How easy/$ effective is it to make a CR box ?

thinfourth · Post by **thinfourth** » Thu Mar 15, 2007 10:02 pm

The caterham fireblade with the reverser box has 6 gears forward and 6 gears backwards

Also holds the world speed record for reverse of 84mph

My caterham has 6 forwards and 1 backwards but is a highly modified Sierra box but very close together about 1200rpm drop between gears. 6th on the 6spd box is the same as 4th in the standard 5spd box. On knockhill you come out of the hairpin in second and are hunting for 6th by the end of the main straight

Rich H · Post by **Rich H** » Fri Mar 16, 2007 9:43 am

Leaning slightly back towards sanity, the cateringvanfield solution fits between the gearbox and the diff. Could be difficult on a transverse engine and transaxel...

ie: it won't fit. I suppose you could do the electric thing if you chop the box case about a bit more and drive the diff direct with an electric motor, but it could be alot to ask as the Elise is significantly heavier than a 7.

When I finally collect my gearbox form Olly I'll have a look....

thinfourth · Post by **thinfourth** » Fri Mar 16, 2007 10:01 am

Oh it would fit just you might end up with a slightly wider track

about 3 foot wider

Rich H · Post by **Rich H** » Fri Mar 16, 2007 10:53 am

woody · Post by **woody** » Fri Mar 16, 2007 1:54 pm

If you really wanted a 6 speed 'box, it'd be easier to use one off another car with a new spacer flange between engine and box, and a suitably lengthened input shaft, as is common enough practic in motorsport. i.e. a few of my friends have had Suzuki swift powered Nova's driving through the original VX box and shafts with use of said arrangement. You'd need to engineer some hybrid shafts as well. Gti6 box has nice ratios, but is maybe a bit long and heavy.

Last time i attempted anything like this, I wanted to fit an Mi16 final drive into a 1900 gti 'box, which would have given a 20% lower FD and the closest possible set of standard ratios. After striping the boxes down, i was diverted for a couple of months, think you can guess the rest....

Rich H · Post by **Rich H** » Fri Mar 16, 2007 7:29 pm

Good idea!

Anyone think of a suitable 6 speed box then? I know for a fact the 6 cog VAG jobbies weigh a ton, how about a yota box? Honda?