Stock ECU fuel management
 

I will be installing a stock MSM turbo to my '04 Miata LS. This will be a entry level turbo upgrade. I want to run ~ 7-8 psi boost and maintain my stock ECU. What will be my fuel/ignition concerns and the most cost effective way to address them? Thanks.

Your fuel / ignition concerns will be that the stock ECU is woefully incapable of compensating for boost.

While you can absolutely pile on several bandaids to prevent it from blowing up, by the time you've actually managed to build a halfway drivable car that doesn't buck when you transition into boost or blow smoke every time you shift you could have just bought yourself a standalone ECU for the same price (or less...).

Phil, where do you live, and what are the emission-testing requirements, if any?

The most cost-effective solution depends largely on your answer to the above, as well as to how comfortable you are with electronics, software, engine-tuning, etc.

At the low end of the scale, you could install a rising-rate fuel pressure regulator (such as the complete BEGI fuel system, with FPR and pump) and just throw on an adjustable crank trigger wheel so you can dial in a few degrees of static retard.

Moving up in the world, there are a number of piggyback solutions which, to some degree or another, work.

Then at the upper end of the scale you have "standalone" ECUs, which completely replace the stock ECU and can properly drive larger injectors, integrate feedback from a wideband exhaust gas sensor, etc. Megasquirt, Hydra, etc., fall in this this category.

I didn't think a rrfpr would work on a '04 miata fuel system (no return line).

How about the FM Voodoo box w/ crank trigger wheel?

Independent of ecu choice you will need larger injectors, map sensor and WB .
If you want to keep the stock ecu then emanage blue with an autotune/clamp is an elegant and cost effective solution. My second hand blue and diy clamp cost less than 100$ and works well up to 460 cc injectors.

I'm not so sure that would be a good idea on a '04.

I've got a complete chassis and engine harness plus ECU from a 04 MSM sitting in my garage. If you want to figure out the wiring and find all the sensors, I'd sell it to you cheap. That'll get you an OBDII compliant ECU, if that's your thing.

Thanks, but a little more than what I want to take on.

I would suggest a ms2 from Reverant. Trust me, its worth it, and only a couple hundred more than the stupid band aids would cost you

You actually got a lot of good answers from these guys. I'm surprised you didn't get instaban.

MSM turbo fuel management
 

I see in your signature your using the Reverant MS2 on your 04 MSM Miata. Did you have much experience with tuning or are you taking it to a dyno?

p.s. I see you went with the Turbosmart BPV...the 38 mm is about 1 1/2". How much boost are you running?

You've done your homework.

It does work, you just have to place the aux pump up front under the hood, and create a recirculating loop, in which the RRFPR's dump line feeds back into the aux pump inlet.



Ah, yeah. I forgot about you late-model guys with your wiggly camshafts.

Straight up. Reverant pretty much hooks it the F up. He builds you the MS to spec, installs the base map which is like 90% good from the get go, emails you the firmware required, and gives exceptional instructions on how to get everything running. AND offers great tech support.

EDIT: Given that. I have learned a lot over the past 6 months with the unit and how to tune with not a lot of prior knowledge.

And I went with the larger BPV because I'm running a much larger turbo and the forge wasn't cutting it. Plus I'm running 15-16psi. And the motor is coming out thursday for new rods and I'm going to be bumping it up to 20-23ish psi afterwards.

'04 Miata to MSM turbo conversion
 

Since I am adding the MSM Miata turbo to my N/A '04 Miata, I have only (1) IAT sensor available to insert into the intake piping (I think the stock MSM turbo setup has (2) IAT sensors). Should the (1) IAT sensor in my setup go right after the MAF on the coldside (before turbo) or in the TB inlet pipe (charge pipe)? Shouldn't the MAF always be before the turbo on the coldside inlet pipe?

It depends on what you run for engine management. With an MS you don't need the maf at all anymore, and best place for the ait is between the ic and tb

I would go with an MS if I were you and a reverant built one sounds like your best option. That is what I run in my MSM and I had no experience with soldering, wiring, or tuning before I bought my MS2 from rev. He sets them up so well that if you can't install it in a weekend then you shouldn't be working on cars.

My car runs well and I picked up a shit ton of midrange over the stock MSM ecu.

04 N/A Miata conversion to MSM turbo
 

I can eliminate the MAF completely by going with a Reverant MS2 setup? Use the TBS for mapping?

Yes.
Not the tps, but the map and ait sensors.

Its a little more than I want to take on either. I had a complete engine/turbo/intercooler from an 04 MSM lined up so I could do a legal turbo swap in my 00, but the dude sold it out from under me. Unless another one falls in my lap, I'll be sitting on this stuff for a while.

I've got a DIYPNP in my 00 and I wish I'd held out for one of Reverants enhanced MS2 units. He builds a great product and consistently gets positive comments. They are more expensive, but the extra features are pretty bauce.

With a MS, you can pretty much delete all emissions related equipment as well. Can clean up the engine bay really nicely.

My stock 04 doesn't have a MAP sensor; and only (1) IAT sensor.

No stock Miata had a MAP sensor. (Well, the MSMs might have- I'm not sure. But it's irrelevant.) The Megasquirt comes with a MAP sensor, and for most applications, this is used as the primary load input. No need for MAF.

you only need (1) ait sensor, and the MS comes with its own (1) map sensor


seriously, stop posting, start reading. This is like 2+2

Answers my questions. Thanks guys.

Oh, Vlad, you really don't need a turbo, you need to get blown.

Oh, this should be funny :drama:

that's what the turbo is for...

Sure thing. I'll be right over. You must give amazing head, seeing that you don't have enough brain power to do anything else, like research what a Megasquirt is and does, and what your car needs to effectively run a mediocre small turbo setup properly

Not a miata, but a few Eunos Roadsters had them, they were fitted directly to the ECU, I ASSume for barometric correction?!

Also my MK2.5 MX-5 has a 'boost' sensor, again I ASSume this is a map sensor for barometric correction - albeit in the engine bay this time.

Although I am confused as to why a MAF equipped car woul need such a correction.

I digress however, this is not really relevant to the OP. OP you should buy a Reverant MS, you can't beat it for the price.

the boost sensor is for the EGR if I recall correctly.

^ That.

All of the NBs had what you could call a MAP sensor, however it was used solely to validate the operation of the EGR system, and throw a CEL if it determines that the operation of the EGR valve (while in a diagnostic cycle) is not producing the expected fluctuations in pressure at the test point.

This sensor is NOT used in the primary fueling calculation, it is simply there to help you fail an emissions test.

The '90-'93 cars did have a barometric pressure sensor (inside the ECU case) which was used as a correction on the volumetric airflow sensor.

Getting back on point, although it is capable of operating in MAF or alpha-N mode, most Megasquirts use MAP as the primary load input. Thus, all* Megasquirts include a MAP sensor on-board.

* = There are certain "specialty" Megasquirt products such as the MS3Pro and the MicroSquirt which do not have the MAP sensor on-board, but rather require that you install an external MAP sensor. This is purely a packaging consideration- they function the same as the regular Megasquirts with regard to the load computation.

The "EGR boost sensor" on my 2002 is clearly a baro sensor, since the MAP is hanging in free air and not connected to the intake or anything.

I was about to reply asking if my 'boost sensor' should therefore be plugged into the intake plenum, I guess not :)

Makes sense now that you clarified it Joe that some of the the early 1.6's had a barometric MAP sensor, they're not MAF equipped, only AFM equipped!

I guess that means an EGR pipe delete to the turbo manifold would produce a CEL.

of course it would.

??

That sensor is supposed to have a hose on it which connects to a port on the intake manifold.

This is how the ECU checks for the operation of the EGR system. It waits until the vehicle is warmed up and in decel, then it pulses the EGR valve itself open/closed and looks for a corresponding change in the reading of the sensor. This change was implemented (in north America, anyway) in 1999, when the EGR syste changed from a vacuum-operated valve to a six-wire stepper motor.

Or were you merely pointing out that you have re-purposed the sensor in your car after having removed the stock ECU?

IIRC there are two.

IIRC, there is one, with a two-way solenoid between it and the manifold. The solenoid exposes the sensor to atmo as a reference, and then switches it to the manifold for the functional test.

There is absolutely no EGR map sensor on my car that is connected to the intake manifold. Same goes for every 01-05 1.6/1.8 Miata here in Greece. Maybe its a EUDM thing.

The "HITACHI BOOST SENSOR" that is above the passenger side wheel is reading free air. Its clearly a baro sensor.

yeah, I think I was confusing the EGR Boost Sensor Solenoid, for a second sensor.

anyways, it references the exhaust flow back into the intake.

https://www.miataturbo.net/attachmen...1&d=1355329431

The one solenoid on my car is (was) there for the fuel tank vapors. It is connected to the canister on one side and to the intake on the other. The canister itself is also connected to the fuel tank and the atmosphere valve and filter.

The Fuel tank pressure sensor?


So, the Euro NBs do have the six-wire EGR valve, but they do not have an EGR pressure sensor?

I'd have to check the number of wires on my car, but I'm pretty sure it has 6 wires.

Could well be an EGR pressure sensor elsewhere in addition to the Barr sensor :)

Great diagram...Thanks.

Correct. We also don't have the VTCS.