1.8 with FM hot side and .86 GT2860R
 

Terrible, 61.7 lbs per liter per atmo.

Forged 1.8 bottom end with 150k miles stock vvt head
Square top with stock tb
FM hot side with 3" downpipe
VVT coils and plugs at .025"
DW200 and gt500 injectors
v8r 62a mounts
6 speed/3.9
fm2 clutch and stock flywheel
800/500 revalved billies
15x9/225 rs4s
Rev ms3
Precision 350hp ic
93 octane pump
(bad) street tuning

https://cimg6.ibsrv.net/gimg/www.mia...f4fa580ddc.jpg
https://cimg8.ibsrv.net/gimg/www.mia...0fc5b0ab31.jpg

your fueling looks pretty good, I probably wouldn't lean it out any more

Moar boost.

David has the map sensor you need sitting on a shelf. Offer him $5 for it.

The problem is that I don't know how to supply the sensor with the required 5v power. The Rev ms does not have a 5v output.

can't you just grab power from the OEM baro sensor?

OEM baro sensor is +12v IIRC. I think that is where I am pulling power for my EBC valve.

62mph seems slow for 300whp

How much boost are you running?

Dotted line in the bottom section of the chart.

:) ddooohhhh.... I didn't see that. Thanks for pointing it out!

Wow! Similar setup to mine:
https://www.miataturbo.net/build-thr...o-93282/page3/

I'm actively working on my tune as well but power seems to be similar at this point. We both have a 6 speed/3.9 setup too and I see you're doing your pulls in 5th. I may give that a try to see how spool compares.

This is what soldering irons are for. :)

--Ian

I actually confirmed the oem EGR baro sensor has +5v, so this is in the works. I don't foresee getting much more out of the setup above 24-ish psi, but I've been wrong before.

You actually may have an edge on me for spool if you use 5th. I saw ~700 rpm difference using 3rd vs 5th.

The TPS also has +5v wire you can use also.

Is that +5 supplied by the MS3? If not, you don't want to use it for an analog sensor power.

--Ian

;)

The Rev MS3 does not have +5 on the db37. It is possible it has it in the OEM harness (although I don't think so). When I faced this issue installing my MAP sensor, I opened up the MS3, picked an unused pin on the db37, and soldered a wire between the +5 supply inside the box and that pin.

Having the +5 that is supplied by the regulator in the MS3 is important, because analog sensors like this return a signal that is proportional to their supply voltage. If that supply voltage is 5% different between the A-D converter in the microcontroller and the sensor (which would not be terribly unusual), then your reading will be off by 5%.

--Ian

"ratiometric"

I see your concern, but I do believe that the ecu supplies +5v sensor power. This should be the case with both stock ecu and ms. If the stock baro sensor receives +5v from the ecu, then it is getting it from the ms, and thus will be correct for my external MAP measurements.

My MSLabs MS3 does not connect any of the wires to the stock EGR/MAP/baro sensors.

Have you checked for +5 with a voltmeter, or just a wiring diagram?

--Ian

Hold up. Where do you think the TPS gets +5v from? The ecu.

How are multiple sensors normally fed power? Splices in the harness.

The factory baro sensor likely gets +5v from the same lead that the ecu supplies power to the TPS from. I have measured +5v at the oem baro sensor plug with a meter, that's what I did when I said I had confirmed there was +5v at the oem baro sensor.

TPS has source impedance which allows the ECU to calculate resistance using voltage. This is the same for the other resistance based sensors.

It wasn't clear to me what "confirmed" meant, which is why I asked.

I'm reasonably sure there's no generic "+5v output" line coming out of my MS3. I built a wiring extension harness for it, and to do that I opened up the case, identified every pin that was actually connected, looked up where it went in the factory wiring diagram, and put it all in a spreadsheet. I only have access to the spreadsheet right now (diagram is at home), but nothing in there looks like it could be a generic +5 output unless it's one of the "instrument cluster" wires (there's more than one and I didn't bother to trace out which did what). I'll go look it up when I get home.

It's also possible that the factory ECU doesn't need that much precision on the few +5 sensors it has. I would expect that if the TPS is off by 5% then it doesn't matter, and the stock MAP sensor is only used for EGR control which is closed loop so can probably tolerate errors. That's not true of the 3 bar GM MAP sensor you're using for primary fuel control.

--Ian

Pretty good mph at the drag strip! That's pretty hot for a BP miata. I bet it's a blast to drive!

https://trubokitty.com/#/ms3xassembly

ECU pin 2I on your 99. That 5v reference is definitely used for the TPS. 5 volts goes into it then voltage drops depending on throttle position due to a change in resistance with a voltage dividing network if I'm not mistaken.

OK, I had that marked as 12v in my spreadsheet -- not sure why.

Are you mounting the GM sensor in the engine bay or under the dash next to the ECU?

--Ian

Ok, so depressing post here. What I was told was a 2860r is actually a 2871. Now I have bad feels about my power and trap speed. Why so low?

Shitty chinese turbine housing needs porting. I can't get less than 22.7 psi above 6k rpm. Spool is a LOT better with .64.

So yeah, 2871R with .64 housing and something holding it back 40 hp.

https://cimg5.ibsrv.net/gimg/www.mia...76e8a844fd.jpg

Looks good. I would keep the wastegate as-is, the extra boost up top is flattening out the torque curve! That's what you want, or, at least what I want. Flat, broad torque curve.

I went from 0.63 to .82 A/R turbine, yeah, I'm going to swap back to the 0.63 A/R. I think I gained 5-10 HP, and lost a ton of spoolage which ultimately made it slower. Cool to see how much it helped your setup!

That's what I want too.