Mx5 gearbox tunnel issues

[jason 82]

Sorry to bother you all, but I have started to build my gearbox tunnel today for my mx5 roadster. The Gillham guide has the diff end of the gearbox at 240mm outside diameter, as you can imagine, this is leaving me with next to no space for my seats. Can I get away with using the type 9 spec tunnel dimensions ? Or at least reduce the 240mm down a little. I haven't got the diff off my car yet, and just wondered how small I can possibly go, where the tunnel still has enough room to function properly. Any help would be hugely appreciated !

[Davidbolam]

Originally Posted by jason 82

Sorry to bother you all, but I have started to build my gearbox tunnel today for my mx5 roadster. The Gillham guide has the diff end of the gearbox at 240mm outside diameter, as you can imagine, this is leaving me with next to no space for my seats. Can I get away with using the type 9 spec tunnel dimensions ? Or at least reduce the 240mm down a little. I haven't got the diff off my car yet, and just wondered how small I can possibly go, where the tunnel still has enough room to function properly. Any help would be hugely appreciated !

The diff on the mx5 has got a propshaft that is offset towards the drivers side. On mine there isn't much space left over.

David

[jason 82]

Bugger. This mx5 stuff is getting on my bloody nerves ! If it isn't the diff arms breaking its the size of the thing getting in the bloody way ! Going to make mine a left hooker !

[Numplumb]

I altered my chassis which was made to book spec to the MX5 dimensions and found that it would have been only the drivers side which needed to be moved, not that helps much for the drivers seat, but I think there is enough room still for the seats to fit but not the mx5 seats without altering them which is what I'm doing to mine.
Regards Mick.

[jason 82]

Cheats for that Mick. I think we are all going to struggle to squeeze into these things, I am not very fat, but when you do the broom broom thing, there ain't a lot of room ! Had a tour of gbs a few weeks ago, the standard car was snug, but they also done a wide bodied version, which felt spot on. It was a Zetec with a type 9 box, so they had a fair bit more room to play with, but as my wife says, a few inches makes all the difference !

[danilo]

I'm a bit confused by this (newby :-)
But I tripped over a Very detailed Caterham SV 'clone', with Miata bits, build in Locost USA site.

http://www.locostusa.com/forums/view...p?f=35&t=13510

Apparently the Caterham SV propshaft tunnel is 4" wide.. outside to outside dimension, then it narrows to the rear by 1/2"
Seemingly his Miata bits fit.. just.. but well, nonetheless.
The chassis is 43 1/2" wide, in total, at the widest point.
No mention of propshaft diff offset issues.
Could certainly have been some.. but none were even mentioned... odd.