My SBC 412 has an electrical water pump,electric fan, MSD 6.0. It has no boltholes low on the driver side, and I had given up on ever having an alternator.
I just bought this bracket

http://alangrovecomponents.com/S.B.Electric_Pump.htm

and I want an alternator that I can switch OFF

Anybody doing that? What alternator and how is it wired?
Thanks in advance for your help.

I'd go with a CS alternator like a 130 or 140. It's more efficient, has ball-bearings front and rear, and can be switched off by removing power from the gen-lamp wire. As an added bonus, it supports remote sensing which can be very useful in a remote battery car (as well as any other). Check out http://www.camaros.net/techref/electrical/dnult_alt/ in the electrical stickies. It shows a wiring diagram along with some technical tidbits that you may find useful.

Thanks Dave

Good article, Dave.

Thanks Everett. It isn't shakespear and perhaps too wordy (or techy) in spots, but hopefully it gives folks some ideas. I appreciate the kind words.

You're welcome. At least now I can change over to a 10SI or 12Si and toggle switch the sense wire to kill it. I thought I could, but now I know. Good science project.

Personally, when running the 1/4, I wouldn't want to turn the alternator off. Electric pumps and ignition systems will have lower output, at lower battery voltages, a alternator will keep system voltage around 14 where its supposed to be. sometimes you can pick up ET with a alternator, if like a fuel pump isn't keeping up. For a drag car, you don't need a really high output alternator, something in the 50-60 amp range is plenty.

50-60 is what I am planning on initially, but got thinkin hey why not put a 100 and get Wolf a boom box ghetto blaster thumper radio subwoofin whatchamacallit yeah maybe that's what I'll do.:) . Or Not.:D
Don't have an alternator right now, car is consistent unless I let batt get low.
With a switch on it, testing ET differences is easy as..... flippin a switch:D

Yes, undee, I know lower voltage affects performance of electrical accessories. But it provides with a 0.25 second advantage with it off. I normally run with sys on.

I presently have a 37 amp ext system. Takes forever to charge battery, because I don't do it at the track, 800 CCA-1000 CCA, whoever is on sale. I might try the 55 amp alt someday.

Thanks,

If you're running an Electric Fans better go with the CS130 and place a 3 Amp Barrel Diode 600PIV across the 85 and 86 Terminals of your Fan Relay or Voltage Spikes and Back EMF will Burn transistors in your CD Module and Distributor Trigger and possibly your New Dash mp3 Player.

If you're running an Electric Fans better go with the CS130 and place a 3 Amp Barrel Diode 600PIV across the 85 and 86 Terminals of your Fan Relay or Voltage Spikes and Back EMF will Burn transistors in your CD Module and Distributor Trigger and possibly your New Dash mp3 Player.


LMAO

Ok at first I thought you were joking, because of the reference to my boombox thumper subwoofin apparatus. But I see you're not. On my stuff at work, we don't have terms 85-86, I assume you are referring to the coil side terminals of the relay. Because we also run suppressors of differing flavors across the coils of relays.

Am I on track so far?

Your right on Tim :o))

OK, so then it seems you are saying that due to the addition of an alternator, and cycling my fan , transient voltage spikes will eat my ignition circuitry?

Yes I ran into that problem. I run a HyFire VI and Mallory Breakerless Magnetic Distributor. I also ran the 63 AMP 10SI and a Rad Fan from a Volvo using a Thermo-Bio SX to trip a Bosche R75 Amp Relay - that did not have a Diode. After 120 miles I blew 3 transistors in the HyFire Module.

When the fan starts Voltage would drop from approx 13.5 to 11 Volts but quickly recover back to 13.5 Volts. I don't believe this would happen with a CS130 or 144. But my biggest problem was the Back EMF surge from the Bosche R75 Amp Relay when the Fan shut off. If there is no Diode Suppression you might get as much as a 600 Volt Back Surge from the Relay Coil which only lasts Milli-Seconds but enough to burn Transistors in your CD Ignition.

The Fan with the 10SI required a 40 Amp Fuse on startup or it would Blow but I believe I can get away with a 30 Amp Fuse if I use the CS130.

All Under Hood Circuits including your CD Module and Fan Motor should be feed from the Horn Relay Bus Bar, NOT the Battery Jct. Also the Alternators Sensing wire should also be wired to the Horn Relay Bus Bar along with the Alternators Out Put Wire. I don't know if your running a GM Amp Guage or Idiot light but if your running the Guage there should be nothing feed from the Battery Jct Terminal or this will upset the Gauge Reading as there is a Shunt between the Horn Relay Bus Bar (which is usually spliced into the Harness just before the Horn Relay) to the Battery Jct and runs Parallel with the harnesses Alternator's Battery Charging Wire.

If you don't have an Idiot light you will require the SI to CS Resister adapter. If you have an Idiot Light the bulb itself is the Resistor and don't need the Resistor Adapter.

I'm presently in the process of Converting to a CS130 an installing a Diode across the Fan Relay. It cost $100 to have the HyFire repaired and some learning experience regarding Old circuitry Back EMF compatability with Transistorized Mico-Processing Units (MPU's) - lol

Good Luck with yours I anxious to see how it works out :o))

Responding to the comments about keeping critical voltages up and flyback surges...

This is where remote sensing earns it's keep. The article shows how you can connect those high-current loads near the battery and remotely sense the ignition voltage to keep it right on target. Fans, headlights, water pumps get a boost, while everything else is spec on 14.2 volts (err whatever)

Good Point Dave, Wish I had considered this when marrying 35 year old low current circuits that only had Switches and what, ONE Relay (The Horn Relay), with High Current Relays and Transistors - lol

Yesterday I dug around for some TVS I haven't trashed(we get extras for adding electric oil pumps and stuff when we do panel retrofits), couldn't find any but I know I have some. I did an internet search for Z-15's 3 amp 600piv diode and found the exact same one he did in the thread you guys had last week/month that also popped up same search.
Good stuff.

Some clarifications
This is a 1/4 mile car
got no stinkin horn or relay
got no stinkin temp controller for the fan relay. Switched relay, stays on unless I screw up and I do.:D
got no stinkin boombox subwhoofin thumpin apparatus:confused:

doesn't have these things, doesn't need em. won't get em.

The car is also getting back halfed, tubbed, re-roll caged and more right now, so my wiring will be a wad in the floor and I'll probly start from scratch

Way I see it shaping up so far...

Got no alternator, gonna put one, having trouble visualizing the need for 130 amp but if they are easily available it doesn't matter because it'll be off unless I screw up. Which I will:D
I will install it using the remote sense, batt in trunk, I got more wire than you can shake a stick at. Can the sense wire be 16 ga? I have some two pair yellow shielded 16 ga that would look good. Murder to strip but I've been itching for a place to get some of it onto Wolf.
I will turn it on/off using the gen light terminal, and I will also do some comparative runs with the belt removed.
I currently have 4 relays, I will put TVS across the coils of all 4. But on my application it is insurance only because each relay is sourced from the batt.

All I got time for today. Got to go work in the oilfield dammit. Been being a bum last few days.

Sense wire can be 16 AWG. Not a current carrying function for charging, just a voltage potential, minimal current, milliamperes.

If needed, use both 16 AWG together. Nothing but time.