Anyone with Edelbrock E-Force Supercharger going through alternators every few months?

Troublesome_Hobby · Sep 3, 2018

My original 2008 Mustang stock alternator died around Jan 2018, about 1 year installing the Edelbrock E-Force supercharger. Didn't think much of it considering it's 10 years old this year.

Anyway I replaced it with a nice Powermaster upgrade, and it has died. Powermaster has been great about replacement. They said the internals were trashed, fan blades even bent and the only thing salvagable is the housing. Powermaster says the alternator is good up to 16,000 RPM then it's overspun and that would cause this kind of damage.

The thing is I drive this car very little, like 1500 miles a year. So I've finished off the stock alternator but also a brand new Powermaster 200 Amp alternator in the equivalent of less than 3,000 miles?

I have the original stock crank pulley, and am using the Edelbrock alternator pulley that comes with the supercharger kit and honors original powertrain warranty. The stock pulley is 2 6/16" and the Edelbrock is 2 1/4" diameter.

Bondsquad73 · Oct 13, 2018

I too also have an Eforce blower on my 2009 Mustang and lm on my 3rd alternator since the install back in 2011. My last one burned up while driving, though I was lucky to take it to my mechanic. Does it have an electric type of noise like humming to "EEEEEEH noise? Dealer that sold me my 2nd alternator claimed it was my steering pump making the noise, which wasn't the case. Nobody can figure out the noise. Had the electrical noise for over 3 years now. The shop that install the blower wants to look at it but that will be towards the end of this month as he said that noise doesn't sound right.

Troublesome_Hobby · Oct 13, 2018

Thanks Bondsquad73 for posting!

For my original one that died, my indicator was failure to charge, there was no noise indicating the failure. For the powermaster alternator, there was the sound of small bearings grinding out which makes a high pitch whine that I guess could sound like an electrical whine. To test, a friend relaxed the belt and spinning the alternator pulley by hand revealed grinding like shaking rocks in a sack. Sure enough, when removed, free spinning the alternator pulley revealed clear failed bearings.

Called Powermaster and spoke with "John in Returns" and he shipped me a new alternator free of charge after I shipped the failed one back. Powermaster fairly is not going to replace it a 2nd time as the Eforce pulley is significantly SMALLER than the stock pulley. By John's and my measurements, it revs the alternator well beyond 17k RPM and the stock alternator is spec'd at 16k RPM max. John said the returned failed alternator was overspun enough to trash the entire internals of this alternator.

A call to Edelbrock informed me I do indeed have the right pulley for my car and have no other replacement size that would bring the alternator down to 16k max. They said they are not aware of any shortening of alternator life due to their smaller pulley size over-reving the alternator.

Since the Eforce pulley has a custom distance to get the belt lined up properly with the alternator flipped around 180 degrees, we're likely stuck replacing over-rev'd alternators far sooner

Litl1016 · Nov 22, 2018

Troublesome_Hobby said:
Thanks Bondsquad73 for posting!

For my original one that died, my indicator was failure to charge, there was no noise indicating the failure. For the powermaster alternator, there was the sound of small bearings grinding out which makes a high pitch whine that I guess could sound like an electrical whine. To test, a friend relaxed the belt and spinning the alternator pulley by hand revealed grinding like shaking rocks in a sack. Sure enough, when removed, free spinning the alternator pulley revealed clear failed bearings.

Called Powermaster and spoke with "John in Returns" and he shipped me a new alternator free of charge after I shipped the failed one back. Powermaster fairly is not going to replace it a 2nd time as the Eforce pulley is significantly SMALLER than the stock pulley. By John's and my measurements, it revs the alternator well beyond 17k RPM and the stock alternator is spec'd at 16k RPM max. John said the returned failed alternator was overspun enough to trash the entire internals of this alternator.

A call to Edelbrock informed me I do indeed have the right pulley for my car and have no other replacement size that would bring the alternator down to 16k max. They said they are not aware of any shortening of alternator life due to their smaller pulley size over-reving the alternator.

Since the Eforce pulley has a custom distance to get the belt lined up properly with the alternator flipped around 180 degrees, we're likely stuck replacing over-rev'd alternators far sooner

Just curious if anyone has come up with a solution to this alternator problem yet. I have a 05 with the Edelbrock supercharger and having the same issues. I am currently in the process of having a custom pulley milled that has the correct Edelbrock offset but with the factory diameter. Just curious if anyone has tried that. I have not seen anyone posting anything on the net yet.

Thanks

Noobz347 · Nov 23, 2018

I have to wonder if there isn't a pulley alignment issue also associated with this setup.

I can see how overspinning an alternator might eat up the electric internals of an alternator like brushes, springs, bearings, rotating coil, etc... The bent blades and other pieces not usually associated with contacting parts while moving, sound like issues that come from a misaligned pulley.

Do any of you have signs of excessive belt wear or one-sided wear patterns?

Troublesome_Hobby · Jul 8, 2019

Sorry for my delayed reply. 0 issues with belt condition, 0 signs of it being misaligned. Belt's in great shape.

Bondsquad73 · Jan 7, 2020

Hello again, I have a new alternator issue. I was driving my Mustang to do some quick shopping and when I entered the parking lot I noticed I was losing steering power. After turning off the car and looking with a flashlight as it was already 9pm I noticed the drive belt hanging and shredded underneath the car, then I noticed that the alternator pulley was snapped off!! This was my 5th alternator and 3rd OEM as the 2 aftermarket alternators I purchased, one was a Powermaster, burned up. Is this a defect on the alternators the E-Force goes through as its mounted backwards? I dont drive the car that much, once a week. Now I have to order another alternator, number 6 to be exact, and also order a new pulley as it was the one that came from Edlebrock. This is crazy!!

Troublesome_Hobby · Jan 7, 2020

The stock pulley is 2 6/16" and the Edelbrock is 2 1/4" diameter, that means whatever alternator it's on spins faster than the stock pulley. I am happy to report so far the replacement alternator Powermaster sent me within their warranty is working great. You definitely need to be using the pulleys that comes with the Edelbrock kit because that matches the new belt.

Did your alternator shaft break? Is that what you mean by 'pulley was snapped off'?

Bondsquad73 · Jan 8, 2020

Troublesome_Hobby said:
The stock pulley is 2 6/16" and the Edelbrock is 2 1/4" diameter, that means whatever alternator it's on spins faster than the stock pulley. I am happy to report so far the replacement alternator Powermaster sent me within their warranty is working great. You definitely need to be using the pulleys that comes with the Edelbrock kit because that matches the new belt.

Did your alternator shaft break? Is that what you mean by 'pulley was snapped off'?

Yes the pulley that came from Edlebrock snapped off from the shaft. I had to order a new pulley, who knows where the other went!!

Troublesome_Hobby · Jan 11, 2020

Yikes! That is what I didn't understand. You'll need a new alternator pulley directly from Edelbrock.

Bondsquad73 · Jan 11, 2020

I'm still in disbelief as to how it snapped off, as I dont drive the car that much. The alternator is almost a year old, even my mechanic buddy of 40 years was in shocked as he was the one who originally installed it!!

Litl1016 · Jul 18, 2020

Ok so I was having the same alternator issues as everyone else with the Edelbrock Supercharger. Yes the problem is, it is being over spun. I had a new pulley machined to the factory outer diameter but with the Edelbrock offset that is required so everything lines up perfectly. I Have been running it for almost 2 years now without any issues on a factory alternator. It was a one off pulley so the price was like $300 or so, but for the peace of mind knowing the alternator would not go out on me at an inconvenient time and leave me stranded it was money well spent. Edelbrock will not admit that they have a problem in the design because of all of the associated costs. You need a new pulley to fix this problem.

Troublesome_Hobby · Jul 18, 2020

WOW Litl! Please share the name of the company who milled that for you since it works - we would LOVE to be able to solve this.

On another note - any chance the reason for the smaller pulley is to get more amps out for injectors and plugs - is that a thing to be worried about? Do you need more amps with higher injection?

Litl1016 · Jul 18, 2020

I had the pulley made at JKPulley.com. I have the stock battery/alternator In the car. I did rewire all of the grounds and added some to different places and on the alternator bracket. I removed all of the factory grounds and sanded the paint off so I have good contact. I have not had any electrical issues since I have changed out the pulley.

Litl1016 · Jul 18, 2020

I have not experienced any problems with my injectors. They are aftermarket, not exactly sure what psi but I’m running just under 600 hp out of it without problems.

Troublesome_Hobby · Jul 18, 2020

I am glad to hear that - it was a theory on why they would underpulley the alternator. It's not rocket science to measure the size of the stock alternator lol. So why undersize it???

Troublesome_Hobby · Jul 18, 2020

Litl THANK YOU for letting us know about JKUnderpulley.com - lol - do we ask them about Litl1016's pulley they made? Can you ask them to give the design a model number for all of us frying alternators?

Litl1016 · Jul 18, 2020

Unfortunately it was about 2 years ago when I had it made. What I did was send them a factory pulley and the Edelbrock pulley and explained to them what I needed. http://www.jkpulley.com is the correct website.

Troublesome_Hobby · Jul 18, 2020

Thank you Litl!

4x4carpenter · Aug 23, 2025

If any one is looking for a replacement alternator pulley for a Edelbrock E-Force supercharger kit 2005-2009 Mustang GT you can use a under drive pulley from a BMW M3 it's a direct fit extended shoulder 6 groove pulley use red locktite a lock washer and impact the nut on.

Anyone with Edelbrock E-Force Supercharger going through alternators every few months?

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