Can the PY-VPS (2.5 from the Mazda6) be swapped into an ND Miata?

I've been driving a Mazda6 with the PY-VPS and a manual transmission and it is such a sweet motor. Nobody would accuse it of having an overwhelming amount of power, but it somehow always seems to be plenty. I feel like this would be a great choice for an ND, but I haven't seen any publicly available information confirming whether it is or isn't possible. Has anyone done it? What would it take?

I have seen that Good Win is doing it on NC chassis, but I feel like the ND is a much more appealing package.

No one has done it AFAIK and likely won't. I doubt the ND manual trans will bolt up to the engine. Plus retuning the ND ECU gives more power and would be cheaper and easier. But if one was to do it the turbo engine from the CX-9 might be a better place to start.

You're not the first to think of it I've looked into transmissions, the 25T from the CX-9 uses a different bellhousing but the 2.5 N/A engine should be good. There will be packaging problems but they're probably something that can be overcome. Engine management will be an exciting challenge, and the ND trans would have a hard time staying in one piece.

Of course, everyone knew the 2.3 DISI turbo from the MS3 would bolt right into the NC...

It's not something we're working on right now.

Is Goodwin really getting 200hp at the wheels out of that 2.5 with just a header, exhaust and muffler?! That would make the NC incredibly interesting.

The 2.5 isn't one of the great sports car engines, but it's pretty effective. I would look for independent confirmation of GWR dyno results, but at least this one's plausible. Mazda Motorsports is big on this swap as well, it's used in a bunch of NC racers.

Thanks Keith. I thought about messaging you directly, but figured it would be good for the community to have the answer somewhere Google can find it.

Are ND transmissions really that fragile?

I guess what it would basically come down to is, could it be done for significantly less than a k-swap.

More than 30hp from chip tuning alone? Really?

white_fly wrote: Are ND transmissions really that fragile?

https://forum.miata.net/vb/showthread.php?t=610318

So you don't have to dig through a long and painful forum thread: yes. Best guess is that it was built for the true 1.5, then the stupid Americans insisted on a 2.0. Trans was a little too gram strategied to hold up.

The K would be easier electronically than the Skyactive 2.5, as it's a generation or two older so it's not as sophisticated an engine. So's the 2.5 MZR, and it's a fairly easy swap in the NC. The effort is a little bit underplayed - we've done one - but it's far easier than a cross-manufacturer swap would be by a significant margin.

As for 30hp with a tune, there are some spectacular claims out there. Not all of them have been reproducible on our dyno.

To add, it looks like Mazda made some significant revisions to ND's transmissions that were built after 9/6/16 IIRC.

The general consensus is that ND's built after 9/6/16 have more robust gearboxes; but to my knowledge, I don't think specs have been released, so no one can say for sure how much torque or shock load capacity has been increased, if at all.

There's a never ending 200+ page thread about it over on M.net if you ever find yourself with months on end to burn...

Some forum members believe that Mazda should be releasing full engineering analyses and drawings to anyone who asks. The upgraded 'boxes aren't a matter of belief, they're real.

Really, all you need to know is that they're all under warranty - which means that Mazda is very motivated to fix the problem AND they're getting all the bad boxes back. IIRC, all the upgrades are to 2 and 3, which is a problem for the racetrack guys who are busting 4th. The Global Cup cars are getting some upgraded gears, which are available to the public.

We had some very entertaining discussions at our Summer Camp when forum members were given a chance to ask Mazda powertrain/chassis engineers in public about the failures. It was one of those "I know everything because I AM ON A FORUM!" vs "umm, actually, I work for the company and you don't know" moments. Sometimes, forum discussions generate information out of thin air and then make it "true" by repeating it enough times.

In reply to Keith Tanner:

Have you guys had a chance to pull apart the new vs "old" ND gearbox yet? I imagine you wouldn't have much reason to with Mazda replacing them under warranty, but I know you guys like to tinker. I would be curious to hear about what was changed (besides part numbers); gear width, tooth count, etc.

There was talk of the upgraded Global Cup Car boxes being for sale; from what I recall, they seemed pricey!

I agree, lots of speculation on forums that people turn into fact. Although the part number changes appeared to be legitimate. Sometimes there's good info on forums though, like when the guys from FM share their knowledge based on info they gathered from experience & your connection to guys like Dave Coleman.

Keith Tanner wrote: It was one of those "I know everything because I AM ON A FORUM!" vs "umm, actually, I work for the company and you don't know" moments. Sometimes, forum discussions generate information out of thin air and then make it "true" by repeating it enough times.

That is actually pretty funny.

In reply to Keith Tanner:

This the second thread I have seen you bring up the ND transmission limits.

Do you have a torque capacity on the unit (and are willing to share) or is this experimental failure evidence you speak of?

EDIT: I appreciate the other forum link, but like the formerly new Getrag in the Mustang GT, I can't tell from the information if it is a small design/production issue or a marginal required spec issue. The Mustang issue ended up being a simple fix. I am wondering if the ND trans would be the same. I am also aware Mazda has put a different transmission number in the car.

I'll preface this by saying I have not been wading through the swamp of the forum thread. I've been working a different set of angles, and not working too hard because I know Mazda's in a position to do something about it and is motivated. Also, our time is better spent on developing products that will make us money instead of idle curiosity. But we'll see...

The Global Cup gears are available to us, I was talking to Mazda about that a while back. You'd have to install them which means some cost, otherwise you'd have to buy a complete trans which means a lot more cost. If anybody wants some, let me know. Honestly, my preferred option would be to blow up your old transmission under warranty and get one of the improved ones as a replacement It's worth noting that the GCC gears are for higher gears than the autoxers are breaking.

We have not torn apart a box yet, nor have we failed one ourselves. AFAIK, the fix is wider gears. Mazda has not published specifications on exactly what the torque limits are, but it appears to be somewhere between the stock torque of the 1.5 and the 2.0 There have been a number of failures by autocrossers and the GCC racers.

I'll have to see if I can access the Mazda parts database. If I can, I'll get the part numbers for the upgraded parts and see just what they are.

There is a TSB. Highlighting is mine.
2016-2017 MX-5 vehicles with VINs lower than JM1ND***H121392 (produced before September 6, 2016)
DESCRIPTION
Some vehicles may exhibit one or more of the following symptoms with the manual transmission.
A grinding noise occurs when the transmission is shifted from 1st to 2nd and/or from 2nd to 3rd gear.
It is impossible to shift into 2nd and/or 3rd gear while there is no problem shifting into other gears.
There is an unusual noise from the transmission while it is in the neutral position and the engine is idling.

This may be caused by damage to 2nd and/or 3rd gears if the vehicle was driven with rapid acceleration and deceleration using frequent shift changes. To eliminate this concern, the configuration of the 2nd and 3rd gears has been changed to increase the rigidity.
NOTE: Transmissions with the serial No. “6TJ0701679” or higher are modified.

In reply to Keith Tanner:

Thanks for taking the time to share the info!

Interesting. I just checked our 2017 RF. It has a production date of 11/16, and a VIN that ends in 101903. I'll have to check the trans to see if it's the modified one.

Well we know the old NC unit will fit as that is the one reportedly used by Fiat.

So 2nd and 3rd have been strengthened and some people are saying the new units are still failing.

If the are still failing I would look at the shafts not being rigid enough causing the gears to separate from a proper mesh state, which leads to tip loading of the gear teeth, which leads to failure.

But Mazda's engineers should know that, but it may be cheaper to just purchase a wider gear.

Flight Service wrote: Well we know the old NC unit will fit as that is the one reportedly used by Fiat.

I can't confirm this, but from what I've read on M.net, the NC transmission will not bolt up to the ND's Skyavtiv-G 2.0L engine. With enough time/money invested I'm sure anything is possible, but it doesn't appear to be a lego parts swap affair.

True, we've checked. So the NC trans will fit inside the tunnel, but that's it. Note that the internal gear ratios are also very different so you'd need a different final drive. The ND trans has a 1:1 sixth and a 2.8 rear.

A T56 will fit inside the tunnel as well

It's a very, very compact trans. There may not be room inside to do a quick bandaid fix. They know what they're doing, they're getting the failed parts and they're motivated. Works for me. So I just let them do what they do.

Keith Tanner wrote: There is a TSB. Highlighting is mine. 2016-2017 MX-5 vehicles with VINs lower than JM1ND****H*121392 (produced before September 6, 2016) DESCRIPTION Some vehicles may exhibit one or more of the following symptoms with the manual transmission. A grinding noise occurs when the transmission is shifted from 1st to 2nd and/or from 2nd to 3rd gear. It is impossible to shift into 2nd and/or 3rd gear while there is no problem shifting into other gears.

Interesting, I already complained to the dealer about the grinding and the occasional 'impossible' change into second. Pre-TSB I was told to 'give it more time for the transmission to loosen up' and 'transmission feels OK to our mechanic'.

I guess I'll be leaning a bit harder on them at the next service.

Let me know if you need the number for the TSB, although they should have no problem pulling it up in the MGSS.

Thanks Keith - I think m.net has the TSB (well they would, wouldn't they? ) but if I run into issues at the dealer I'll ping you if I still need it.

There was actually a new one issued on the 15th. TSB 05-001/17. Change in symptoms bolded:

A grinding noise occurs when the transmission is shifted from 1st to 2nd and/or from 2nd to 3rd gear or in the neutral position with the engine idling.

Thanks. I've had both the 1-2 and 2-3 grind, 100% when the transmission is cold and occasionally when warm.

Must try harder .

Keith Tanner wrote: The ND trans has a 1:1 sixth and a 2.8 rear. A T56 will fit inside the tunnel as well

That makes the old T5 a very capable and swapable box as well as the straight cut top loader.

Also that 2.8:1 rear diff makes bike engined locosts really nice and easy. for the gearing calculators I have used.