Thinking of getting a 2006 Miata but I want to turbo it eventually. But am concerned with it’s reliability. There is not a ton of info on Turbo NCs and I don’t want my engine to blow up in 10-20k.

How do the early NC 2.0l and manual transmission hold up with turbo?

I’m not looking for crazy numbers. I’d be very happy with 250hp.

How much life can I expect to get out of my engine?

 

No turbo knowledge from me but I drove a cammed 2.5L swapped nc for a race team many years ago and we would blow up transmissions. They could also change it right on pit lane in what felt like 10 mins, all the bellhousing bolts were not used for this reason. The car was awesome, I would pass bmws and all kinds of expensive equipment.

 

Isn't it an NB 6 speed in a new casing?

 

A quick google search is giving me mixed info on that, hopefully someone will chime in that knows for sure. Why is the nc drivetrain not used more often as the original poster isnt finding much info on turboing them. Emilio posting about that datsun z with the nc underpinnings and that has me wanting do it with one of my datsuns.

 

I know the later NC2+ came with better engine internals, but with how cheap those 2.5 fusion motors are I'd boost the **** out of your stock 2.0 and swap to a 2.5 if it broke. Though I doubt it will fail at ~250whp.

 

IIRC there is a thread on what is required for tracking an NC I am pretty sure Emilio either started it or contributed, can't remember what if anything it says about turboing one though. Search is your friend.

 

Mine has been very reliable with an NC2 2.0L and fab9 gt 2860rs turbo kit, but it isn't street driven and I haven't put a huge number of track miles on it. Only making around 210hp for my race class. I also followed as much of this forum's wisdom as possible when assembling it and made custom heat shields, oil drain hard pipe, downpipe brace, etc..

The 2.5 isn't a terrible motor as long as you have realistic power expectations and keep the revs low. That means 180-190whp and a 6500-7000 redline. They won't last long on track at 7000+ rpm, and you can dump a lot of money into building one and still end up with only 200-210hp and not significantly improved rev capabilities before it lets go.

The NC 5sp is an NB 5sp in a new case. The early RX8 6sp is an NB 6sp in a new case. The NC 6sp is an all new design and shared with the later RX8.

The NC 5sp is reliable for naturally aspirated but not much stronger than NB 5sp with boost. The NC 6sp gears are strong but they have a few weak points, mostly in the shifter mechanisms. Mazda Motorsports has a relatively cheap 6sp upgrade kit that supposedly fixes almost all of the 6sp problems, but I haven't heard much feedback on it. I'm going to try it in my car next season after blowing up a 5sp last year and then taking this year off.

 

Interesting, AFAIK we only got the 6-speeds (and the auto).

I had an interest once in going racing with an NC, after reading your post I'm rather glad I never went down that rabbithole.

 

Everything you want to know on NC miatas is at your finger tips at Miata.net
Many different turbo kits, top mount, bottom mount, and soon to be released rear mount.
Easy tuning with multiple vendor or DIY ECU flash systems.
1.8, 2.0, 2.3, and 2.5 easy low cost builds and swaps.
5MT, 6MT, and 6AT. BTW there are essentially no carry over/swap-able parts between the NC and NA/NB

 

Street only, dual duty or track only?

 

do you have a picture or link to ‘oil drain hard pipe’ ?

 

I thought I posted it in my build thread but I guess not. "Hard pipe" was the wrong choice of words... it's more just an extended nipple that gets the drain hose away from the turbine housing. The original setup with the Garrett nipple and rubber hose with heat sleeve would only last maybe 2-4 weekends before the rubber got so hard and brittle that it made me nervous and I'd have to change it. The high temp silicone hoses I tried were way thicker than regular rubber hose and would almost touch the turbine before adding heat sleeve.

I bought basically all of the aftermarket NPT and AN flanges made for this turbo and couldn't get any of them to fit in the tight confines between the turbine housing and brake hard lines and wastegate actuator rod, so I finally just made my own.

Before:






After:

 

street only