Alternator na/turbo/s2 question

ae1969 · 02-20-2002, 05:36 PM

re: 86 944

Does anyone know which one has the more power output? (na,turbo,s2)

Are they all the same size/ and fit in the same mounting brackets?

Has anyone had an alternator re-cored to get more amperage out of it?

Is it possible to get a different voltage regulator to bump up the power output?

Thanks

Ehab · 02-20-2002, 05:42 PM

The three different models have different alternators of different sizes, I think the na is 90 amps, and the turbo and later na models have a 115amp alternator. The stock regulator is 14volts, but you can get one that gives you 14.5 ... but I don't see what gain you get from that, besides risking burning out some fuses (although .5Volts seems small, if you put it through a 1 ohm resistor, you get 1/2 amp of current) ... I remanufactured a couple of alternators at a shop close by, he put new bearings and brushes, and now I get about 13.9 Volts when the car is running ... didn't cost much at all.

good luck. make sure you disconnect the battery (both terminals) when working on the alternator.

E

ae1969 · 02-20-2002, 10:33 PM

Upgraded my stereo.............really putting a strain on the electrical. Things were fine until I ran 1,000 watts through my car.

SO I was looking at my options.

IceShark · 02-21-2002, 06:33 AM

There are two seperate issues here. One is the amperage output capacity of the alternator. I have seen people selling our 115 amp alts that have been upgraded to put out 140 amps. Not sure exactly what they change out, probably the stator and diodes.

The other issue is the voltage regulator. You can get a new regulator which is rated higher than 14.0v such as the 14.5v mentioned, but be aware that this is irrelevant once you load up the alternator with a reasonable draw. I don't have my test figures handy but once you hit about 40 amps of load, the alternator can't keep voltage much above about 14.0v anyway.

But it is a good idea to set the regulator at 14.3 to 14.4 or, I guess, 14.5v, to bring your battery back up to full charge quicker when there isn't much of an electrical load on the system. The rate of battery charging is dependent on the voltage differential. The quicker you get the battery charged up the quicker you take that recharging amp draw off the alternator and have more power available for other items. This will make a very big difference in increasing overall system voltage.

The down side to higher voltage and why Bosch is in the school of low voltage regulators is that you can cook the battery if you put voltage too high. But many alternators run up almost at 15.0v and you don't hear too much about cooked batteries. I got an adjustable regulator for under $20 and set it at a little over 14.3v and have noticed a big increase in system voltage - I now usually run at about 13.9v. I would recommend you put in a new regulator set somewhere around 14.3v - that is a nice tradeoff voltage setting.

Oh, one other thing: make sure your air cooling hose to the alternator heat shroud is there and in good shape. That also makes a big difference as the cooler the alternator (and diodes) is the more power it can put out.

ae1969 · 02-21-2002, 10:35 AM

ICESHARK: Which adjustable regulator did you get? DId you have to pull the alternator, or could you get at it in the car?

I think I will try the voltage regulator. IF not, I am sure my alternator may not be producing enough amps. IF the voltage regulator doesn't work (or cooks my alternator and battery) I will get my alternator rewired for higher amperage.

I am running a minimun 1000 watts RMS through the car, with 1 Farad Cap on it as well. It did help with some of the spikes in the system when powering the 2 Subs, but once I crank the bass, my headlights flash in synchro with the music.

EHAB: what would it normally cost to get an alternator re-wired??

Thanks guys

IceShark · 02-21-2002, 12:51 PM

The adjustable regulator is made by Transpo, # IB372A.

I have a 951 and had to take the alternator out because I wanted to test it. I'm not sure if you could install it with the alt in place as it is really tight in there. If you can get the heat shield cone out for some room then you should be able to do it.

You might also want to think about putting in heavier ground wire and positive from alt to battery and battery to fuse board. Like #2 gauge. That may reduce your voltage drops from resistance enough to get you by. If your headlights are dimming with the bass you definately have a problem. LOL!

ae1969 · 02-21-2002, 01:02 PM

I did run a new larger ground to the battery. Maybe I will change the power one as well.

I am definitely putting a strain on the system.....

You should of seen without the CAP on. The voltage gauge would run fine.....then crank up the bass..... 100db 120db....the thing would be swinging from 13.5 volts to 10! In synchro with the music. The gauge started looking like my TACH the way it would swing up and down........

With the Cap on, it stabilizes so no sudden drops below 12 volts....unless I really turn it up.....then we get the massive drop in voltage.

I normally don't drive with it cranked up, but I was setting my crossovers and eq settings at 120db........when I noticed the dancing lights......LOL .... so I figured I would improve my electrical system.

Thanks

IceShark · 02-21-2002, 02:47 PM

Where are you pulling the power for your amp? If it is off the fuse board and you have stock wiring from the battery over to the fuse board, you are losing quite a bit there as that wiring isn't heavy enough for the loads you are running. You could also rewire the headlights; they will still suffer but it won't be quite as bad. You might want to put a volt meter on them to see how much is getting down there under load.

Not that replacing wiring is going to be a total miracle given your loads but every little improvement helps. You should add up your total watt/amp draw and see what that is compared to your alternator rating (do you have the 115 amp alt or is it lower?)

ae1969 · 02-21-2002, 03:32 PM

I am running 4 gauge to the amp, direct from the battery.

I am not sure if I have the 90 or 115amp alternator. I have an 86 (so if it applies as the latter 944's I must have the 115 amp, but I will check)

Uhhmmmm I may try to run larger gauge wire to the lights as well...

Every little bit should help.

Thanks again.