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Hello, wanted to start a thread featuring the boosted NB I picked up last night. This is my first Miata so I'm trying to learn as much as I can. Hoping someone might recognize the car as well and be able to tell me more about it.
I don't know much about it, here's the little bit I know:
* CX Racing Turbo kit
* T3 .48 AR 8PSI TURBO CHARGER 2.5" V-BAND EXHAUST 0.60 AR COMPRESSOR
* Manual boost controller
* Megasquirtpnp Pro Gen 2 #MM9900
* Tuned by Ethan at Trackstar
* brand new aem wide band 0300-08061
* brand new NGK spark plugs
* brand new mobile 1 10w-30
* Avanti Storm S1 15x8 4x100 ET25 Wheels
* Custom 2.5” exhaust
* Race land Coilovers
* Extended knuckles
* Godspeed control arms
* Aluminum radiator
* Super miata coolant reroute
* flyin Miata FM Level 2 clutch
* Megan racing strut bar
It seems to run pretty good. Gets into boost fine doesn't break up or anything. It makes 8lb and I like it, for now. A couple concerns:
Noticed it spatters some oil out the muffler on a cold start. Nothing crazy but it's noticeable. Wondering if I should do a catch can before I start pricing internals?
The other thing I noticed is a sort of clunk sound in the rear end only when taking off from a start. I'm not familiar with the suspension/subframe setup on these cars yet but I'm guessing diff mount?
The tune. Afr seems rich everywhere but wot. I posted the tune in another thread, I will post it here as well if anyone wants to have a look. Someone mentioned concerns that it says it has 440cc injectors, I will replace them. What does everyone recommend?
Last edited by boosted_na_2025; Mar 9, 2025 at 09:27 PM.
I had a similar clunking noise not too long ago that turned out to be a failing driveshaft. If it sounds like this you're probably going to want to swap a new on in pretty soon.
I had a similar clunking noise not too long ago that turned out to be a failing driveshaft. If it sounds like this you're probably going to want to swap a new on in pretty soon.
https://youtu.be/AzjerJr3i0c?si=kRK8vjaBgJ2cgQc4
Are you sure it's oil coming out of the tail pipe and not just condensation?
It could be condensation but it's staining the concrete. My k24 civic blows a ton of condensation out on cold start but it doesn't stain the concrete. It could just be soot from the pipes I suppose.
The sound I'm hearing is very similar to the one in your video. I will put a driveshaft on the list. Is there a particular one you recommend?
You snuck the injector rec in before I replied. I will look at those. I've had pretty good luck with DW injectors myself.
I've had my car do a similar thing and it stained my concrete, but it doesn't do it consistently. I think the main time was after I built the engine and my trigger angle was off. No idea how much effect it has, but it might be worth checking the cranking ignition angle in the tune? Are the cold starts pretty quick or does it take a bit of cranking to fire up?
I got a junkyard shaft for about $100 when I needed one next day for a trip. That lasted a couple years before failing as you can see in the video. I'm on a dorman unit now and it seems fine. Someone else on here ( @SlowTeg maybe?) compared the dorman unit to the flying Miata unit and said they looked identical, so I wouldn't pay the premium for that one.
The car has stock motor mounts, on Honda's they're always one of the first things we upgrade. I like Innovative mounts, how much NVH do they add on these cars? Are they worth it in a rwd application?
First thing that jumps out to me regarding fuel is that you have very little resolution in boost. You could probably change it to jump from 60->80->100 and use the free'd up rows to get a bit better resolution in boost.
The other thing is that EGO is enabled (basically AFR correction) but the "Active above RPM" is set to 8000, so it's never going to do any corrections.
After saying that though, the AFR target table is pretty rich in most places, so if you do enable that, you're probably still going to run rich. The spacing here is pretty weird as well.
Keep in mind I'm not a professional by any means, but that's my $0.02. It's not the worst I've seen posted on here, but this seems a bit sloppy for a "professional" tune.
First thing that jumps out to me regarding fuel is that you have very little resolution in boost. You could probably change it to jump from 60->80->100 and use the free'd up rows to get a bit better resolution in boost.
The other thing is that EGO is enabled (basically AFR correction) but the "Active above RPM" is set to 8000, so it's never going to do any corrections.
After saying that though, the AFR target table is pretty rich in most places, so if you do enable that, you're probably still going to run rich. The spacing here is pretty weird as well.
Keep in mind I'm not a professional by any means, but that's my $0.02. It's not the worst I've seen posted on here, but this seems a bit sloppy for a "professional" tune.
Thank you for the feedback. I will start looking for someone to tune it locally. The car does seem to run pretty well, other than dying on me twice when I had the clutch in coming to a stop. Started right back up both times though. Idle is a little rough, kind of surges from 1k to 1.2k every few seconds.
Oh yeah, one other thing. Keep an eye on that little breather filter you have on your valve cover. I ran a setup like that for a bit and it was fine, but it will probably saturate with oil at some point and start dripping onto your manifold.
Oh yeah, one other thing. Keep an eye on that little breather filter you have on your valve cover. I ran a setup like that for a bit and it was fine, but it will probably saturate with oil at some point and start dripping onto your manifold.
Noted, thank you for all your suggestions. Would a catch can be a better option? I saw this one: CATCH CAN
I just ordered the Dorman drive shaft, pretty happy with the price to. $210 shipped seems like a deal. I did a little more research and when I reverse the car shudders and makes almost a clunking sound. Saw a guy on reddit with the exact same issues I'm having and the shaft was his issue as well.
Oh yeah, one other thing. Keep an eye on that little breather filter you have on your valve cover. I ran a setup like that for a bit and it was fine, but it will probably saturate with oil at some point and start dripping onto your manifold.
I just noticed you're from Idaho. We left the Boise area in 2021 and moved to OK. Small world lol.
I was really confused about that sound when it first started happening for me. Pretty sure it started after swapping suspension so I thought it was the springs binding up or something similar. I posted that video on here and someone called out the driveshaft pretty quickly.
If it makes you feel better I did a good amount of street miles (maybe 1000+ ?) and 2 days of autocross, 1 of those with a codriver, and the shaft held up fine. It probably won't explode on you tomorrow, but better to get it done sooner than later.
If you were near downtown you might've seen me around. I got my Miata in late 2020 and was living by the co-op.
My opinion is that $220 for a catch can is pretty insane. I've just got a hose going into a blender bottle with some kitchen scrubbers and that's working fine for me. Evil Energy seems to make decent enough stuff and theirs is $35 and I doubt you'd be able to tell a difference compared to the expensive one, but to each their own.
I should have said in the first post, my goal for this car is... Basically what it is. Just want to get it driving well, and running well. I'm not a young dude out street racing or autox'ing, I drive my cars on the street and occasionally like to do a 3rd gear pull. Otherwise I don't really beat on my cars. That being said, I don't want to add anymore power, although I would like to be able to run ethanol blends. So at this time my plan is to get the clunk/shudder in the rear sorted ( order the driveshaft last night), injectors, fuel pump, flex fuel, retune. Nothing crazy.
The way this car even came about... I bought a low mile 1999 for my daughter this past Friday, I drove it from Tulsa about 60ish miles home. When I got home I told my wife I want one of these, but with more power. Started looking on marketplace and saw this car. Messaged the dude and we met up. Came home with the car. Really digging it so far. I'm pretty meticulous and this car has some cosmetic issues but I swear I won't try to fix them... Just drive the car and enjoy it. It seems mechanically sound, AC/heat both work. Engine seems good and tight, trans is actually way better than I ever expected, well, shifting it anyway.
Flow Force 640's ordered along with a DW 200. Hopefully be able to get them installed this weekend along with the driveshaft.
I did confirm the current injectors are yellows, which might explain my poor idling.
Looking for ethanol sensor now. Once I get all his done I'll track down someone to tune her and just enjoy her, I'm sure there will be other thing's that pop up, there always is.
She looks a little different today. Got the Milwaukee sticker off, cleaned her up and got her some new tires. Noticing a clunking sound rear drivers wheel when taking off and stopping. What should I check first? Axle? When they changed the tires it looked like the upper control arm was brand new.
I got the back of the car up trying to track down the noises and issues. First thing I notice is a missing bolt on the subframe brace. I remember seeing one in the console so I grab it and try to get it in. Threads are stripped. This doesn't seem like it would be a source of the clunking when starting and stopping. I even saw a few guys mention they don't even have the brace on their car. I will fix it, I'm not taking it off. Just trying to track down rear end noises. I checked the drive shaft, I couldn't move it by hand, no play. But visually it looked like the U joints definitely had some play, probably under force. I'm starting to really hate this car lol. The car I traded for it was low miles and had zero issues.
Boosted NB, where to start...
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