What alternator to use

[sprinterjon]

Can anyone recommend what the best and most compact alternator I can use on my 302 engine ?
Thanks , Jonathan

[emiel]

Much depend ofcourse how much electricity you need.fuel pump,ignition,lights,a/c,fans and so on.I use an small Japanese alternator and it works for me.Emiel

[Phil]

Jonathan
I am using a Ford alternator...can't recall what model it came off, but it was converted to a one wire setup, sure saved a lot on wiring etc. Take a look in some of those catalogs like Summit, and they may have some good choices. The only thing I have seen thats very small are some of those Japanese types as Emiel mentioned, or some of the race alternators, which cost a bundle. You can take a look at some other mounting options if space is a problem, particularly down low where there is more available space on most chassis.
Good Luck
Phil

[Sandy]

Another option I found when they didn't have the one wire/internal regulated fords was to just use a GM internal regulated 1 wire job (1980's style). The will fit right in with a simple redril of the one mounting hole and a new spacer to align. Ran one on my Mustang for a while until I got a Racemate. People gave me crap but it worked well with the one wire setup and was cheep since everyone one was doing one wire GM's at the time. Powermaster, and others now do internal regs for Ford which is nice.

Sandy

[DaveWharran]

I started out with an 80 amp Ford alternator and quickly found out it was too small. The radiator and oil cooler fans are BIG users of power. Combined with the EFI, 4 coils, fuel pumps, etc. the 80 amp unit failed. Power usage was tripping a 50 amp breaker.
I replaced it with a 140 amp single wire Powermaster. It does fine but requires a quality vbelt if you are using vbelts.
Also ran a second 50 amp feed to the dash area dedicated to the fans.


Dave

[Ron Earp]

Ditto what Sandy said.

I've got a Powermaster (not a GM config, some small funky 3 bolt one wire they make) on my Jensen race car, pricey, and I'm not sure I like it - here's why: it isn't a commonly available alternator I can get at a local parts store so if it goes bad I'll be spending some time making some brackets to race.

Advance Auto, Pep Boys, etc. do have one wire GM alternators many times in stock as we've had to test that with the TR8. If not in stock with 24 hr delivery. So if you are concerned about losing some track time I'd get a very common alternator. On the Lola I have a GM style one wire I bought from Brian (New England GTD build) and I think it'll be a smart choice because it is easily replaced anywhere.

Ron

[Larry]

Same here...I used the single-wire GM on my BEC GT40.

[Sandy]

"It's all about the power" Or something like that quote from the Movie Apollo 13.

I have done a couple of cars with the Racemates are either 30amp or 60amp. I have a 30amp in the Mustang, and it is not somthing you could drive on the street at night. With lights, ignition, fuel pump it is net negative and running on the battery until about 5000rpm due to the pulleys. If using underdrive pulleys expect the full power capacity of the alternator to come later in the rpm range, but not really sure how they ramp out depends on pulley and alternator.

All the juice adds up quickly depending on what you got in your car, the killer is fans and high current halogen bulbs (120watt bulb ~ 10amps each at 12volts). Fans can be huge too, not sure on the smaller ones, but I recall 7-10 amps x 2.

Fuel Pumps can be from a few amps for Holley's/Mallory style (range of 5amp) and some of the larger EFI pumps state 10+amps for the bigger (SX Perf/Aeromotive Inlines). Ignitions like MSD's 6s are roughly 1amp/1000rpm, Add AC and blower fans (??), trans cooler pump, 2500 watt boom box stereo, and neon running lights with dual nitrous with the rapid machine gun style purgers (read as sarcastic) and it adds up quickly.

Switches, Relays, Fuses and Breakers current capacity are important too, as is often overlooked wire size and connector capacity, especially from the alternator if running an alternator with 2x-3x the capacity as stock. Check some of the older threads on AC and Ignition switch issues with some of the cars.

Too much coffee today

Sandy

[Neal]

Geo Metro alt is very small. Likely the minimum output necessary (60 amp) assuming no neon or disco balls are part of your build and you can get over the stigma of using a GM part...

[sprinterjon]

thanks for that info.
jonathan