Ok Ok Ok.

I have to many gadgets in my car for a 75 amp alternator to support. They all work great but they are pigs:
Heated seats
high power stereo
Sub woofer w/ amp
HID headlights
windshield washer pump
Interior / map lights in rear view mirror
etc.

So I have a seperate circuit and an electrical sub-panel to support the load safely but simply put:

"I need more power Scotty!"

Took my old 50 amp Bosch to an alternator / starter rebuilder and after looking at it a bit they recommended the AC Delco 100 / 105+ amp single wire alternator with integral regulator for $110 rebuilt. He stated that it could run the dash idiot light too.

Not quite ready to bypass the voltage regulator etc.

I am sure this mod is probably old hat for some.

Thoughts?

Thanks in advance,

Pete

It really should just come down to whether the Delco unit would fit in the available space and the wiring harness can be modified. Haven't really heard much in people replacing their alternators with higher power ones. Have you added up the amperage required by your items? Do they add up to over 50amps?

You might want to check with Sol Snyderman at Perfect Power in Buffalo Grove to see if he's ever heard of such a swap. Brad Mayeur at 914Ltd in E. Peoria would be another great source of information if no one hare has any experience with the larger alternator.

HID's actually consume less current than halogens.
Why do you think they're in Priius's?
About 35W a side.

As George mentioned, space is the big factor unless you're you're going to use bracketry like an AC compressor. The other big factor is cooling, which is already a little marginal for a high-amp alternator in the stock location.

"Standard" alternators (front-engine application) tend to live out in the free air and can dissipate their heat load. Getting cool air to and hot air from a 914 alternator is a challenge.

I think you should go with the GM alternator. I run a GM style Powermaster 180 Amp unit. There is no advantage to keeping the stock VR unless you intend to concourse the car.

Biggest upgrade for the buck is up sizing all wires. I run a #2 charge wire and have upgraded all grounds. I bet your stereo wiring is bigger than most of the stock 914 wiring. Add extra grounds, bigger wire. Add a ground from the alternator to the battery.

If your amplifier has a 20 amp fuse, that means it can take spikes of current up to 20 amps. The factory alternator charge wire is a #8. This is barely adequate for 20 amps of DC current. The car battery acts like a buffer, not allowing all that current into the battery at one time to recharge. This is mostly due to internal resistance. Your amplifier need instant current flow. Here is the advantage of a charging capcitor. The cap will charge and discharge instantly to help out.

Most people do not realize that DC current takes a bigger conductor than AC current. Because of this, most will quote AC amperage charts. The world realized this and chose Tesla's AC power over Edison's DC power. Edison needed a 4" diameter conductor to push DC down a single block of homes. Tesla only needed a 1/4" conductor for the same distance with AC power.

When I was manager at a car stereo shop (and master installer), we would use #8 amplifier wires at a minimum. We also upgraded the ground from battery to chassis and battery to engine block. This worked well for night time headlight dimming problems.

The wiring and chassis on your 914 is old, rusty and corroded after 40 years. The wiring has reached its life span. The unit body is now grounded through rusty metal and spot welds. Start with upgrading your wiring first.

Can we see some pics of that alternator installed?



As far as an easy swap, the 75 amp alternator from a VW bus fits right in, I have pics in my Blog with side by side pictures. That gives you an instant 25 amps, or bring it to your alternator guy, I had the 75 amp rewound to 120amp

Hasnt blown anything up yet

I like the idea of having a modified or rewound unit that is a direct fit.
Have you had any cooling issues with the 125 amp?
Where / who did it?
How much did it cost?

I have gone over the rust throughout my whole car and she is solid plus(longs in and out as well as rear suspension and hell hole etc.

I like the idea of adding and updating grounds. I already upgraded the ground from the battery to the body. I like the idea of adding a ground between the battery and the engine block. I think that will be my next move.

A capacitor should be a good idea to even things out while I am at it.

I am concerned about the cleanlyness and reliability of bypassing the VR and am not a fan of splicing into the wiring harness to accomplish the mod. Although I might not have to at all sans the idiot light accomodation.

PLEASE SHOW US SOME PICS OF HOW YOU FIT AND SET IT UP.

Interested in this too.

A friend of mine has just fitted a Mazda Alternator to a Notchback, but not had the engine running as yet I'll ask him for some images too..

davep was building higher output alternators. Try sending him a PM.

No cooling issues, works just like the original. Purchased the unit from a vendor on Evilbay, the guy that was selling it had a bunch of brand new units.

forgot the guy

no idea what i paid


Im sure there are units out there.

Not to be nerdy, but don't you have that backwards.

Which leads us to the inevitable question - how do you know it's actually producing (or capable of producing) 125A?

And the next question - are all the wires between the alternator output and the battery rated for 125A at 12V ?

1500W is serious energy - like 2X a typical 911 alternator - and they have way better cooling - are lots larger.

Color me skeptical...

I'm glad it's working for you, but I am highly dubious it's actually capable of producing anything like 125A.

In the words of Al 'White and Nerdy' Yankovich - No.
Tesla and Westinghouse put AC on the map.
Edison championed DC and - well - he's famous for other stuff...

I don't see why you would ever run a one wire setup.

This is for a different vehicle but here is a link to a discussion on one vs. three wire connection and converting from a externally regulated alternator to an internally regulated alternator. Bob Skelly's Alternator Site

The CS series alternators and the 12SI series are supposed to have excellent cooling.

What would you use for a pulley? I think these typically spin at about 1/2 engine speed. The pulley on the fan is pretty big which means you should have a big pulley on the alternator. The pulleys on modern alternators are pretty small. Maybe they are suppposed to spin faster.

[quote name='pnewman' date='Aug 18 2012, 09:08 PM' post='1725729']
Ok Ok Ok.

I have to many gadgets in my car for a 75 amp alternator to support. They all work great but they are pigs:


If “They all work great” why are you worrying about the size of your alternator?

The stereo bumps, i mean it really really pushes in on your chest

And the wiring was all upgraded. Everything is brand new, from the custom Jeff Bowlsby harness with 2 runs of 8g wire, then the o gauge power and ground. then I added ground wires from the alternator bolt to multiple ground points in the engine bay.

Yes the wiring can handle it. None of my added electronics are using stock leads. I run power and ground from the battery all the way up to the Desmazes Delayeator.



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[quote name='damesandhotrods' date='Aug 22 2012, 03:34 PM' post='1727607']
[quote name='pnewman' date='Aug 18 2012, 09:08 PM' post='1725729']
Ok Ok Ok.

I have to many gadgets in my car for a 75 amp alternator to support. They all work great but they are pigs:


If “They all work great” why are you worrying about the size of your alternator?
[/quote]
I would answer that they may work but if they are working near the maximum output, you may find yourself dead on the road. I would prefer to have a buffer zone.

Then why not install an amp meter and monitor your current draw? I don’t mean to get all Myth Busters on you, but if you don’t know, you’ll never feel confident in the car.

This also gets into your switches. If your devices are wired through the switches and they can’t handle the current you’re looking at a potential fire. If you’re drawing so much current the switches should be controlling relays and the relays handling the current.

You are most certainly correct ! I had it backwards...ha !

Don't get too excited... I don't have a T4 engine... Don't you read my build thread?

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Cheater

[quote name='damesandhotrods' date='Aug 22 2012, 12:34 PM' post='1727607']
[quote name='pnewman' date='Aug 18 2012, 09:08 PM' post='1725729']
Ok Ok Ok.

I have to many gadgets in my car for a 75 amp alternator to support. They all work great but they are pigs:


If “They all work great” why are you worrying about the size of your alternator?
[/quote]


A ha!
"They" in the statement of pertaning to the gadgets refers to the individual gadgets as working great. Together or in multiples they simply consume too much juice. Using them individually "they all work great."



I would like to take managing electrical load out of the driving experience.

I spoke with an alternator / starter rebuilder and he was trying to pitch the GM unit. One of his pitched pro's was it's smaller pulley which he stated: will provide higher alternator rpm at idle; giving you more current at idle which is a shortcoming of larger pullied units.

The smaller pulley will rob 1-2hp due to spinning the alt faster. You may not notice it though. As long as you don't exceed the max rpm of the alt you should be fine.

Ammeter: I see a "voltage drop" on my voltmeter. The issue is obvious with usage of multiple accessories when used simultaneously.

Fire Hazard: I created a secondary (sub ATC fuse panel) with its' own main back to the battery which is also routed through a main fuse at the battery. Said panel is triggered off of a relay triggered by the ignition switch. The relay/wires/fuses etc all are good for their respective loads.

Oh and I have been a full time FireFighter for 12+ years. Kind of watchful of those risks. So much so that I have an extinguisher mounted at the ready.

Thanks for the info:
Very productive.
I like the idea of a capacitor.
I will definately upgrade and add grounds. Good call.
My body is now more rust free than most 10 year old cars let alone 40 year old cars. That was no easy task.

I am looking into upgrading the alternator wiring too. I am trying to decide which route to go in regards to choice of alternator first.
I would prefer to not rewire twice. i.e. if I am not happy with the results of just rewiring my 75 amp.

thanks again for the ideas

I found davep on the members list and sent him a pm .

Thanks for the lead.

I thought sports cars didn't have all that FLUFF

When you upgrade to this one wire, can I have your old alternator?

In the mid '70s, the owner of a Waycross, GA VW shop told me that since VW took over its engineering from Porsche it had always used too small a wire. Guess that extended to the 914.

Wire costs something and it weighs something.
When you go from making 1000 cars a year (Porsche's original sales model) to a million, the value engineers get into the picture bigtime.

In the 914, even the radio was not on the standard equipment list; electrical loads were low.

But even contemporary 911's had 'marginal' wiring, as anyone who's dealt with their headlights knows. Barely adequate for the original 55/60W lamps, and all the current went through the switch. Gets back to that weight and cost factor...

Wife comfortable or limited the rides will be (Yoda)


We need a "yoda" Smilie

http://www.914world.com/bbs2/index.php?sho...=195244&hl=

I will be posting pics asap of unit on a core engine so that it is easier to see what I am doing.
Peace,

Pete

We have one.