Erm, are you sure about that?
I’d go with the Audi box if I were starting out with a gearbox failure… Unless they can guarantee parts/labor that the Jubu gears won’t fail…
Frank I’ve done a bit of research into this and I can’t find one with suitable ratios…
That my worry with Jubu.
Have many 2_11,s failed with 260 bhp ?
Just wondering how close to destruction mine is …
From the comments about the larger module thicker gear teeth in the Jubu set then I take it that it’s the helical teeth that are shearing off under the increased torque.
What is the logic for going for oil coolers on the toyota box? If you are seeing bearing failures then it may be related to temp and viscosity but if it’s tooth load fatigue then the cooler isn’t likely to do much to help. Typically the most significant rises in oil temp come from too much oil in a transmission or poor air circulation around the box.
Gearbox swap all the way. If the ratios are a worry then you’ll just have even more of an excuse to tune your engine…
The guys that race these, break them and strip them down say that the lack of cooling is a major contributing factor.
Combination of better gears, better oil and better cooling is what the experts are saying is the way to go.
Ex77
[quote=wesj111]From the comments about the larger module thicker gear teeth in the Jubu set then I take it that it’s the helical teeth that are shearing off under the increased torque.
What is the logic for going for oil coolers on the toyota box? If you are seeing bearing failures then it may be related to temp and viscosity but if it’s tooth load fatigue then the cooler isn’t likely to do much to help. Typically the most significant rises in oil temp come from too much oil in a transmission or poor air circulation around the box. [/quote]
Well about 1200+ miles on track this year and 3k on the road and all is still well with my upgrade, I think your issue is you don’t want to be first to run more power through the Jubu gearset and I can understand your worry, but somebody has to do it, if the tax man doesn’t come and take away all my money I might well add more power in the later stages in the winter. What I will say is you can always put in a Celica gearbox (like I did) till you make up your mind, I paid �300 for mine and it worked well for 5 months while me and JSR got all the parts together to do the upgrade on mine.
As for the question as to what breaks, all the teeth come off the gears, 3rd and 4th are the narrowest of the gears in the gearbox and are also in the middle of the shafts, so when the shafts flex they are most likely to partially unmesh and with them been narrow and made out of metal that closely resembles cheese, they eventually fail. You further compound the problem if you track the car a lot, I have had reading of the gearbox casing been 40 degrees above the maximum running temp for the oil, it was so hot you could not touch it.
It sounds like yours went about the same as mine IE peak torque, which is no surprise 
I like you thinking 
Would like to go the down the gearbox but there is no way I can justify �4k for drive in and drive out audi box swap that JSR wanted, particulary for a solutions thats not been tried. If they could have done it for half that, then I would of have bitten their hand off!!
This gives with me 2 options…
1 - Attempt to do the gearbox conversion myself. Use a local engineering shop to fabricate an adaptor plates and custom mount, then purchase a custom made flywheel, driveshafts etc. Downside is it could take a lot of time, and potentially the costs could stack up. I’m also not sure that the audi box is ideal, really need ratios like the Type R boxes - There is also no guarantee this will work!
2 - Rebuild (or replace gearbox), and fit Jubu gear set. This isn’t a cheap option in itself as the gears alone around �800. I spoke to a friend yesterday that owns Force 23, and he reckons the jubu gears should last but as advised me to speak to Transmission solutions in Doncaster for his opinion. Transmission solutions rebuld a lot of the elise trophy cars boxes so have good experience with the C64. I’ll give them a call this week to dicsuss…
Racing is different to 20-30 min track session, and a lot different to road miles. I made the same comment on Seloc if a oil cooler is really required. I get the impression some of the racers are experiencing a different problems with their failures being the syncros and bearings. The problem we have is the tooth load with 200ftlb is just too for the std helical gears.
Exactly that Ade…Gearbox rebuild + Jubu + Clutch will probably cost �2k in itself, then will need to be fitted. If it fails again the only solution would have to be a different gearbox and I would have wasted a good chunk on money 
I must admit I have faith in what I have done and trully believe it will last the course and 350hp+, when you look at the gears the difference is so obvious the toyota ones really are made of cheese and the gearboxes do overheat on track, these are both known facts so I have gone about fixing them.
Also it makes a difference the way you drive, race drivers are more likely to destroy syncros etc as the rarely use mechanical sympathy they just want to win, heel and toe will also help as it takes away a lot of the shock loading on down changes, I also stay clear of saw tooth curbing when on power, if you are racing these will be a different story probably.
I was really torn between send �����’s fixing the gearbox for good or amking t a disposable item like brakes but in the end decided the cost of missing track time was too costly, so went with the big upfront cost and fix for good.
You do have a tough choie in front of you, but if you need your car stick in a �300 celica gearbox for winter while you make your choice, iyou have a spare weekend you can save yourself �300 fitting cost.
Whatever you choose to do it will be the best choice in your own mind and nobody else can tell you any differently 
But a least you know it does work and is tried and tested, it is not just me running their kit either
Don’t forget that most of the parts to convert, are not available off the shelf. One off parts are always a chunk more expensive than those made in their thousands.
To go down the Audi route, we have figured that you need
Adaptor plate
Fylwheel
Clutch
Release bearing, and adapt to the push fit Audi slave connector
2 x driveshafts, you could reuse your old outer joints, but this is only a �100 pound saving
Gearbox
Diff, if wanted
3 x mounts. The Audi box only really has fittings for 2 of these, so some creative thinking is required
All the fittings, mostly fine pitch threads which are way more expensive than standard ones
Starter motor and adapt loom to suit
Check over of the donor gearbox
Make the gearcables fit, which should be just extend one slightly
It all soon adds up,and all you have is nice pile of parts. Then you need to add in 17.5% of VAT on top of it all.
With regard to oil temps, if the casing is too hot to touch, then imagine how flexible the casing is at this point. Ally is great, but in thin sections like the OE casing, it sure does expand when it gets hot. All of this helps the gears to go out of mesh, then you are only running on part of the teeth and it will fail.
Thanks for he input. I do understand whats involved, and I userstand totally from a commercial point view where the costs lie for you guys. Doesn’t make the decision any easier though
The guys running 270bhp must be on the limit, there won’t a lot of difference a torque between a 300bhp car -one bad gear change could just be enough to over load 3rd gear.
This is a great thread guys!
I feel very frustrated that the Toyota engine is easily able to give more power… the CN 260 upgrade is just a simple start! But I am not going there as I dont want to then have a big bill for the gearbox fix!!!
Given there are hundreds of SC Yota cars out there, it will only be a matter of time until a cost efficient and realible ‘fix’ to this weakness is found.
I notice the 211 race cars run a Quaife gearbox… why has this not been suggested as a fix for the Exige then?
BTW, is it easy to fit a gearbox oil cooler? I may get this done as prevention!
Hope you guys can arrive at a solution that you feel will really offer the gearbox realibility that even the Honda guys dont have to worry about!!!
it is not bad gear change per se, I have always thought shock loading will have a much worse affect on the longivity of the gearbox as it is the torque that breaks the teeth off, bad gear changes will usually just ruin the syncros (which are also not the strongest).
Speak to JSR they did mine, very easy to do and not too expensive laminova based which I thought was best.
I just rang Quaife…all they can offer is the sequential gearbox which can be purchased through one of their distributors. It is very expensive, and will not really be suitable for road/track car.
The 2zz-ge seems to now be used in a lot of caterham 7 replicas, so there are some off the shelf adaptor plates / flywheels on the market for different gearboxes…something to look at.
Quick update…
I’ve had very good qoute to remove, rebuild and refit the gearbox by a guy that does alot of the Lotus Trophy cars. The expensive buit however is the Jubu gears at �800!!
There is however a conversion kit in the pipeline to fit the 6 speed civic type R box to the 2zz. I have a feeling its going to be v.expensive, but I should hopefully know more next week…