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goinbroke2 07-08-2025 03:16 PM

Alternator choice?
 
Running a stock ford alternator an regulator etc and was wondering what people use for alternator sizes?
1 wire 140amp? (one wire seems simpler...)
regular ford 48amp?

A 140amp alternator would give me peace of mind but how much drag will various alts have? Once the batt is back full the drag should be minimal regardless of size no??

Alan Roehrich 07-08-2025 07:35 PM

Re: Alternator choice?
 
Powermaster 100 amp 1 wire. They;re even available adjustable for voltage output.

Crisco 07-09-2025 07:36 AM

Re: Alternator choice?
 
House of Payne makes really nice 12v @ 100 amp alternators in a Super Mini and an Ultra Mini.

https://whitehouseperformanceparts.c...2v-alternator/

cordoba13 07-09-2025 11:21 AM

Re: Alternator choice?
 
napa full size Delco 1 wire 60 amp ? SW something, only about $60

goinbroke2 07-09-2025 03:43 PM

Re: Alternator choice?
 
Checking them out now. I'll get a 100+ amp one just so I won't have to worry between rounds!

Thanks, for the info guys!

Paul Precht 07-09-2025 06:11 PM

Re: Alternator choice?
 
Quote:

Originally Posted by goinbroke2 (Post 714144)
Checking them out now. I'll get a 100+ amp one just so I won't have to worry between rounds!

Thanks, for the info guys!

I don't run an MSD in my race car which I guess is a big draw in amperage but I run a stock 1963 30 amp alternator in my race car with a small pulley on the damper and never have to charge between rounds and I run the electric water pump and fan between rounds to cool sometimes.

Rory McNeil 07-10-2025 12:12 AM

Re: Alternator choice?
 
Like Paul, I have found the factory equipment alternator more than adequate. On my 85 Mustang Stocker, as well as my 78 Fairmont bracket car, I used the factory alternator and external voltage regulator, Ford offered them in several different output ratings, I think the alternator that has been in my Fairmont for almost 40 years, is less than 50 amps. That said, I am also using a full sized conventional battery, with 500-600 CCA. My cars have much of the typical drag car stuff, like an electric water pump, electric fan, electric fuel pump (s), and a MSD ignition, although I run 6 series boxes, I believe the 7 series boxes take a fair bit more current to operate. Over the years, I have found that as long as I had the battery fully charged before the race weekend, with the full size battery and alternator, I can usually go thru a 2 or 3 day race weekend without having to fire up the generator and charging the battery between rounds. About the only time that I charge the battery, is if I am in a "hot lap" situation during later rounds, especially on a hot day, so that I have to run the fan and water pump a lot. Obviously, if your alternator is non functional, that wouldn`t work.

Eman 07-10-2025 11:46 AM

Re: Alternator choice?
 
How much amperage do you think you need? What gauge wire are you running from the alternator that can carry the amperage?

cad 07-10-2025 12:37 PM

Re: Alternator choice?
 
Ive spoken with Tuff Stuff Performance. Their CS130 alternator is exactly the same one that is re-sold by hop. They can be purchased from summit. I have had both, and currently running the Tuff Stuff branded alternator. 7500rpm and it puts out 14.1v at 1000 rpm...
I do use hop's starter which is fantastic.

CMcAllister 07-10-2025 08:59 PM

Re: Alternator choice?
 
Nice stuff? Paynes

Budget? Delcotron with a one wire kit. You can carry parts for it - diode trio and rectifier - and fix it at the track if it breaks.

Robin Lawrence 07-11-2025 08:36 AM

Re: Alternator choice?
 
You didn't clarify your estimated amp draw on your car. I had a conversation with Larry Hill about this very subject late last year.

If you're running a carburetor with a stock type coil you can get away with a lot less.

I run an EFI system that uses wide band 02 sensors in each primary for data and 2 more in the collectors for the EFI system. Add a EFI High Pressure fuel pump, Large Cooling Fan, electric water pump, 2 Digital Dashes and a Race Pak the little items add way up.

Last car we logged years ago didn't have the Race Pak, 02's on primaries or digital dashes. I was drawing 60 to 65 amps during a chassis dyno run.

Since I was at Holley when I built this car I opted for the MSD 5361 160 amp alternator.

Fuel injection loves Voltage. I also have 2 Optima Red Tops that have worked well. Most times after a run the batteries state of charge is at 95% unless I run the fan and water pump in the pits to cool down.

I think that you cannot go wrong by having too much capacity.

Good luck!

Robin

Jeff Niceswanger 07-11-2025 09:31 AM

Re: Alternator choice?
 
Quote:

Originally Posted by Robin Lawrence (Post 714206)
You didn't clarify your estimated amp draw on your car. I had a conversation with Larry Hill about this very subject late last year.

If you're running a carburetor with a stock type coil you can get away with a lot less.

I run an EFI system that uses wide band 02 sensors in each primary for data and 2 more in the collectors for the EFI system. Add a EFI High Pressure fuel pump, Large Cooling Fan, electric water pump, 2 Digital Dashes and a Race Pak the little items add way up.

Last car we logged years ago didn't have the Race Pak, 02's on primaries or digital dashes. I was drawing 60 to 65 amps during a chassis dyno run.

Since I was at Holley when I built this car I opted for the MSD 5361 160 amp alternator.

Fuel injection loves Voltage. I also have 2 Optima Red Tops that have worked well. Most times after a run the batteries state of charge is at 95% unless I run the fan and water pump in the pits to cool down.

I think that you cannot go wrong by having too much capacity.

Good luck!

Robin

Last summer while on the dyno (down at Gales) we had an unexpected 10 HP drop out of nowhere. Looking at comparison data it looked identical.... except Tony had forgot to turn the charger back on in the dyno room. The voltage had fallen to 11.5 volts during the pull. This was an L-98. That dyno room has a 7AL2 for ignition juice. Turned the charger back on and we instantly was back to normal power levels.

Alan Roehrich 07-11-2025 10:50 AM

Re: Alternator choice?
 
Quote:

Originally Posted by Robin Lawrence (Post 714206)
You didn't clarify your estimated amp draw on your car. I had a conversation with Larry Hill about this very subject late last year.

If you're running a carburetor with a stock type coil you can get away with a lot less.

I run an EFI system that uses wide band 02 sensors in each primary for data and 2 more in the collectors for the EFI system. Add a EFI High Pressure fuel pump, Large Cooling Fan, electric water pump, 2 Digital Dashes and a Race Pak the little items add way up.

Last car we logged years ago didn't have the Race Pak, 02's on primaries or digital dashes. I was drawing 60 to 65 amps during a chassis dyno run.

Since I was at Holley when I built this car I opted for the MSD 5361 160 amp alternator.

Fuel injection loves Voltage. I also have 2 Optima Red Tops that have worked well. Most times after a run the batteries state of charge is at 95% unless I run the fan and water pump in the pits to cool down.

I think that you cannot go wrong by having too much capacity.

Good luck!

Robin





Race engines run on gasoline, most of the time. Race CARS run on electricity.

goinbroke2 07-11-2025 10:54 AM

Re: Alternator choice?
 
Thanks for the replies everyone. I am running 6AL and a holley fuel pump as well as dual fans off of something from the junkyard (charger I think?) The waterpump drive is being replaced with an electric water pump. Oh yeah, the big killer, power windows up and down a dozen times trying to keep cool, lol!

Total amp draw? Don't know but I'm always thinking "rather too much and not need it than need it and not have it." (paraphrasing Sun Tzu, lol)

Go for eye surgery Monday AM so everything will be on hold for a bit, pull the trigger when I can...or stay with stock alternator with a new belt.....hmmmm....

Billy Nees 07-11-2025 11:08 AM

Re: Alternator choice?
 
Quote:

Originally Posted by Robin Lawrence (Post 714206)
Fuel injection loves Voltage. I also have 2 Optima Red Tops that have worked well. Most times after a run the batteries state of charge is at 95% unless I run the fan and water pump in the pits to cool down.

I think that you cannot go wrong by having too much capacity.

Good luck!

Robin

Ya know, a LONG time ago, I was playing with a FWD Pontiac Sunbird Turbo. PFI, tons of boost and OBD 1 but still an ECU. I couldn't feed that car enough juice to make it happy. I even had a local shop hop-up a big GM alternator for it. The supercharged Buick and the Cavalier (yes, even the Cavalier) that I play with want LOTS of amperage.
To be clear, what you're building probably won't need a lot of amperage to get it down the track if you have a large, fully charged battery in it. On my old 6 cylinder stuff I would shut off the alternator if I had to go fast but I also was turning off everything but the fuel pump and the ignition box.
You're better to have too much and not need it.

Eman 07-11-2025 11:47 AM

Re: Alternator choice?
 
Quote:

Originally Posted by goinbroke2 (Post 714214)
Thanks for the replies everyone. I am running 6AL and a holley fuel pump as well as dual fans off of something from the junkyard (charger I think?) The waterpump drive is being replaced with an electric water pump. Oh yeah, the big killer, power windows up and down a dozen times trying to keep cool, lol!

Total amp draw? Don't know but I'm always thinking "rather too much and not need it than need it and not have it." (paraphrasing Sun Tzu, lol)

Go for eye surgery Monday AM so everything will be on hold for a bit, pull the trigger when I can...or stay with stock alternator with a new belt.....hmmmm....

You didn't say what gauge wire from the alternator to the battery. Where's the battery? The longer the run the bigger wire you need to carry amperage.

goinbroke2 07-11-2025 01:57 PM

Re: Alternator choice?
 
2 Attachment(s)
I have OO ga wire (I think) to ground on engine block and to the starter solenoid. The factory starter wire going to the starter. Batt in stock location front right of car and alternator wire is factory whatever that is 10-12ga?

Battery is 550CCA and new last year.


Edit: Went and took a look and then took a couple pictures. Forgot that the original wiring also includes a plug and significantly smaller wire from Alt to Batt than I thought.

Yes, it may be ugly, but at least it's slow....no, wait....lol!

Larry Hill 07-13-2025 09:15 AM

Re: Alternator choice?
 
I think the Power Master on line catalog has gage wire and maximum length recommendations. Easy to read and follow.

340Cuda 07-14-2025 03:51 PM

Re: Alternator choice?
 
My son has run a CS130 alternator on his 68 Barracuda drag and drive car for many years and it has worked great for him. I think it was from O'Reilly's

With electric fan, water pump, fuel pumps, ECU and Coil Near Plug Ignition it supports a full load.

One of the reasons he chose it was that it came on thousands, if not millions of GM cars and they are easily available at most any auto parts store.


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