Miata Turbo Forum - Boost cars, acquire cats.

Torsen 2

LeoNA — Tue, 02 Jun 2026 18:02:23 GMT

Torsen 2 $325+ship. Located in CA.

Gauge Setup

Paisa — Tue, 02 Jun 2026 01:25:37 GMT

Currently have an MTXL Plus, and a Glowshift Boost gauge. I'll be adding a water temp, oil temp, oil pressure, and e85 content gauge. I am running a DDMWorks 3 gauge radio panel which places three gauges where the small cubby used to be.

I am looking at an A pillar setup, but was wondering if anyone has a different three pod setup? Has anyone ran a three pod setup on top of the tombstone? I am not looking to repurpose the AC vents either.

Attached Thumbnails

Turbo 'death' diagnosis

tfbmiata — Mon, 01 Jun 2026 17:34:11 GMT

I have an EFR 6258. Starting a year after I had it, and several months after I had a massive oil overheat issue where I left the car in gear while on a tow dolley, then drug the engine to it's death, I started getting HEAVY amounts of white smoke after start up. If I just let the car idle, the heavy smoke never seemed to go away. If I immediate drove the car from cold the smoke was still there, but was 1% of what it was during idle. After driving the car to 'warm' it would still smoke, but again, just barely. The worst part about it, was just the smell. Acrid burn smell that originally thought was because I didn't have a cat, but one cat later and it was still there. This led me down the path of thinking there was something wrong with the turbo, as the gentleman I bought my current engine off of said on the previous car it never smoked even a little. I believed him because even after the installed and dyno tuning, it took another several months before the smoke started.

Anyhow, I bought a used 6258 (thanks Greg Peters) off of FB marketplace, and just started to pull the old one. I should mention, the performance of the system never seemed effected at all. I just did a full track day and other than the officials seeming to think my engine was about to explode, no issues, no over heating, no 'loss' of oil (via dipsitck). When I pull the turbo out, I noticed the downpipe was covered in a white residue and you'll see in the pictures below so was the hot side impeller. I've inspected teh turbo as best I could and compared it to the one I bought and there are two things of note. The first, is the collar below the impeller. On the smoking one, it was initially gritty and hard(ish) to twist, but after twisting it for a while, what is behind that collar seemed to work itself out and while not as smooth as the one from GP, it is fairly close to normal. The second was when I removed the oil feed AN adapter from the smokey one, I got a nice wiff of the same nasty burning smell that comes from the car. It almost smells like burnt hair or popcorn.

Other things that may be of interest:

Up until this last track day, it had always had a turbo blanket on the hot side. I was tired of replacing them since they always seem to fall apart and now I just have a heat shield around it.
The oil temp when I pulled my first motor to its death was 300+ as my gauges top out at 300 and when the incident happened, I turned the key forward to see what the gauges were. Again, this happened with this turbo, but it was MONTHS after getting everything back working with a new motor that the smoking started.
No performance lost whatsoever
Shalft/impeller spins freely, no wiggle I can tell.

I'd love some advice / ideas from anyone here to see if they think this is/was at all my problem (i'm still waiting on an adapter before I can install the new to me one). And if so, can this turbo be refurbished, hopefully cheaply so I can either resell it or keep it as a spare.

Hot Track Days are so in right now - Cool Shirt vs. Ultra Chiller

tfbmiata — Sun, 31 May 2026 19:23:10 GMT

Anyone had experience with the ultra chiller? Seems a tighter package, but their website leaves a lot of explanation to be desired. I'm coming back from a 15 minute session soaked through, so it's finally time to drop $$ on this as an upgrade.

Cruise Control Setup w/ K24 and Haltech 1500

redursidae — Sat, 30 May 2026 23:43:09 GMT

Hi all. Recently I worked on configuring cruise control on a 1990 Miata with a K24A2 swap, KPower premium harness, and DBW throttle. We wanted to re-use as much of the OEM components as possible to make it look stealthy (use the stalk and OEM speed signal). We finished tuning it today and I wanted to share what I did in case someone else wants to try this.

https://docs.google.com/document/d/1...it?usp=sharing

Happy to answer questions or add any info I may have forgotten. Your cruising may vary, and cruise at your own risk.

Cheers,
Ricardo

Does anyone have internal schematics of the footwell 30A Heater Circuit Breaker?

funkyguns — Sat, 30 May 2026 21:57:45 GMT

So i did a thing. I was reading that all my blower motor needs is a new 30A fuse, located in the driver footwell, so i looked. It did not show any kind of fuse but this Hoseiden box, i opened it to check for a fuse and there were loose parts inside. Does anyone have any advice for replacing these parts back correctly?

MASSIVE Parts Clean Out - 6speed, 3.9, Eagle Rods, Etc.

stj553 — Sat, 30 May 2026 21:47:13 GMT

Cleaning out my stash of Miata parts. Recently had my second child and sold my Miata track car.

Located in Atlanta, GA. Willing to ship smaller parts, would prefer not to ship the larger items at this time. Feel free to make offers, don�t be mad if I decline though.

Engine

Eagle Rods BNIB - $SOLD

Wossner 12:1 83mm Pistons BNIB - $500

Boundary VVT oil pump gears BNIB - $200

VVT OEM header - $50

Volvo valve springs BNIB - $SOLD

Turbo

Garrett GT2860rs BNIB - $700

Vibrant #12800 Intercooler w/ mounting brackets (Same core as Fab9 350hp intercooler) - $220

Driveline

6 speed transmission - $900

3.9 differential - $800

Supermiata 1.6 lightweight flywheel BNIB - $250

South Bend stage 1 heavy duty clutch - $250

Powerflex black series diff bushings - $60

Treasure Coast serviceable driveshaft BNIB - $225

Aero

R Theory V3 Rear diffuser BN - $300

Singular hood vents BNIB - $SOLD

Singualr fender vents BNIB - $SOLD

Garage Vary ducktail lip spoiler BNIB - $200

RGR Front Spats BNIB - $35

NLR front canards BNIB - $SOLD

Brakes

Technafit Braided Lines full set BNIB - $SOLD

Hawk DTC-30 rear pads for NB2 sport brakes BNIB - $SOLD

GLoc R8 rear pads for NB2 sport brakes BNIB - $120

Suspension

V8R sway bar mounts BN - $50

Misc

Passenger seat mount for Element fire extinguisher BN - $40

Wideband Woes

f3d0ra — Fri, 29 May 2026 14:12:29 GMT

Hello friends, longtime listener first time caller. I've recently supercharged my Miata, and am experiencing AFR oscillations in tunerstudios. I am using an AEM 30-0300 controller with a Bosch sensor; along with an MSPNP-Pro. I have searched the forums, and this is what I've tried to remedy the situation:

checked wideband calibration in TS
rewired the sensor output directly to the optional connector on my ecu, using sensor ground and analog in 2.
given controller its own dedicated power and ground, both good and clean connections.
confirmed I am using the analog out wire on the sensor controller, and not the other data out wire.

I understand that the ECU almost certainly refreshes faster and has less smoothing than the gauge, but I see much more drastic swings in TS than I do on the gauge, and it "feels" like there's more at hand here. Hoping someone could shed some light on what I'm experiencing, and what my next steps might be. Attached is two logs, one showing oscillations and one from before, not oscillating. This issue was not present prior to supercharging the car, but I didn't touch anything sensor side when supercharging, so nothing has actually changed.

Thank you for your time.

Attached Files

new oscillating.mlg (6.07 MB)

Old no oscillation.mlg (4.37 MB)

MKTurbo manifold options

Robh22 — Fri, 29 May 2026 13:34:27 GMT

Hey!

While doing some hard driving in the mountains this weekend, my MKTurbo manifold cracked� causing my downpipe to crack.

I have cracks running on the top and bottom sides of the turbo flange and a crack on the 1st runner.

I�ve already sent an email to Lars, but was wondering if anyone had any other ideas.

Will another manifold fit or get close to fitting? I�ll already have to get the downpipe welded up.

I would like to eventually track the car a couple times a year, but wouldn�t this just happen again?

I do have the softest Innovative poly motor mounts which might have contributed.

Just trying to weigh my options (hopefully the most economical). Between finding a different manifold, buying a replacement MK, or getting it welded up.

TIA

I have been Summoned

trvcknutz — Fri, 29 May 2026 02:31:02 GMT

How is everyone doing! My name is Dween I drive nb2 and i have come across a kraken manifold recently. long story short I have been daily driving with a hand full of drift track days ( Midpond, Driven Luck Circuit, Lanier Raceplex, Mexico streets) and its time to turbo :p

Engine is good, my driving skills are naoki level, waiting for my square top gasket to come in so intake and injectors will be upgraded slightly, kraken t25 manifold with downpipe+ ISR catback circuit exhaust with muffler. I am in no rush for this build as these are just things that faith has brought me i do have access to a 3d printer incase i need mockups or special tools

My Goal is to maintain daily status and be able to drive to the track, thrash on my car on the track and back home which will hopefully consist of the following // T28 disco potato, kompact turbosmart BOV, FM silicone inter cooler piping, vibrant performance or FM intercooler, 6speed m/t ,, koyorad or eBay 2/3 row radiator, and i guess keep my A/C and P/S systems all whist pushing .5-.8 Bar

Here is what I do know. I am special, working as euro line tech so I can probably figure out stupid diagnosis situations and help out others with at least an opinion or my pov, I am still missing lots of bits and pieces, megasquirt pnp is hated on still i think?? my car is ugly yes i know

A couple things I don't know but i really am interested in would be CAD, self-Tuning, being social lol

just a real to make interweb friends that i can drive with in the near future!! Ichiban! if you made it this far thank you for your time have an amazing day or night!

Ill upload some horrendous pics of my car. track inchident

Midpond is amazing cant wait for track expansion

Why spend $$ on a new front end when i can use that same money to turbo my car!!

cant wait to make this thing rowdy!!

Knock Detective (FWLR Tuning)

SimBa — Thu, 28 May 2026 21:02:19 GMT

SOLD SOLD SOLD
~~$120 Shipped CONUS~~

Pretty cool gauge, but I haven't been using it since I moved over to the G4x and started using it's knock processing. This gauge has LEDs to show knock level, a 3.5mm jack to listen to the knock audio (IE electronic detcans) and an output signal that can be fed into your ECU. I used this with my Speeduino so I could view the knock signal in datalogs.

Includes the following

Gauge

Bosch Donut style knock sensor.

I made a little harness for it with some Dupont connectors. The knock sensor doesn't have any pins on it, but if you want I can throw some on before I ship it out, just make sure to remind me.

Also worth noting that the knock sensor will not fit in the stock location without a custom stud or drilling out the sensor. I drilled out the sensor and haven't had any issues. There were some custom studs (m10->m8 I believe) that were being sold on here as well.

Requesting Assistance Diagnosing CLT Sensor Issue

cmcc — Thu, 28 May 2026 15:05:53 GMT

Hi all,

I just finished bolting back together my new engine setup for this season (which I will make a build thread for eventually, feel like the PO did a great job with that so I feel I should take the helm), and my CLT sensor has stopped reading. Car is a 10AE with VVT swap, PO's build thread is here in case anyone is curious or familiar: Hairdresser HP - An NB 105kpa max HPDE Build - Miata Turbo Forum - Boost cars, acquire cats. Here is kind of a rough sequence of events:

Assembled and dropped in engine, got everything wired up and ironed out, engine (w/ new 264/264 cams, sounds badass!!) fired up and ran successfully with reasonably good CLT feedback (as compared to my temp gauge in the cabin).
Perhaps unnecessarily removed ECU from car to solder in wire to flex pin (#26 on the MS3 Basic. This isn't working yet either and I wonder if I have a bum sensor; will report back after trying second sensor).
Reinstalled ECU and now the CLT sensor is reading 180F at all times, which I believe is an indication of failure. Car will still start and run just fine when given some gas.
1. Have had issues in the past where a few of the parameters go haywire, and I noticed that depressing the harness connector or the female USB port towards the ECU a bit seemed to correct the issue until I guess the car shook it out of position again (for what it's worth, this never affected how the car ran or drove). This has been ongoing since I've purchased the car, was never super bothered by having to jiggle the connector once every few months.
2. A note: the harness connectors are aftermarket, PO had the harness extended so the ECU can live where the passenger airbag used to. It's a nice touch for sure, but the connectors are VERY tight and require some force to get out.
3. If I change the Bias Relay value in TS to something small, like ~400 ohms or less, I can get the CLT to jump around a bunch. Not sure if this means anything but maybe it's useful data to someone who is more electronically savvy than I am.

Based on 3.1 and 3.2 above, I feel as though there was a loose connection somewhere in the ECU (long L-shaped pins that are soldered to the board from the female connector port?) that I may have finally killed reconnecting the harness. So, I pulled the board out of the ECU housing and found that some of the teardrop-shaped solder points at the bottom of the board (below connector 2) looked like they were almost scraped off or something. I'm not sure how that happened, but I'm also not sure if this would really affect anything electrically either (looks like the connection to the board is still made). Picture below, do we think that I should maybe attempt to resolder the points that have this damage?

My other thought was maybe to try to find the bias resistor on the board and see if it's functioning okay. Based on past symptoms and things I've changed recently, I'm doubtful it has anything to do with anything beyond the connector, but it may be worth checking. The ECU is like 12 years old now w/ lots of track time vibration/abuse.

Even though nothing has changed with it since it became inoperable, I checked out the CLT sensor harness with a multimeter and got some results that I'm not sure how to interpret. Here is a reference picture of the connector:

So both of the "top" pins are reading just under 5V when grounded to the valve cover, which I feel is maybe not right because I believe one is supposed to be a ground? The "bottom" pin reads something like 9V -- I'm not sure if that's weird or not, but I do know that pin is for the dash so I kind of care less about it at the moment. I know that one of them is supposed to have 5V, the other two results I'm not sure how to interpret. I will determine which of the top pins is the ECU signal and verify continuity to connector 2E later today (as the aftermarket harness is definitely a variable here) as well as perform a good visual inspection of the wiring.

Has anyone had issues like this, or have any feedback on the information above?

Thanks very much,

CJ

Saying Hello :)

Simik — Wed, 27 May 2026 11:28:59 GMT

Hello,

Im deciding to go turbo on my 1997 1.6 NA Miata. I am from Europe so that was a factory option and Im getting ready to finally make some power. :)
Currently looking at some Bofi-Racing kits and/or the Kraken Turbo Kits, if you know of any other reputable ones from Europe, please lmk :)

Yet another annoying misfire (?)

DuneBugDrew — Wed, 27 May 2026 04:37:40 GMT

Having a dumb issue I can't figure out.
My nb1/bp4w was running great, then developed a very inconsistent problem. Occasionally, under high boost, it will cut out for a split second. Sometimes for longer, almost like the key is rapidly being cycled on/off. I discovered that the RPM signal drops to, or near zero at these times. Attached is a very short log of it happening once.

I also have a composite log of it happening a separate time I will link to here: https://drive.google.com/drive/folders/1Qfua2N5VJoNFqzfRq9e7woXCTh69SOp3?usp=drive_link
I found a couple of brief instances where the cam pulses seemed to happen too far apart, while getting too many crank pulses-triggering the red sync error in MegaLogViewer. I'm new to reading that type of log.

Cam/crank sensors are both pretty new - Mitsubishi/Beck/Arnley, respectively. Tried a different cam sensor with the same result, and zip tied the connector to make sure it's not coming loose. Might try a different crank sensor, too, but don't want to go full parts cannon. I have extensively messed with trigger wheel gap. Brand new main relay, replaced because of a separate issue I had.

Really confused at just how sporadic and random it seems to be.
Seems to almost always happen in 4th, 5th, or 6th gear which makes no sense to me.

Running LS coils from FlowForce, they've been great other than having to replace plug wires recently.

Attached Files

2026-05-17_10.08.30.mlg (426.2 KB)

6 speed transmission not shifting

rb92673 — Tue, 26 May 2026 14:51:00 GMT

I posted this in my build thread, but I thought I might get more information here. This is for a track only Ecotec swap NA. No forced induction.

A few weeks ago we swapped a used six speed transmission in to replace the five speed that grinds into fifth. We put Ford Motorcraft transmission juice in with half a bottle of lightweight shock proof. Ecotec flywheel, Supermiata clutch and pressure plate.

On test day it was determined that the six speed was not shifting at speed. At a stop it would shift fine into any gear, but at speed it would not go into gear unless you rev matched perfectly. It felt like something was blocking the shifter from going into gear. It wasn't grinding, just not going in. I read something about some bolt that should not be removed on the six speed, and we may have accidentally removed it during install thinking it was a fill hole, or tightened it too much because it was loose. We bled the clutch and tried again, no improvement.

We pulled the trans and the took the pressure plate off and the clutch disk had some strange wear marks. The pilot bearing also fell out when the disk was pulled, and the seal was off on one side, so we replaced with a spare we had in another pressure plate. Could the pilot bearing have been out of the flywheel? The damage looks circular. Flywheel and pressure plate looked fine.

We made the call to toss the five speed back in and the team had it done pretty quickly. Slapped it back together and the transmission worked all weekend. We really only needed fifth at the end of the main straight, but most of the time we just let off when we got to the end of straight in fourth.

The team appreciates any feedback or ideas you may have.