RB26 S13 – Upcoming Plans

The next 3 months are going to get very busy for the S13.


If you have been keeping up to date, you will know that the rewire on the car is booked in to start tomorrow. That’s great news and I’m really excited, but the only problem is I won’t be able to touch the car for 4 weeks. I can still make things for it at home and get some redesigns happening for certain pieces, but I’ll be a bit limited without being able to see the car.

I’m going to spend a lot of time doing research and possibly ordering a few little parts I need so that I can get back into it 100% when it’s done. Once I have it back, I need to finish some more fab work, organise my gearbox setup, fit some new parts and sort out the tune. The fabrication list isn’t small, but luckily most of the jobs won’t take too long. A lot of it is engine bay related things along with some rear end mounts and a new gearbox crossmember. I’ll obviously try and get everything done but I’m not going to go crazy like I did last year. I’d like to keep my sanity this time around.


I should have a few fresh parts ready to go on the car before going in for a tune. I’ve been looking at ordering cams lately, but only if I can afford them. I run standard cams at the moment and the car drives amazing, but it doesn’t have the note I originally wanted. Realistically I’m just aiming to get the car driving again so putting cams in would only be a luxury. My list is prioritised with the necessities at the top, so before any luxuries come along, I need to concentrate on whatever is top priority.

Speaking of that, I still need a gearbox.

Since destroying the RB25 box in December last year, I have looked into multiple options. I could quite easily just put another RB25 gearbox back into the car and drive, but there is no guarantee on how long it will last. I am almost certain the rear tubs are what killed the gearbox, but I still have that thought in my head that something else could have caused it. If I don’t find that problem, I could quite easily go out and break another one. Only way I will know is by testing the car, but if for whatever reason it goes wrong then I would have wasted a bunch on money on another useless gearbox.

A used RB25 box I can pick up for $1,500 or I can order a brand new box from Nissan for $3,000. Either option is doable, but the thought of another failure might be a bit too risky.


Second option is a Z33(350z) or Z34(370z) setup. I’ve found a little bit of info covering the different versions of gearsets and have also heard from a few people that the later models can take a bit of stress. Apart from an adaptor kit and a longer pivot ball, I haven’t found much more information on what’s needed to make them fit. The later model CD009 and JK40 seem to be the best option as they have a revised gearset with stronger synchro’s. The other bonus is these are a 6 speed box, so the gearing will be slightly shorter than RB25.

They seem to be around $1,300 for an earlier model Z33 and $3,000 for the later model CD009. The final model JK40 in the 370z is closer to $5,000 which isn’t that cheap for an OEM transmission, but they have been put to use behind 1000hp V8’s which means they are obviously well designed to handle power. The other thing I have to think about is the conversion kit to fit the box to my RB26. Add in another $1,000 and I would have a very solid OEM setup, but when you put the cost of the gearbox and conversion together, things start looking expensive.


My third option is a G-Force GSR 4 speed dog box. This is the strongest, most expensive of everything I looked at. A lot of the pro level cars use these behind big tyres and big power with no issues, so I imagine it would barely notice a thing in my car.

The down side to the GSR is the cost, $7,000. It’s almost achievable in my current situation, but even then it’s still an extremely hard figure to get to. The engineering behind these is outstanding! If I want to get the GSR I would have to take into account a lot of other options, which will make it very difficult to have the car driving again in September.


Ultimately my first choice would be the GSR, no questions. I’d never have to change a broken gearbox again which is great and being able to swap gear ratios to suit different driving styles is an awesome bonus. Along with all of that, the servicing is very straight forward compared to older OEM gearboxes.

In the end, my driveline would be ridiculously strong, with the only worry being my diff which I doubt I’d break with such little power. If I officially decide to go for this gearbox, I will have to get a 3rd job and eat peanuts for a few weeks. Otherwise I would be looking at a November/December test day instead of September. Every single way I have budgeted and thought about the GSR as an option, it just isn’t possible for me to save that amount of money in 8 weeks.

But, I still have a lot of deciding to do. Hopefully I can have an answer next month.

The reason I want to make it happen by September is so I can run another day at Wilby. I decided earlier this year that I won’t be driving Queensland Matsuri 2017, which is a bit unfortunate, but I think driving the event 3 years in a row is a pretty good effort.


I’ll be organising another event at Wilby later in the year where I’m hoping I can run the car at it’s full potential. No power steering issues, no wiring problems, just a good driving session with a solid gearbox setup.

The final thing to do before that September session is get the car tuned with the Motec. I’m still deciding on a few things with the tuner, but I’ll need to hurry that up and make a decision by the end of July. There is a fair bit I want to incorporate by using the functions on the Motec, so I want to make sure I’m 100% happy with the tuner before saying yes.


Aside from all of that I’m still working as much as possible and saving every single dollar I can. The car goes away for wiring tomorrow which has been my highest priority all year. Like I said before, I won’t be able to touch it for 4 weeks so it looks like July might be one of the quietest months I’ve had in years!

I’m really looking forward to driving the S13 again, especially after sorting through all the little issues I’ve found.


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