Need: small planetary gear for NCSU Mini-Baja car

Grant

New Member
Joined
Mar 20, 2005
Location
Colorado
I am having trouble finding a source for a small (very very small) planetary gear to use in place of a chain reduction on this years baja car.

Does anyone know of a vehicle that had a planetary reduction in either a transfer case or possibly an automatic transmission? I need something similar to the 200 series aluminum-housing NP transfer cases, with a fixed ring gear.

Ive heard some 4wd cars had low range, but i figure this is the best place to ask for local knowledge on some obscure stuff.

Grant
 
80's Subaru's had a low range.. we had a '83 hatchback with one, I guarantee that sucker was small.
 
The one we had was a '82 or 83, I don't recall the model, but it was a 2-door hatch, like a Honda Civic. Had a fog light in the middle of the grille behind the Subaru badge, which would fold down.. it was cool.. :cool:

EDIT: turns out it was probably a '81 GL. Looks like this, but a 3-dr. hatch.
awww.cars101.com_sub83_skicar.jpg


http://www.cars101.com/oldsubaru.html#1983 Subaru
 
Yeah, for some reason, I couldn't find docs for anything other than the brat (no low range)... Now, I know there were other subarus than that back them but its one of those things missing from the database...

J
 
We did our car using an ATV differential, facing backwards, with a custom quick change gearbox to change the direction of the driveshaft. It looked and worked something like a Halibrand rear on street rods. We used sprint car gears wire edm'd to half thier width and made a box to house them. That was a nice setup, we could change ratios when we needed to, and simpler and less complex than an planetary gearbox. Only 2 gears involved with the whole deal.

Hmmm, well, that was for the Formula SAE car, but it might work for Mini Baja as well.
 
gavan said:
We did our car using an ATV differential,....We used sprint car gears wire edm'd to half thier width and made a box to house them.
Click to expand...

Where do you get such bad ass tooling to play with? I shoulda gone to college.. I was busy being all I could be... :lol:
 
eh, the wire EDM want as cool as the water jet cutter.

Now, we visited GM powertrain, and they had a (couple of) 5 axis CNC machines the size of a medium house. They would make a V8 engine block out of a solid piece of aluminum. THAT was cool.
 
Subaru GL 10 had them for most of the 80's. I believe the 4wd Civics and Sentras from that era did too. I'm thinking hard to find you an alternative.
 
Thanks for all the replies. Now, who or what junkyards should i check with to see if they have such treasures?
 
the front piece of a BW1354 or BW 4405 t-case out of an explorer is about 4" long and mabey 10" in diameter. It houses the planetary reuction set for the explorer and ranger t-case's.
 
Hey - I haven't looked at the guts of it, but how do those optional low range gearsets work in the mid-late 1970's wagoneers? I know you can get the standard T-case with no low range, or get the low range gearset that bolts to the T-case to add low range.

Anyone know what I'm talking about?
 
Im not really finding anything useful on car-parts listings.

What i need is something really, really small. For those that dont know we have a 10 hp Briggs lawnmower engine. The whole thing weighs less than 400 lbs.

Are there any good subaru forums or sanything like that? Im having a hard time seeing a large aftermarket following for 80s 4wd subarus.
 
Your probably not going to find a huge following or even many spare parts for that year subaru. It's not what you would call a "collectors item". I'd probably look into one of those belt driven clutches the jr. draggers use. as it gets faster the pulley moves apart to get smaller.
 
Other things Grant left out (from another guy working on the baja car)-
This car already runs a CVT (3.69:1 to .7:1 ratios) and it still needs about another 9:1 reduction before the final drive. It's 10 hp and we idle at 1800rpm and max out at 3800rpm, so the CVT is pretty crucial. Some teams try to run ATV gearboxes, but it would be real aggravating having a 2000rpm power range to work with when shifting 5 times.

At any rate, about that other ~ 9:1 reduction - we typically run two chain reductions about 3:1 each. It would be nice to be able to have a planetary gear box to account for one of those reductions just to make packaging of the drivetrain easier. The planetary gearset would just be used in our own housing.

We're just looking for a small set of gears (small = light and we only have 10 hp)

Will be looking for a Subaru or an old Corolla Tercel. Thanks.
 
If I had to guess, 2 chains would be much more efficient than a planetary reduction. You would be spinning alot of gears for only 10 HP...
 
fryedaddy said:
Your probably not going to find a huge following or even many spare parts for that year subaru. It's not what you would call a "collectors item". I'd probably look into one of those belt driven clutches the jr. draggers use. as it gets faster the pulley moves apart to get smaller.
Click to expand...
im gonna have to agree with that. i saw it on TV a few nights ago about canada's mini-baja champions ands thats what they used
 
If you need 9:1...why a planetary? Two chains would make life a lot easier...and way lighter. And why such low gears anyway?
Either way, you might try looking at some industrial lift/vehicle axles...plenty of them have planetary hubs.
 
Found a planetary set - just using one out of a Torqueflite 904. It's about 4.5" OD and should only be about 2 inches thick for the whole box when we're done.

Why do we need so much reduction? 10 horsepower. That, and the fastest we'll ever need to go is 40mph. CVT (slipper clutch to some) provides 3.6:1 to 0.7:1 reduction when fully spooled.
 
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