nice video. I hope that humbles people.
Be glad to look at dyno numbers - never seen any other than butt dyno.
I didn't notice any on my 3.0L. It's only 5lb at startup, once it's spinning the momentum change does not equal 5lb. As well at speed the fan is not in lockup so the CFM load is quite a bit less. And no one ever knows the CFM of the factory fan to give a fair comparison to HP needed to run an electric at the same CFM.
The real savings are in the electric fan not running at all at speed, where as there is some constant load on the clutch fan - even in non-lockup.
As for reliability, I still have my clutch fan for when the fan controller fails.
I assume you wrote this before watching that video you posted.
think of the assumptions you had and why.
OK, so its been proven that at 5000 rpms in still air the energy to spin a fan is significate.
what if the speed of the fan is tuned to match the air flow coming thru the radiator at 70 mph? then the fan would be approaching free wheeling and should use considerably less energy to spin.
what if the clutch in the fan is a variable 1-way design? that could be where its temperature dependent and the 1-way portion would have the engine driving the fan but if the air flow was greater the fan would be released to spin faster.
anybody up on fluid dynamics and have a super computer laying around?
maybe red-neck engineering will work, strap a fan to the roof and see how fast it spins at 70 then change pulley sizes to match it at cruising rpms.
and thus the age old debate...and stupid that comes of it. assumptions and misapplied math. I know the end result...from doing it.
we have had some silly ass debates concerning electric fans over the last 20 years on here. I know people in the oem that I begged to bring the data here...because I want good information here and it is the reason I will spar with the debate.
I am not a computer whiz...not a math whiz. not formerly educated.
but I do build engines...I have extensive time dealing with dyno tuning and parameter changes over the last 30 years...
most of my close family works in product development and r&d...and most of that with ford.
somebody will put some efficiency conversion loss formula up....but like listed above and what you guys are thinking or at least were thinking...
somehow people with a formula explaining electrical conversion loss believe momentum provided by the running engine will take the energy required to move a mass 30 times that of an electric fan blade magically away. it is fukking ridiculous.... same with air speed. the formula is right but what is not understood it is also better then the mechanical frictions involved...
I know just having the belt on a stock 302 in gt dress with no load on the alternator or power steering costs 12 pk hp. with no fan. that's just the mass of the systems pullies and belts in free wheel!!! even after momentum is supposedly going to magically take away the requirement somehow...once everything is spinning...
and people will argue the clutch fan cant take power because of inertia...
as to the going 70 mph thing...the other big magical unicorn GOTCHA...
the turbulence caused in the engine compartment actually increases the fan drag in many situations....easily proved with a fuel meter via bsfc measurements. its so old and outdated ....this information... you would think it would be readily available.
the electric fan offers maximum efficiency provided it is set up correctly. you guys already know this for the right reasons. its only on when it needs to be.
the clutch fan is regarded industry wide as using about 1 hp full off...which is around 10 percent lockup. so no matter what its more then an electric fan running constantly.
the mechanical/electrical hybrids can 100 percent deactivate and have near 0 fan blade drag....problem is they still use 1 hp from mass....but can have a ridiculously powerful fan that actually works at 60 mph and pulls 30-40 hp....but WORKS LIKE A MOFO. the mass it takes to support that fan costs some power...but nothing like it used to. problem is they are very complex, expensive and a reliability issue.
electric fans are more expensive then mechanical fans. everything is electric now because max efficiency demands it.
but like I said before...no guarantee for gain....but I can say you wont lose power.
the fact that rearanger noticed no gain just proves that 10 hp don't fawkin matter unless your a max mpg guy.
I can notice a few hp on a 150 hp engine wringing It out....I cant on a 700 hp engine.
so your butt dyno is not calibratedthe same asmine....the ol ymmv