View Full Version : high output alternator

07-31-2007, 07:03 PM
Does anybody know if anybody makes a high output alternator for our cars? Does anybody have one and if you do are you happy with it? Thanks for the help

08-01-2007, 05:10 AM
i searched a ton and couldnt find anyone with a HO alternator that put out enough amps at idle. I had mine rewound for $170 so now it puts out 115 amps at idle and 180 peak. im happy with it.

08-01-2007, 07:04 AM
Why do you want a high output alternator?

08-01-2007, 07:10 AM
Why do you want a high output alternator?
The biggest reason is aftermarket stereos. There are other reasons as well, I know the guy A400 on AW upgraded his because he has a lot of draw from the heater for his dry sump system.

You have 3 options.
1. Ultranator
2. Dominick Iraggi
3. Get it rewound locally

08-01-2007, 07:28 AM
99% of the time people don't need an upgraded alternator or those ridiculous caps the size of thermoses. Upgrading the wiring to and from the alternator and battery and running a large dedicated ground back to the front of the car will do it. Think about it. You're running massive power lines to the back of the car but are relying on current transmission through galvanized sheet steel to complete the circuit. Do you think a power wire made of sheet metal would be as good as one of multi-strand oxygen free copper? Exactly.

Bring the entire circuit's wiring up to the same level. Then you can see if there are any issues on the component level. If you want to see some really nice capacitors then pop the top off a high quality amp. You'll see a bank of them matched specifically to the current demands of the amp. Save the cap mpney and buy better amps.

FWIW, I've built very simple systems that won SQ awards but would never get any attention because they were invisible. I've also done a 454SS pickup with 4 a aircraft alternators, 8 Optima batteries, and a half dozen caps that weren't hooked up. The caps were just for show. This was a corporate demo vehicle and they wanted them on there. It helped sell a ton of those things. This was back in 93 and the truck had 12 15" pro drivers for sub bass, 4 10" drivers for mid bass, and several component sets. It used a Rockford digital EQ that automatically corrected for all the extra equipment so it still sounded good between shows.

08-01-2007, 08:26 AM
I'm getting to the point where I'm running about 4,000 watts right now and when I've got the a/c running and running high volume levels the alternator is having issues keeping up so I'm gonna upgrade the alternator. As for my amps I'm running 2 fosgate BD1500's to my solo x 12, and a fosgate 800.4, to the qsd's up front and qsc's in back. So at this point I think I'm justified in upgrading my alternator. Thanks for the help guys I appreciate it.

08-01-2007, 08:30 AM
Haven't a good ground is supremely important. But as long as you have a secure metal to metal ground point at the back of the car with a properly sized, good quality wire, I don't see any reason to run a ground wire to the engine compartment. Perhaps I misunderstood your post. You want a similar ground at your battery again tied securely to ground. If you plan on running amps in the back size your power wire appropriately.

IMO there are reasons for using caps. I don't however in my car, and I may pay for this later with a fried alternator due to the surges (draws) from my power hungry amps. Having a cap in place doesn't put any less demands on your alternator but does even out the power draws associated with car audio amplifiers. It may improve your SQ but that would be dependent on your amps, electrical system, and the drivers you use. I can't imagine it would help a midrange or tweet but possibly a sub.

Again, I have a high power stereo and I haven't used a cap but I may try just to see if I notice a difference in SQ. If nothing else, I've been told by some knowledgeable folks that using a cap will save my alternator down the road. I doubt upgrading an alternator would help at all. I'd start with good quality amps, forget the alt. upgrade and worry about the rest later. [up]

08-01-2007, 08:37 AM
4000 watts! [eek] Damn, you may have to add a couple of batteries too! [:p] Are you competing in an SPL contest or what?

And I thought my 1200 watt sub amp was overkill, and it is!

You're running a solo 12? Is it in a box or infinite baffle?

08-01-2007, 08:53 AM
That truck we did was over 20k watts and didn't need a cap. That is what big batteries are for.

There is no reason for 4k watts unless you are competing. If you need that much power there must be some inefficiency to overcome. My home theater is an audiophile setup that is flat to 16hz and does 146.2 db on 250 watts to one sub. The total system is 500 to the subs and 45 to each of the other 5 and it is way louder than can be tolerated for long. The secret is ultra-efficient drivers and sub-bass design. The same thing is true in cars. You can usually make more with less and have it sound better.

If you are competing then let me know. I may be able to offer some assistance.

08-01-2007, 09:07 AM
My best friend manages a stereo shop in town and I compete locally so his stereo shops name is on my car and I get a lot of business sent to him so in turn they give me really really good deals on my equipment. As for the box it's a 3.5 cuft ported box with a .3 cuft port tuned to 35hz iirc as per kicker tech specs.

08-01-2007, 09:14 AM
Sounds like a nice arrangement. You'll probably need a custom wound alternator. I used to find a replacement alternator at a junkyard and then send it to an aircraft mechanic that specialized in electronics for a full rebuild. He could set a competition only alternator for a higher output at low rpms. We would also change pulley sizes to get the rpms, the power demands, and the alternator's sweet spot to line up.

The reason I used an aircraft mechanic is that he is much more knowledgeable about RFI than a normal alternator guy. Aircraft instruments are very sensitive to RFI and he already knew which precautions to take to ensure noise free power.

That sounds like a box that would hit pretty hard. For the theater I went with a pair of 8 cubic foot sealed enclosures of braced HDF with a 1.125" thick front baffle. They each house a 15" Adire Audio Tempest and have a natural F3 of 12-14Hz. They are now powered by a 55 pound QSC3500 dual monoblock capable of 1600 watts. The extension is sick. I had to sell the Behringer Ultrabass processor (like an Epicenter) because it made my wife queasy.


08-01-2007, 09:45 AM
nice one of these days I'll manage to do a home system but its just the car for now. I'll have to see if anybody can re-wind the alternator here in town

08-01-2007, 10:39 AM
yeah i think thats the best bet. i had a customer with 3 amps running 0/1 ga. and already did the BIG 4 (big3+1) and 3 batteries with the isolators. With the AC and the system it would drain everything until the car would almost turn off.

08-01-2007, 10:56 AM
There may also be a compatible part from a past VAG engine. I don't know of any off hand but it might be worth a shot. With that much power you should be running a second deep cycle battery dedicated to the system and isolated from the main battery. A pair of system batteries isn't a bad idea with 4000 watts. I've been out of the scene for awhile but there were a couple devices on the market that would step up the 12v to 14.4 or 16 so that running an amp straight off the battery was better than when the car was running. With enough amps (the electrical unit kind) in reserve (multiple batteries) the amps (fun kind) have all the power they've every wanted and enough time to enjoy it.

I forget the math but you can easily figure out what the max current draw is of your existing system. You can also measure what you're actually pulling at high listening or competition levels. Add it up and add in a time element and you've got your electrical demand. Buffer as necessary.

That truck ran a straight regulated 14.4 volts off the batteries with the engine off. It would run hard (feel it in your chest 50 yards away) for 5 or 10 minutes but it could demo for hours. That would be background music with occasional blasts to show off. This was back when this stuff was still pretty new so it scared a lot of folks. When the batteries got low it tripped a warning light and then eventually tripped the head unit's cell phone mute wire which killed the signal and let the amps idle. Since the amps were running solely off the batteries the power was incredibly clean and consistent. The dynamic headroom is enormous with fully charged batteries.

08-01-2007, 11:46 AM
A second battery is also a good idea I just need to find some place to mount it. Thanks for the help guys.