building a fireblade engined mini. Using the old subframes as there in great shape and the engine is going in the front with an extended front end.

the thing I cant get my head around it the drive ratio I need. im mechanicly mninded but final drive ratios and whats needed for the weight of the car is above me

so. I have got the cbr893 engine running a turbo at the minute and runniing maybe £170hp but im gunna put it back to standard before fitting it in the mini so that im not dealing with too much at a time.

the standard engine I think produces 125bhp so my question is what number teeth sprocket and drive gire should I be looking for ?

im not wanting to achive massive high speeds my indy blade topped out at 110 and I was happy with that because it used to get U there so quickly.


also while on the subject..once to take the crown wheel off a diff it effectively has no ratio until u put the sprocket on ?? am I right ??

thanks in advance people

[Edited on 8/3/13 by tompat3463]

once to take the crown wheel off a diff it effectively has no ratio until u put the sprocket on ?? am I right ??
Yes. :-)

The ratio will be that of gearbox to sprocket as on a bike

Here is a link to a sprocket ratio calculator (.xls) for the CBR 893
Calculator (.xls)

Another useful calculator can be found on Gearing Commander

Biggest problem with fitting a bike engine into the front of the Mini is getting enough space for a suitable sized differential sprocket.
Large sprockets could foul with the rear of the subframe or the steering rack.
Usually a 41 tooth sprocket is about as big as you could go (I normally recommend a 39 tooth)

In any case you are going to be running a very short chain which can effect chain life.

To get a sensible final drive ratio you will probably need to fit a smaller gearbox sprocket.
I'm not sure if 530/13 or 14 tooth sprockets are available - maybe Andy Bates knows?)

Again - the smaller front sprockets combined with a short chain run could mean a short chain life.

This forum may have the answer. Bike engined mini

Thanks for the replies guys. So e useful information. Would anyone happen to know diameters for sprockets ? May be helpful for working out my max size .

I'm using an extened front end so I wanna cram as much in as possible

Tia Alan

quote:

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Originally posted by tompat3463
Thanks for the replies guys. So e useful information. Would anyone happen to know diameters for sprockets ? May be helpful for working out my max size .

I'm using an extened front end so I wanna cram as much in as possible

Tia Alan

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