24 replies to this topic

[minimender]

I've run without a mechanical fan with no problems
The electric one I had behind the wing worked very well and I only had to switch it on in heavy traffic if the weather was hot.

It was a four blade fan with big blades, not sure what it was off

two fans can restrict air flow if they are not running at exactly the same speed and are pulling/pushing the same amount of air.

Forward motion will cool the engine and the radiator without a fan but by how much depends on weather and speed

just my opinion

[Cooperman]

I'm simply amazed that anyone would risk 'cooking' their engine by replacing a constant-cycle mechanical fan with a less than 100% duty-cycle electric fan just to gain a perceived very small power gain. What might be the advantage. To move a required volume of air through the radiator requires a certain amount of mechanical work to be done. If it's not done by the mechanical fan which gets its power from the fan belt (i.e. from the crankshaft) it gets electrical power from the alternator, again via the same belt (i.e. from the crankshaft). If less power is being taken by the fan from the engine output then it's because less cooling air is being shifted. You don't get electrical power from the alternator for 'free', the higher the electrical demand, the more power is taken to drive the alternator.
So what is the advantage of just having an electric fan?
The only time you might get the increased power is when the fan is manually switched off, but the time you need the power is when driving flat out on a track, and at that time max power will produce max heat, so the fan will need to be on.
Still, if some think deleting the mechanical fan is worth risking a cooked engine for, then go for it.

[MGBailey007]

he was only going to leave the fan off until he got the new parts, he was asking if it would be ok to run the car just on the electric one until they came in

[firstforward]

It is all about efficiency, an electrical setup is always going to be more fuel efficient than a mechanical setup and quieter running. It is for that reason all cars have moved over to electrical. The big question is, will a side mounted radiator in a mini cool sufficiently not having a mechanical fan. I have seen many over the years that have not used a mechanical fan without any problems arising, the electrical fan on its own is very efficient at passing air over the radiator when the need arises, which incidentally is normally when in slow moving traffic or stationary, it is not running all the time. At full chat/speed there is sufficient air flow over the rad.

After all that there must be a reason somewhere why a mechanical fan on a side mounted was kept.

[Bungle]

nope

modern cars went over to electric fans because of their front mounted rads not needing the fan on all the time

a electric set up is a lot more controllable than switching a mechanical fan on and off

every time you turn a source of energy from one thing into another you loose a bit

so you going from spinny round engine to belt, from belt to spinning around the alternator, alternator to electric, (electrical loses in the wires and switching), electric to spinning around again (motor)

[firstforward]

Nearly all car had front mounted rads when did that change?

Precisely what I have said, mechanical fans were not needed as their constant “on” was a power drain, they tried to reduce that by viscous couplings that were notorious for breaking, and with reliability of switches it was a win win going electrical. Indeed not relying on a mechanical fan belt breaking added more reliability to boot. Therefore from an efficiency point of view electrical is always going to win, unless the electric fan is always running for which it is not.

[ian2000t]

There are several advantages to running just an electric fan:

- Quicker warm up on cold mornings (warm heater faster, optimum oil temp quicker, less "on-choke" time, and hence better fuel economy and less engine ware especially for short runs)

- Less drain on the engine, especially at high revs. Agreed when the elec fan comes on this point is null, but on the motorway and generally at speed (when you would be revving most) it won't be needed very often due to the air flow through the grille. Therefore, greater power and economy most of the time.

- No "over-cooling" of the engine. An engine will run most efficient at full working temperature. I find the fan on my engine can "overcool" sometimes. You can control this far better with a good electric fan.

- If your engine needs cooling, you still have a fan, which providing you have chosen carefully to ensure it moves the same amount of air as the original belt driven one, it will still cool your engine just as much. Mini's in good condition have NO need for 2 fans!! Mine has a 92C stat, standard rad, standard water pump, higher BHP than standard and has never overheated, even stuck in an hour traffic queue on a very hot (for UK) day on the motorway.


It's something I've toyed with for a while, and if I had a suitable elec fan and temp sensors I'd try it tomorrow. It *may* not be worthwhile - i.e. if it turned out that the fan was on the majority of the time then not worthwhile due to the extra drain on the alternator and also elec fans have a lifespan - they are not designed to be used for too long so you would risk the fan dying leaving you stranded.

Edited by ian2000t, 24 May 2012 - 12:52 PM.

[JustSteve]

if using more electrics, does it actually put more strain on the engine, turning the alternator?




I've said in another thread, that I plan on trying to run without the mechanical fan. I dont really know why, but I'd rather not have it. I'm sure, that there is going to be enough air pushing through the rad while driving... with a good rad I think it'll be perfectly fine and the elictrical fan wont need to be on all the time. I also thought about making a duct to force air from the grill, so it would be, like any modern car with a front mounted grille.

Edited by JustSteve, 24 May 2012 - 12:58 PM.

[ian2000t]

if using more electrics, does it actually put more strain on the engine, turning the alternator?


If yes, then i think it's pointless.

If no, then i think it's potentially a good idea.

As I said above - yes, the extra load on the alternator makes it harder to turn so will put greater load on the engine. BUT, it will not be on anywhere near as much as the mechanical fan... so it's not pointless.... unless you wire it permanently on... then it is VERY pointless...

[JustSteve]

if using more electrics, does it actually put more strain on the engine, turning the alternator?


If yes, then i think it's pointless.

If no, then i think it's potentially a good idea.

As I said above - yes, the extra load on the alternator makes it harder to turn so will put greater load on the engine. BUT, it will not be on anywhere near as much as the mechanical fan... so it's not pointless.... unless you wire it permanently on... then it is VERY pointless...

I agrea with what youre saying. I'd obviously fit some sort of sensor so that the fan only came on when the engine got hot.

I think, as long as the electrical fan idea does work, it has to be more efficient...