Hi all, I have a 240 Turbo (intercooled) and I am thinking of replacing the fan and fan clutch with a primary electric fan. I am wondering, though, if the alternator will be up to the job. It is a 55 amp unit, reman. and installed recently.

I don't have a fancy stereo, or even fog lights, just the regular stuff, power windows, A/C, and the auxillary pusher fan that never comes on anyways.

The fan I am looking at is a Perma Cool unit, rated at 2100 CFM, and 8.9 amps. I have heard many people mention the Mr Gasket fan, and the GM junkyard fan, but the M.G. fan is rated 2000 CFM and 11.4 amps, and is thicker to boot. Ok, so the MG fan is $5 less than PC at Jeg's.

Any advise?

Thanks in advance,

Greg Wong

MINE (55A alt) is OK and I have the Mr. ass-Gasket 11.4 A fan. (BTW, plenty thin to fit, with tons o'space to boot, plus I think the 2000 vs. 2100 cfm is a tad specsmenship)

Just keep your belts properly tensioned and brushs in good shape. The thing with me is: My biggest ELECTRICAL loads are during the winter: lights on, heater blower going, rear window defroster, seat heater, etc. My fan NEVER comes on in the winter. Just with the recent 70°'s it's come on a few times, but I didn't have much else on.......other than the hot tub, beer cooler and vibromessage....just kidding.

Watch the voltmeter, you can tell when the fan cycles...

/// The electric fan will come on at stops not when you are driving at highway speed.

No alternaor has it's rated output at 'Idle RPM.' In fact the output may be less than half and I have seen charts that show as little as one third rated output at idle.

There are cures such as changing the size of the alternator pully to increase the alternator rpm slightly, or installing a dash pot (electric or vaccum) to up the idle when the A/C cycles on.

Using the information above changing the alternator will only gain you from one third to one half the difference in max rated output when at idle. Use that to gauge what upgrade you will need.

Example, possible upgrade to a 90 amp rated output less 55 your current alternator rated output, is 45 amps divided by three and then by two gives from 15 to 22.5 amp gain at idle.

That increase in alternator output will load the engine too. You may have to readjust the idle with a heavier load.

An alternator can typically run continously at half of it's rated output, without overheating, so in your case about 27.5 amps. It can run higher, but not continously. You might find an auto electric shop, turn on all your accessories, and have them measure your current draw. Then add the rated amp draw for the fan, and do the math. There is probably a higher output swap for your car if needed. Let me know if you wan't me to check on that. MK