transmission, any one know

Are you looking for a transmission, or a transfer case? Or both? The transfer case in a 4 wheel drive vehicle is where the hi/lo range comes from. What do you mean by an SUV type approach? Do you mean the physical weight and dimensions of an SUV tranny and xfer case? You can go smaller, but it will likely cost you. Just look up "Rock Crawling" and see what they use to put the traction down.

200-240hp at a max 14,000 rpm !

<falls off chair>

This is a LOT bigger than anything I have worked with (mind you most of my experience is in the electrical field). How much torque do you want at 14,000 rpm!

Oh, when you mentioned a small but very powerful motor I have assumed electric. Is this the case?

First thing I thought of was a small ATV transmission but you said that wouldn't work & I see why with your requirements.

But couldn't you use the ATV transmission as a model but build it out of much stronger materials? Materials like they use in the aircraft industry. Light but Strong.

Why redesign the wheel when there is already a model out there? Sure after you get the prototype working then maybe yuo can improve on the original. But I've always found when working with a new anything its best to work with as many know factors before improving on them. That way when something doesn't work its easier to narrow down why it didn't.

sounds like someones trying to make a 4wd vehicle from a large displacement motorcycle engine :D (my K7 GSXR 750 puts out 150hp and 55lbs torque... just a guess as to the application)

You'd be hard pressed to find something off the shelf to suit your purposes... what about a junked out Suzuki Sidekick or whatever?

One of the possibilities is a hydrostatic transmission. I realize that eng speed will need to be reduced. But if you were to hang a speed reducer on the end of the engine, and attach a hydraulic pump on that, it should not take up too much space. Split the hydraulic output to two hydrostatic transaxels. The only manufacturer I can recall is Eaton. Try a search of hydrostatic transmissions. Good luck.

To solve a problem you need to know what the problem is.

Your post gives SOME information but not enough to make any intelligent solutions.

What is the power unit? Electric, Turbine, Gasoline? How much does it weigh?

What is the vehicle's purpose? Racing, Hill climbing? Etcetera.

Do you need full time four wheel drive or selectable?

Do you want an automatic or manual transmission?

The more information we have, the better the answers.

None of us are Mind Readers!

( I built a Snow Cat out of a AMC Eagle and used it in Lake Tahoe for years. I do know how to build "different" vehicles.)

The only thing that will handle your conditions is a racing transmission (be ready to spend big bucks). I would suggest giving application engineers at Xtrac (www.xtrac.com) in the US or Hewland transmissions is the UK or Ricardo transmissions in Europe. All three manufacturers have done work for F1, ALMS, NASCAR and Lemans prototypes.

Good Luck, let us know how it works out.

Google Weismann transmissions. They offer a complete line of high speed, high power transmissions for drag bikes (1200 hp, 16,000 rpm), off shore racing boats, and F1 race cars. My friend paid $7500 for the transmission on his 16,000 rpm, turbo'd, nitrous and nitromethane powered drag bike. So far he and the transmission have survived several 197 mph passes. Lots of luck !

Try the transmission from the Mitsubishi Lancer EVO8, Subaru Imprezza or similar vehicle.

It handles somewhat higher torque than what you need but it is off the shelf and thus not so costly. The extra torque capacity translates in only a few kg extra which may be OK for you given the affordability.

But why the hi/low ratio? Are planning muddy hill-climbing?

Something with high torque required like in http://www.youtube.com/watch?v=zoIyTlAD_1w?

Or rather high power at high RPM like in another kind of hillclimb:
http://youtube.com/watch?v=4-DGMrLGnLg

Randolph

Thanks for the reply.

The purpose of the trans is going to convert a motorcycle eng to an 2wd, 4wd, low 4wd and reverse. The bike eng has already got 6 forward gears so been able 2/4wd will be based on driving surface. Low range is for rock climbing and steep hills..

I have been toying with the idea of an 4wd atv. The only problem then is that im restricted to eng size, as well as the problem of adding 600 or so pounds to a stock drive line will probably lead to a lot of broken parts. And the only cure for it that l can see is running some type of planetary at each wheel to reduce the load on the drive line… in turn loosing top end speed. How much speed I don't know. The bike eng stock is good for around 280kph, and the max that I will need will be around 100/150kph. So I might be ok. All this isn't taking in to factor sprocket size of the bike eng. Atv eng runs a cvt type set up that might be an advantage……..

But at the end of the day, I might be out to lunch with my theory so at this point feel free to correct me.

Planetary drives at each wheel can indeed help increase torque but also ground clearance. This principle is often applied on military vehicles. I guess you need to do some engineering work then. I don't know if it is easy to find off the shelve components.

I know that there is a whole bunch of people in the UK doing the kind of hill climb you describe. I just can't find any link at the moment. You might find something there I think.

Good luck

Don't forget to compensate for the difference in wheel diameter.

A planetary @ eaach wheel will add unsprung weight, for maximum speed over unsprung weight should be as low as possible