Electric fan conversion..has anyone done one?

[aardvarkash10]

stationary or moving, it takes power to drive a fan. If the fluid clutch on the viscous fan is buggered and its locked solid (typical viscous drive failure state), that power is being consumed all the time, moving or not, needed or not.

Electrics, not so much.

Given the size and cooling efficiency of the average 2xx-7xx,9xx radiator, the fan should pretty much never be needed in normal operation ie not towing or hauling ass up a long incline. Perhaps around town on a hot summer day (what, two or three days a year in Blighty? ;-) ).

A small electric would be easily enough if there is not air-con or heavy use to deal with.

[tofufi]

Originally Posted by TonyS9

Well I'm gonna be contraversial.

You are wasting your time, the you tube comparisons of BHP loss are invalid. There are no losses when the car is moving anythihg more than about 30mph. The comparisons are done stationary.

If you want to massively improve your economy get a mpguino and learn to hypermile. Its possible to get 40mpg in a 940.

Strange, I gained a couple of MPG when I fitted the electric fan. I'm averaging 45MPG from my 740 diesel these days, and that's sitting at motorway speeds on cruise control. The engine did also feel slightly more responsive, but that could have been a placebo.

Originally Posted by aardvarkash10

rather than fitting an oem volvo unit, I'd go with an aftermarket kit. It will have everything in it you need.
.

Not sure I'd agree - that kit doesn't have a shroud (which will improve fan efficiency) and almost certainly isn't built to the quality of the OEM bits. I'd imagine a breaker in the UK would sell the fan with shroud, relay and wiring for around the same price as the kit, and being Volvo bits it will look like a much neater installation. Edit: Not to mention getting 2 fan speeds instead of one

[Laird Scooby]

Originally Posted by tofufi

Not sure I'd agree - that kit doesn't have a shroud (which will improve fan efficiency) and almost certainly isn't built to the quality of the OEM bits. I'd imagine a breaker in the UK would sell the fan with shroud, relay and wiring for around the same price as the kit, and being Volvo bits it will look like a much neater installation. Edit: Not to mention getting 2 fan speeds instead of one

I don't agree Jim - there is a shroud on the fan :



Get the right size and when it's fitted, won't actually look that much different from a factory fit jobby.
Also bear in mind the original fan shroud was designed for use with the vicious fan to maximise air flow from the fan and is in fact restrictive to air flow without the fan.

As for getting 2 speeds off one motor, it's easy enough but you need a two-element switch (if memory serves, Vauxhall Omega fan switches are useful for this), a second relay and a 10A bridge rectifier to get the lower speed.

When the first element of the switch is made, it switches relay #1 in sending +ve power to the fan via the -ve terminal of the bridge rectifier and out the +ve terminal to the fan.
When the second element is made (higher temperature), the second relay is operated and the contacts of this realy simply link the -ve and +ve terminals of the bridge rectifier, effectively shorting it out so full power is delivered to the fan.
Going through the bridge rectifier will drop the supply voltage to the fan by about 1.8V which is enough to reduce the fans power by considerably more than the expected drop from losing 1.8V - it's something in the region of 20-30% less power from memory, i did the maths quite some time ago and can't remember the figure off the top of my head.

[aardvarkash10]

Originally Posted by Laird Scooby

Going through the bridge rectifier will drop the supply voltage to the fan by about 1.8V which is enough to reduce the fans power by considerably more than the expected drop from losing 1.8V - it's something in the region of 20-30% less power from memory, i did the maths quite some time ago and can't remember the figure off the top of my head.

yeah we worked that through about 18 months ago I think Dave - iirc I even drew a diagram!

[Laird Scooby]

Originally Posted by aardvarkash10

yeah we worked that through about 18 months ago I think Dave - iirc I even drew a diagram!

I know one of us did and i think it was you. It's since been used and proven at least twice to my knowledge.

[Stephen Edwin]

My experience with a Morris 1100 was a 10% fuel saving by fitting a Kenlow fan. I have seen similar figures quoted for electric fan conversions upstairs in the 240 section.

Kenlow claimed that savings came mainly because engines could be run at a higher more efficient temperature.

But. If I convert the 240 to electric fan my wife will no longer hear and instinctively know if my 240 is started up outside. An essential part of theft prevention.

.

[tofufi]

Originally Posted by Laird Scooby

I don't agree Jim - there is a shroud on the fan :

By shroud, I meant the large backing plate rather than the bit around the edge of the blades...

[Laird Scooby]

Originally Posted by tofufi

By shroud, I meant the large backing plate rather than the bit around the edge of the blades...

With apologies to Croc Dundee II :

That's not a shroud - THIS is a shroud!

Good point, well made Jim! That shroud will also improve flow through the electric fan whether it's powered or not, compared to the shroud for the vicious fan.

[aardvarkash10]

The shroud does improve fan efficiency. It does this by ducting the air so that turbulence at the blade tip doesn't reverse air flow. The ring that most after-market fans have connecting the fan blade tips does the same thing albeit highly localised. Since we are doing quotes, Its a shroud Jim, but not as we know it.

In any case, electric beats viscous AND vicious imho.

[monkeh]

That fan looks familiar...
You still not fitted it yet?

Originally Posted by tofufi

By shroud, I meant the large backing plate rather than the bit around the edge of the blades...