Fast355

Same fans and motors

I have the massive big block radiator too. 34" x 19.5" x 2.25" core.

Vindii

A Tahoe has a 6.0 in it?

I assume your saying the 5.3 and 6.0 used identical fans?

Fast355

The fans I have came from a Police Tahoe with a 5.3. The fans have the same housing, fan blades, and motor as a 6.0L 1500 truck. GM does not even build the newer 6.0L HD trucks with electric fans.





Compared to a coupled up Duramax fan, there is no comparison. The electics might pull as much around idle but as the RPM climbs the mechanical quickly pulls far more CFM.

3500Silverado

Just FYI, Flex-A-Lite lists a 282 (I wouldn't even consider using), a 284 (DuraMax), and 294 fan and shroud assembly for 34" core radiator GM trucks. The 282 has a pair of 15" straight blade fans, has a 28 amp draw, and flows 5500 cfm max. The 284 (DuraMax) and 294 (custom, for their radiator, but mounts the same) kits have twin 15" S blade fans, are rated at 6000 cfm, draw 36 amps, and have 50 amp circuit breakers. All three kits have variable speed control.

I am not sure that 6000 cfm at low speeds, under heavy throttle, and especially at high temperatures, is enough.

According to Flex-A-Lite, the fan kit is rated to 18,000 pounds total weight (vehicle, trailer, and cargo) however, the electric fan kit is not suitable for a diesel as primary cooling air flow under heavy towing.

The 284 kit for the DuraMax is $159 higher than the 294 kit for Flex-A-Lite's custom aluminum radiator, although they appear to be dimensionally and functionally identical.

I do not know that an 8.1 gasoline engine will put as much heat in the coolant as a 6.6 diesel engine. Also, while modified engines that make more HP also make heat, it should be noted that the stock engine and stock tune, especially with the stock exhaust, will labor more and longer under a given load, and may make more heat, due to the lower power and efficiency. A seriously modified engine will push more heat out the exhaust, and will also not labor as much under a load.

I think the problem might arise if you do not have enough power to pull the load without long periods of heavy throttle, and are not able to maintain enough speed to generate additional air flow. If you have to use over 35% throttle and can't get over 40-50 MPH, you will probably see over heating.

Fast355

The factory Tahoe fans I ran have 2 different blade counts for noise cancelation, but are the same motors. The motors wired in parallel on high speed draw 40 amps. When wired in series they draw 10 amps and run at half speed. The factory relay setup had dual fuses and 3 relays to allow the PCM to switch between low and high speeds. I had the fans under PCM control. They move a massive amount of air but not nearly as much as a clutch fan with the clutch engaged. With the engine at 3,500-4,500 rpm climbing a long grade at 60-70 mph the electric fan setup would start to overheat and rise up to the 220-230*F range. Now with the Duramax fan blade and HD clutch even with a 25% underdrive (reason I used the Duramax blade to get a more aggressive pitch) on the crankshaft, when the engine starts to get up to the 190-200*F range now, the clutch engages and the temps drop INSTANTLY. The hottest I have seen it run is 203*F and that was after thrashing it on the highway coming back from San Antonio on a 105*F day, I had to come to a dead stop for about 30 minutes while the highway was cleared of an accident. It leveled out at 203*F after a few minutes and just stayed there until I was able to get the engine rpm higher.

Kerr

they suck

ive spent more damn money on controllers than i did the fans, i tossed it all in the trash last time. not to mention i called them for a fan blade and they told me they couldnt help because i didnt have the fan blade part number... i was like WTF, you all build the **** no me..

so i went with a company on line, custom built for the suburban about half what flex a lit crap is and they are quite, and cool better..

Kerr

FF Dynamics they will ask you a bunch of questions, i think mine is same size as a truck, so you could just get it copy of what i did, they probably have it on file


there e mail says it is " chevy 2500 extreme stage 5" but i cant find it in the links on there web page..

anyway they cool fine, we play a LOT in the mud and off road in the mountains and its never gotten above 180* after the install,

DEWFPO

Am I reading you right...? Your running a DMax fan blade on an 8.1 H.D. Fan Clutch, or is it a Dmax H.D. Fan Clutch. How are you underdriving it?

DEWFPO

Fast355

01-04 Duramax fan blade on a 2007 Trailblazer SS thermal fan clutch on a 1997 L31 350 in an Express van with March underdrive pulleys.

Before spinning the fan on


GMT400 5.7 Tow fan vs Duramax


Installed (Before underdrives)

DEWFPO

Thanks,

DEWFPO