elec fans more pwr or more hasstle?

[doncannon]

Hello All,

In a quest for more power and to add more cooling for my new 6.2TD? Summit has a nice dual electric fans for trucks (summit#FLX-290). It is on page 176 of the new catalog. If fits 32" and wider rads (mine is 34"). They advertise 5500 cfm of flow.
Thank you all in advance,
Don

[TimK]

I wouldn't do this myself. I have never been too happy with the single pulley alternators on the 6.2L engines running the V-belts. The belts are prone to slipping unless they are gut wrenching tight. Running electric fans would make this worse. If your cruising down the hiway you are getting a lot of air being forced through radiator and the engine is probably running at an RPM where the alternator can easily keep up. I think the problem is going to be at idle, stop and go traffic or off roading where there may be a lot of engine idling. This when the fans will want to kick in and with engine only at idle the alternator will not be able to keep up with the load. However with the stock set up, the engine barely recognizes the increased load from the fan clutch kicking in when the temp rises.

That's my $0.02.

TimK

[grape]

I ran my 6.2 with a banks for 2 years with no fan at all.

[doncannon]

TimK,
diddo on the gut wrench tight otherwise I get the horrid squeal or the alt does not charge. I am not sure about how elect fans could make this worse because you would still have the pulley on the w.p. I do understand about forced air through the rad at highway speed and the alt keeping up. however at idle is my problem I do not understand. The idle should be faster because no fan to kick in (ie to drive the fan takes h.p.)
Sorry for not being able to see your point. maybe it is my lack of understanding of engines.
Could you maybe explain it again.
grape,
I wish I could be so lucky.
Thanks all in advance,
Don

[TimK]

Don,

The way I see it if you have electric fans, when the car is at idle and there is no air being pulled across the radiator. (I assume if you have electric fans then you have removed the mechanical fan from the water pump.) Therefore at idle the electrical fans are more likely to turn on then if you were cruising down the hiway at normal speed. The fans will draw a pretty good electrical load. At idle the alternator probably will not be able to keep up with the electrical draw of the fans. If your cab heater or lights are on, the alternator will definitely will not keep up with the electrical load. Now if you have the cronic problem that a lot of us have with the alternator belt wanting to slip, the alternator will be even further behind in keeping up with the load. If your driving routine is such that after periodic idling the engine is brought up to high enough RPM's so that the alternator can recharge the battery then you will be ok. I could see on a hot day in stop in go traffic where the electric fans could drain the batteries.

The mechanical fan in the same situation has the advantage. Even without the fan clutch engaged, the fan is still turning and still pulling cool air through the radiator. It's rare that my clutch fan ever kicks in. (It's sounds like and airplane propeller when it does.) The horsepower gain from not having a fan is negligible. For example, let's say the fan draws a 1/2 horsepower with the fan disengaged and 3 HP with the clutch engaged. Those HP levels are barely recognized by the engine. However, the equivalent electrical load to assume the same amount of cooling from the electrical fans would be 375 watts or 12volts x31.25 amps for a 1/2HP load. The 3 HP load would be 2,250 watts or 12volts x 187.5 amps. This doesn't take into account any inefficiency in the conversion of the mechanical to electrical energy. That's a lot of amps for the alternator to keep up with.

When the viscous clutch on my Range Rover died after 150K miles and I chose not to spend $475 for a new one, I replaced the stock fan and clutch with a pair of electric fans. The fans were on a thermostat so they only turned on when necessary. I had a hard time keeping the battery charged in summer city driving. The rest of the year I had no problem. Since I was aware of the problem I would make sure at long lights to shift into neutral and to bring the revs up so the alternator could keep up with the fans kicking in. However my wife wasn't so savvy with my mechanical tinkering and would periodicaly drain the battery.

I think electric fans as backup would be good but I wouldn't replace the mechanical fan. I hope I explained my opinion better.

TimK

[moondoggie]

Good Day!

Do a search, probably in the 6.5TD forum. This has been covered extensively in previous topics.

(From memory) If you do much low-speed towing, in other words hills/mountains, you might see overheat problems with electric fans. The stock fan moves ≈ 10,000 cfm, which is way more than any normally-available electric fan. If you remember what they sound like when they kick in

[doncannon]

thanks guys,
Yes timk that was a good explanation and now I can see what you mean.
Ok moondoggie I will check the 6.5 forum.

Would a fan with more blades help our clutch driven fans or should I stick with stock.
Just trying to keep things cooler with the turbo.
Thanks again,
Don