Looking for some advice/direction...

I have a 72 with a 455 and several electronic components on the car:

• Sniper EFI
• Sniper Hyperspark and Hyperspark Coil
• Dual electric fans each wither their on 40 amp relay
• Electric powered vacuum pump
• LED Halo rings in headlamps
• basic pioneer head unit
• Vintage Air AC system
• OEM power windows

I did the conversion a while back before I added all of these items and now that I finally have it running good, when i get home in garage I like to pop the hood to allow it to cool off (I'm in FL and it reaches on avg 205 when I only cruise around the neighborhood ).
Since my motor is a fairly new build I like to also lean in and inspect for leaks, etc. and tonight I caught a faint but direct smell from the alternator, like an electric burn smell....I have to get within 1 foot of distance and I can pick up the smell

I have the OEM wiring setup and again the Internal reg conversion with the pigtail at the Alt and the jumper harness at firewall.

Is my Alt getting overloaded ? I don't want to keep driving only to have it melt down. The smell is strongest @ front just behind the blades of the alt....

** according to my Sniper handheld LCD its charging just fine at 13.3-13.8 volts....I have an Optima Red Top Battery as well

 

Been thinking about this all night. With my current 12SI alt I’m just wondering if it’s enough with all I have added. Maybe I should just grab a CS130 105 amp and just get a conversion pigtail ? I’m thinking this is why I am getting a faint smell from the 12SI... both fans going off as well as fuel pump and EFI...thinking I’m maxing it out ?

 

Brian - I can't speak directly towards your exact issue, but if it were my situation I would examine each item you have listed, examine the amperage draw for each item you have listed, add up the total amperage draw for all items to arrive at your total amperage draw with all systems turned to the ON position & running. That is, IMO, the best manner to determine if the amperage output of your current alternator is capable of accommodating the total amperage draw.

 

Thanks Norm - makes logical sense

 

Brian - I most likely missed a couple items (ones you don't have listed in your list) which remain in the ON position while the car is running, but you obviously understand the overall theme here. I don't recall without having to look stuff up, but I believe in general you'd like to see about a 35% overhead (if possible) for peak usage...i.e. if you're drawing 100amps you'd like to see an alternator output of ~135amps. I realize this example is not correct for your car, but just an example using easy numbers.

 

If I do the math on what I have I arrive at this:

EFI = 30 Amp
Fuel Pump - 30 Amp
vacuum pump- 10 Amp
electric Fan # 1 - 25 Amp fuse (40 Amp relay)
electric Fan # 2 - 25 Amp fuse (40 Amp relay)

If all on at same time that's a 120 Amp need...I know my current 12SI is not in that range.

Is there a CS130 that fits my brackets that's in the 140 Amp range ?

 

Regarding the EFI, Fuel Pump & Vacuum Pump - are those the listed (by manufacturer) Maximum Amperage Draw ratings or the fuse ratings? The fuse amp rating (if I recall this correctly) is dependent on the AWG wire gauge size, as well. I have used an easy to remember formula of the fuse rating should be 125% of the amperage draw rating for the wire (which should equate to the device amp draw, since the wire needs to be capable of handling the current [amperage]). Therefore, each electric fan (25 amp fuse) should be ~125% of the duty cycle (amperage draw) for each device yielding about 20 amps/fan (40amps), resulting in your total being closer to 110 amps. So, you need to ensure you have the correct numbers for the fuel pump, vacuum pump and EFI - if you're using the fuse ratings, they'll "generally" be ~125% greater than the duty cycle (maximum amperage rating) for each device - I don't know which number(s) you're using for those devices. Sorry, I can't answer your CS130 question.

 

There is no way the EFI pulls 30 amps. That’s may be the fuse rating, at most I would expect the EFI to require well under 15 amps, and most of that is fuel pump current draw.

The cooling fans probably pull 30-40 amps at start up, then settle down to 15-20 continuous.

The ignition takes a few amps to run. I recall reading in a MSD catalog their race ignition box requires around 2 amps per 1000 rpm. I would think a street ignition system would pull much less.

Headlights, wipers, heat and A/C, all the other accessories probably draw 10-20 amps each. Add this all together it’s possible your close to the maximum output of the alternator.

The easiest way to get an idea if your current alternator is up to the job is to start the engine, turn on every electrical item and monitor charging system voltage at idle. Let the engine run long enough for the surface charge of the battery to drain off, let the cooling fans cycle a few times. If the system voltage begins to slowly drop, the alternator can’t keep up with the load. It might recover at higher engine speeds, but that’s not really ideal.

The advantage of a modern alternator is more capacity at lower engine speeds. The CS130 alternator on my Olds is capable of putting out almost 80 amps at idle (I have verified this on my Snap On battery/charging system test machine) and well over its 105 amp output at higher engine speed. Your current (ha!) alternator probably puts out a maximum of 75 amps, and around half that at idle.

Just make sure you upgrade the alternator output wire to at least 8 gauge.

 

EDIT: I have to leave (play golf) but others will certainly help you (and make any corrections to my suggestions). I think you may be just a little high on your total amp usage equation without going into granular detail. Remember, you're just adding up amperage on those listed items, don't forget your amperage draw on the remaining units in the car AC, pioneer amp, etc, etc. I think the largest duty cycle 12SI is rated at 94 amps? You're quickly getting to the point of a pretty decent draw rating. Wish I could assist longer but have to run.

EDIT: Good deal, matt jumped on board.

 

I went to the Manufacture sites for the #'s and I rounded up just slightly, here are the numbers as they publish:

EFI = 20 Amp draw (30 amp fuse)
Fuel Pump - drawing 15 amps at 60 PSI and 13.5 Volts.
vacuum pump- 10 Amp
electric Fan # 1 - 25 Amp fuse (40 Amp relay)
electric Fan # 2 - 25 Amp fuse (40 Amp relay)

So looking at these #'s as exact as I can get them I'm at 95-100 Amp's - so a 105 Amp CS130 would fit the bill I believe
** Also let me ask, I never did them when I converted to the 12SI...I see mention of upgrading the gauge wire from alternator to Battery....is this the wire from the back of the Alt. to the starter ?

 

Matt really offered great suggestions. IMO, the greatest piece in your puzzle is to ensure you're employing the correct AWG gauge wiring - critically important. Good luck!

 

Regarding the wiring - critical. You need to provide the least amount of resistance in the wire to achieve the maximum current flow (load-carrying capacity). Therefore, a smaller gauge wire provides greater resistance than a larger gauge wire - you want the least resistance so employing higher gauge wire (as Matt suggested 8 AWG) is critical. I might even employ a 10 AWG or 12 AWG.

 

Thanks for Jumping in Matt ...Enjoy the course Norm - Raining in FL right now. Nothing worse than a conference call and grey and ugly outside my window.

So Matt I missed your post as I was replying to Norm but I never did the wire upgrade, is this the wire from the back of the Alt. to the starter ? Just run a new 8/10 Ga ?
Also yes based on more precise math I'm maxing out my 12SI.

I know I can get a 105 amp CS130...can I just run the 12SI to CS130 Pigtail on top of the fact I already have a 10DN to 12SI pigtail ? is there a pigtail for this jump...or just splice the wires to the pigtail and call it a day ?

 

Really have to run now. But, Matt provides greater understanding of the reality of what's occurring with his statements regarding start-up amperage and continuous amperage draw (I actually used the incorrect term in my first post by suggesting the duty-cycle of the device, but I was typing rapidly).

 

So Matt - we are talking about this wire correct ? and it would need to run down to the starter ?

I have a repo aftermarket OEM style harness I added when I did the engine swap, my original was too brittle, looking at the overall diameter of the wire it measures in the 8 gauge range...am I looking at this incorrectly ?

 

You have no idea how thick the insulation is vs the diameter of the copper. It's the copper that determines wire gauge, not the insulation diameter.

 

ok so here is what it is...and I count 19 copper strands as well within it...so I believe it is an 8 gauge as 8 gauge is supposed to have 19 strands...according to Google LOL - But Joe I'll take your word on it if you agree or not

 

Keep in mind, the fuel pump is powered by the same fuse that powers the EFI. So part of the 20 amp EFI draw if powering the pump.

The wire off the stud on the rear of the alternator is the one you need to upgrade. If your still using the horn relay as the junction block, you also need to upgrade the wire from the horn relay stud to the battery. The factory wire is 10 gauge, there is no way a 10 gauge wire will support much more than 50-60 amps continuously. The remaining alternator output current will get consumed in the form of heat instead of charging the battery. Eventually the wire will fail.

 

Thanks Matt ! And yes it’s all setup as factory right now using the horn relay, however based on what I have I do have it’s 8 awg (19 strands of copper within the sheathing) , should I still look to go to a larger gauge such as 6 ?

and yes I am getting a CS130 105 amp based on discovering via this thread my 12SI is not going to cut it.

 

Well I was able to answer my question...I remembered I purchased some 8 gauge for a project on our RV...this is clearly 8 gauge so what I have is not...easy enough to run the 2 wires from Alt to Horn Relay etc..

 

Hey Brian - I made a mistake this morning in a frenzy to provide information as I was attempting to run out the door to play golf. In my head I was thinking the stock OEM was 10AWG or 12AWG and I wanted to suggest to you to go up at least one (as Matt indicated) or even two gauges (when I suggested 10AWG or 12 AWG). Instead I typed what was in my brain (10AWG-12AWG). Now that golf is over, I can apologize for my misinformation. I would have no problems for you to go up (in thickness) at least one gauge (minimum) or two gauges. Therefore, an 8AWG or even a 6AWG would be a better choice providing less resistance and more load-capacity throughput. I would suggest (as Matt has discussed) 8AWG gauge wire at a minimum. I'd have no issues with a 6AWG and even a 4AWG gauge wire. Those two would provide far less resistance and clearly far more load-capacity throughput for you. Sorry I rushed this information to you this morning.

 

Thanks Norm ! - Really appreciate yours and Matt's advice here. 8 Gauge wire upgrade and a CS130 105 Amp alternator are the result of this thread - just what I needed to know.

 

Gents - quick question to make sure I’m not missing anything. On my 12SI model I have this ground pigtail to the alternator body and it just runs right to chassis. On the new CS130 that arrived I do not see a provision for that so my question is is that still needed? Do I need to somehow run a ground somewhere to the alternator ?

 

The CS130 is the one that really needs the ground strap. Just use the threaded hole in the rear frame.

 

Perfect - thanks Joe !
does gauge wire matter here as much for the ground ? I did get 6 gauge for the 2 new runs for the ALT and I got it as a bundle off Amazon, 10 feet red and 10 feet black so I can also make a new ground to chassis using 6 gauge as well .. overkill ?

 

So long as it has at least the same gauge as the wire to the BATT stud, you'll be fine.

 

As per what Joe stated. 6AWG is not overkill. As stated earlier, larger gauge equates to less resistance which equates to more current throughout.

 

Check it out guys I’m glad I smelled it when I did I got lucky the wire meltdown had already begun!

 

Hey guys incremental update and another question...

I got all the 6 gauge wire created and run, definitely a pain in the you know what dealing with headers and getting that wire on the starter stud.

my question on finishing the install is I guess I can no longer use this alternator bracket ? I ordered the alternator as if it were 1990 custom cruiser with the 307 engine everything lines up great except for this back bracket

I also snagged this CS130 pigtail that plugs right in... also has an in-line diode

 

Correct, that rear bracket won't work with a CS130, since it's shorter. Too bad, as that bracket would have been a fine "ground strap". The 307 cars use a different strut to pick up that rear bolt hole, but frankly you won't need it with the smaller alternator.

 

Thanks for all the help guys the install is complete
as you can see here 6 gauge wire for ground as well as 6 gauge wire to the horn relay and then again from the horn relay down to the starter another 6 gauge wire. I should be all set, I’ll fire it up and check the charge after my next conference call

 

Very nice work

 

^^x2^^

 

Just to confirm - do you have a fuse on the 6 gauge wire from the battery to the horn relay?

 

no sir

 

Updated my comment: "do you have a fuse on the 6 gauge wire from the battery to the horn relay?"

 

no inline fuse at all on the new 6 gauge wires.

 

Not sure about in your installation but typically the wire that runs from the battery to the horn relay has some type of circuit breaker in place. In OEM applications it was a fusible link.

 

The ignition switch has a built-in circuit breaker. All other feeds coming off the horn relay have their own fuse as well as other sources that get 12v that I have tapped into have their own fuses

 

Hey Brian - This is a customary courtesy check (LMAO). How did things turn out? Odd smell gone? You stated in your first post you were seeing ~13.3-13.8 volts (as measured w/ your Sniper handheld LCD). You'd prefer to see a charging voltage on the battery of ~14.3V - 14.7V. Just curious if your voltage is w/in this range or your previous range, if the odd smell is gone and things are running smoothly - hope so.