Alternators

Any paticular model you guys are using for a strictlly race application? What diameter pully?Surely a one wire connection?
Thanks.
Al

Al, Since most alternarors are overdriven (spin faster than the engine) I figure that most common alternators aren't going to be happy at 7000 engine rpms, so I'd tend to gear things down a bit if you're using OEM stuff. With good race units, not so much. I'm also one of those guys who likes to put a switch in the field circuit so that I can put the load on the alternator when I choose. That's just a matter of personal preference though...lots of guys want 'em working full time.

Aftermarket ones Im curious about. And pulley size...

I'll check the one in my garage.

One-wire race mini alternator....3" v-pulley.

Thanks.

stock gm

I ran a small stock GM sprint unit for a while on my race car but it did not seem to keep the voltage up at the finish line. 12.3 on a good day..
Switched to a powermaster 120 or 150 amp deal probly underdriven about 50% it works well. 13 volts or better at the finish line with everything running including my fans, etc.

dkp

Al.,
I use a Powermaster #8162 that puts out 30 at idle and 50A WFO.
It works great.
True One Wire Units
30 Idle/50 Max. Amps



8162 (93mm) - 12 Volt
8168 (93mm) - XS Volt
Weight: 5.68 lbs.


Also Available:
28162 - POLISHED Finish - 12 Volt


Thanks,
Keith

Al.
I think that I spin it about 50% crank speed backwards.....
I almost forgot.
Plus...I use Gilmer belt drive
Keith

Thanks Keith.
Regards.
Al

ive always used a stock( 1980 and older) ford alt converted to 1 wire, not the big 100amper ford has ,but the small one.they will do 14.7 , we haved switch to a powermaster this year only beacuse they are lighter the the old ford alt,


-RICH

Al, most any alternator that will physically fit your application will be adequate. I incorporated a unit from a Datsun, I think it was an Intenso (maybe). It was small physically and provided excellent amperage and simple to wire. To this day it continues to provide excellent service. On the other end of the spectrum, my '68 Mustang has a Motorcraft unit on board. The unit standard for the cars era.

As mentioned in other posts, the most important test is required amperage. Simply use an amperage measuring device and measure the accessories you will be operating. The MSD ignition units I have require elevated amperage as the demand of the MSD unit is raised. They are some what hard to test but I'm sure MSD can offer each unit's requirement.

As to larger diameter pulleys, I've found if you slow down a standard performance alternator it will not provide the required amperage to maintain the battery's voltage. Your engine will not sustain a high speed for an extended period of time, so IMO the speed of the alternator will not be a concern in a drag race application. Those larger pulleys came about when production and other cars with low (ratio) axle gearing were driven for extended periods. IMO, keep the pulley diameter basic.

I'm not saying the stuff I use will fit everybody's needs, but they will work given a bit of common sense is incorporated. I too feel the new stuff has many options I do not know about. So flip a coin and serve it up!

Dave.

i called most all of these places a few years ago, msd was 12.7 volts min same for mallory,and a few others, we have data logged some 27 sec truck pull ( 300 feet)runs in the last few weeks to show info, this cost money to do this test buy the logger etc. , install and run,please keep this in mind when we give out some of this info,thanks


started with 2 batts fully charged just engine it went to 13.7 went down to 10.5 27 sec's latter running water pump, fuel pump,msd box,logger, fan, steering , now shutengine off went up to 12.5, then draw tested batterys thinking ok lets see, THEY WOULD NOT RECOVER BACK TO 11.5 , and the plugs looked a little fat.

NOW my guy says wow!

i have told these guys forever put a alt on there that can stay in the 13.5 to 14. range ( maybe as low as 12.7) with everything running you will be fine

now this guy runs an alt


SOMETIMES ITS A LOT OF WORK TO INSTALL ONE but worth it