Alternator Number 4 - Why?

[bonhamsurf]

If you've eliminated the obvious (inadequate or loose grounds, etc..) then your electronics are simply drawing way too much power.

That's about all my small brain will allow me to internet diagnose this. Best of luck with the fixes bonhamsurf. You're in uncharted territory when you try to make a 1000hp engine built for 270hp, a daily driver.

You can try to contact Danny in Las Vegas. He's got the only 1000hp (but his was WHP) I know of. He pretty much had to redo EVERYTHING on his setup.

Thanks for the suggestion, what's Danny's Prime name?

- - - Updated - - -

I am going to stick with my original observation that heat is the cause of the problem; however, its may be a combination of external heat from higher underhood temperatures plus internal heating of the alternator. If you look at modern alternators, they are much smaller than the alternators from 30 years ago. As an electrical engineer, I can tell you that there is no magic involved. They increase the wiring gauge to handle larger currents, increased the speed to make up for the fact that they have space for fewer wiring turns because they had to make room for larger diameter wire and reduced the amount of iron in the frame to make room for more wire.

A modern, compact 120 amp alternator will put out 120 amps; but, unlike an older 35 amp alternator, don't ask it to put out 120 amps on a continuous basis. The internal heating from continuously high current loading is probably cooking your alternator. Without going out to the garage to look at mine, I can't remember whether it has an internal or external fan. Since you are likely loading the nuts out of your alternator, you need to make sure that it is getting a good supply of cooling air. However, I expect the reality is that you will need to explore a much larger alternator if you are going to retain all the stuff that you have added to the car. I recommend against trying to upgrade the existing alternator as jamming larger diameter wire into the frame and turning it at a higher speed is just going to create heating problems. Go for an alternator with a higher current rating that is physically larger. I recognize that this may cause fitment issues.

There is nowhere near 100 or 120 amps of continuous current load in a stock NSX. Honda sized the OEM alternator to provide a reasonably long life with the typical electrical loads in the car. Significantly increasing the steady electrical load in the car is going to shorten the life of the alternator.

I agree, I think it's overloaded. I am going to see if my local re-builder can make a 200amp alternator for the car.

 

[Mac Attack]

Thanks for the suggestion, what's Danny's Prime name?
.

Danny (lowellhigh...) uses the same Weldon fuel pump I do.

I don't know exactly what your alternator problem is, but I have a few suggestions:

1) Get rid of one of your Walbro pumps. It isn't needed for your current power (boost) level and it is putting an additional 20 amps of unnecessary load on your alternator pretty much all the time.

2) If you don't want to get rid of the extra pump, you should really put in fuel pump voltage regulator(s) to decrease fuel pump noise, help the pumps and your alternator live longer, and decrease fuel recirculation heatup.

3) It wasn't clear if this was the original alternator rebuilt three times by the same repair shop, but you may consider buying a new Denso unit from Amazon for ~$225. Maybe the repair shop just doesn't know what they're doing?

I'm with Old Guy - I don't think a rewind is the right thing either and would rather remove a fuel pump than do an alternator rewind.

Good luck!

Dave

 

[bonhamsurf]

Danny (lowellhigh...) uses the same Weldon fuel pump I do.

I don't know exactly what your alternator problem is, but I have a few suggestions:

1) Get rid of one of your Walbro pumps. It isn't needed for your current power (boost) level and it is putting an additional 20 amps of unnecessary load on your alternator pretty much all the time.

2) If you don't want to get rid of the extra pump, you should really put in fuel pump voltage regulator(s) to decrease fuel pump noise, help the pumps and your alternator live longer, and decrease fuel recirculation heatup.

3) It wasn't clear if this was the original alternator rebuilt three times by the same repair shop, but you may consider buying a new Denso unit from Amazon for ~$225. Maybe the repair shop just doesn't know what they're doing?

I'm with Old Guy - I don't think a rewind is the right thing either and would rather remove a fuel pump than do an alternator rewind.

Good luck!

Dave

Thanks for the suggestions. Removing a pump really isn't an option as I have them in a Radium Engineering Surge Pump setup, so too much money and time spent on the setup to change it.

Where can I get a fuel pump voltage regulator?

Thanks

 

[Old Guy]

Thanks for the suggestions. Removing a pump really isn't an option as I have them in a Radium Engineering Surge Pump setup, so too much money and time spent on the setup to change it.

Where can I get a fuel pump voltage regulator?

Thanks

I think Aeromotive makes one

 

[jwmelvin]

I think Aeromotive makes one

This?
http://aeromotiveinc.com/products-page/accessories-electronics/fuel-pump-speed-controller/

 

[Old Guy]

This?
http://aeromotiveinc.com/products-page/accessories-electronics/fuel-pump-speed-controller/

That's it! Lets see, one for each pump plus installation costs and miscellaneous messing around - reducing the number of pumps and other stuff or installing a physically larger alternator is looking like a viable alternative.

 

[bonhamsurf]

This?
http://aeromotiveinc.com/products-page/accessories-electronics/fuel-pump-speed-controller/

That's it! Lets see, one for each pump plus installation costs and miscellaneous messing around - reducing the number of pumps and other stuff or installing a physically larger alternator is looking like a viable alternative.

This isn't a bad idea. I took the alternator back to the local rebuild shop, and it tested fine. Simply put, the stock alternator is being over worked with my extras and can't charge enough. So, they're going to take it and turn it into a 200amp alternator. Then test it and decide if they're going to run it as a single wire amplifier or non-single wire. I'm going to try this route first as I'm in Hawaii and if they Aeromotive idea doesn't work, I can't return it. However, if the 200amp doesn't work, then I have options to return to my local rebuilder.

 

[ftuhy]

Have you (or your electrical guy) measured the actual maximum current out of the alternator when all 3 pumps and other items (stereo, air conditioning, headlights, rear window defroster, etc) are turned on? There are inductive current probes (it just clips over the 12V lead out of the alternator and measures the electric field created by the current flow in the wire) that can accurately measure the current without disconnecting any wiring or making any electrical contact. (Fluke is one lab-quality manufacturer of such probes & meters, but there are probably lower priced ones available). With an actual current reading, then you can chose a new alternator capacity based on data instead of a WAG.

Note that if the alternator can handle the load, its output voltage should be such that once the battery is recharged after starting the car, current drain on the battery is near zero. With your setup, maybe that doesn't hold at a 700-800 rpm idle, but should be true at anything above about 1200-1500 rpm.