Great Odin's Beard! NC Miata Options Went Bonkers this Year!

I've been considering getting another NC Miata for a while now. I shouldn't have gotten rid of my NC2 last time around. At the time I sold it, when it came to competition options, it was a ghost town. No place to run competitively in the SCCA due to the ND. Not allowed/prohibited from competing in NASA TT6. Seemingly they're not remotely competitive in TT5 or Gridlife CTR for a number of reasons. 

Fast forward a couple of years and the track market for the NA/NB seems to be migrating over to the NC. Finally! An emerging Miata market for the one I actually fit in! 

The SCCA added the CSX class in order to hit the "easy button" for the NC2/NC3 if you want to autocross or do spec time trials. 

If you want to run in TT5 or GL CTR, Kpower now has a full K-series swap kit to allow you to compete in those classes, with NA Honda reliability and power: https://kpower.industries/products/complete-kpower-nc-swap-package

And I just recently discovered Flyin' Miata's 50-state CARB legal turbo kit for the NC! https://flyinmiata.com/collections/nc-2006-15-powertrain-forced-induction

^^^As someone that needs to retain my OEM catalytic converter(s) to maintain street legality, the FM turbo kit is an absolute game changer that makes aftermarket boost a real option for a street car!

Suspension options also opened up drastically- of course FM's Fox setup and the guys over at 949 finally released their Xida coilovers. 

Thinking about getting another NC has my brain overloaded with all the sweet paths that are now available and what I would want to do with it!


There are now so many options that didn't exist just a year ago for these cars. I figured when they bottomed out in price and prices on NAs/NBs went up the market for the NC would open up a bit, but I didn't expect so many major options, so quickly. 

If you bought an NC, which route would you take with it? 

Hmm...  the FM turbo kit does look interesting.  

Personally, I would search out a clean folding hardtop model as that would better serve my occasional daily driver needs.  

roninsoldier83 said:

If you bought an NC, which route would you take with it? 

Buy the wrong options for CSX and plan to run it in Sport 6 SCCA Time Trials in 2025 while being completely outgunned in CS and later STR.

What's not acknowledged in that writeup is that we're currently at the emissions lab getting an EO for 11 psi on that kit :)

Our Fox suspension has been available for the platform for over a decade, FYI. NC parts have never sold as well as parts for the other generations, let's hope the market is finally here for them.

A plan is formulating:

-Acquire another NC2 / NC3. 
-Drive to FM to acquire a CARB legal turbo kit. 
-Pick Keith's brain on how to keep the car healthy and alive, long term. 
-Get either the FM Fox setup or Xida's (I'll need to do some reading). 
-Wider wheels and sticky tires. Consider upgrading the rear diff at some point. 
-Autocross the car locally in our SCCA XS-B class (there's essentially no rules in XS, other than the car has to maintain a finished look, be fully road legal, run 200tw tires and meet minimum weight requirements). 

I'll probably avoid road course work and just use the 128i for the higher speed stuff. Keep the NC for dodging cones and having fun on the street. This sounds like a much better plan than running CSX. 

Keith, I can't believe you guys pushed through with a fully CARB legal kit and are already turning up the boost!

I should have kept this to myself to avoid NC prices going up before I have acquired another one. 

I found a 2010 Stormy Mica Blue last spring to replace the one I never should have sold in 2014.

I think the NC is a lot more fun on the track than the earlier generations once some simple mods had been done.  Mazda recognized the shortcomings of the first car and released the MS-R "trunk kit" that fixed the boaty suspension.  Some bolt-ons and a tune for more HP and a mostly stock NC is a natural track and AX machine.

I would also strongly consider the 2.5 swap with appropriate mods.  One of the guys I've run with did that and the car is pretty damned quick.  11 psi would be nuts, how will it hold together?

The biggest problem the NC has is that the chassis is too good for the engine - at least once you get decent shocks on an NC1/NC2. It doesn't really wake up until you crank up the power/grip ratio. 

We actually built and tuned the kit for 11 psi all along, but the EO we had was only for 8. We had to go back for some further testing due to some specification changes since the original application, so why not? :) We do recommend keeping it to 8 for the NC1 engine.

I also proposed testing on an 2.5, which would have had the very entertaining side effect of making the 2.5 CARB legal but only with our turbo kit installed. But that would have delayed things much longer. 

Keith Tanner said:

I also proposed testing on an 2.5, which would have had the very entertaining side effect of making the 2.5 CARB legal but only with our turbo kit installed. But that would have delayed things much longer. 

That would indeed be hilarious. Any plans to do it once the 11 psi EO gets granted?

So the 2.0L with FM turbo puts out basically the same, maybe a hair more WHP than a K24A swap for a LOT less money...and the boost is getting ready to be turned up?!?

I don't need a Miata and don't really want a Miata, but stuff like this has me hearing the siren song of a rebuilt title NC (especially when it comes to consumable costs) so long as the power is reliable on circuit. 

If I wasn't already neck-deep in a K swapped NA race car, I would be building an NC for the track.  I would look seriously at a 2.5 with cams or a 2.4 build before doing a K swap on the NC... I think you can get to the same power level with less expense because of the high cost of the swap kit.  That said, the NC K swap has the advantage (compared to the NA/NB kit) of retaining the balance shafts, and cheap motor replacements.  The FM turbo should easily put out 40-60hp more than a stock engine K swap.

For me, the NC PRHT is 'peak' street Miata.  I know the ND is objectively better in performance, but the fully retracting hardtop and slightly roomier interior give the NC the win for me.  We had a '13 Club PRHT years ago and I wish we had kept it, but this summer picked up an NC2 PRHT GT to be our 'forever' street Miata.   I don't think NCs are going to be on the downside of the depreciation curve much longer... and some of them are already going up.  Low mile NC2/NC3s, especially PRHTs are bringing premium prices and I don't expect that to change.

Ours will always be a street car, but wheels, tires, and Xidas have already been installed... just waiting on the FM Turbo kit to 'finish' it.

In reply to Keith Tanner :

That's the first thing that at popped into my head: 2.5 with an FM turbo kit.

Piguin said:

Keith Tanner said:

I also proposed testing on an 2.5, which would have had the very entertaining side effect of making the 2.5 CARB legal but only with our turbo kit installed. But that would have delayed things much longer. 

That would indeed be hilarious. Any plans to do it once the 11 psi EO gets granted?

It's unlikely. The math doesn't work. It would have been okay if we'd shoehorned it in to the one test, but the cost of testing would never be recouped with 2.5 swap part sales.

flyin_viata said:

So the 2.0L with FM turbo puts out basically the same, maybe a hair more WHP than a K24A swap for a LOT less money...and the boost is getting ready to be turned up?!?

I don't need a Miata and don't really want a Miata, but stuff like this has me hearing the siren song of a rebuilt title NC (especially when it comes to consumable costs) so long as the power is reliable on circuit. 

I'm not sure I would say there's a hair more power from the FM turbo (it seems a bit more substantial to me). Most K24's with basic bolt-ons in a RWD application (a bit more drivetrain loss vs FWD) seem to put down somewhere in the neighborhood of ~215whp or so with normal breathing mods. FM seems to be indicating that their turbo kit (I'm assuming on ~8psi of boost) is putting down closer to 250whp (before they turn the boost up to 11psi). That seems pretty substantial in a ~2500 lbs car. 

I would also point out that while FM's kit is only $5000, the K-swap kit is $10,000 before factoring in the cost of the engine or any supporting mods. Realistically, I think the K-swap is likely going to run you $12,000-$15,000 by the time you're done. 

FM says on their site that they've ran 45 minute sessions at High Plains Raceway (a high elevation track here in Colorado) in their turbo setup, which is impressive. Especially considering our elevation out here (high elevation= higher oil temps/harder to cool on track). 

Keith, I'm curious: what supporting mods are needed to keep your turbo NC alive at HPR? I'm assuming bigger radiator and an oil cooler? Beefier clutch?

With that said, I think if I was setting up a dedicated time trials car, especially for a specific class, I would likely spend the extra money on a K24 swap. Those motors have been proven to take serious abuse on track for extended sessions- I mean, it's a stock Honda motor. For a class like Gridlife CTR, you have to run a "stock" engine under 2.5L- which is why so many people in that class (seemingly everyone that's competitive?) seem to run a K24. In SCCA TT, either of these setups bumps you into Max, with the K24 putting you into Max 4 vs the boosted setup placing you into Max 3- all things being equal, I would think a K24 swapped NC would be more competitive in Max 4 vs a boosted stock motor in Max 3 where you're running against OEM boosted cars like an RS3 that comes stock with 400hp before modification. In NASA TT, it's all power-to-weight based, but if you're running the popular Maxxis Victra RC-1 tires, at full weight, I think you could eek a K24 swapped NC into TT5, which in my mind, would be preferable over running an aftermarket boosted car in TT4. 

For the street or autocross, no doubt, I would prefer the turbo car. I've owned plenty of high revving Honda's over the years- VTEC is great, but it's hard to argue with smile-inducing mid-range torque! 

For someone like me, living here in a place like Colorado, in the metro area where we have more stringent emissions laws (you now have to retain OEM or CARB certified catalytic converters), it's a no brainer- FM turbo kit. Double the stock power while still passing emissions annually with ease. That's a tough proposition to beat for a street car. 

When I got my Z28 back in exchange for my NC Miata, one of the biggest reasons was that I wanted to get a better, cleaner NC anyhow- probably a Club model. I still want a soft top, but I want to pick up the removable hard top for it. 

I keep telling Legendscar95 that if he doesn't like the NC Miata, he just doesn't like Miatas at all. The "Touring" spec is, in my opinion, the best spec for the NC1s.

"Seems to be indicating their turbo kit is putting down closer to 250rwhp...I assume on ~8 psi of boost" :)

From the writeup:

8 psi of boost out of a GT2860RS turbo means roughly 250 hp at the wheels on the stock 2.0 engine

Anyone got a dyno run for a "basic" K24 to get an idea of the area under the curve? Also, Ronin, remember that you'll lose 20% of your naturally aspirated power at altitude but not on the turbo car.

The test car that was used on track is equipped with an upgraded radiator (from Flyin' Miata, of course) and an upgraded clutch (guess where we got it). I would recommend the larger turbo if your plan is hard track use, as the lower backpressure will make things easier on the cooling system. I think one and possibly two customer installs (initial test installs done at our shop) are on stock clutches but if you're looking to harden for the track I'd recommend a clutch to be sure.

On the other Miata platforms, turbocharging the stock engine to a power level that can be supported by the stock internals is considerably easier and less expensive than doing an engine swap. It's only once you start chasing the really big numbers that it becomes financially worthwhile. I see no reason why the NC would be any different.

I don't think NC prices will ever climb into the classic car appreciation range the way that the NA has, because they're not the icon. But as the supply ages, the value of good ones will climb like it always does when a car hits 15-20 years old. Ironically, this is also the timeframe that the grassroots crowd starts to lust after them, so they then get to complain about how you used to get them for $150 only five years ago...

Keith said: Anyone got a dyno run for a "basic" K24 to get an idea of the area under the curve?

Here's the K24A (JDM K24A2) in my NA swap.  Stock engine other than a 50 deg cam gear and swap related intake/exhaust, tuned on Link.  Lower curve is BP6D I/H/E tuned on MS3.  Both on 91 pump.  K24Z3 is usually ~10hp down.  The turbo NC is going to make it look like the 1.8 by comparison....

Yeah, you'll feel the difference there even before the altitude loss. The turbo car has more torque from 3200-7000 rpm than the K makes at peak.

Keith Tanner said:

It's unlikely. The math doesn't work. It would have been okay if we'd shoehorned it in to the one test, but the cost of testing would never be recouped with 2.5 swap part sales.

Would it also have made the 2.5 swap CARB legal in NA/NB cars?  I seem to recall that CARB has weird rules about backdate application and that it includes more chassis than you'd expect.

codrus (Forum Supporter) said:

Keith Tanner said:

It's unlikely. The math doesn't work. It would have been okay if we'd shoehorned it in to the one test, but the cost of testing would never be recouped with 2.5 swap part sales.

Would it also have made the 2.5 swap CARB legal in NA/NB cars?  I seem to recall that CARB has weird rules about backdate application and that it includes more chassis than you'd expect.

 

It all depends on how the application is written. If the application includes naturally aspirated versions of the 2.5 and includes a parts list/instructions/description of a 2.5 swap into the NA and NB - maybe. It's more likely that CARB would say "ha, no".

Regardless, the MZR 2.5 swap isn't an easy one into the NA/NB. There are better options for the level of effort/expense. There's no Mazda DNA that makes it easier than any other inline four swap other than the fact that it bolts to a Miata-shaped transmission without an adapter.

In reply to Keith Tanner :

You're preaching to the choir on not losing as much power at our elevation! I'm sold on the FM kit. If I would have paid more attention and known it was coming, I might not have bought my M2 a couple months back. 

I wasn't planning on hard track use with an NC, I was just asking out of curiosity. Maybe an open lapping day at HPR for fun, but nothing competitive. I was going to use my 128i for any harder track use and use the NC for autocross, so I was leaning towards the smaller turbo for responsiveness when dodging cones on ~60 second parking lot courses. 

With that said, if someone was building a dedicated TT car, I still think the K24 starts to make sense for reasons listed above. NA cars lose a lot of power up here, but if you're running let's say, NASA TT, you still have to dyno the car and locally they use full SAE correction on a Dynojet, regardless, which nullifies the smaller power loss at altitude. Even our local SCCA TT chapter has gone away from the national rule-set and switched over to a power-to-weight system (loosely mimicking NASA) that involves a trip to a fully corrected dyno, so the boost isn't really an advantage up here. Because of the rule-sets of the organizing bodies, I can see why a K24 swap would make sense. 

For an autoX class like SCCA XS-A/B, there really are no rules, it just has to be a street legal (registered/insured), full interior, all necessary parts to run on a roadway (headlights, windshield wipers, etc) and fully finished car over a certain weight. For that, the FM turbo setup makes all the sense in the world. 


The guys over at Speed Academy built a K24 powered NC a few months back and dyno'd it: https://www.youtube.com/watch?v=H58OhG1Ki-M&list=PLp8FsoRYWYK5On5JilQDxcRwbNllan9uX&index=6


I stole a few snips from the dyno they posted at the end of the videos: 

Essentially a base-map: 


Dyno tuned: 




There's no doubt, any person in their right mind would feel the extra shove in the low and mid-range from the turbo setup. 

I concentrate on the hardware and leave the classing questions to other people. Classing changes too often to try to design parts for it.

It would be interesting to do a few more dyno runs on that tuned K. We've found that the ND is smarter than a lot of tuners and will learn its way around a tune. First run looks great, by the time you're at the third or fourth a lot of the gains are gone. Because of that, I always take "tunes" with a very large grain of salt.

In reply to Keith Tanner :

That's interesting about NDs 'unlearning' tunes... I'm assuming that's with an OEM ECU, since not too many folks are using standalones in NDs?

In reply to Rodan :

Yes, the stock ECU. Properly retuning a stock ECU is different than just throwing some advance in the timing table, it's more a matter of setting different targets from what I understand. Working with Calibrated Success on the NC was an eye-opening experience - an OE-level tuner works very differently than your typical neighborhood dyno shop.

In reply to Keith Tanner :

FM's efforts to get the calibration done at that level is a big part of why your turbo kit is so attractive.  I've talked to a number of NC owners who had unexplained engine failures with forced induction and 'flashed' tunes.  I think what happened is exactly what you're talking about with the ND 'unlearning' tunes.

In reply to Keith Tanner :

I'm pretty sure the K-swap kit comes with a Haltech Elite 1500 ECU, which I thought was a standalone? 

They've done a few episodes running it out at their local track and it seemed pretty quick on their front straight, leading me to believe the tune is pretty consistent: