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mechanical fan vs electric?? with proof?

Just scanned this thread, and I don't see any mention of motor spool up time between mechanical fan and e-fan.

The main reason I switched from mechanical fan to e-fan on my NA 245 with M47 was to get better spool up time with the manual transmission. A noticeable difference, especially if the motor is cool and not running the fan.

Anybody else have data relating to motor spin up time of mechanical versus electrical fan? I'm guessing a clutch mechanical fan motor spools up faster than a straight fan setup...

And I realize a turbo motor is different than NA, just curious if others notice a spool up difference.
 
50hp fer-shur.


It's like 1-2hp maybe if the fan clutch is near new, I couldn't honestly say I could measure it, healthy it pretty much unlocks instantly once the temp comes down.
I did a couple pulls with it as heat soaked as I could get it with the A/C on, now that I think of it, I was down ~4-5hp (stick shift car though, which makes things easier), but that could just be because the intercooler is behind the A/C condenser, so more likely than not the fan itself drew ~1hp and the A/C pump (though it was unlocked for the peak HP moment of the pull having iced the evaporator already) and reduction in charge density is responsible for the other 3-4HP.

For a DD turbo car, if you don't want to move/reinvent anything, the OE Aisin T-static clutched fan works pretty well if it's healthy.
10,000rpm or severe packaging constraints, maybe not.

If the mech fan won't unlock quickly off idle like it mostly should, it will make a lot of extra noise.

That thing does run diesel-smoke rich...good lord! Seemingly consistently diesel-smoke rich though :lol:
 
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What was the HP drop with the fan clutch engaged? That's what would be beneficial to the conversation.
 
^This and many posts prior.
I want to do the e-fan conversion, but if there's no real gain to cooling performance or difference in parasitic drag; I guess I will just replace the fan clutch with a new one.
 
Seems that instead of swapping efans everyone should be running 93 instead. Those gains from good gas alone are silly.
 
@ 7.5:1 I'm running 87 because 93 is a waste of money.

Oh and with a big hot turbo and kitty strapped to the side of the engine I want airflow at all times so it's mechanical & tropical for me...
 
So a tropical would beneficial for just about any car? It's quicker to kick on to cool and turns off a bit faster, I would assume.
 
Cool to see some actual Volvo specific data here, thanks for taking the time to gather and post that. So it's pretty much as I suspected, the mechanical fan doesn't draw all that much power. The reduced noise and cleaner engine bay is enough that I'm still tempted to convert to electric fan though.
 
Cool to see some actual Volvo specific data here, thanks for taking the time to gather and post that. So it's pretty much as I suspected, the mechanical fan doesn't draw all that much power. The reduced noise and cleaner engine bay is enough that I'm still tempted to convert to electric fan though.

This is my reasoning. Haha
 
On that note, do all LH 2.4 ECUs support controlling the electric fan? What if I burn a ROM from a 940 with factory e-fan and put it in the ECU of my 740? Using the ECU to control the fan seems like the cleanest way of doing it.
 
Cool to see some actual Volvo specific data here, thanks for taking the time to gather and post that. So it's pretty much as I suspected, the mechanical fan doesn't draw all that much power. The reduced noise and cleaner engine bay is enough that I'm still tempted to convert to electric fan though.

That is what you got from his "scientific" test? A worn out mechanical fan on a sketchy running 244 from 3 runs that may or may not have had decent gas coursing through the fuel line.

Sounds legit.:roll:
 
Sounds close enough, and aligns with my hypothesis. The test was done both with and without the fan and shows no correlation with presence or absense of the fan. I'd welcome more scientific testing using a car that is in tip top stage zero condition but this is at least some Volvo specific data. It's not proof, but it's a start.
 
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