I'm considering taking out the fan and fan clutch, and replacing it with a heavy duty flex fan and spacer. Any reported problems with this? How about any posted horsepower gains? Thanks.

 

Just remember that at low speed and high rpm you will have no cooling ability. As you know when the fan flexes, it draws no air. If you want to increase HP try a Syclone fan that can be engaged/disengaged electrically.

Les

 

I have also been thinking about doing this. My understanding is that the flex fan flattens out when it reaches maximum draw and that has less to do with the RPM's it's turning but more the flexibility of the blade. For example, if it reaches that stage at 2000 RPM, another 1000 RPM will not pull anymore air. If the blade was stiffer, the maximum draw could be reached at say 2500 RPM's with any increasing RPM's not affecting the air flow. That is how they save energy at higher RPM's. If you do install one, let us know how you like it.

alanscott

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These engines are designed to run with the stock fans, I've tried this with the older 7.3 diesel and it did not work as good as the stock system, I went back to the stocker.

 

 

yes I had problems with fan clutches come on to late then sometimes not at all carry extra on with me just in case but since I put the derale fan on it stays around 200 at 70 mph and has 8000 rpm ratings on fan I’ll never get that never faster you go faster fan goes summit is where I got the Derale fan and spacer from California it was hard to find because the size it has to be but now they have a adapter that screws on just like the clutch fan I’m thinking of buying it just to have it makes it even easier to put any fan on you want! Have not pulled a load with it yet but will shortly and I’ll get back to ya and tell you about the experience also I think just putting the fan on saved me the price of a clutch every year and a lot of work. It’s not actually called a flex fan just a derale fan looks like one but blades are fixed so they don’t flatten out always blows the harder you throttle almost forgot my truck is a 1999 f250 2wd 7.3 Dana 80 rear limited slip 3/4 with airbags they seem to do better than stock suspension plus coil over shocks all from summit racing that is a cool place to visit but it might cost ya so many things for your ride and NELLYBELL is worth it that is my rides name by the way I try to take care of her so she may return the favor. Does anyone know what temps should be or not be under a load I think 230 on all is limit but not sure I’ll try to find out before I pull a load

 

230 seems higher than mine goes under a load, without there being a problem. Even heavy loads, mine stays basically right above thermostat open temp. I need to get an egt sensor put in, as thats more significant than ect, under normal/non problematic conditions

 

OEM fan and clutch work perfectly. No need to fool with a good thing.

Most of these trucks do not have a way to accurately monitor coolant temps from the factory. Anything over ‘1/2 way’ on the gauge in dash is indicative of a problem in my experience. (Usually coolers full of mud/bugs/debris) Engine oil temps will get up to 230 or even a bit more under certain conditions, but coolant basically never gets that warm if everything is working correctly.

 

I guess mine should stay a little over thermostat since it’s 195 at least I hope it does. I use a bully dog to check everything it seems to be right in tune with it. I’m not downloading nothing into the motor just monitor only it has a six position chip works fine on 75 don’t want to go passed that.