WB gauges are not discreet regardless of where you mount them. Sell it. Profit. Buy/install a mini led meter with adjustable decimal point and hide it in your gauge pod.

A small step... here's what I came up with. A hole saw, a Dremel wheel and a file give you a wideband gauge mounted in a pocket. Add a bigger hole saw and that big fat bezel is sunk flush.
https://www.miataturbo.net/attachmen...ine=1430708693
I'm under the impression that I can't install the MTX-L's sensor in the stock bung, what with the one it's packaged with being an inch long and the manual going on about how the sensor is designed to go shallow into the exhaust stream to help with temperature control. There's another step for step one.

Hey, all. Some updates:

For ease of reversability come inspection time, I grabbed one of Singular Motorsports' ECU brackets. Of the pile of holes in it, no four accommodate the MS3X. Drill, drill, and it fits. Note that if you do this, you'll want a USB cable with a right angle connector so it doesn't butt up against the firewall and you still have room for those immense harness cables.
https://www.miataturbo.net/attachmen...ine=1435420561

Yeh, it's not going under there (which is fine):
https://www.miataturbo.net/attachmen...ine=1435420561

The top of the case touches the brake pedal bracket, but it's not a vicious fit:
https://www.miataturbo.net/attachmen...ine=1435420561

Tipped this shot to show the pillar's natural orientation... I went for the A-pillar after all. The gauge body shows a bit because I hadn't pressed it in completely at this point.
https://www.miataturbo.net/attachmen...ine=1435420561

So, with the yellow injectors in, the MTX-L reading right and the stock IAT (I'll install the GM one post-intercooler and pre-heatsoak when things are more permanent there), autotune has been working great, making fewer and fewer adjustments. Idle and start are dreadful, though.

If idle speed isn't 1700 RPM, it's cycling around 800-1200 while switching between open and closed loop idle. Open loop, it's about healthy at speed and AFR, but when closed loop kick in, it goes crazy lean and dumps down toward 500 RPM. Open and closed just go on and off like a yo-yo. I'm at a loss as to how to square this up.

I haven't looked into how to fix the start yet, as idle is more important to me. It bogs a little bit before it gets to speed, although a little punch to the gas wakes it up quicker. My 500 RPM column can't be anywhere near correct.

Update:

The intercooler and piping are in place, with the IAT sensor tapped into the cold side tank. I used the "expanded hole behind the headlight" method on the driver's side.

The exhaust manifold parts should arrive complete by tomorrow afternoon. I opted for full mild with weld-els. A question: If I do an EGR blockoff, will the stock ECU throw a code if the EGR valve is still in place and connected? My option is to pick up a (or equivalent?) and fix that to the manifold.

Further, I'm trying to sort a clean way to finish the exhaust. I know that more than one DIY has used the OE exhaust from the downpipe back. Nobody's going to recommend that, though. Am I best off picking up a downpipe/midpipe/cat assembly and DIYing the axleback? FM's out of stock, and I'm not certain what's worth buying beyond that.

The only bit beyond that which I'm stumbling around is the oil feed. Good advice is welcome.

Pics to follow...

Are you building your own manifold? If you can weld then you might as well build your own 3" exhaust. Cost is not to bad as long as you use aluminized steel instead of stainless. Check out my MKTurbo group buy thread for pictures on what the exhaust should look like and the part number for the big ass magnaflow muffler.

Barring a bit of heat shielding, a mild loose wire tuck and a pile of tuning, I reckon it's done. I had a buddy fab up an extended EGR ferrule, another craft up and weld the manifold and downpipe, a local shop build up a pair of oil lines, and with a couple other mechanically inclined friends, I was able to come up with this:

https://www.miataturbo.net/attachmen...ine=1440434421

I'll sling a few more shots of the works up here later; the anticipation of the cheers and jeers is killing me. ;)

No apologies for the blue!

Long time, everybody! The tuning went great, and I came up short of completing the boost map because my clutch started to give. I have a FM happy meal in the garage, ready to go in. Trick is, I have to sort out an overheating condition first.

So far:
The coolant and oil both look healthy. There are no signs of leaks.
The radiator I have now and the one before had the same results.
The fans I have now and the OE ones before them both blow in the right direction.
The OE thermostat I just installed and the OE thermostat that was in already had the same results. Both open properly.
Update: Stant and Duralast (Autozone) thermostats have not changed things.
I've got measurable airflow from the grille through to the back of the radiator, and no front license plate.
I've used the magic funnel for best burp results.
I've done the chemical combustion leak test, and the fluid stayed blue.
My water pump was replaced with an OE unit when I did the timing belt about 3 years and 12k miles ago.
The stock undertray is installed.

I had a buddy come by who's a mechanic by trade, and he suggested that I ask you this: If you squeeze the upper radiator hose down pretty tight, will giving the throttle a hit give your hand a good bump with pressure? Same without squeezing the hose, will it make the coolant in superfunnel drop and pop back up? These are things he expects from experience, and they're not things that are happening right now!

shrouding/ducting in order?

Admittedly, no shrouding or ducting, but at idle with the hood open, a fan blowing into the bumper opening and the radiator fans running, the temp should be dropping - or at least stabilizing - and it's not.

Thoughts on my coolant questions?

How do you use the magic funnel to burp the car? You need to lift the front of the car as high as you can and then put the funnel on. My method is that I let the car come up to temperature at idle with the nose in the air. I set the first fan to turn on at 207, and the second fan at 215.. Shut off at 200, or 195 if you want. I let the fans turn on and then turn off 3 times while keeping water in the funnel. Watch temps in tuner studio. After that I put the cap on and let the fans cycle one more time to make sure it is all working.

Also what fans do you have now? Are the expensive SPAL's? Or knockoffs?

I've got the front end lifted, and I've been using the Haynes recommended method (reach temp, hold at 2500 for five minutes, bump to 3000 for five seconds, drop to idle, repeat four times). It worked when the car was N/A.

The fans I have now are knockoffs, but the stock fans didn't seem to fare any better.

If the car overheats with the hood open you've got a problem. Chances are your fans not up to par.

Yes, there's definitely a problem. I know there's no blockage to the radiator, the stock undertray is in place, I know the stock fans couldn't keep up, and I know that even simply cruising around town or on the highway didn't seem to make a difference. I don't think air is a problem.

I do want to know what you think of this, though:

if you think your water pump is broken or clogged just replace it. really easy and really cheap. I've never heard of that "test" but I guess it might work to test that the pump is cycling the water. have you done compression/leakdown test? haven't heard of many Miata's losing a water pump only

PS: stock fans with stock shrouds can and do keep up. all but the very best aftermarket units are utter crap, and I would always stick to oem

Go back to OEM fans. Unless you have the $200 SPAL fans, nothing aftermarket are as good.

When idling you should be able to cycle the fans on and off with temps not hitting much above when your fans turn on.

I'll be pressure testing the cylinders on Friday. I know that the water pump should be fine, but if I can diagnose my problem solidly before spending more money, that would be preferential. OE fans are an interference fit with my coldside piping and FM antiroll bar.

I'll see how the pressure test goes. If the head gasket is good, I have to lean toward the water pump. I didn't break 9psi, which I didn't hit many times due to the clutch, but the hg has to be suspect. I'd really appreciate it if one of you (or more, why not) would put a glove on and check the hose pressure out for kicks.

The least costly option to solve the issue on line two, without disobeying line one, is to clearance the space you need and re-install OE shrouds and fans. I have even had non-shrouded SPAL fan(s) not pull as much heat as an OE set-up. Miata's haven't proven to be any different. And SPALs aren't present here, so you aren't even close.

As far as the pressure difference when you feel in the hose? Yes, it will go up when you increase RPM, because its a pump, and you are increasing its RPM.

I always look at the simple things first. I wouldn't pressure test anything yet.

The thing with that is, it was overheating the same with the stock fans and with the stock radiator. The fans should be wholly inconsequential at highway speeds, and it overheats there, too, just like with the stockers, all of this without boost. I'll give you the likelihood that the fans probably don't pull like the OE shrouded ones, but there's no room for them. (FWIW, when I said that the OE fans don't keep up, I didn't mean "they don't hold their own" - I meant they don't keep up with the problem in the cooling system.) The passenger side one would require so much trimming that it would lose a brace. If I'd be better off with the stock radiator and fans, then MT.net wisdom might be worth the time. Meanwhile, my problem definitely lies elsewhere.

If revving the engine should spike the pressure in the hose or bump the level of the fluid in superfunnel, then my water pump may well be hosed, its youth be damned. That would be preferential to the only alternative I can imagine at this point. I know they don't (and shouldn't) fail often, but it's not showing much for signs of life.

Here's my plan: I'll try the Lars burp technique, and if that doesn't clean things up, I'm going to pressure test the cylinders. I can't blame any of the parts that I've changed nor their predecessors. That leaves me with air in the system, head gasket or water pump, unless anyone's got an idea that I've missed.

Vital information that wasn't posted before (or I overlooked it, lol).

But yes, I don't expect any fan system working with a "hurt" cooling system to keep the temps at bay, it would be over-engineered at that point.

Only other thing I could think of is maybe a faulty thermostat that isn't opening fully at operating temp, which also would restrict flow in the coolant system. Maybe throw another thermo at it first since its quite a bit easier to get to.

Yeh, I think you missed it. That'll happen. :D

I put an OE thermostat in just a few days ago, replacing the OE one that was there already. I was hoping the same thing. No bueno.