4 wheeler transmission

[Logjam-grant]

Anyone here work for a 4 wheeler shop?

I have a 3 cylinder geo metro engine with a 5 speed manual. I'm not too excited about it.

I was thinking it would be nice to have a transmission out of one of the "automatic" polaris 4 wheelers. The Low, High, and Reverse type. I like the idea behind a CVT too.

I imagine that a 400-700cc 4 wheeler makes as much if not more than the 1000cc geo metro engine. And even if it doesn't I'd just go easy. Anyone want to help me find this thing? I really don't want to spend TOO much money on it. Something used? I was thinking that it would be easier to hook an ATV automatic to the metro than converting mine.

What do you think?

[ih4x4]

you will break the transmission,
the older polaris transmissions are chain drive front and rear and the newer ones are shaft front and chain rear, you will constantly smoke the belts rockcrawling,
I have a 6x6 tranmission in my scrambler and in low range it crawls pretty good, bike weighs 500

[Logjam-grant]

The project is an ATV style buggy. I don't want to use the term ATV too much here because it isn't exactly what would come to your mind when I say "ATV". I don't even know where to start. It will be built with a gambler sprint car chasis, a geo metro 1000cc engine (and possibly the metro 5 speed), 45x18" tractor tires, and toyota mini-truck axles. I imagine the finished weight will be around 2000lbs.

http://www.goodyear.ca/tires/tirecatalog/TSGSize.html

The tires weigh 120lbs each, and for now we'll assume the weight is about 1000lbs from the tires and axles. I'm not sure yet what the G10 suzuki engine weighs, or the tube chasis, but 3 people can lift the whole thing (minus the tires and axles of course!).

So, with that in mind here is my project. I would like to place a CVT setup in front of the 5 speed transmission in place of the clutch. I really like the feel of my Polaris 400 Sport ATV. Thats the drive behind this effort. That, and I don't like manual transmissions. I would like to keep the 5 speed transmission because with the transaxle welded it could serve as a transfer case. 4th and 3rd gears could possibly serve as High and Low "speeds", and of course reverse for going backwards. ;)

I have found information on my G10 engine from a Japanese website.
http://translate.google.com/translate?u=ht...Flanguage_tools

So, the 3 cylinder Metro engine:
HP: 52 @ 5,500RPM
Torque: 54.97ft lbs @ 3,500RPM

The 4 stroke Polaris Sportsman 800 has these peak outputs:
54.8HP at 6000RPM
51.8ftlbs at 4,800 RPM

I followed the curves on the Sportsman 800 and compared it to the G10 Suziki engine:

The G10 makes 52HP at 5,500 RPM, the Polaris 800 makes 50 at the same RPM.
The G10 makes 55ftlbs at 3,500RPM, the Polaris 800 makes about 49 at the same RPM.

The powertrain will be the engine, CVT, 5 speed, -possibly- a transfer case, and then the toyota axles.

I'm not quote sure what a CVT can offer for a ratio range, but I imagine its 2.5:1 to .7:1?
The 5 speed offers me:
1st: 3.416:1
2nd: 1.894:1
3rd: 1.280:1
4th: .914:1
5th: .757:1
Rev: 2.916:1

The differential portion of the transaxle provides an additional 4.388:1 to all the above 6 ratios.

The toyota differentials are geared 4.38:1.

I would like a speed of 25MPH at 3,500RPM. With a tire circumfrence of about 139" that means a total reduction 18.4:1 at full speed...

3500/(((25*5280)/60)/(139/12)) = 18.42

That isn't a "hard" number by any means. However any more agressive gearing and it will be like driving a riding lawnmower.

4.388*4.38*.914 = 17.56 for 4th gear

So hopefully the CVT can comletely compensate for the rest. In the case that it can't, or where more speed control is needed there is also 3rd gear that could provide 24.6:1.

I'm not completely sure how the weight of a 2000lb vehicle and the goal ratio of 18.5:1 at 3500RPM will all fit together.

I'm not sure that I am comfortable with using 2.5:1 off the engine to the input of the geo transmission. That's a possible 150ftlbs and it really makes me worry!

[ih4x4]

here is a metro with a diesel and cvt http://utterpower.com/10hp_chevy.htm

what about using an automatic transaxle

[Logjam-grant]

That's cool. :) Way too small pictures!

Somehow I've managed to post these pictures in quite a few places tonight.

Each tire and double beadlock rim combo weigh 202lbs..

Anyway, here is the rear axle for the crazy ATV project:

"Full Size" toyota: (about 41" between sidewalls!)
http://media.diywelder.com/images4/060405-06-me_on_axle_3121.jpg

Its about as wide as the F350 SRW:
http://media.diywelder.com/images4/060405-07-axle_side_3117.jpg

[Numidian]

You expect a quad transmission to stand up to those?!!! Lay down the crack pipe, retard...

[Logjam-grant]

Transmission, yes. Gearbox/transfer case - probably, but I'm not using that.

I don't know what your problem with it is. My engine puts out less than a performance snow machine. Almost twice as little.

[b1pig]

it won't hang with it. Skip that idea. There are way too many issues at stake. I have a 250 Trailblazer that was used and abused. I just replaced the chain in the tranny. It's comparable to a SB Chevy 350 tioming chain. I would not trust it. The case is thin aluminum. If you want to swing it search Ebay. They are on there.

You'll spend more time trying to convert the tranny to drive the axles.

Why not go like that VW powered rock buggy. longitudinally mount the engine with each half-shaft pointing towards an axle. Offset diffs would be better suited... but either way it's a stretch.