[BillyGman]

I have no idea what I am looking at here....an alternator mounted on the rear end pumpkin??? What??? For what purpose? I'm thinking that I must be missing something obvious....can someone cue me in?....

Powermaster 8-410: Pro Series Third Member Alternator Kit 55 Amp | JEGS

 

[67-468]

That’s the style alternator they use in nascar. No load on engine.

 

[bracketchev1221]

Yeah, keeps it out of the way in the engine compartment. One less thing to remove during engine swaps.

 

[Busted Knuckles]

And to think I gripe about having to change one that's on top of the engine with a serpentine belt and 2 bolts.
My guess is it'll be fine as long as you can stay out of the dirt, mud, water, tall grass and sand, among other things.
I've actually seen 'em that have a pulley on the driveshaft and bracket for the alternator. I saw a 4-wheeler that mounted his air compressor like that. I'm getting too old to roll around on the ground when the option is leaning into an engine bay.

 

[BillyGman]

That’s the style alternator they use in nascar. No load on engine.

But the engine is still supplying the power to turn the alternator whether it's in the engine bay or on the rear end, right? I mean the engine turns the whole entire drivetrain including the rear end. So I don't understand why that would save any horsepower. Looks like just a gimmick to make $$ to me.

And to think I gripe about having to change one that's on top of the engine with a serpentine belt and 2 bolts.
My guess is it'll be fine as long as you can stay out of the dirt, mud, water, tall grass and sand, among other things.
I've actually seen 'em that have a pulley on the driveshaft and bracket for the alternator. I saw a 4-wheeler that mounted his air compressor like that. I'm getting too old to roll around on the ground when the option is leaning into an engine bay.

Yeah that's the first thing I thought about too. Having to crawl under there or even put the car on a lift just to adjust the alternator belt.

 

[shovelrick]

Just think about road debris kicking up and taking out the belt, I'll keep mine where they've been for 100 yrs.

 

[RAIDER SS]

I'd be curious to know the top drive ratio of a Nascar tranny. 1:1 like a Muncie?

Is the alt. turning at a slower or higher speed mounted down there?

 

[DZAUTO]

Some street rods used to mount the alternator down below, and attached by some method to the rear of the transmission or to the rearend yoke. Nothing new.
The alternator on my jet boat is installed down low on the back of the bell housing. Look closely and you can see the pulley for the alternator welded to the rear of the yoke on the back of the flywheel.
To replace the alternator belt, the engine must be removed, so again, look closely, there is a spare belt secured by brackets on the rear of the bell housing. If the belt breaks, or begins to come apart, there is a spare belt ready to go. Been that way since I had the boat built in 73. Works great.

 

[Bonkerman]

The Nascar guys usually use that location for a pump not an alternator. The pump is used to circulate diff fluid threw a cooler and back into the diff.

 

[2/75NastyNewbs]

But the engine is still supplying the power to turn the alternator whether it's in the engine bay or on the rear end, right? I mean the engine turns the whole entire drivetrain including the rear end. So I don't understand why that would save any horsepower. Looks like just a gimmick to make $$ to me.
Yeah that's the first thing I thought about too. Having to crawl under there or even put the car on a lift just to adjust the alternator belt.

I see what you’re saying about losing power because the engine has to drive the alternator regardless of where it is. However, wouldn’t it be a fraction of the power used from the engine versus the power used by the rear end based on trans and rear ended ratio? Example: TH400 in 3rd gear (1:1) with a 4.10:1 rear gear would use rough 1/4 of the horsepower? That doesn’t take into account pulley ratios though. So that calculation is probably a bit off.

 

[Derek69SS]

I see what you’re saying about losing power because the engine has to drive the alternator regardless of where it is. However, wouldn’t it be a fraction of the power used from the engine versus the power used by the rear end based on trans and rear ended ratio? Example: TH400 in 3rd gear (1:1) with a 4.10:1 rear gear would use rough 1/4 of the horsepower? That doesn’t take into account pulley ratios though. So that calculation is probably a bit off.

it's driven off the input of the pinion so 1:1 is 1:1
it's only under-driven on 1st and 2nd gears.

Street rod guys do this to keep engine bay uncluttered, I don't see any other benefit.

 

[2/75NastyNewbs]

it's driven off the input of the pinion so 1:1 is 1:1
it's only under-driven on 1st and 2nd gears.

Street rod guys do this to keep engine bay uncluttered, I don't see any other benefit.

That makes sense. I learned something today and it not even 8am. Thanks

 

[pbcbob]

battery in the trunk, alternator in the back, it all adds up

 

[Rosinbluth]

Demo car guys put a brake disc and a caliper back there and use it for thier brakes. I'd say keeps the brakes from being disabled from a wheel hit, and maybe is better stopping the driveshaft vs the wheels.
Ever see the water pumps that have the alternator built in? Circle track guys used to like to run em. I never ran one, or an alternator, but that was a dirt car.

 

[Georgia69]

So your alternator doesn't turn unless your car is rolling? Not a good idea. Imagine being stuck in a traffic jam, barely rolling a few feet at a time, with the A/C on. As stated above, NASCAR has a gear oil pump back there, not an alternator. Also, what gear you're in has nothing to do with how fast a pinion-mounted alternator spins - it even spins in neutral if the car is rolling. Alternator speed is therefore a factor of road speed, tire diameter, and R&P ratio, nothing else.

 

[BMR Sales]

That’s the style alternator they use in nascar. No load on engine.

they use a similar design on a lot of IMSA cars

 

[shovelrick]

Just thought about this...I'm guessing the RPM's those Nascar engines spin they don't worry about throwing belts with that set up?

 

[David Ray]

I have had this type of alternator on my 23' T bucket blown, injected street car for decades, no problems, but, I also run an electronic trigger magneto on the engine. Battery condition isn't a problem, and I use a battery tender between rides in the thing. I built my own setup, converted 3 wire to single wire, 94 ampere GM alternator. I didn't use a V bent, I used a Gilmer toothed belt, inside a closed case.

 

[2/75NastyNewbs]

I have had this type of alternator on my 23' T bucket blown, injected street car for decades, no problems, but, I also run an electronic trigger magneto on the engine. Battery condition isn't a problem, and I use a battery tender between rides in the thing. I built my own setup, converted 3 wire to single wire, 94 ampere GM alternator. I didn't use a V bent, I used a Gilmer toothed belt, inside a closed case.

That sounds like a really slick set up. Would love to see pictures of that.

 

[BillyGman]

I have had this type of alternator on my 23' T bucket blown, injected street car for decades, no problems, but, I also run an electronic trigger magneto on the engine. Battery condition isn't a problem, and I use a battery tender between rides in the thing. I built my own setup, converted 3 wire to single wire, 94 ampere GM alternator. I didn't use a V bent, I used a Gilmer toothed belt, inside a closed case.

What was the benefit? Is it because you wanted an uncluttered engine bay?