I have a '71 Corvette w/o air conditioning. I have a 10SI currently in there, but I'm not sure of the amps. It can be as much as 63 amps. I'm adding dual electric fans and a fuel injection TBI system.

a. If I have a 63 amp, can it handle the new additions?
b. Should I go up to a 12SI with 94 amps and if so, is there any wiring modifications required?
c. Should I go up to a CS type alternator and what modifications are needed going this route?

Thanks!

 

If it is the stock one it would be a 43 amp. You can easily upgrade the guts of the alternator to 80 amps and still use the same case. I run fuel injection dual fans on mine with an 80 amp conversion just fine. Here is where I got mine from and did the conversion myself.

http://www.alternatorparts.com/gm_al...kits.htm#10-si

 

This is a great alternative Gordon. I am seriously considering this.

Curious... Do you have any cooling problems with the alternator itself? I've heard that's a problem with the SI's. Also, did you have to modify the wiring (thicker gauging) or modify the Ammeter/Voltmeter?

Thanks!

 

I have never had an issue with heating it up. As for the wiring I am running the stock wiring but I did modify where I run my fans from. I ran a heavy gauge wire from the starter terminal lug to a remote lug. I run the fans and the lead for the fuel injection system from this lug, but the wiring from the alternator is stock.
As for the gauges I ran the stock gauge this way. I have since gone to aftermarket gauges and run a volt meter.

Heavier gauge wire is never a bad idea though. If the harness is old or has been spliced a few times a new heavier wire is cheap insurance.

 

I rehabilitated both sides of the factory under-hood harness as well as the interior's harness. Looked over each wire, inspecting for any worn insulation or bad contact on the ends; checked each wire with an ohm meter to ensure continuity, primarily. Nothing showed up with an overt resistance level either, all normal stuff.

I chose to run a CS-130. There has been a lot of discussion in CF how bad the bearings are in that particular alternator but I haven't had any problems with mine. I tend to believe early CS units may have shipped with crappy bearings and those are no longer a problem like they may have been. I've run 10K miles in the year since returning car to the street and not a lick of trouble.

Like Gordon, I ran an extra heavy gauge wire but chose the factory breaker connection on the driver fender by the squared vacuum can (older C3) and ran it directly to the positive side of the battery. It is routed through the trans tunnel and tightly secured to the firewall and positive batt cable.

Also like Gordon, I also added another remote lug. Put mine behind pass side wheel-well by fabb'g up a bracket to screw on the #1 body mount, under the heater fan. To this, I mounted the Spal controller for my electric fan as well as adding a 40A breaker for it and the MSD. Used a small section of bicycle inner tube for breaker's insulation.



Everything runs nice and bright and haven't had a single problem crop up. Works for me.