Also remember that this is rear wheel horsepower so the numbers shown on the charts are 15% less than the actual horsepower that the fan consumes.

Nice to see a well cared for Land Rover in original kit. Not jacked up, big tires ,and an oversized V8 stuffed into it.

While a fixed blade fan will use more power as RPM rises, it's far more of a factor on a dyno where the airflow through the radiator is static. Going down the road, the airflow through the radiator reduces this load considerably. Much like a propeller on a boat/airplane at it's design cruise speed.

good video , Volvo during the late 70's early 80's had these types of fans the worked incredility good and did this test on their CIS engines with and without the fans and found a difference of 5/6 hp at 2650 rpms and as much as 9.5 hp at 70 mph or above, so i upgraded to clutch type fan and noticed a difference right away and got 2.5 mpg better

I found that very interesting. Many years ago I was told 'if you fit an electric fan then remove the old one as it is not needed and will impede performance. So now we know. Yes there are variables but not that much gain really in this case. You made a good point which I was going to mention and that is you probably won't be running your Land Rover at 70 MPH but that was a good 'base line' to keep things on track. Thanks Steve please keep up the good work. 👍👍

Love the dyno videos. This made me remember when you had the mustang club come in and do runs. Honestly I love all you videos, but these are pretty cool and interesting to watch.

I would say that is a significant power gain for zero cost. Leaving the engine fan in place when you have fitted an electric one is a practice that has always puzzled me.

In horsepower numbers, it doesn't seem like a huge difference, but a 7,5% increase in power is a LOT. Think about what you would have to do tuningwise to get that number.

Interesting to see your results, that is a massive percentage of the total power used by the fan! I have removed the engine driven fan from my RZ4E Isuzu pickup, combined with a tyre size change from 255/60/18 to 235/65/18 (identical dia) and A rated for fuel economy tyres i have seen a dramatic improvement in economy. 40.5mpg UK average over 10,000 miles with some journeys in the 50's! If you are not pulling massive loads in high temperatures get that fan off!

I have a suzuki vitara geotracker 99, and replaced the switched viscous fan and get and instant feeling of a lighter engine and better throttle response. I like your video where you put numbers to my feeling, thanks

That was super interesting and the effort it took you to prove and re prove was very good of you to do the work to find out. I have a diesel series 2.25 liter which i have owned 25 years and i have from the beginning always done the bmw ethos of efficient dynamics ie lots of tiny things adding up to a lot and consequently got my gas mileage up around 38mpg and more at times but the 38 is about avg. so 3.9 diffs , freewheeling hubs,O/D,fan removed,larger wheels to aid taller gearing, ep75 gear oil all round. But mostly a light right foot and backing off when climbing any kind of long incline

I have a 1966 Lancia Fulvia which came with a mechanical fan driven from the crank pulley. My car has a modified 1300cc engine which revs out at 8000rpm. I decided to remove the fan , belt and pulley as I believe in this story of power loss. Your video confirmed this. Never had the chance to dyno my car with or without.

Interesting video. Great to take data on something to prove what it actually does!

Much thanks. I love those old Landies!

Great video. Lovely to see the true evidence provided by somebody who truly knows what they are talking about - good work!

Made a noticeable difference on my MGB.

in the early 70's I had a 302 cubic inch Ford v8 , on the dyno, removing the fan gained 12 hp. interestingly so did removing the air cleaner, a gain of 12 hp

Although not a factor with the Landie a fixed fan can make a lot of noise at high engine revs. I think you could hear the difference between the with and without fan runs in this video. Don't know if that was noticeable inside. Viscous fans usually go to full slip at about 3k rpm so should not get any noisier after that.

I love your Landy mate,nice car. Hi from New Zealand!

Thanks Steve!

Very interesting....took mine off 30 plus years ago. Would imagine be a bit quieter as well. Nick in the UK.

Awesome concept for a video! I'm rebuilding my 4cyl pinto, and wondering about fans... especially without a shroud / clutch!

Now you know how much the fan uses when stopped at a light while revving the engine. Having the vehicle actually moving down the road will reduce the fans drag as the air is already moving leaving the fan much less work to do and may even add some power if you are driving fast enough. Not likely in a stock Land Rover.😉😊 You don't need a fan at all if you are moving at least 30 mph. My favorite part about using a flex fan is when the blade breaks off from flexing so much and cuts though 12 tubes in the rad leaving a person stranded at the side of the road in the middle of the night with the temp at -40° F. Don't ask me how I know.😒😒

Interesting test; thanks for posting. If you keep the original fan you need to fit the fan-shroud as well, so that it can suck more air through the radiator.

Fascinating test, I don't think I've ever seen this test before...

I had a Rover 80 fitted wìth this engine. It was a luxury saloon / sedan which was virtually silent, except for the fan whine. I removed the fan and in 2 years of UK driving never noticed any increase in engine temperature, except when stuck in stationary traffic. I then fitted an aftermarket electric fan which only came on once in 2 years. The car was quieter and warmed up better on cold days. I felt it had more power and fuel consumption improved by a small but measurable amount as well.

Lovely car... Awesome video

great stuff thanks

I can remember driving my 850 Mini in the 70s when the fanbelt snapped. The charging light came on instantly but the biggest clue was the sudden surge in power - like I was suddenly driving a Cooper S!

No way that this Land Rover is so low on power, wow! Im impressed... Great video!

Nice Landy!

I've got a 62 IIA 88" that is relatively stock. I did an electric fan conversion a few years back and I am quite happy with it. I have no good way to measure the HP increase but 3-4 HP at the wheels is not insignificant. Also runs quieter, and gets about 1-2mpg better, and less wear and tear on the belt and water pump. at 60mph I get about 18mpg (safari hard top) One gotcha is making sure you've got enough alternator for the fan. The Series III in this has a lucas alternator. Not sure how many amps they were good for. I put in a 60 amp delco (replacing a 40) as part of my conversion. I had to play some games to get the original ammeter to still work but I did it.

Nice Landy 👍

My last pommie car was a MGC GT 69 mod, it ran a plastic fan, seemed to work just fine!! Mal in au.

I've owned and driven old Land Rovers for the last 30+ years now. Here in the UK it was often talked about as one of the major HP improvements alongside free wheeling hubs, overdrive etc. Given the stock motor was stated as 65bhp its quicte interesting to see one on a dyno and to see the difference. I think it proves that in the real world its not worth pulling the fan off of a series truck. After all the fan and rad were set up to keep the engine cool for a wide range of conditions and environments. Nice to see another RHD over there. When my brother emigrated to Texas from the UK he shipped his S3 over too. great fun driving one in the USA.

The fan blade on a AC is that size 1/6 hp to 1/8 hp to max of 1/4 hp to turn it up to full speed.

It's not just the more rwhp but also the slightly faster throttle response at higher rpm ( yes I realize on the Landy that's a oxymoron) and faster getting to operating temp and less engine noise. Did this to all my vehicles back in 70s

I have not driven a car with a mechanically driven fan for years. I am in a relatively cool climate (UK) and found that most of the time the electric fan would only start if I was stuck in traffic on a hot day. Back in the 1970s and 1980s we used to use fans and shrouds from Fiat 128s in our engine swapped cars. From memory I think they used about 7 amps, cheaper than an accessory fan and they had shrouds as part of the assembly. Of course a lot of cars are retro fitted with electric fans at a point in their life when the cooling system is underperforming. Free horsepower, quicker warm up, reduced noise and an easier life for the water pump.

My '76 Valiant runs the factory 3-core, HD cooling radiator, shroud & clutch fan with 7-blades. Running a 318, Thermoquad 4-bbl, dual exhaust with a cam better suited to the combo (2.76 rear gear, mediocre compression). I've had friends who have put on aluminum radiators & electric fans, but for the cost and issues they've had...it's not worth it to me even if I got a few HP at best.

There are more advantages to be had from removing the fixed mechanical fan from the LR S3 so long as there is a fully functional electric fan: 1) Quicker warm up of the engine, which will benefit the longevity and be a distinct advantage in winter when the heating is required. 2) The mechanical fan is a PITA in deep wading that the LR is capable of. It churns up and sprays water throughout the engine bay, potentially soaking the electrics. Without it you can rely on a bow wave and a depression in the engine bay to keep the water below the external level to such an extent that water can flood over the bonnet due to the depth and the engine will still suck clean air under the bonnet and the electrics will stay dry. The radiator is kept cool by the water 3) The woeful automotive fan belts can barely transmit the power to the fan, alternator/dynamo and water pump. Remove the fan and take the strain off the fan belt. Alternatively fit an industrial fan belt. In this application the fan is not in a shroud so its effectiveness is significantly reduced and you could expect that it is oversized just to account for this inefficiency. 7.5% power increase is not to be sniffed at. Imagine what engine modifications would have to be made to attain that figure say, multiple carbs, tuned exhaust etc. Removing the mechanical fan is a no cost improvement in power and probably a reduction in fuel consumption. The LR cooling fan installation is very poor from all aspects and the fact that an electric fan has been deemed to be necessary shows how ineffectual the standard system is. Why waste power and fuel on such inefficiency?

Very interesting. Can you do an alternator test with a constant electric load and then without any load?

Increase sounds reasonable as transmission oil has warmed. In sixties in U.K. it was generally considered that a sun shield on windscreen cost 5mph and likewise a roof rack. The 3hp gain seems reasonable as it is a low speed long stroke engine. Remember them well from the military biggest cause of failure was high speed running on rear axle shafts or peaking out traction in soft going. Often finished schemes just using front wheel drive as runout of rear half shafts.

70 mph nice. Not sure I could push my ‘63 that high! More Landy vids please.

Rebuilding my mk 3 owned since 1983. I did fit a kenlowe fan in the late 1980s, saving fuel the main purpose, it still works so it will be refitted,I wonder how much fuel the freewheeling hubs save, i have fairy ones fitted same firm has the overdriive, interesting post.

I think there was a FIAT with a thermostatically controlled clutch that drove the fan, I guess variably controlled pitch blades would be the ultimate. On the Air cooled racing Porsches, they accounted for the power taken for the fan (about 10 hp if I remember correctly, remarkably low for a racing engine, and accounted for by no radiator drag) so it could be compared with other engines.

thank you, very clear explanation and very consistent test.

I was just shocked to see the speedo reach 70 MPH. My old 2A would only do that if it was pushed off of a high enough cliff. Then I realized that there was no rolling resistance from the front wheels and no air resistance at all and it made more sense.

Efficiency, fuel economy and less noise were the reasons auto manufacturers went on to electric fans that were controlled by a thermostat switch. Those percentage figures for power can translate to good fuel economy on long distance drives. At 40 Kph a vehicle pushes in enough air through the radiator to not need a fan, and the colder the ambient temperature the more a fan is not needed. Mechanical fans and also the old style "V" belts take up energy to drive them.

The other thing to think about is fuel consumption, for a given speed it'll be more economical.

Interesting video I'm assuming this was a direct drive fan with no viscous clutch... I'd love to see what the horsepower change is with the transmission brake versus the x brake .....

Install an electric fan with 2 speed control it will be more economical ,,, or a fan with electro clutch Peugeot style ,, but all is adding complications and weak links ,, great analysis , thank you !!

and that's why a vicious fan clutch wins its free wheeling till its needed.

Thank you for sharing this information. Can I ask what are the front tyres? thank you in advance

You need the fan to blow air around the engine as much as anything because the bulkhead is a real air blocker. I run the fan and no free wheel hubs, because if I want economy a 58’ landy is a real bad place to start :D Nice S3. Very ‘clean’.

With solid (old style) fan blades, biggest difference I have seen with SBC was about 20+ hp. I have not tested with my H3, but when the cluch fan is on, it feels like towing a small trailer. When I replaced the fan with two electric ones of my -79 Blazer, there was a noticeable increase in mileage, as it has Turbo 350 that is 3 speed only, so the engine rews all the time. And, it is no longer a leaf blower when I start it in the fall...

Seen various videos about removing the mechanical fan. Seems every test shows more power and torque without the mechanical fan

You are also gaining fuel mileage and, of course, throttle response. There is a reason all modern vehicles have gone to electric radiator fans and skeleton alternators. Not a huge gain but an easy one to acquire. Over about 35 MPH the movement of the vehicle is enough to keep it cool so some of the readings might have been influenced by the hot engine requiring alternator current to run the electric fan that under normal driving would not be necessary.

Be interesting to dyno the vehicle running with the alternator under load running an electric fan, though in theory an electric fan wouldn’t run as constant as the engine driven one but nonetheless be intriguing to see a comparative power loss…

A series LR, especially a RHD must be a rarity in the States. The experiment is interesting but it more or less confirms scientifically what I always stood for: Do not modify factory equipment, it is designed and set for optimal performance under varying conditions. I hope you know how to operate correctly the Transfer Box (Red and Yellow levers) on this old boy. Not many people do either in the UK or elsewhere.

For most on road vehicles electric fans using less power from the engine can add a few mpg's. If something happened to the battery or alternator getting towed to a place for repairs isn't a problem. For off road where if something happened to the battery or alternator, an engine powered fan would let you drive the vehicle farther than an electric fan could. This could get out of a situation and back to a safe place to repair your vehicle. For drag racing or some other short course racing running an electric fan and water pump might give you a slight HP advantage over mechanical versions. All this said, you just have to determine what your needs are and use what best fits those needs. Doing this testing on a Dyno gives a definite value to how much HP it takes to run the fan. If you have several versions of fans to test on one engine this could show the difference between fan types. Your 4 blade steel fan against a 5 or 7 blade or even a 2 blade fan. Same with flex fans, getting several blade counts. Clutch fans might be an interesting variable to add in also.

I once switched from mechanical to electric on a first gen Grand Cherokee. Forget power, the low load smoothness sold it to me. Takeoff from a stop felt sooo much better without the fan.

Thanks for sharing this cool test! How would this Land Rover do with a light plastic fan bolted in place. I have an extremely original ‘72 MGB with overdrive. The engine has about 88hp with the twin HIF carbs, but no air pump. I’d like to see how much could be saved around 3200 RPM when on the Interstate.

4HP on 40i s 10%. which is non-trivial. There's also the fact that in a temperate climatr, the fan is likely over-cooling, which delays warm-up and wastes fuel.

more series!

I love these type videos.

But was either one on a viscous clutch? I think that's the thing that eats more horsepower than a solid fan. I swapped the viscous clutch fan on my pickup to an electric fan mainly because the lift one of the previous owners did was sketchy. But now I've been thinking of doing the same to my Volvo 240 to save some fuel.

I saw a test in the states where they tested the fan , water pump and alternator and the alternator used by far the most power to run. Swop to an electric fan and the alternator needed more hp

Also saves fuel as it warms up quicker by not pulling extra air thru the rad, not a lot, but any is good. In the UK we used to remove them for winter to aid heater and rad temps.

Just a shroud would help a lot with the efficiency of the cooling fan, is ridiculous heaving a pulling fan so far away and without any device to focus its power to pass air through the radiator

In tuning terms a 7 or 10 % gain is really impressive, I was surprised it was so much !

Back in the 70s, I had a Toyota with a fluid coupled fan, allowing it to not turn at engine speed, but still draw air thru. You could stop the fan with your hand. Spooky, but I saw it done.

The problem with flexing blades is that it takes power to make them flex. There is no such thing as a free lunch. Back in the late 1950s, early 1960s there were articles in the UK motoring press about people who had made DIY electric cooling fans and removed the metal fan. More m.p.g. was claimed. Kenlowe soon began selling fans as an aftermarket mod and much later electric fans were fitted to many new cars as standard.

A very interesting test 👍

they did an extensive test on engine masters s2e02 on that subject and the results were kind of mind blowing if y'all curious

It sounds like the engine has a knock. FWIW, back in the 70s I owned a '65 rhd 88. It had seen had use in its life, so I rebuilt the engine. Later I installed a Rochester carb that made a big change in the power.

Always interesting to see dyno results for a vehicle and a knowledgeable analysis of those results.

What RPM did you run the Landie to?

Tyre pressures on the rollers looked a bit low - that will sap the power a bit!

Really Interesting video. Just a shame you didn't do a couple more runs with the fan on. When you are talking such marginal gains in the measurable units. There was an 8% variance in your benchmark runs. Using the upper and lower benchmark datum points the Landy gained between 10% & 19% power without the fan. Ask any engine tuner is that sort of gain amazing for a no cost 10minute job. Hell yes it is! Its all in the stats😅

I wonder if there's a way to test this at road going Speeds where air is already being pushed through the radiator theoretically taking less power to turn the fan? I was driving a 79 ford with a 460 cruising down the freeway and the fan clutch locked up from a bearing going bad and i couldnt believe how hard it pulled the engine down! Felt like someone dropped an anchor!

I ran my Slll for many years without the fan. Quieter too.

Viscous clutch fans on high horsepower motors makes heavy traffic safer but still little power robbing at high speeds!

On a moving vehicle all types of fans will windmill as road speed rises. The biggest advantages of removing a mechanic fan is faster warm up and improved fuel. Consumption

Just for the record I run a 200 tdi defender with no viscous fan and no electric fan, hasn’t had a fan in 15 years, no problems whatsoever in traffic, towing or heatwaves, obviously more thermo efficient than 2:25 petrol but just putting that out there

You also remove noise and fuel consumption at cruising speed

Interesting bye bye fan!

I would be interested in seeing how it improved the driveability of the car on the road rather than just rolling road figures as i feel thats where the difference may be more apperant

How much faster will the land rover be if you take the tire off the hood? I hate opening the hood with the heavy tire up there.

That old mechanical fan doesnt even have a shroud. Fit a shroud and you could get away with a fan with less aggressive pitch

Smaller fan in winter?

As someone who lost a finger in the auto industry. Removing fixed metal fan is removing a genuine weapon waiting to eat parts of your body.

Hi bro, adjust the timing and do am proper tune up on the engine,..

a 7 % decrease in fuel will nice thank you.

Wow 40 rwhp. Pretty amazing gear reduction engineering making the Rover so capable, I mean to still go anywhere and modern Jeep can. Awesome stuff.

A fan is more like a revlimiter, it won't hurt performance much on low revs.

Same tires in 2015 and now?

The petrol is supposed to be around 80 hp if im not mistaken? Where is all that power going ! Is the transmission soaking 50% ? The ford flex fan is new to me what a great idea

The other factor is the ratio of the crank pulley to the fan/water pump pulley. Some fans run at crank speed, some faster, some slower. This varies HP used to run the same size fan. One things for sure, Landrover built that car with no horsepower, and it still has most of it left 😂.

Just remember that fan is there for a reason.

You didn;t really compare the graphs for the 2 cars properly. The point with the flex fan is perfectly demonstrated by the power graph for the Ford where the power loss due to fan shrinks a lot as rev's increase, the power gain is in the upper midrange, whereas for the Landy the power difference continues through to higher RPM