I am a part of a University race team where we build small off road vehicles to participate in SAE organized, mini baja events. In past years our school has went ahead and used a CVT to power our car, and this usually works pretty good, but this year we are wanting to try and incorporate a gearbox. We figure something out of an ATV would probably give us just want we need.

Some of the things we are aiming to get out of our drive-train is we want to try and get to a minimum top speed of 50 km/h (though more is always better) in the high gear and in the lowest gear we need to be able to muster up a steep grade hill from a stop. The weight of the vehicle will be around 350-450 pounds. We definitely want a reverse on the gearbox, and we were thinking that a three speed would be enough, though if you think that four or a five speed would provide better results we could go with one of those. And we will need it to be a paddle shift.

The biggest limiting factor we have for speed is the engine. What is unique to these competitions is that every car is required to use an unmodified Briggs and Stratton Model 20. The specifications for this engine can be found at there site here...

http://www.briggsracing.com/di...uter.asp?Docid=101377


So does anyone have suggestions as to what model gearbox would work to best meet those specs and why that one? The best way to get one cost effectively (buy from a dealer, a scrap yard, etc)?

 

a manual atv transmission has at least 5 gears and reverse, the problem lies in the fact that the gear box is part of the engine itself in manual atvs. only cvt transmission are separate from the engine. A manual motorcycle gearbox from a Harly Davidson would seem to be a perfect ticket as they are separate from the the engine itself. a belt will connect your motor to it. ebay would probably be the cheapest way to get one as a new one or even a used one from a junk yard will cost a pretty penny. this trans may be what your looking for harly trans

 

'99-2002 explorer and 2000-2002 sportsman 6x6 has hi and lo and reverse. Reverse is hi only. CVT belt drive. You just have to adapt the drive assy to the briggs. I would think its possible with a little machine work. Chain drive rear and shaft front. '98 and older explorer is chain front and rear off of the same shaft so you could just machine a spacer to eliminate the front sprocket. Brake rotor is also on the same shaft so you dont need brakes at the axle. Good luck and keep us posted.

Steve

 

CVT is also in the best gear at all times so no time wasted shifting. Same as a comet clutch on a mini bike or go cart but able to handle 50+ horse power.

Steve

 

I am V8JOHN a professional Engineer. I was asked about a decade ago how to solve this problem by a Teaching Hospital to aid the disabled. To the point, you can eliminate the gearbox for a gasoline engine by encreasing the number of cylinders, yet the cubic inch capacity of the engine & side valve etc remain the same. The reason is with a 4 stroke only 90 degrees out 720 degrees of rotation is producing useful power. I designed a small 4 stroke V8 that has 8 x 90 degree power, hence we have 720 degrees of rotation producing usefull power. The need for the engine went away. If you guys are interested I could revive it however, at my age I may need some push. EPA allow up to 3 engines per individual to be exempt (once only) plus if used for racing it is also exempt. I do not know others who have completed such a design. Question if the CI and SV or OHV remain the same does the number of cylinders really matter?

Anyway, as we say Australia, I hope you guys find a solution.

 

I too having the same problem.
Can anyone help me for Best suited and best fitted CVT or Manual transmission for "Briggs and Stratton M20 Engine".

I am (we) preparing for Mini BAJA Competition.

Please please help me out.
-erjainrachit
erjainrachit@gmail.com

 

please suggest the best suitable CVT along with forward reverse gearbox and the differential....for the Briggs and stratton Model 20 engine for mini baja purpose....

also it would be better if we have to make minimal modifications...... for connecting all the components......

 

hi every one
we want to choose a gearbox for our mini baja and we couldnt decide which one is better
1.manual
2.automatic
3.ivt
4.cvt