Increase Alt Idle output?

CplCuddles

Certified Meme Warrior
Nov 9, 2014
471
4
Topeka, KS
Hey guys,

So, I put in my Mechman 320 amp alt. At 800-1000+rpm I don't drop below 13.8, But at idle my Tahoe is at about 500 rpm. I have horrible voltage drop when idling. Like if I play full volume I saw it drop to 10.7. Not really sure what I can do. I left the stock serp belt on because it was still nice and tight even though it does recommend a 1/2-1 inch shorter belt, can't see how that would be the issue though. Is there something I can do to fix this issue or am I fukt?

Also, my battery I think may be "dying" its slowly been resting at lower and lower voltages since I got it about 7 months ago. I'm sure that was because my stock 130amp couldn't keep up. I'm thinking maybe this alt doesn't put out enough at 500rpm and its trying to pull form the battery but it doesn't have much to give so dropping voltage? Any help is appreciated.

Thanks m8s

 

Popwarhomie

Team Lethal Pressure
Jan 22, 2010
6,095
248
Florida
Im guessing it already has a smaller pulley on it since they recommend a smaller belt?

Overdrive pulleys work but have a chance of over spinning it as well.

 
OP
CplCuddles

CplCuddles

Certified Meme Warrior
Nov 9, 2014
471
4
Topeka, KS
Im guessing it already has a smaller pulley on it since they recommend a smaller belt?
Overdrive pulleys work but have a chance of over spinning it as well.
It's pulley is slightly smaller than the stock, I don't wanna waste money on a shorter belt if it isn't even going to fix my issue. :/

 

Popwarhomie

Team Lethal Pressure
Jan 22, 2010
6,095
248
Florida
It's pulley is slightly smaller than the stock, I don't wanna waste money on a shorter belt if it isn't even going to fix my issue. :/
It could be slipping causing the drop. Do you see belt residue on the alternator?

 

staan

CarAudio.com Veteran
May 10, 2016
555
2
la
turning on your ac compressor should bump up your idle, see if that helps

 

wew lad

wew lad inc
Mar 22, 2015
5,731
55
MA
If it's drive by cable you can tighten one of the screws on the throttle body that will make it idle a little higher from what I can remember when I pulled my intake off. It's a piece of plastic on the wire. I have a tuner and raised it by about 100rpm's. Helps, but nothing major.

How far over is the idler pulley when you put it on? Did you have to just barely move it over to get the belt on, or was it nearly maxed out?

It's kinda a dangerous game. Higher idle and you have issues stopping or holding the car at a light because you need more brake pressure and our GM's have squishy *** pedals

 
OP
CplCuddles

CplCuddles

Certified Meme Warrior
Nov 9, 2014
471
4
Topeka, KS
If it's drive by cable you can tighten one of the screws on the throttle body that will make it idle a little higher from what I can remember when I pulled my intake off. It's a piece of plastic on the wire. I have a tuner and raised it by about 100rpm's. Helps, but nothing major.
How far over is the idler pulley when you put it on? Did you have to just barely move it over to get the belt on, or was it nearly maxed out?

It's kinda a dangerous game. Higher idle and you have issues stopping or holding the car at a light because you need more brake pressure and our GM's have squishy *** pedals
Explain this please, My mechanic dad assisted on this, he actually did the belt part. I may just be reading it wrong, but it's not making sense to me lol.

"How far over is the idler pulley when you put it on? Did you have to just barely move it over to get the belt on, or was it nearly maxed out?"

 

dbjunior

CarAudio.com Elite
Jun 26, 2009
1,375
5
ma
Explain this please, My mechanic dad assisted on this, he actually did the belt part. I may just be reading it wrong, but it's not making sense to me lol."How far over is the idler pulley when you put it on? Did you have to just barely move it over to get the belt on, or was it nearly maxed out?"
You have notches on the tensioner. One at no pressure and one at max pressure. You have an indicator on the tensioner arm should be in the middle of the two marks if its only 1/4 of the way away from least tension its to loose. But black residue from belt slip on the alts is tge easiest way to tell if your belt is slipping.

 

wew lad

wew lad inc
Mar 22, 2015
5,731
55
MA
You have notches on the tensioner. One at no pressure and one at max pressure. You have an indicator on the tensioner arm should be in the middle of the two marks if its only 1/4 of the way away from least tension its to loose. But black residue from belt slip on the alts is tge easiest way to tell if your belt is slipping.
Hmm never see that on mine, but eh I never have belt slip.

Mine's almost maxed out, as in I have to go fully counter clockwise, to get the belt on.

 
OP
CplCuddles

CplCuddles

Certified Meme Warrior
Nov 9, 2014
471
4
Topeka, KS
You have notches on the tensioner. One at no pressure and one at max pressure. You have an indicator on the tensioner arm should be in the middle of the two marks if its only 1/4 of the way away from least tension its to loose. But black residue from belt slip on the alts is tge easiest way to tell if your belt is slipping.
Looking at the tensioner from the front, it is basically in line with the right line, so I assume that is the Max.

 
OP
CplCuddles

CplCuddles

Certified Meme Warrior
Nov 9, 2014
471
4
Topeka, KS
Sounds like u need a Hairpin alt... excessive amperage are nice... I never liked mechman
My mechman is a Hairpin, according to them. (sorry for late reply missed your comment)

 
OP
CplCuddles

CplCuddles

Certified Meme Warrior
Nov 9, 2014
471
4
Topeka, KS
You have notches on the tensioner. One at no pressure and one at max pressure. You have an indicator on the tensioner arm should be in the middle of the two marks if its only 1/4 of the way away from least tension its to loose. But black residue from belt slip on the alts is tge easiest way to tell if your belt is slipping.
Doesn't seem to be slipping.. feels and seems tight.

Hmm never see that on mine, but eh I never have belt slip.
Mine's almost maxed out, as in I have to go fully counter clockwise, to get the belt on.
Here's a pic of mine, not sure which notch be looking at tbh. I tried a half inch smaller belt and I had turned the tensioner over 90 degrees and still couldn't get it on there.



 
OP
CplCuddles

CplCuddles

Certified Meme Warrior
Nov 9, 2014
471
4
Topeka, KS

Users Who Are Viewing This Thread (Users: 0, Guests: 1)