Finally past the point of no return with the gearbox and I've sent it off for rebuild.
I've been back and forth on this more times than I care to count, should I run it to destruction (if ever?) and fix it then, or be proactive and try to use it as an exercise to optimise performance a bit more? The big sticking point was the diff, I really wanted to try one in my car and I just couldn't justify the cost and effort of install without doing the strengthening stuff whilst at it.
Obviously I decided to go ahead, still not sure if it's the right decision or what - hopefully I've not ruined the car and hopefully it rewards me with years of happy motoring and trackdaying... we shall see.
I opted for the following 'upgrades':
SSC 3rd and 4th gears, same ratio as standard - just chunkier, and still helical so hopefully not too noisy.
Kaaz 4.8 Final Drive
Longer 6th gear from a Corolla/Celica
TRD LSD from an MR2
Added to that I've got a Stage 2 clutch and lightweight (4.5kg) flywheel from Competition Clutch:
What I've calculated to end up with looks something like the following:
Effective wheel torque should be +10%ish through gears 1-5. At most circuits I go to regularly I'm at the very top of fourth and usually short shifting into 5th just to give me breathing room coming into the braking zone. I expect to be using more of 5th now, and hardly any of 2nd (if at all). The change I don't think is too extreme, it was very tempting to go all in on a very short box using either Kaaz gearset or a 5.0 FD with stock gears but ultimately I leaned towards a more conservative setup.
The diff I know is a controversial topic, I don't think there's a clear right or wrong answer for the Elise platform so I just need to try it myself. Fingers crossed...
Gearbox is with a local specialist (http://www.stephenbreargearboxes.co.uk/
) who do a lot of Toyota stuff and I have a few first hand reviews of their work in Lotus circles too so hoping for a top job.
Jury is still out on gearbox cooling, from the temps I logged last year I'm not convinced my stint lengths would benefit from one, but I shall continue to log temps and I will of course add one if needed as the new gears may generate more heat just through altered tolerances etc.
Suspension is also off to Chris @Type116
for Zinc plating, I'll topcoat it with something (probably POR15 clear) when they get back.