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Did you know that the Aisin AZ6 6-speed transmission from the nb2 is also used by Toyota and Nissan in cars like the Lexus IS200 or the S15?
Did you also know that by modifying the countershaft you can reach a torque of 500Nm? Here are two articles for you to take a look ...
What do you think? Did you know about this solution or had you researched this topic?
It seems something interesting ... or maybe I'm wrong
elpazos aka IG @jrmiata
Post update: a few months ago I made this mod on my car and I am very satisfied with the results, after 2 trackdays and intensive road use there have been no problems and the transmission works perfectly. The car makes 400hp and 500Nm of torque and I have installed a ceramic double disc clutch, therefore the transmission must withstand greater loads. So you can imagine the level of power this mod can achieve. It is the first Miata to make this mod, it has never been done before and it really works.
The countershaft modification was done in Neat Gearboxes. Who wants to request the measurements to DIY send me a DM. See my post where I explain the assembly procedure: Aisin AZ6 6-Speed Gearbox “CIRCLIP MOD”
Last edited by jrmiata42069; 01-25-2022 at 07:45 AM.
You're onto something. Props. Think we'd give this a try in the next few months to come.
edit: Also reading the miata variant is called Y16M-D, while the articles relate to J160, no mention if the same mod applies to a Miata AZ6.
Well, I think I'm not wrong and the transmissions are the same. So it could be great news! Simply by taking the countershaft to a machine shop and making the modification described in the post we could have a very significant improvement in our transmissions with a gain of 500Nm!
At first glance it does not seem complicated and it would be easy to test. In my case I have already destroyed 2 transmissions and this opens up a world of possibilities ...
elpazos aka IG @jrmiata
Last edited by jrmiata42069; 04-19-2021 at 01:48 AM.
Confirmed! They are the same gearboxes. I have sent an email to the guys at Neat Gearboxes and they have confirmed that the modification can be made in the 6-speed transmissions because the counter shaft is exactly the same as in the Nissan Silvia S15, Z33, Lexus, Toyota etc. I reproduce the answer below:
Hi Ramos, Yes, the clip modification works for the Miata / MX5 6-speed transmission, we have done at least 5 or 6 Miatas. While I don’t have any lab testing or anything, we do have over 60 of these in the real world being used since 2015. I have seen one break in a BRZ with 303kw@wheels. And in fact, it was not the clip that broke but 4th gear itself. Other than that, I don’t think I’ve heard of any breaking with our modification. I have a Lexus IS200 with a turbo charged BEAMS motor. it is on run-in tune but will be easily capable of 300wkw. I have done the C-clip modification to that gearbox too, so it will be a good test. The difficulty is that the shafts must be sent to us in order to machine them correctly to suit our larger, stronger C-clips. It does make logistics a little harder and more expensive.
Kind regards, Sam Charlick Owner/manager Neat Gearboxes
It is a really economical option compared to other solutions such as Kmiata and its conversion kit to BMW transmission.
elpazos aka IG @jrmiata
Last edited by jrmiata42069; 04-22-2021 at 01:31 AM.
If the rx8 and brz boxes are the same does that mean they're adaptable? Rx8 transmissions are far cheaper than miata 6 speeds nowadays...
Not likely. The input and output shafts are likely to be different lengths. Just looking at pictures of some of them, the tail shaft on the NB variant looks much longer to retain the internal shifter.
This is great news! I've been following this thread since it popped up. Lucky me for once being in Australia Will be far cheaper than a BMW trans swap for me.
Some time ago I came across the same source and managed to contact Neatgearboxes and asked if the reinforced gearbox would withstand my assumptions (around 500hp and flat 450nm of torque). Unfortunately, they are not convinced about it, let me paste in the answer.
Hi Jarek,
That's a lot of power for an AZ6. I'm not certain the gearbox will hold, but the clips won't be the failure point once you do out upgrade.
For me, the game is not worth the candle, I was fixated on the point of staying with the stock gearbox, but to strengthen it properly for such powers, in my opinion, you would need to make a C-Clip mod from Neatgearboxes and strengthen the rest of the gearbox, e.g. in Walter Motorsports (but the 6-speed gearbox is work in progress). My case is slightly different because I would have to import everything to Poland, which drastically increases the costs of the project.
I could decide to do it, if I was sure that the gearbox would be bulletproof, but I do not have such certainty, and if something happens to it, even not necessarily because of its durability, I'm left with huge costs to bear, in addition, I have to wait six months until another gearbox can be strengthened in two companies at two corners of the world.
For these reasons I decided to swap to ZF 8hp70, at least in my country this gearbox is cheaper than the 6speed from Miata, it shift very very fast and it can handle around 1200nm of torque. The swap cost is comparable to or even lower than building a 6speed Mazda. When I sell my clutch from SuperMiata (around $ 1,400), I have already covered about 70% of the costs.
Did you know that the Aisin AZ6 6-speed transmission from the nb2 is also used by Toyota and Nissan in cars like the Lexus IS200 or the S15?
Did you also know that by modifying the countershaft you can reach a torque of 500Nm? Here are two articles for you to take a look ...
What do you think? Did you know about this solution or had you researched this topic?
It seems something interesting ... or maybe I'm wrong
elpazos aka IG @jrmiata
I stumbled across this thread just punching in circlip mod in Google
I have a Nissan S15 that has just completed this modification (and extra bits), I did things a little differently but happy to share prices, approach and the outcomes as I break the box and diff in over the coming weeks.
Some time ago I came across the same source and managed to contact Neatgearboxes and asked if the reinforced gearbox would withstand my assumptions (around 500hp and flat 450nm of torque). Unfortunately, they are not convinced about it, let me paste in the answer.
For me, the game is not worth the candle,... I decided to swap to ZF 8hp70, at least in my country this gearbox is cheaper than the 6speed from Miata, it shift very very fast and it can handle around 1200nm of torque. The swap cost is comparable to or even lower than building a 6speed Mazda. When I sell my clutch from SuperMiata (around $ 1,400), I have already covered about 70% of the costs.
Curious to know where these can be found, as in what is/are the source vehicles.
Curious to know where these can be found, as in what is/are the source vehicles.
Thanks in advance.
This gearbox runs in a truly countless number of cars. So it will be most convenient to link to Wikipedia. The difference between the manufacturers is mainly the bell of the transmission which forces a different adapter. https://en.wikipedia.org/wiki/ZF_8HP_transmission
Thanks. Not sure I am ready to step up to an auto.
Nevertheless, I'd be interested in your build thread for this conversion, particularly for the adapter and controls electronics. Please keep us informed.
I am seriously considering giving this a shot with my spare 6 once I get the EFR on. Would be huge if it's this simple since it should support *most* people's built power goals.
I have heard firsthand that 2 smaller entities are developing more cost-friendly bmw trans swap solutions, so I'm also on the fence until those are released
04-18-2021, 05:47 PM
500Nm of Torque in the NB 6-speed Transmission
3
Will be far cheaper than a BMW trans swap for me.
