Looking for darn small alternator options.

69427

The Artist formerly known as Turbo84
Joined
Mar 30, 2008
Messages
2,972
Location
Clinging to my guns and religion in KCMO.
A couple years back I pulled off the 11# stock Delco alternator (37A) and installed a 7# Denso alternator (41A) over on the other (righthand) side (for weight reduction and balance). Despite the lower weight, it's still overkill for what I need most times, particularly on track days. I need about 4-5 amps for the ignition system, and a couple amps (just guessing at the moment) for the brake lights. Anybody have any wild ideas on how I can generate a few amps while out on the track, and still end up with less weight on the front end? The regulation and control of the voltage is an easy enough task to do but I need some ideas on what's available to generate the power.

Thanks for any suggestions.
 
I would try fishing around a place that deals in Farm equipment, got one down the road called Tractor Supply......they may well have some oddball gear that takes just that part......:beer:
 
Check out speedway motors, some are roughly 4x5". Also, won't oversized pulleys help to reduce hp loss. They sell those too.
 
Calculate your amp draw (at more than just idle), disconnect brake lights for track days. Gauges and ignition system should be all you have. Find out what your amp hours are for the battery and just run off of the battery. You might survive a 20 minute session without an alternator. Just dont stall it 15 minutes in... :D
 
I have a tiny one on my racer I found on a welder. It's a NipponDenso and tiniest one I've seen. (And I've been watching for over twenty years). I'll look for numbers on it in a few minutes.
 
I have a tiny one on my racer I found on a welder. It's a NipponDenso and tiniest one I've seen. (And I've been watching for over twenty years). I'll look for numbers on it in a few minutes.

Thanks. My present alternator is a 7# Denso (paid $3 for it at a scrapyard a few years ago). I see a few 5.8# Denso lookalike alternators in some of the speed catalogs, but damn they're pricey.
Thanks for what ever input you can offer up here.
 
Calculate your amp draw (at more than just idle), disconnect brake lights for track days. Gauges and ignition system should be all you have. Find out what your amp hours are for the battery and just run off of the battery. You might survive a 20 minute session without an alternator. Just dont stall it 15 minutes in... :D

I understand what you're saying here, but I'm a bit gunshy about running without brake lights. If needed I was going to look into some LED tail lights to lower the system electrical load.

I've got ABS sensors in the front hubs, and have some timing/speed projects planned that would use the AC signal off the sensors. I would love to figure out a way to upsize this type of system to power the electrical system.
 
Check out speedway motors, some are roughly 4x5". Also, won't oversized pulleys help to reduce hp loss. They sell those too.

I checked Speedway Motors. They have some slightly lighter alternators (5.8# versus my 7# unit), but the price is out of my budget.

I'm currently running an undersize crank pulley to slow the accessories, but the present alternator still has the stock (damn small) pulley, so chances are it could handle being slowed down a touch yet. WTH, until I find a lighter alternator option I can certainly look for a replacement pulley (with 15mm shaft bore IIRC) while I'm perusing the junkyards.

Thanks.
 
Here is the Nipon Denso 75Amp fitted to my car,

thum_39345b9f5e5a8151f.jpgthum_39345b9f5e5a91c07.jpgthum_39345b9f5e5aa4fb8.jpg

One wire, simple upgrade and 7.29 Lbs.
Indeed I am running no accessories like radio, pw windows. Just elec fuel pump, and keeping all the lights working.
 
I found some smaller ones . like for small equipment but 45amps or less and definitely not rated to more than 3000rpm . So not really good at charging a lower revs if fitted to our car with a different pulley to accommodate a 7000 or more revs.
But again, I looked at using them with a lithium battery. And did not because of the price of the battery.
 
Here is the Nipon Denso 75Amp fitted to my car,

thum_39345b9f5e5aa4fb8.jpg

One wire, simple upgrade and 7.29 Lbs.
Indeed I am running no accessories like radio, pw windows. Just elec fuel pump, and keeping all the lights working.

My present Denso alternator looks just like that one, albeit 41A IIRC and 6.9#. The difference in weight may be the pulley, as that one looks a touch bigger diameter. I'm trying to find a slightly larger pulley like yours to slow the alternator RPM down a touch.
 
I got the water pump (with the half pound lighter cover) put back on the engine yesterday. I weighed the three groove stock w/p pulley, and it's 2.6#. I suspect that an aluminum replacement would be lighter, but I also suspect it would be rather pricey. Just for amusement I'll probably try to find one of these on somebody's site, and see what the numbers are.
 
What did you do for your alternator

Unfortunately, nothing so far. I still have the same 7# alternator on the engine, but finding a larger pulley that fits (and reasonably priced would be nice) has been more of a challenge than I anticipated. I've made a couple junkyard excursions looking for pulley candidates, but I keep striking out.
 
Maybe belongs on the weight saving thread -- but...

Just a thought...

Have you considered going - LOST LESS?
OK - I don't know the duration of your track time - or the size of your battery - but I'd bet it is LIGHTWEIGHT. Still, I be you could go a weekend on no alternator (output) sessions.

So, install an alternator for track time that has no WINDINGS (less weight too) for the track time. You'd still have full compliment of pulleys and belts, then reinstall a normal regulator for the drive home.

Not much weight savings in the Alternator - but a USEFUL HP boost! Remember 1 HP = 10 pounds - so a savings of a few HP could equal a load of stuff!

Just call me, A well Hit 3-wood in a Tile Shower! :flash:

Cheers - Jim
 
Then Again...

Looking at the engine bay picture - Maybe a "delete" pulley instead of an alternator - and move the alternator to the driveshaft. Weight low, belt and pulley and placement complications - but could also be turned off ( i.e. removed) for track sessions.

Cheers - Jim
 
Top