Does the OEM fan have this blade shape on it? (too cold to go look at mine lol)

https://www.rockauto.com/en/moreinfo...t=2181&jsn=448



Blade shape matters in flow... s-blade flows less than this design in pic above. If OEM has that blade shape, it explains why those that delete the fan clutch can get away without the mechanical fan. HPT indicates it should be a 2 speed fan yet the link indicates a 2 pin connector which would be a single speed fan. if it is a 2 speed fan then it might be that they are using PWM to control it or, reduced supply voltage to it. Anyone have some insight on it?

https://www.cumminsforum.com/threads...amber.1706266/

 

Yes to the blade shape. This was my nonworking OEM fan. I do believe it was a two pin connecter when I looked at the plug.


I wouldn't be brave enough to do a clutch fan delete and rely on it alone. Even if the blade shape is highly efficient at moving air, the fan covers too small a portion of the radiator. I don't recall coming across any threads with accurate temp measurements after the clutch fan delete .

I can confirm however, that the clutch fan can do the job all by itself. I'm pretty sure my E-fan wasn't working for over 80K, till I replaced it last summer.

 

Thanks for the pic! The fan by itself as you noted does not cover enough of of the radiator core to give that 100% comfort level in the worst conditions.

I may have to re-assemble the test chamber and compare them. IIRC the motor has that same 3 bolt mount setup, might be possible to swap the motor over if it does indeed have the same radius if the CFMs are off enough to make that effort. If it proves to flow less then the volvo fan then it might be worthwhile to do the volvo fan + shroud swap. The dual fans on the Ram have kept it plenty cool with just the low speeds. I have towed with it a few times and never had a problem, temps did rise some as expected (+5~10* on grades) but nothing the cummins motor could not handle.

One of the todo tasks on the ram is to yank the fan setup and redesign it to better allow me to leverage the heat that gets pulled. Also wanting to experiment with some ducted cooling setups.

 

The Volvo fan would be the better choice. The factory electric fan is only a booster, likely designed to keep it from overheating with the air on at idle/just off idle when a mechanical fan is at its least effective. I have no idea if the factory electronics will handle the Volvo fans, but if nothing else Delta Current Control makes a fine fan controller. Or, at least they did when I last bought one in the early 2000s.

 

I used the factory 01+ pigtail to fire a 75 amp relay, which went to the Mark8 fan.

Now I have 2 SPAL fans wired directly to the factory pigtail with no issues.

 

The controller for the Dak fan, the assumption it either supplies 12V or completes ground, will have to look at the FSM and see how it is setup. Will measure the Dak fan current and determine if the low speed on the Volvo would work ok with the Dak controller. If not, there is always the volvo controller which takes a ground connection to activate lo/hi on one of 2 wires. I know the hi setting has a startup that is over 30A & it would need an in-rush current suppressor to give it a soft start if it is used. (have p/n's for it if needed)

 

Have a CumminsForum buddy in TX that had his setup light up using 2 taurus fans... Suggested the part I mentioned above with the in rush suppressor and me mentioned he was going to a mechanical clutch again. That lasted all of 2~3 months and now he is back to fixing his e-fan setup. This guy tows 23~25k gvwr IIRC regularly with the 2 e-fans. Back when I was testing I snagged a tarus fan & tested it against the volvo, it edged the volvo out by something like 200~300 cfm. S-Blade Taurus vs straight blade Volvo... (details in the thread linked in #1)

why did you ditch the Mk8 fan?

 

The mk8 doesn;t fit the scirocco radiator/intercooler combination. It's still in the garage on a shelf.

Factory wiring is a constant ground with relay'd positive off the PDC. It's #10 wire and factory fuse is 30 amps I think. The PCM triggers the relay in PDC.

 

That would be awesome to use the factory trigger... drop the Volvo fan in there connected to the low setting and let the PCM do the work. If needed, could add a 2nd temp sensor setup like what is on the ram to trigger the high speed. I doubt that would be needed... to date, the ram has never needed the high fan speed.

 

Stock AC fan is not gonna cut it, not when you're towing, heard a lot of guys with running this one only and gotten into problems.
I know you wanna change the thermostat and still run 195F, but i do know one thing with our 4.7L, they don't behave well when overheated.
This is my only concern with this engine, overheating the engine and have a valve seat drop.

So a bigger fan is a must when delete the clutch.

I heard, but i don't know and i don't even think so, the PCM would be capable of switching up tp 50 Amps.
I've got the little Saab Fan in stead of the AC OEM fan, think it's about 30A, just cut the factory connector and it's directly controlled by the PCM exactly the way the OEM AC one was.
This is a 2 plug connector, so 1 speed only.

Our PCM drive a 1 speed fan signal, the viper ones uses 2 speed fans controlled by PCM, don't know and don't think this is changeable in our PCM's, they both are basicly the same JTEC PCM's but.....

I should let the high amperage fans be controlled from the PCM using a relay, this way you're always safe and have factory, automatic control of the fan, like Magnethead suggested