What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[Doubeleive]

Ouch. $$$$

they have a 250amp one that does 180amps at idle for $399

 

[Rocket Man]

they have a 250amp one that does 180amps at idle for $399

 

[Doubeleive]

I sent them a message to see if i can order the 320amp one with a stock sized pulley $499, lol it's only money right?

 

[Rocket Man]

I sent them a message to see if i can order the 320amp one with a stock sized pulley $499, lol it's only money right?

Yessir, only money. My favorite saying as you know.

 

[kbuskill]

i'm thinking I may just bite the bullet and buy a mechman there 320amp says it does 200amps at idle (hot) I may have to run a slightly smaller belt, but my conclusions are I need more amps at idle otherwise it's going to be draining the battery, amp calculator say's I need 245amps (with everything going)

I am slightly confused... how did you come up with 245 amps needed???

 

[gooffeyguy]

How long you plan on idling with everything on?

I know mine idles at like 535 rpm or so. The alternator you have now, what does it put out at different rpms? Like what's it put out at 550, 750, 900 rpm? Maybe it'd be easier just to raise your idle a few hundred rpm to get the charge you need?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[Rocket Man]

How long you plan on idling with everything on?

I know mine idles at like 535 rpm or so. The alternator you have now, what does it put out at different rpms? Like what's it put out at 550, 750, 900 rpm? Maybe it'd be easier just to raise your idle a few hundred rpm to get the charge you need?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

I’ve always wondered if that would affect fuel mileage.

 

[BG1988]

talked to a guy at quality power he said I can do a external regulator but.....there is no way around the "service charging system" message, so that would have to be programmed out of the bcm or I can run a alternator that puts out the "amps" needed at idle so it's not draining the battery, they sell a $435.00 250amp alternator that gives 160amps at idle or a $530.00 320amp that gives 180amps at idle, ouch....

i like mine it gives me 185 amps at idle 600rpm

 

[iamdub]

I’ve always wondered if that would affect fuel mileage.

By that wording, the short answer is 'no'.
When idling, you're achieving no mileage per unit of fuel burnt. Can't get any worse than 0 miles per gallon. A higher idle results in more consumption, but not worse mileage. I don't know what the proper terminology for idle consumption would be. Hours per gallon?

Miles per tank will be affected, so if you calculated your fuel mileage by the tank as most everyone and everything does, then you'd see a lower MPG but that would be averaging in the fuel burnt at idle.






...Yeah, that was an over-complicated and almost contradicting reply, depending on how literal you wanna get. You're welcome.


...Wait- what was the question, again?

 

[Rocket Man]

By that wording, the short answer is 'no'.
When idling, you're achieving no mileage per unit of fuel burnt. Can't get any worse than 0 miles per gallon. A higher idle results in more consumption, but not worse mileage. I don't know what the proper terminology for idle consumption would be. Hours per gallon?

Miles per tank will be affected, so if you calculated your fuel mileage by the tank as most everyone and everything does, then you'd see a lower MPG but that would be averaging in the fuel burnt at idle.






...Yeah, that was an over-complicated and almost contradicting reply, depending on how literal you wanna get. You're welcome.


...Wait- what was the question, again?

I don’t trust the vehicles calculation since that’s never been what I actually see. I divide the miles travelled by the gallons between fill-ups. That’s what I consider MPG.

 

[Doubeleive]

I am slightly confused... how did you come up with 245 amps needed???

quality power has a calculator on there website, you enter all the things you have on your vehicle some have a box to enter the watt's then it keeps a running tally at the bottom. mine added up to 245 with me entering a moderate rating of 2000 watts on my 5000 watt amp & subs, i'm sure it doesn't peak since I have it turned down

 

[Doubeleive]

How long you plan on idling with everything on?

I know mine idles at like 535 rpm or so. The alternator you have now, what does it put out at different rpms? Like what's it put out at 550, 750, 900 rpm? Maybe it'd be easier just to raise your idle a few hundred rpm to get the charge you need?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

it's California and pretty much 90+ all summer, so A/C is going full blast, seat coolers, stereo, that + heat is keeping my battery's below a charge that I'm comfortable with, when the charge gets below 11.5v my alarm starts sending me voltage warnings, the alternator I bought is supposed to be 300amp but it was pretty cheap, I don't think it is up to the task in this summer heat, it starts out good but a few miles down the road it is hot and volts are sinking.

I don't know what it's actually putting out I don't have a clamp meter, these alternators are internally regulated by the bcm, I don't think it is putting out 300amps like it should especially when it is hot

 

[Rocket Man]

quality power has a calculator on there website, you enter all the things you have on your vehicle some have a box to enter the watt's then it keeps a running tally at the bottom. mine added up to 245 with me entering a moderate rating of 2000 watts on my 5000 watt amp & subs, i'm sure it doesn't peak since I have it turned down

5000 watts? Sweeeet!

 

[Doubeleive]

5000 watts? Sweeeet!

ya if I turned it up though it would blow my JL's so the gain is almost all the way down

 

[swathdiver]

By that wording, the short answer is 'no'.
When idling, you're achieving no mileage per unit of fuel burnt. Can't get any worse than 0 miles per gallon. A higher idle results in more consumption, but not worse mileage. I don't know what the proper terminology for idle consumption would be. Hours per gallon?

Gallons Per Hour, GPH

My average is 2.12 GPH over 23,998 miles.

 

[Tonyrodz]

I sent them a message to see if i can order the 320amp one with a stock sized pulley $499, lol it's only money right?

Why not reuse your old stock pulley to save some $$, unless it won't fit.

 

[Doubeleive]

Why not reuse your old stock pulley to save some $$, unless it won't fit.

sometimes the shaft's are different size, mechman makes there own case so no telling if it would fit or not.

 

[Tonyrodz]

sometimes the shaft's are different size, mechman makes there own case so no telling if it would fit or not.

Gotcha.

 

[kbuskill]

sometimes the shaft's are different size, mechman makes there own case so no telling if it would fit or not.

I am curious what they tell you. My guess is with the standard size pulley you will have the same problem of not charging at idle.

 

[Doubeleive]

I am curious what they tell you. My guess is with the standard size pulley you will have the same problem of not charging at idle.

ya the drive pulley on the 6.2l is to big (7 3/4) so putting the stock pulley on the 320amp would make it less amperage than there 250amp unit that comes with the stock pulley, so I went ahead and ordered there 250amp unit just now, 399.00 out the door, 2yr warranty, free shipping, no tax. 2-week build time so I should have it first of next month. I didn't want to have to change drive belts, this alt should put out more at idle than the oem one does maxed out. They recommended upgrading the charging wire so I will probably check into getting a welding wire made