Interesting topic about the Pentastar fan. I don't currently have a LS swap but have a 2014 JKUR which I using for towing a 2700 lb trailer out here in the hot west (Sacramento). When going up long and steep grades in ambient temps over 95, I can see temps on the EVIC go up over 240. If I try to keep speed, the vehicle will go into limp mode whcih limits RPMs to around 4000 and then it cools rapdily. I attribute some of the problem to having 4.10s with Wrangle Duratracs (34.4) casuing engine RPMs to jump above 5000 for a prolonged period, but I don't think that is the whole story. I did have some Drake off-road inserts in the grill whcih I have since removed. It has not been warm enough as of yet to see if the insert removal will make a difference. I have read and observed that the Pentastar fan really does not kick on until 210, and does not reach full duty cycle until the temp is 226. A company called HPTuners makes a tuner that you can reprogram the fan to reach full duty cycle at any temp you choose. I have read that another Jeeper was successful in aleviating his over heating issues by reprogramming the fan to reach full duty at 214. So MoTech having all this expereince with the Pentastar fan, do you think this would be an effective strategy to keep the stock Pentastar from overheating and going into limp mode while towing out here in California?
Appreciate your input:grin2: (PS about 4 years from an LS swap)
Both the Pentstar and Camaro SS fans are far superior tot he discrete, DC, unsealed, brushed, single wound(two speeds through a JK fan. Many Hemi applications run the Pentstar fan full time. The Pentstar fan(like the SS fan) is PWM controlled, an outrunner design for more torque and larger fan blade, brushless, sealed.....
The issue with these variable speed fans is if you run them to hard for too long they will overload. If you have a winch, lights, grille inserts, etc., in front of your grille once you get going down the highway most of the incoming air gets diverted over the hood. So at 80 mph you have the cooling fan screaming for hours to keep the engine cool. These fans can pull 350+ watts and I have seen the cables melt from the heat generated. We have upgraded to 8 and 6 gauge wire to help avoid this. The fans will shut down if worked too hard so the manufacturer needs to limit the fan output to work within the fans ability. The discrete DC fan motors had no logic and would run until they failed. We limit the duty cycle of these fans to between 80-85% to protect the fan module from overload. The solution if you have a heavy JK or tow is keep the grille obstructions to a minimum. Even screen mesh in the grille openings will cause surface tension creating a barrier deflecting the air flow over the hood. Don't run reduced opening grilles like angry eye grilles, sink the winch, put the lights outboard, put the license plate down below, run a manual condenser if possible and get rid of the useless trans cooler in the bottom of the automatic AC condenser.
I have seen Hemi's overheat with this fan but you can't wind the fan up more or it will fail. The Camaro SS fan seems to be more tolerant to shutdown than the Pentstar fan so I personally prefer it but it is not a drop in like the Pentstar.