L322 Electro Viscous Fan in a P38

So as i said in the other thread im planning on fitting the elctro viscous fan from the L322 4.2 SC into my P38.
Its fitted in the car now with permanent wiring to it and the controller still just lying in the passenger footwell.

The fan fits into the stock 4.6 cowling with some persausion from a heat gun in some spots to gain more clearance. I ended up with about a 5mm gap all round so its quite tight but i havent seen/heard it touching yet.

So we went for the first proper drive with the car yesterday. It was about 100km both ways and ambient on the way there was about 31 deg and on the way back 26 deg.

On the drive there with the hotter ambient.
How my software is set up currently coolant would warm up to about 96 deg when on a flat section to a slight incline, at that point im requesting about 900 RPM fan speed.
Then on a hill coolant gets up to about 98 deg and i then request about 1200RPM fan speed, as i go down the other side coolant quickly drops back down to 92-93 deg.
So i would call that a success.

On the drive back with the colder ambient coolant was constantly about 92 and then it climbs to about 96 on a hill and drops to about 88 on the way down.

So i still need to do alot of software optimization, getting the requested fan speed in relation to coolant temp graph correct is going to be critical and then i have to think about of all the error states that could happen and decide how to react to them.

One thing ive noticed is when at engine idle and im requesting 0 fan engagement the fan will sit in a slightly engaged state. If i then bring up engine RPM at a slight to moderate rate like pulling away at a robot(traffic light) the fan will stay engaged for a while until engine RPM reaches about 2400RPM. But if i pull away with full power the fan disengages almost immediately. So what im wondering is if that is not maybe caused by the solenoid on the fan being abit leaky. Its an old unkown history second hand fan that i got for cheap so i can see if this will work. If anyone could give some input on this that would be great. Will a new fan have a less "leaky" solenoid?

Some info ive found that might help someone do diagnostics on one of these fans.

Pin 1 : Grey : Hall effect sensor 12v+ supply
Pin 2 : Green : Hall effect sensor GND
Pin 3 : Blue : Hall effect signal out
Pin 4 : Black : Fan solenoid GND
Pin 5 : White : Fan solenoid 12v+

Pin 1 and 2 is basically power to the hall effect sonsor. Pin 3 is the signal output from the hall effect, inside the ECU pin 3 is pulled up to 12v+ through a resistor and then whenever the hall effect is triggered Pin 3 gets pulled down to GND by the hall effect sensor. The hall effect gives 6 pulses per rotation of the fan. Pin 4 is controlled through a mosfet that is sent a PWM signal, from my limited testing with the car just standing in the garage idling 3Hz PWM frequency seems to work best. Pin 5 is just connected to 12v+ battery power. The solenoid seems to use about max 1.6amps

Not sure if I've seen the other thread..
What's the point in putting this fan in to the p38?
In my opinion 98c is too hot.. the thermostat is fully open at 96c but you can't do much about that.
I think if i did things over, I'd look at an electric water pump, i think that would be an effective upgrade.. coolant flow at idle, in my opinion, is too low

https://www.landyzone.co.uk/land-rover/viscous-fan-speed.349729/ the other thread

Slight improvement in cooling ability because of larger fan diameter and better/more effienct fan blade design.
Improvement in fuel economy beacause of way more control over what the fan is doing and more effiecient fan blade design.
The ability to turn the fan off for wading. With the fan in a fully disengaged state at idle i can touch and stop the fan with my bare hand.

Just abit of an update.

Ive been running the new fan in the car since ive started this thread and it seems to be performing quite well.
I dont have any actual numbers relating to fuel consumption because driving around town i quite like the sounds when i press the loud peddal.
But we are going on a offroading trip this weekend with a decent stretch of highway driving there and back. So ill be able to get some actual numbers.
Then ill also be able to see how the fan performs while offroading and how i should change my software.

Ive also completely removed the AC condenser fans in the name of less restriction to airflow through the coolant pack.
Interestingly with the car stationary and holding the engine at about 2000rpm and then fully engaging the main cooling fan it actually pulls enough air through the coolant pack that it will start spinning the AC condensor fans without them even being on.

It was an exceptionally fun trip. Extremely wet and lots of mud.
So we left friday afternoon after work. Before leaving i filled my petrol tank.
We drove to the fuel station nearest to our accomodaction and refilled again.
Distance covered 264km
Dash indicated fuel consumption 12.7l/100km
Dash indicated average speed 76km/h
While cruising we drove between 100-110km/h
I refilled the tank with 30.707l
So that equates to 11.63l/100km

My brother in his P38 with larger tyres(235/85R16)(i have 245/70R16) and a torque max cam got 13.2l/100km

My previous best fuel consumption was 12.65l/100km, I achieved this on a 236km trip with a similary loaded car and driving style, with maybe a slightly lower average speed.

I realise this is just one data point so not super reliable but that 11.63 looks extremely promising to me.

In terms of keeping the engine cool the fan performed really well on and off road.
The fan keeps the coolant temp at around 93deg most of the time.

I did have one issue. On saturday morning it felt like the fan was touching the radiator cowling, i checked it mutiple times but couldnt see anywhere that it was touching. But after driving a particularly hard obstacle it was definitely touching the cowling. After some inspection i noticed that i had completely ripped the left hand engine mount, which was allowing the engine to bounce to the right and up if the car was bounced to the right or under heavy engine braking. This was partially solved with a piece of wire wrapped around the mount to just limit the amount of bouncing. So there is abit of a groove worn into the cowling but not extensive damage to the fan or anything else.
So ill be replacing engine and gearbox mounts in the very near future.

Ill post some footage later. Just waiting on some nice footage from other people.

This was a very slippery mud hill, not thick mud just exceptionally slippery.


Im pretty sure it was on that bounce that i ripped the engine mount. I probably bounced about a meter to the right.


This was when i actually got up the obstacle.

FEI said:

This was a very slippery mud hill, not thick mud just exceptionally slippery.


Im pretty sure it was on that bounce that i ripped the engine mount. I probably bounced about a meter to the right.


This was when i actually got up the obstacle.

Click to expand...

Cool, what a burble

FEI said:

Just abit of an update.

Ive also completely removed the AC condenser fans in the name of less restriction to airflow through the coolant pack.
Interestingly with the car stationary and holding the engine at about 2000rpm and then fully engaging the main cooling fan it actually pulls enough air through the coolant pack that it will start spinning the AC condensor fans without them even being on.

Click to expand...

How does your fan mod spin the AC fans if you have removed them ?

It was while i was testing the main engine cooling fan that i noticed that it would spin the AC condensor fans. It was after i noticed this that i made the decision to remove them.