Engine/Transmission (1998.5 - 2002) Alternator

[JCyrbok]

I'm thinking about putting on electric fans which pull alot of amps when they run. I'm also thinking about on board air, if i dont go engine driven. I'm wondering if I would need to upgrade the alternator to a higher amp one.



What is the amp's of the stock one? Whould going higher cause any damage to anything in my truck? Would staying with Stock cause a problem if I did the fans and electric air? Which alternator would members recommend? Etc?



Thanks

J-

 

[B.G. Smith]

You have about 136 amps output, at least that is what is in 99 model. Unless you plan to propel the truck with the fan you should have plenty of output and enough left over to run a small air compressor. bg

 

[Midnite]

Remember though--that's 136 amps *peak*! Most people don't go driving around all the time with the engine at 2700 - 3000 rpm.



This kind of stuff was what got me thinking about replacing my stock alternator with a large case Leece-Neville model. It may only be rated at 140 amps peak, but the lower rpm output is supposed to be significantly better than the stock alternator. Unfortunately my fabrication skills are non-existent, and I could never find an auto electric shop around here that was willing to make up a custom bracket.



Mike

 

[bmoeller]

HO Alternators- http://www.mean-green.com/products/index.html

 

[monkfarm]

leece-Neville

I do like the idea of installing a Leece-Neville (alternater. ) But besides (different) mounting brackets, don't the Leece-Nevilles require more wiring than the stock OEM alternater????

I have a Leece-Neville 160 amp on my Peterbilt 379, and really like it (no problems, plenty of Juice )

 

[Midnite]

A long time ago someone here posted something about a Leece-Neville large case alternator swap, but I don't remember who it was. If I remember right, in addition to the new bracket he also had to replace some fusible link, but I'm not sure what else.



Mike

 

[15w40]

Some time ago, someone posted the horsepower use by the stock fan when the clutch locks up. I don’t remember if it was 10 or 20 HP but it surprised me. Being a nerd, I thought I would calculate the number of amps required to make 10 HP.



10 HP = 7457 watts.



When the alternator is putting out 14 volts, it will need to generate 533 amps to generate as much power as needed by a 10 HP fan. If it is limited to 136 amps, the batteries will have to supply 397 amps.



I don’t know what electric fan you will be using but if it is a powerful as the mechanical fan, you will need a couple of alternators.

 

[bmoeller]

In the US Gear ad for their Cyclone fan (Ford PSD and V-10), they claim up to 40 horse loss. I doubt it though.

 

[JCyrbok]

The fans I'm thinking of going with are Flex A Lite, dual 15inch fans, that pull 5500CFM at 28amps ( If i recall correctly). Is there any problem with the 28amps and a stock alternator? I would think that the fans would not actually run much and they have a "computer" that varies their speed and amp draw based on need. The only time that they would run alot is when the AC is on. Other than that I would have a temp switch at 185 or so and a manual override/manual on switch to turn off when not needed or on when needed.



Any input would be appreciated.



J-

 

[Midnite]

You should be perfectly fine. The aftermarket lights I've added to my truck pull about that much power and I have no problems at all.



Where you might run into problems is if you have other things that pull a lot of amps as well (big stereo system, offroad lights, etc. ), and you have them all turned on.



Mike

 

[JCyrbok]

Cool thanks Mike and all others that replied. It looks like I will have no problem with the stock alternator, especially since im leaning heavily to an engine driven air compressor instead of electric.



J-