electric fan conversion

[Laird Scooby]

Originally Posted by tofufi

I found the electric fan gave me around 1mpg more

Probably makes less difference on diesels Jim because they have all the torque down the lower end of the rev range. I know on the petrols i've done it on, i've usually got 12-15% improvement in economy and a similar improvement in liveliness, best was my Jeep Cherokee, got about 18% improvement on that (24mpg) and that was on LPG as well!

I know when i took the vicious fan off this 760, i thought i'd gone deaf and it warms up a lot quicker too. Haven't as yet fitted the "normal" cooling fan to it, been running a couple of years now with just the secondary A/C electric fan keeping it cool.

[TonyS9]

Originally Posted by griston64

I have been told it gives a few more mpg ?

I very much doubt that, even the 1 mpg claims, wind direction, air temperature, diff and gearbox temp, driving style will have more of a difference.

An in-line engine will move through the air pushing the fan, negating any drag or load on the engine it creates. Fans are really just to keep the engine cool at idle when the car isn't moving. Transverse Engines like the mini, may benefit more because the fan is not in the line with the airflow.

Noisewise the viscous fan is vary quiet unless the engine is warm in which case it sounds like a bus, but this normally goes ayway after 30s or so of traveling at 30mph. This is much like the electric fan. I only get the bus noise on rare hot days in the summer sitting in traffic.

In the 940 a 2 speed electric fan is used only for AC models, because the idle engine load can be very high aswell as heat created by the AC cooler. It is not 'better' than a viscous fan in principle, It is just the idle speed is too low, electric is more flexible this way.

[griston64]

Originally Posted by TonyS9

I very much doubt that, even the 1 mpg claims, wind direction, air temperature, diff and gearbox temp, driving style will have more of a difference.

An in-line engine will move through the air pushing the fan, negating any drag or load on the engine it creates. Fans are really just to keep the engine cool at idle when the car isn't moving. Transverse Engines like the mini, may benefit more because the fan is not in the line with the airflow.

Noisewise the viscous fan is vary quiet unless the engine is warm in which case it sounds like a bus, but this normally goes ayway after 30s or so of traveling at 30mph. This is much like the electric fan. I only get the bus noise on rare hot days in the summer sitting in traffic.

In the 940 a 2 speed electric fan is used only for AC models, because the idle engine load can be very high aswell as heat created by the AC cooler. It is not 'better' than a viscous fan in principle, It is just the idle speed is too low, electric is more flexible this way.

Thanks for all the advice guys. I've pretty much decided that for all the faffing it's not worth it. I have plenty other jobs to do that will improve the car ( all new front suspension etc ) so I'll be getting on with those rather than something that doesn't.

Cheers, Mark

[tofufi]

Originally Posted by TonyS9

I very much doubt that, even the 1 mpg claims, wind direction, air temperature, diff and gearbox temp, driving style will have more of a difference.

That was over 30k miles of experience driving that car (which I still have), not over a short journey or two. It was a consistent improvement readily apparent as soon as I made the change. The viscous fan is less efficient than an electric fan.

[Laird Scooby]

What Jim said! ^^^^^

It definitely improves mpg and power - there are dyno tests on YouTube that prove this not to mention my experience, Jims and a whole host of other people who have convereted to an electric fan.

Generally speaking, those that have, never go back to a vicious or straight coupled engine-driven fan.

I don't keep such meticulous records as Jom does but i do keep an eye on how much fuel i use and there has been a definite improvement since removing the original noisy thing. It also warms up much quicker too, a bonus at this time of year!

[tofufi]

Originally Posted by Laird Scooby

What Jim said! ^^^^^

It definitely improves mpg and power - there are dyno tests on YouTube that prove this not to mention my experience, Jims and a whole host of other people who have convereted to an electric fan.

Not to mention: name one current production car with a viscous fan. There's a reason manufacturers aren't fitting them any more!

[kelvinp]

Originally Posted by Stephen Edwin

Possibly yes. Basically by running the engine hotter, well that was the Kenlow theory. On a Morris 1100 A series I got increased mpg. Kenlow claimed 10%. That was in the days of fixed fans, not viscous, but is that relevant?

Some members have spent effort and money on going electric fan. The results have varied from good to difficult. In my opinion, you are wise to look before you leap.

I think the thinking behind the electric fan is that it only runs when needed and so it is not putting a constant load like the old fixed fans where the blades cause a lot of drag - plus they cool the engine when they don't really need it. Think the problem with viscous coupled fans is when they pack up and seize, they end up as inefficient as the fixed fan.

I've got a '59 Singer Gazelle fitted with an aero-fan, these were one of those 60s & 70s gadget with variable pitch fan blades which were supposed to be more efficient. How much they actually are I don't know.

Volvo certainly could have fitted electric fans, my 740 has the viscous fan and sounds like a 747 on take off when pulling away.

[griston64]

Originally Posted by tofufi

Not to mention: name one current production car with a viscous fan. There's a reason manufacturers aren't fitting them any more!

They are plenty of things on my 940 that manufacturers don't fit to production cars anymore....that's why I like it

Despair ye not though,as I will put the fan in a safe placeand once every other job is done I will re visit

[TonyS9]

Originally Posted by Laird Scooby

What Jim said! ^^^^^

It definitely improves mpg and power - there are dyno tests on YouTube that prove this not to mention my experience, Jims and a whole host of other people who have convereted to an electric fan.

Generally speaking, those that have, never go back to a vicious or straight coupled engine-driven fan.

I don't keep such meticulous records as Jom does but i do keep an eye on how much fuel i use and there has been a definite improvement since removing the original noisy thing. It also warms up much quicker too, a bonus at this time of year!

It definately doesn't improve mpg or power in a real situation. The dyno tests are completely invalid for a moving car.

Long term records are not reliably consistent, you need a precision measurement that can be repeated to say that it makes a difference.

If your viscous coupling was faulty/siezed then you will notice a difference in noise/warm up etc. In 30 yrs I've never had a faulty one, I suspect they are more reliable then electric fans.

I'm not saying there arn't benefits, but the power and mpg are not significant or probably measureable.