HO Alty's @ IDLE not what the say?

[BassAddictJ 5,000+ posts]

sooooo im talking to a guy at a shop that specializes specificly in alternators and custom alty installation (fabrication custom bracket and such)......guy's been in the business for 26 years...tells me that no matter what, the higher the amperage you get in a HO alty, the lower the amperage it will put out @ idle, no execptions... he tells me 130amp alty will put out far more power at idle than a 260amp alty @ idle..........got me wondering since most of the time my rpm's arent that high cause im cruising in 5th gear or causes not in gear and im rolling...in fact my rpms are rarely above 3000......got me kinda leaning towards a no so much HO alty....

yet i see all these companies that list high idle amperage on thier HO alty's.....eveything from iraggi to Ohio Gen to Mean Green........opinions with evidence to back anyone???

Click to read more...

 

[johnecon2001 5,000+ posts]

That guy is an idiot.

 

[2loud4u 10+ year member]

well my 300 amp alt puts out 130-140 amps at idle and 300amps at 2000rpms

 

[yacob.naif 10+ year member]

99% of cheap upgrade alternators are simply factory rebuilt alternators that the people pick up at autozone, and they change something that effects the 'charge curve' to make it develop peak amperage @ higher rpm's and thus creating lower efficiency at idle, but higher peak output.

i have no idea what this actually means, but i've been told the same thing by truckers who told me the only way to get more idle amperage was to increase the size of the core, bosch customer service, as well as the dude @ hifonics who was giving me hell about upgrading my alt with a rewind opposed to larger core replacement (which would NEVER fit in my car)

 

[UndercoverPunk 5,000+ posts]

I need to go to autozone and get a test done by someone who knows what's going on.... I know I'm getting ATLEAST 280ish at idle out of my pair...

 

[2loud4u 10+ year member]

(which would NEVER fit in my car)

Dont say never.

If you lived close i could jam a 300amp alt in there no problem.//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[knukonceptz 10+ year member]

A properly built HO ALT will yield 50-60% rated output at idle, so if it is 200A Alt you should get about 100A at idle. (idle being 500-750rpm on most cars) Your stock alternator can probably put out 75% of its rated power at idle. so if that's 100A your getting 75A at idle.

Most HO alts reach max output at 2000-2500rpm, most cars cruising on the free way are in that range.

Now why does efficiency go down? Simple, you want more power so you have to trade lower end power for more power at higher rpm. Look at what changes in a HO ALT, the rotor and stator, they must be wound differently to accommodate the higher power, in doing so it has some lower rpm loss.

Think of it like a High Current amp, less power at 4 ohm, lots of power at 1 ohm. The torrid in the amp is wound to allow more power at lower impedance, similar situation with the ALT.

 

[yacob.naif 10+ year member]

haha, ya i can't say never, i could do it if i moved my airbox and created a custom mount on the side of the engine....

i'd have to change the route of the belts, tho

 

[UndercoverPunk 5,000+ posts]

i'd have to change the route of the belts, tho

Try doing that with two larger alts. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Anything's possible.

 

[yacob.naif 10+ year member]

so maybe somewhere down the line i'll keep the 240A in there, and put another one on the side somewhere.

I think the engine's gonna need to be rebuilt before i ever buy enough amps to require more than 240A, tho //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif 192,000 miles and counting. Go audi, go //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[UndercoverPunk 5,000+ posts]

so maybe somewhere down the line i'll keep the 240A in there, and put another one on the side somewhere.
I think the engine's gonna need to be rebuilt before i ever buy enough amps to require more than 240A, tho //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif 192,000 miles and counting. Go audi, go //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

243,000 miles... go chevy go.

 

[yacob.naif 10+ year member]

haha, nothing like quadrupling crank bearing stress ~ 200k+ miles //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

I'm scared everytime i turn the igntion, i'm waiting for my car to grow an arm and *****slap me across the face //content.invisioncic.com/y282845/emoticons/crying.gif.ec0ebefe590df0251476573bc49e46d8.gif

 

[UndercoverPunk 5,000+ posts]

haha, nothing like quadrupling crank bearing stress ~ 200k+ miles //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif
I'm scared everytime i turn the igntion, i'm waiting for my car to grow an arm and *****slap me across the face //content.invisioncic.com/y282845/emoticons/crying.gif.ec0ebefe590df0251476573bc49e46d8.gif

This car is only worth ~600 in present condition... I'm trying to see just what I can do to it... backseat wall coming....eventually.

 

[meade916 10+ year member]

sooooo im talking to a guy at a shop that specializes specificly in alternators and custom alty installation (fabrication custom bracket and such)......guy's been in the business for 26 years...tells me that no matter what, the higher the amperage you get in a HO alty, the lower the amperage it will put out @ idle, no execptions... he tells me 130amp alty will put out far more power at idle than a 260amp alty @ idle..........got me wondering since most of the time my rpm's arent that high cause im cruising in 5th gear or causes not in gear and im rolling...in fact my rpms are rarely above 3000......got me kinda leaning towards a no so much HO alty....
yet i see all these companies that list high idle amperage on thier HO alty's.....eveything from iraggi to Ohio Gen to Mean Green........opinions with evidence to back anyone???

the person who told you that ^^^ is telling the truth and is NOT an idiot like a few people tried to say. This is the exact reason Dom will try and talk you OUT of a 300amp alt (in most situations) and try and keep you around 250-260 tops. The smaller the alt the more @ idle youll get. The larger ones do suffer while sitting at a stoplight with RPMs low. You gotta get them turning to make the power.

 

[vetkilr 10+ year member]

the person who told you that ^^^ is telling the truth and is NOT an idiot like a few people tried to say. This is the exact reason Dom will try and talk you OUT of a 300amp alt (in most situations) and try and keep you around 250-260 tops. The smaller the alt the more @ idle youll get. The larger ones do suffer while sitting at a stoplight with RPMs low. You gotta get them turning to make the power.

yepppppppppppp