2 rotax 800 engines in buggy.

[LEE1969GB]

I know I have touched on this in the past but with one engine driving each rear wheel but now I am trying to use the 2 engines both driving to one diff.

I have been messing with the MR2 engine and trans in my buggy for about 5 weeks now and still can not get it to work properly and there is an event I want to do next weekend so its coming out and I am going to try to get the 2 rotax engines in. I have taken one rotax out of my 800 pilot along with the subaru diff and all of the mounting brackets to join the engine to the diff. what I plan to do is remove the sprocket on the front of the diff and replace it with 2 bigger sprockets, thats one for each engine and bigger to allow for the much bigger tyres. the second engine which is in bits at the moment, will sit higher up so that its exhaust will clear the carbs of the first engine and also help the engine clear one of the 5 link mounting points. A lot of work as this time next week I will be racing it! Yes In the dark so I need to fit lights as well

[K-fab]

Okay, this needs pictures...

[XRH348]

the tractor pulling guys have been doing this for a while, on the subject of tractor-pulling ( and sorry to digress a bit).
You may get a kick out of this.

LiveLeak.com - John deere engine blows up at tractor pulling contest

[TheDoc]

Like K-Fab said, a picture is worth a thousand words.

What about some sort of limited slip diff first the out to your Subaru diff, that way it will compensate for lag between the 2 motors?

Only a brain fart, it might work the rest know better than me..



Good Luck.

Nick.

[millbilly]

Look up sled ice speed records. They run 2 motors on some of the sleds

[LEE1969GB]

Ok some pics of the engine as taken out of my pilot, mounted to a plate which is rubber mounted then bolted to another plate which is bolted to the diff. you can see the sprockets, thinking of putting 2 bigger sprockets on the front of the diff one for this engine and one for the other.
Not sure if I have all the bits to do it or the time, just wonder how well it would go with one engine for next weekend. K Fab How heavy would you say that DezTez was with the 2 stroke snow mo engine and how well did it go?

[LEE1969GB]

Originally Posted by TheDoc

Like K-Fab said, a picture is worth a thousand words.

What about some sort of limited slip diff first the out to your Subaru diff, that way it will compensate for lag between the 2 motors?

Only a brain fart, it might work the rest know better than me..



Good Luck.

Nick.

I am thinking that each engine will contribute to powering the diff input shaft so each engine will be constantly under load and the cvt drives will do there thing in the normal way. even if one engine has a bit more power than the other the cvt,s will keep it all under control. Thats what I hope anyway

[K-fab]

The old original Deztaz weighed about 1100 - 1200 lbs. (500kg - 550kg)

It had an Arctic Cat 1000 triple in it and it ran very well. The old two smoke was a ripping engine.

[LEE1969GB]

Today I rebuilt my second rotax engine then pulled the MR2 engine and box out of my buggy. Then I dropped the rotax engine/ subaru diff sub assembly roughly in place then tried the second rotax engine in the 2 spaces available and was also looking where I could put the secondary clutch and shaft (see pics) The pic with the engine on the left looks best with the secondary clutch under the engine.
I wonder is it ok to mount the secondary clutch under the engine or in front of it because It seems the engine is designed to have it to the rear like in a snow mo, there is a flat that you use to brace off to the bearing behind the secondery clutch. If mounting it under the engine is it trying to pull the crank cases apart?

The other thing I am thinking about is the gearing, With the rotax engine in the pilot I had a 14 tooth sprocket on the end of the secondary clutch shaft driving to a 28 tooth sprocket mounted on the diff input shaft then the diff is 3.9 to 1 and the rear tyres are 21 inches tall, this set up seemed ok and I am thinking along the lines of the pilot with rotax engine weighed about 400kg and the 2 seater with 2 engines will weigh about 800kg so I only need to change the geraing to suit the taller 30 inch tyres on the 2 seat buggy and I am thinking 40 teeth?
Could anyone work out what the top speed would be with those figures, I am not sure of max rpm or the ratio between the ski doo clutches at there maximum, I am looking for around 80 to 90 mph

[LEE1969GB]

On thursday night I decided getting the 2 engines in and running was not going to happen in time for an event on saturday so I would give it a go with one engine. on friday had it up and running so tried it up the road, it seemed to go quite well but not enough top speed then something let go, I got out and the belt (which has been used for a while) was totally shreaded. I fitted a new belt and noticed the clutches were not in line, I got them closer but not perfect then changed the sprockets to give a better top speed. I tried it again and it seemed to have better top speed but then it started slipping at top speed. I had only done about a mile and looked at the new belt and there was string hanging out of it!
The buggy weighes about 700 to 800 kg which is almost double what the pilot (which was fine and only ever ate one belt)with one engine weighed so I am thinking 2 engines and clutches sharing the load and the pulleys lined up correctly the belts will last ok and with the gearing I tried first it will go faster with the 2 engines because the clutches will move out more?

I think it will work ok as long as both engines are doing there bit and the belts sharing the load but any comments?
Also I will need some belts, wayne (ak pilot)tells me I want carlisle ultimax 3 belts with number 140-4352u3 but his local dealer only has 3 and they seem expensive, I could do with about 5 of them shiping to the uk.