Classic Retrofit: Six phase high output alternator.

[Jonny H]

We're just closing out testing on our all new 6 phase alternator. We have chosen Denso 6 phase 'hairpin' internals. These units are in widespread use and have been designed to support the high loads of modern vehicles with all the gadgets and stop/start systems.

The units are highly efficient and generate very little heat which is the killer of rewound Bosch or Valeo units. They have internal cooling fans too.

The major work has been in designing a casing to fit the 911 fan shroud of which there are 3 variations over the years. The unit will fit the earliest fan housings without modification and the later years by using a spacer.





Some changes to the wiring are needed in the car, namely the positive and negative cables to starter and engine case need uprating to 25mm cable ( 4 AWG ). See the red and black cables in this picture:



The alternator output specification is as follows. Note this is alternator RPM. Typically 911 fan pulleys are 1.8 ratio but they do vary over the models:

Weight - Kg 5.3
Alt RPM 175A
500 0
1000 0
1500 96
2000 135
2500 148
3000 156
3500 164
4000 169
4500 173
5000 176
5500 177
6000 178
6500 179
7000 180
7500 181
8000 182
8500 182
9000 182
9500 182
10000 182
10500 182
11000 182
11500 182
12000 182
12500 182
13000 182
13500 182
14000 182
14500 182
15000 182
15500 182
16000 182
16500 182
17000 182
17500 182
18000 182

Lamp off 500
Cut in 1050
Cut out 1025

Although the unit is rated 180A, it is unlikely that a single pulley would be capable of transmitting that kind of power. Internet wisdom suggests that a single pulley limit is around 120A but the Internet is full of it, best find out first hand....

We are currently running the alternator at 140A with no pulley slip. We currently have 90A at 950 engine RPM , falling slightly when warm. (To put this into context, a 964 110A unit only produces 40A at idle)

Great news for electric A/C and also for electric heat which is now in development.

Hope to have the alternator ready for sale in a couple of months. Pricing TBD.

[Jajohnsen]

Oh, this sound interesting, always wanted to get writh of the heath exchangers.

Any more info on your electric heat project. Will it work with your high power blower?

[Tom_in_NH]

Awesome! We are very fortunate to companies like Johnny's, continuing to develop improved components for our classic cars. This is one component that has been sorely lacking. Converting to EFI, high wattage lighting, and of course, electric AC, etc, meant taxing the stock alternator beyond it's original design limit. Some of us northern babies even add heat to our seats! Thanks Johnny!

[old man neri]

Any thought given to just putting a more off the shelf alternator where the AC compressor would normally be and running it off the accessory pulley?

[Tremelune]

This is great. The stock alternators are expensive and weak, and rebuilding is a bit of a gamble depending on who does the work. I'm hoping to put electric AC, heated seats, and a proper stereo in my car this year, and this will help. I find I usually need AC the most when stuck dead in traffic...where it's hard to get much at idle.

Are these the "large case" or "small case" hairpins? Is the voltage regulator adjustable or is there no real drop using fresh 4awg wires? What size are the existing wires? How hard is it to run wires in these cars...?

[evan9eleven]

Very cool Jonny. I have my alternator out right now (part of my EFI/ITB retrofit) and if this were available now I would grab one to skip the double labor. I think I'll do the wiring upgrade now while I'm re-doing the the engine harness anyway. If you need a beta tester... just sayin'...

[356911930]

Quote: "Any thought given to just putting a more off the shelf alternator where the AC compressor would normally be and running it off the accessory pulley? "

I have seen that done and it is not very elegant... there is a big ugly lump and the fan belt go get in your way like the AC compressor which is a pain to work around or remove and hang on the rear fender. But to each his own I guess.

Rahl

[Tremelune]

Originally Posted by 356911930

Quote: "Any thought given to just putting a more off the shelf alternator where the AC compressor would normally be and running it off the accessory pulley? "

I have seen that done and it is not very elegant... there is a big ugly lump and the fan belt go get in your way like the AC compressor which is a pain to work around or remove and hang on the rear fender.

I'm still interested in this solution, but I know of no off-the-shelf product one can buy to relocate the alternator...What is the fan attached to with no alternator?

[356911930]

The external alternator was a flat fan 911 engine. Great looking engine except for the alternator hanging there. The fan could spin an a gutted stock alternator /shaft and bearings.

Rahl

[Jonny H]

Originally Posted by old man neri

Any thought given to just putting a more off the shelf alternator where the AC compressor would normally be and running it off the accessory pulley?

Any thought? Remember this is all we do, all day, every day and sometimes at night even!

My guess is that the second alternator idea is driven by the notion that it *might* be a cheaper solution (even though we haven't announced a price yet). I don't think this would be the case if you think about all the parts involved to provide a complete kit (custom mount, alternator, belt, pulley, wiring, special regulator or splitter).

There are technical issues too, you can't just run two alternators in parallel, neither should you spin a disconnected alternator without it connected to a battery, it will damage it. Practically, if the alt is now on a separate belt, how would you know if your true fan belt is broken? (ignition lamp would not light).

The labour involved in fitting a second alt would be greater too as you'd have to get to the back of original alternator anyway which is half the job of changing it. I can't imagine any workshop recommending a second alternator as a sensible solution.

Sorry for the slightly negative response but we are dedicated to providing fully integrated and elegant solutions for these beautiful machines.

[faapgar]

I run the alternator off the back of the 4,5,6 camshaft on my racecar.The only downside is there is no charging until 1800 RPM as the cam turns at 1/2 the crankshaft speed.I use a gutted alternator with just the shaft and there is no horsepower loss and you can spin it to 9300 and no belt issues or slippage.I wonder how much H.P. loss there would be at 140 Amps.Ciao Fred

[Tremelune]

Less than 5hp, I would expect...

https://electronics.stackexchange.com/questions/121662/mechanical-load-of-an-alternator

140A at around 13v is 1820 watts. 1hp is 748 watts. It's like 2-5hp from 100% efficiency to 50% efficiency on the alternator at full load (AC on, subwoofer blasting, headlights on, seats heated, charging your phone, charging the battery after an engine start, rear windows defrosting, etc).

Alternators aren't particularly efficient, but for intermittently powered devices, electricity is divine...and you can't beat the packaging advantages.

For HVAC concerns, the big win is having more power at idle than a stock setup does at speed. Having more on top while driving is a nice bonus, though...

[Duc Hunter]

Jonny, you strike again. I assume this work up through the 3.2 fan housing, but not for a 964?

[Jonny H]

Originally Posted by Duc Hunter

Jonny, you strike again. I assume this work up through the 3.2 fan housing, but not for a 964?

Correct. Plans afoot for 964 though. Gotta keep on keepin' on!

[pmax]

Originally Posted by Jonny H

There are technical issues too, you can't just run two alternators in parallel, neither should you spin a disconnected alternator without it connected to a battery, it will damage it. Practically, if the alt is now on a separate belt, how would you know if your true fan belt is broken? (ignition lamp would not light).

With the belted in place, the inline alternator can be removed I would think. Helps preserve the precious fan housing with the reduced load and no more dealing with the pesky bat wing diverter for alternator replacement.

The labour involved in fitting a second alt would be greater too as you'd have to get to the back of original alternator anyway which is half the job of changing it. I can't imagine any workshop recommending a second alternator as a sensible solution.

Labor is free for us DIY folks on this forum

[pmax]

Originally Posted by Jonny H

There are technical issues too, you can't just run two alternators in parallel, neither should you spin a disconnected alternator without it connected to a battery, it will damage it. Practically, if the alt is now on a separate belt, how would you know if your true fan belt is broken? (ignition lamp would not light).

With the belted in place, the inline alternator can be removed I would think. Helps preserve the fan housing with the reduced load and decouples the fan speed from alternator, better in slow traffic. A dedicated pulley will also drive a bigger alternator than the inline given the single belt limits and additional space on the side compared with shoehorning into the fan. Your replacement already requires a new harness so that's a wash.

I'll sacrifice some engine compartment aesthetics, which won't be a lot given I'm running a stock CIS system now , for better cooling and cheaper maintenance.

[mepstein]

A custom alternator seems like a great solution. A rigged up 2nd alternator might fly in an old Chevy but look strange in a Porsche 911.

[Duc Hunter]

Originally Posted by Jonny H

Correct. Plans afoot for 964 though. Gotta keep on keepin' on!

Well soon I will have your AC in my Rat Rod, and I have your fuse blocks...so if you want some hot climate, humid climate, high load testing I am happy to test it here in Florida.

[Jonny H]

Originally Posted by pmax

With the belted in place, the inline alternator can be removed I would think.

Try taking your alternator out and putting your engine fan back on. . Post a video of the engine running.

[uwanna]

Originally Posted by Jonny H

Try taking your alternator out and putting your engine fan back on. . Post a video of the engine running.

Yikes! Not a lot of critical thinking from that poster. LOL