Clutch fan roaring in 1st/2nd?

[kennythewelder]

@kennythewelder did you notice any difference with the e-fan install?

Over the OE 5 blade fan, yes there is a difference, mostly noticeable @ higher RPMs. Big difference over the 9 blade that I had installed. Much better AC. I am still running on my first tank of gas. IDK yet how much better MPGs, but definitely better MPGs. If I had to put a HP number on the swap, 10 HP or so I guess, but the thing is, the more RPMs you turn, the better because of the drag of the fan on the engine. As for the 9 blade, man that thing was killing me. I lost about 1.5 MPH with that fan. Not to mention HP. The faster I turned the (RPMs) fan, the more drag it had. It would scream between 3500 and 5500 PRMs. As for the AC, it cools the truck even @ idle. My truck never did that before.

 

[kennythewelder]

Sent from my Commodore 64 using 300 Baud Modem.

I had one of those, way back when

 

[Macfluke]

I had one of those, way back when

me too... actually I think that was way way back then

 

[L31MaxExpress]

Over the OE 5 blade fan, yes there is a difference, mostly noticeable @ higher RPMs. Big difference over the 9 blade that I had installed. Much better AC. I am still running on my first tank of gas. IDK yet how much better MPGs, but definitely better MPGs. If I had to put a HP number on the swap, 10 HP or so I guess, but the thing is, the more RPMs you turn, the better because of the drag of the fan on the engine. As for the 9 blade, man that thing was killing me. I lost about 1.5 MPH with that fan. Not to mention HP. The faster I turned the (RPMs) fan, the more drag it had. It would scream between 3500 and 5500 PRMs. As for the AC, it cools the truck even @ idle. My truck never did that before.

I am guessing something was wrong with your fan clutch. I did not notice even 1/2 mpg from electric fans when I ran them compared to the plastic GMT400 tow package fan. Driving 80 miles a day at that time mostly highway speeds. I was still pulling down 500+ miles out of a tank. I think my normal was about 510 miles with the mechanical fan and about 540 with the electrics. I had a motor go out on the electrics after a year and had overheating issues and a/c cooling issues in hot weather prior to that. When I installed the Duramax with a new clutch I was getting about 530 miles to a tank. I added the GMT400 pusher modified to fit the Express van at the same time controlled by the PCM to run under 50 mph, with a/c on or engine temp higher than 190°F. Fillup is about 28 gallons with the gauge on E on the 31 gallon tank.