zwede

I left the AC on by mistake once on the dyno so I can tell you the old A6 compressor will kill 30 rwhp at 5,500 rpm, and the belt didn't squeal.

As for mechanical fans I saw some dyno tests years ago where the clutch fans used 15 hp and the cheap flex fans 25-30.

lionelhutz

I can't believe that. Have any data to back up that claim?

71VetteLover

With the recent discussion about using electric cooling fans and after watching the Engine Masters video comparing the horsepower loss of the different styles of mechanical fans I decided to take the plunge and bought a Derale #16217 fan assembly that comes without a shroud for $165 from Summit Racing.

The opening of my 454's OEM fan shroud is 19" in diameter and so is the outer diameter (across the mounting lugs) of this #16217 Derale so I'm going to mount it into the opening and use four 5/16" bolts screwed from the outside in to attach it. I'm going to screw my 210 ON/195 OFF fan control switch into the left rear hole in my Air Gap intake manifold and use my 6-fuse BUSS fuse block on my firewall to power it. I'll use a Derale heavy duty 50 amp relay to take the grounding load off the fan control switch and I just ordered a new 90 amp stator and 50-amp diode rectifier for my 10-SI alternator.

I'll receive my alternator parts, fan switch, and Derale 50 amp relay by Wednesday of next week so that's when I'll make the swap. The acid test will be running my A/C in town next summer when the temperatures around here will reach 110+ degrees.

By the way, these Derale #16217 cooling fans are rated for 2400 cfm @ 25 amps which equates to 350 watts or .47 horsepower. For a 12 volt fan motor that's a lot of horsepower in a small package. From turning it slowly by hand I can tell it has permanent magnets in it.

lionelhutz

Nice fan, but a 10SI upgraded to 90A will be marginal at idle.

71VetteLover

Yeah, but I very seldom idle my engine and the few times I do I kick it into neutral which raises the idle speed to 1000 rpm with my fast idle solenoid kicked on. What is really different about this installation is the fact I'll be using my OEM fan shroud that covers the entire 18" X 26-3/4" radiator core.

2airtime2

The several hundred CCA battery will more than handle the load during idle.

lionelhutz

Lol, sure run on the battery. The lower voltage will slow the fan but that's not a big deal.

71VetteLover

I'm always looking for things to fiddle with so I thought I'd see how well Derale's highest performance fan works when mounted in my OEM shroud. I have never seen anyone mount their electric fans in their OEM shrouds so I thought I'd give it a try. If it matches the performance of my severe duty 7-blade clutch fan I'll leave it and if it doesn't I'll use the fan for something else.

Kid Vette

I'm running the stock clutch fan and stock exhaust manifolds and '69 style side exhaust and Quadrajet carb. I'm sure there are some on this forum who are convinced my Vette shouldn't be able to move under its own power.

cv67

One guy here mounted the fan on his shroud, if it were me just put it closer to the radiator use a thermostatic switch that comes on a say 200? or when your AC is on then you have the option of adding a mech fan

on elec fan dragging the battery down at idle have experienced that super annoying;even after having a cust built unit done up .
I like the freed up space but not sold on electric fans; do not like seeing the temp gauge fluctuate. Its only steady on the fwy when its not on at all.

71VetteLover

My $165 Derale fan motor has two speeds. I'll start off using the high speed only and see how it acts. I can always add an additional fan control switch and relay if I want to use the low speed too. The best part of it is I'm having fun while learning new things. When I start the installation on Wednesday I'll start a new thread and take pictures along the way while posting them for you to see.

cv67

Definitely do. Fan tech is coming along nice...the 16" spal I use works fine but feel the need for something better. It, with a DeWitts does cool but feel it could be improved. Electronic dummy here so pics help. Like a pop up book I understand now.

I like that idea, makes sense. Are you using the GM or holley one?

Been plagued wiht an issue when I hit 190 deg this thing gets a lazy idle doesnt matter what carb, motor I think its this chit gas
Decided I do not want EFI on an old car & Not sure I want to fool with the IAB any more that switch would solve the problem.

Grumpy 427

I have seen more electric fan failures over a good mechanical fan. Just my preference.

71VetteLover

Are you talking about the fast idle solenoid? It came off a '68 350" Firebird that had a QuadraJet and I made a bracket for it that bolts to my intake manifold. The only thing I don't like about it is it doesn't have enough magnetic strength to open my throttle but it will hold my throttle open once I "blip" the throttle. If I extend the bracket an inch higher it may have enough force to kick the throttle open because of additional leverage. To maximize my alternator belt life I'm running a larger-than-normal 3-3/8" pulley which does limit the charging at idle in DRIVE but it'll produce a heavy charge at 1000 rpm so when I'm stuck in city traffic with my A/C on I'll just kick it into NEUTRAL and it'll immediately go to 1000 rpm because of the solenoid already being energized.

71VetteLover

With the recent interest in electric cooling fans I decided to try one just to see if it'll do the job. I bought the most powerful fan Derale has to offer (the 17" #16217) that is rated at 2400 cfm @ 24 amps. But I'll have to wait until next August when the temperatures reach 110+ degrees to see if it'll match the performance of my 7-blade clutch fan with my A/C on. I was tickled pink to discover it WILL fit into the mouth of my OEM fan shroud with a minor modification because nothing beats the OEM fan shrouds for covering the entire 18" X 26-3/4" radiator core. All of the installations I have seen were showing about 8" of the core being exposed which would equal a 33% loss in cooling power.

Bloodzone

Even with a dewitts radiator and a HD fan clutch my car would run on the hot side of 220 in traffic. Dual Spals got me where I wanted to be. 190* tops, usually lower in Georgia Summer traffic heat.

7T1vette

Auto A/C draws somewhere around 5-6 HP...MAX. You can't get a V belt to hold 30 hp. (Don't know where you got those numbers...)

A 100 amp alternator will draw around 3 hp (accounting for the 1200 watts output [max] and the inefficiency of the alternator).

71VetteLover

As belt driven mechanical fans can consume 30 horsepower at 5500 rpm I'd say a v-belt CAN tolerate that much of a load. And as that same belt is also driving the alternator the load easily exceeds 30 horsepower. The width of the belt needed is dependent on the weight and rpm of the device that is being spun.

2airtime2

That heavy gauge red wire connected to your alternator connects directly to the battery...fyi. Surely you know the alternator keeps your battery charged.


It'll be fine, trust me.

71VetteLover

The Engine Master's fan tests were interesting but not entirely accurate because the "winner" (the OEM style 6-blade clutch fan) wasn't operating in real world conditions. Had the air in the dyno room been heated to 100+ degrees and with 200 degree water circulating through the radiator the fan clutch would have had a lot more driving force and the fan would have consumed a LOT more horsepower. But even with that discrepancy the tests DID reveal how much horsepower the mechanical fans consume at 5500 rpm.

And they also didn't test a true 6-blade Flex-A-Lite stainless steel fan that increasingly flattens as it's spun faster. Logic tells me a flat fan won't be pulling nearly as much air so I wish they would have tested one.

My single wide mobile home has a swamp cooler rated at 2500 cfm that uses a squirrel cage fan that is powered by a 1/3 horsepower motor and it produces a pretty sizable blast of air. My new Derale has a .46 horsepower motor and is rated for 2400 cfm so the performance should be similar. I'll find out after I get it installed.