, and a stock solid aluminum fan.  The flex fan did the worst, the lighter fans used marginally less HP BUT the clutched fan used the least HP.  

here are some screenshots from the video