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Alternator

Hey folks
Jfairman posted a eBay link to a alternator that he spoke quite highly of. Can anyone point me in the right direction? Jim. You still lurking around?
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81 Pacific Blue 930 Euro coupe slicktop on a strict diet, Rarlyl8 headers, Blowzilla turbo, Tial waste gate, Full bay I/C, Home made center out exhaust, Leask WUR, MSD 6AL, PLX wideband
Wevo shifter, LSD. Next up, Cams, Heads and port work
Old 06-12-2018, 07:28 AM
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I bought one from BNRPARTS on ebay. If you search for "Porsche 160 Amp Alternator", they show up.
Not sure if that is what he mentioned, but only what I purchased. $225
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1987 911 Turbo, Marine Blue, GT35R, BB Headers, Tial, Andial IC
Old 06-12-2018, 08:25 AM
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Quote:
Originally Posted by a930pilot View Post
I bought one from BNRPARTS on ebay. If you search for "Porsche 160 Amp Alternator", they show up.
Not sure if that is what he mentioned, but only what I purchased. $225
Thatís the one.
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89 Carrera
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87 Turbo; EFI project.
86 Turbo; Ruf wannabe, 3.4 liter twin plug, 964 cams, lots of Ruf parts.
Old 06-12-2018, 11:57 AM
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Sorry guys. There is no way that a rewound original Bosch or Valeo alternator can sustain more than 100A of output for any amount of time. Why? Because the design has no internal cooling fans which leads to meltdown of the stator winding insulation. Been there, done that, even put the fire out! Also, the idle output will be 40A at best. *

This is why we have developed a 911 alternator with modern internals. It is rated 180A and has been tested at 145A on the single 911 fan pulley without slip. The idle output is 75A at 950 Engine RPM. It is a six phase alternator with internal fans.

Upgraded Porsche 911 Alternator

* During our research we found that most alternator rebuild shops don't realise that the 911 alternator 'lives' inside the fan and housing. When they test them, they run them open to the air on the test machine where of course they get enough cooling. The irony is that the alternator is prevented from being cooled by the engine fan which encases it and does not help it cool. After stopping the engine, the fan, housing and alternator soak up the heat. This is the 'danger zone', when you restart your hot car and ask for high output, the windings melt.
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Last edited by Jonny H; 06-12-2018 at 03:07 PM..
Old 06-12-2018, 02:53 PM
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https://www.ebay.com/itm/Porsche-911-Alternator-1984-1989-High-Amp-160-Amp-High-Output-Generator-HD-/253668779900?_trksid=p2385738.m4383.l4275.c10

They're still on ebay for $225.
It is proven and works r e a l ly great.
Cost a bit less too.
Rebuilt in the USA.

Last edited by JFairman; 06-12-2018 at 05:52 PM..
Old 06-12-2018, 05:16 PM
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Thanks fellas. Most appreciated
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81 Pacific Blue 930 Euro coupe slicktop on a strict diet, Rarlyl8 headers, Blowzilla turbo, Tial waste gate, Full bay I/C, Home made center out exhaust, Leask WUR, MSD 6AL, PLX wideband
Wevo shifter, LSD. Next up, Cams, Heads and port work
Old 06-12-2018, 06:53 PM
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Quote:
Originally Posted by JFairman View Post
It is proven and works r e a l ly great.
It might work for 'occasional' peak load high output - maybe a couple of minutes but it cannot work for sustained load as there is no facility to get rid of the heat in the standard Bosch alternator case.

This is what happens to a standard Bosch unit rewound to 'just' 110A when subjected to sustained continuous output of 75A:



The blackening of the milar insulation will eventually lead to failure and in some cases fire. Been there, done that.

And here is another, again rewound for 110A. This one passed test on the bench but managed just 30 minutes at 75A in the car.

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Last edited by Jonny H; 06-13-2018 at 06:16 AM..
Old 06-13-2018, 06:07 AM
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I'm curious, in what conditions would you expect to sustain a 75A continuous load for 30 minutes?
Old 06-13-2018, 07:54 AM
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Quote:
Originally Posted by flightlead404 View Post
I'm curious, in what conditions would you expect to sustain a 75A continuous load for 30 minutes?
Good question.

LED head lights make more sense.
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89 Carrera
89 Turbo; K27, Turbokraft intercooler, 964 cams, Fabspeed exhaust.
87 Turbo; EFI project.
86 Turbo; Ruf wannabe, 3.4 liter twin plug, 964 cams, lots of Ruf parts.
Old 06-13-2018, 08:16 AM
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Johnny has developed this high output alternator to support his electric A/C system (very nice) and he working on electric heat for air cooled 911's.
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1977 930 Slant, MS3 EFI, Carrera intake, Twin plug, Powerhaus headers, Magnaflow muffler, Garretson intercooler, GTX3071R
Old 06-13-2018, 09:00 AM
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Quote:
Originally Posted by Jonny H View Post
Sorry guys. There is no way that a rewound original Bosch or Valeo alternator can sustain more than 100A of output for any amount of time. Why? Because the design has no internal cooling fans which leads to meltdown of the stator winding insulation. Been there, done that, even put the fire out! Also, the idle output will be 40A at best. *

This is why we have developed a 911 alternator with modern internals. It is rated 180A and has been tested at 145A on the single 911 fan pulley without slip. The idle output is 75A at 950 Engine RPM. It is a six phase alternator with internal fans.

Upgraded Porsche 911 Alternator

* During our research we found that most alternator rebuild shops don't realise that the 911 alternator 'lives' inside the fan and housing. When they test them, they run them open to the air on the test machine where of course they get enough cooling. The irony is that the alternator is prevented from being cooled by the engine fan which encases it and does not help it cool. After stopping the engine, the fan, housing and alternator soak up the heat. This is the 'danger zone', when you restart your hot car and ask for high output, the windings melt.

I tend to be wary of rewound alternators so I've hesitated on the e-bay one.

Are your alternator internals off the shelf parts that can be replaced or repaired in the future? Is the alternator rotor redesigned as well?

I rebuild my own alternator and would like to keep doing so therefore parts availability is important to me.
Old 06-13-2018, 09:11 AM
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Quote:
Originally Posted by flightlead404 View Post
I'm curious, in what conditions would you expect to sustain a 75A continuous load for 30 minutes?
Porsche deemed it necessary to update the alternator from 75A to 90A on the 3.2 Carrera. They would have been working on a safety margin of 20% meaning that a Carrera 3.2 could potentially need 72A continuous. Close enough?

If you have added any other toys. High power stereo, heated screen, heated seats, oil cooler with fan, rally lighting then you are very close or over the limit.

For you Turbo guys, allowing a safety margin of 20% would put the early Turbo alternator (75A) at a weedy 60A continuous.

The idle output is very poor at around 35A.

Quote:
Originally Posted by nocarrier View Post
Are your alternator internals off the shelf parts that can be replaced or repaired in the future? Is the alternator rotor redesigned as well?
Yes, our internals are the Denso 'hairpin' 6 phase. Google it. These alternators are found in many modern cars and service parts are widely available Worldwide. The outer case is custom billet to fit a 911 fan housing (all years) and the rotor spindle is custom for the 911 fan.
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Last edited by Jonny H; 06-13-2018 at 12:27 PM..
Old 06-13-2018, 11:29 AM
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BNR does more than just rewind the 90 amp Valeo alternators. It looked like the cast aluminum case was cleaned and bead blasted and everything inside was bigger.
No internal fan? lol...
Last I checked there's a big aluminum/magnesium engine cooling fan mounted on it's shaft blowing lots of air across it. I guess that doesn't count huh...
If you have questions BNR puts their phone number in their ebay ad. I called and talked to them before buying one.

Here's a few pics of the one I installed on the '87 turbo I used to have.




Here's the BNR 160 amp alternator on the left and the 90 amp alternator on the right.


BNR 160 amp in the top pic and Valeo 90 amp in the bottom pic.




Installed in the fan housing ready for install.


I put dielectric grease on the electrical terminals to help keep them from corroding and two of the ARP head studs I installed are somewhat visable in the background.
Old 06-13-2018, 01:27 PM
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Quote:
Originally Posted by JFairman View Post
No internal fan? lol...
Last I checked there's a big aluminum/magnesium engine cooling fan mounted on it's shaft blowing lots of air across it. I guess that doesn't count huh...
No it doesn't count. in order to cool the stator, the air must go through the alternator. All the engine fan does is go around it. It's worse when the deflector is fitted too. If you look at a 964 alternator (115A) you will find they had to add a fan to the back of it for exactly this reason.

The old school bunched style stator windings cannot get rid of the heat. On modern alternators, the stator is wound with an airgap that allows flow through the windings. Denso have a patent on it called the 'hairpin' winding, Google it.

Both the burnt out alternators I posted earlier were brand new and built with all new parts. We commissioned them to discover where the limit was with the Bosch / Valeo case design. The results are plain to see.

Btw, your alternator cables are nowhere near thick enough. If that alternator makes the claimed output they would need to be 25mm2 which is AWG 3.
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Old 06-13-2018, 02:40 PM
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Here's a couple more pics of the wires I used.
The original power and ground wires are still there and I doubled them up with the thick red power wire going to the alternator positive terminal and the thick black ground wire going to a case nut.
I got the red and black wires from a local marine hardware store and soldered the marine grade wire ends on before shrink tubing them.

The skinny blue and black exciter wire is still there by itself.



The alternator fan has some holes in the front that let some air in to cool the inside of the alternator and the plastic air guide cone on the back of the alternator looks like the air flow going around it would pull some air through the alternator.

I sprayed marine grade CorrosionX on the magnesium fan housing to make it look nice. xbmwguy turned me on to that stuff too.

https://www.amazon.com/Corrosion-X-Corrosion-Technologies-91002-Corrosionx/dp/B0009GYRWW/ref=sr_1_4?ie=UTF8&qid=1528934479&sr=8-4&keywords=corrosionx+marine

Whatever... it all worked well for me. I sold the car because I needed $.
Old 06-13-2018, 04:06 PM
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Quote:
Originally Posted by Jonny H View Post
Yes, our internals are the Denso 'hairpin' 6 phase. Google it. These alternators are found in many modern cars and service parts are widely available Worldwide. The outer case is custom billet to fit a 911 fan housing (all years) and the rotor spindle is custom for the 911 fan.
Genuine Denso?

And If I am understanding you correctly, the rotor is updated as well just re-machined the end for the fan.
Old 06-13-2018, 04:12 PM
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Quote:
Originally Posted by nocarrier View Post
Genuine Denso?

And If I am understanding you correctly, the rotor is updated as well just re-machined the end for the fan.
Yes, of course genuine Denso.

Here's a few pictures:

Internal fan pulls air through the stator:



Here's the stator part showing the patented hairpin design: The wires are spaced apart:





The alternator has 6 phases, rather than the conventional 3 phases of older designs. This makes the alternator more efficient, meaning it generates less heat. You can see that the alternator has 12 diodes ( six are black and a further six inboard are shiny).



We provide the uprated 25mm2 / #3 AWG cables with the unit:



Here is the unit in action. The current clamp is measuring 75 amps with the car at idle. After i shot the video, I realised my voltage gauge is under reading due to the voltage drop. At the battery, the voltage is 14.4V above 1200 RPM and 13.2 at idle with a 75A load. The electric air conditioning is providing the load.



The main engineering design is in the case and the shaft. The unit is direct fit to the early housing and the mid year and C3.2 use a spacer.


JFairman, I'm glad to see you doubled up your wires!
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Last edited by Jonny H; 06-14-2018 at 08:43 AM..
Old 06-14-2018, 01:23 AM
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