Hello.


My car is '92 XJS facelift 5.3L, I changed the mecha fan to a 2-speed electric fan from taurus.
I also changed the aux fan to an aftermarket one which claims 1500 cfm (I really doubt it though, because it has 80W motor and it can't produce such air flow)
I control both with 3 relays.


The ability of cooling itself isn't a problem. The problem is high current draw of those electric fans.
In Japan summer is crazy, it often reaches 100F during the day, so I need powerful fans. That is why I chose the 16.5inch 2 speed taurus fan.
But they consumes a lot of current. When high kicks in, it consumes 28A, while the aux fan consumes 7A at the same time.
The voltmeter in the instrument drops around 12.5V, the tachometer starts jumping (I have already add earth line to the instrument pack)
In addition, when the high kicks in I can feel the vibration through the steering wheel.


I want to ask those who did the conversion what fan you use, how much current the fan draws(if you know), and if you have vibration problems or not.
I am thinking of changing the fan to a more efficient ones. Seeing the tachometer hopping around is really frustrating, and the big amp draw makes me a bit anxious.


Mine is a facelift and already has 115A alternator. Plus I changed the battery to a bigger one by cutting off the bracket to make room for it.


Any info is appreciated.

 

A Vibrating fan is likely out of balance. The fan motor may have a label for a part number and then you will be able to find the mgfr spec sheet that lists the amps at various speeds.

 

I have done a conversion but I have no vibrations, and as far as the consumption is concerned its significant if the aircon is on full blast,
so much so I have rewired them so the left one comes on with aircon and water pump switch., and the right one comes on when a fan switch in an alloy hose adaptor reaches 90c, I went down your path initially but having now fitted the v12 performance setup I realized I had wasted my time, I didn't use the v12 performance wiring though,

 

A decent 16 inch fan should not draw more than 20 amps absolute max. Perhaps change the fan to a Spal or a Pacet? Also make sure that the rubber cotton reels that go into the OEM shroud fixings are 100%. If these changes still leave vibration, I am not a fan of using the OEM shroud for a big electric fan as it is not robust enough IMO for that purpose.

So if vibration persists after a fan change (in the absence of an RGP-type proprietary system) may I suggest that you mount the fan pack on a home made aluminium chassis that you suspend at the top from underneath the radtop cross panel on rubber cotton reels (the same ones that Jag use as standard on the OEM fan mountings, oil cooler and condenser rad mountings) and from the bottom on studs welded horizontally to the rear of the cross member, also via cotton reels. If you do this and the fans are not unbalanced you will feel nothing in the car.

Greg

 

My V12's all have the Aussie Ford Falcon twin thermo fan assembly fitted.

They are single speed and pass some serious air. No idea of CFM, but blow the hairstyle significantly.

They draw 7 amps each. Start up is "about" 12amps each.

Mine are wired with the RH as thermo only, utilising the factory sensor in the bottom hose inlet casting. The LH is a/c only.

With the a/c ON, and the LH fan obviously running, I have NEVER had the RH thermo on, even in our 45c+ summer temps.

I am happy.

 

Thank you everyone,

Warlock, I hope it is not out of balance, for I use a brand new fan. At least I still have an option of making the shroud stronger and remaking the bracket, as Greg suggests.


rgp, so you eventually go for a twin fan option... I am interested in a twin fan conversion too, using the shroud of the twin fan, I think I can reduce the amp draw by that.


Greg, thank you for your help all the time. Actually I don't use the rubber bushings to mount the fan shroud. I wanted to use them but I had no space between the crank pulley and the fan shroud. If I use the bushings their thickness make the shroud come nearer to the pulley.
The Taurus fan is really strong and cheap, but most 16" fans are not as strong as that but they are much expensive, so if I am supposed to have another 16" fan I can shoose twin fan option... Maybe I will go for that.


Grant, many thanks for the data. I actually look for some vendors which can sell and send the AU Falcon fan to Japan but in fail. But your comment about the Falcon twin fan is really attractive, I will look for Ford or GM twin fan, which is likely to have similar specs.

 

JT
I think no rubber mountings will always produce quite noticeable vibrations, even with a perfectly balanced fan. Maybe worth trying out some rubber before buying a new fan?
Greg

 

Greg,

Thank you. I see, I will try that. Fortunately fall soon comes and I won't need high fan for a while, I will but the rubbers on the mounts and see how the vibration goes.
However the high current draw problem will still exist, I am thinking of changing the fan before next summer anyways.