EMU or EMB ?
 

Greetings from Greece!

Let me first describe the situation I'm currently in...

My set up is a Moss MP62 with an A/A I/C running at 7psi on a 1.8 2002 MX-5. I use PC-Pro for fuel handling (came along with the kit) and the fuel injectors are also stock (but soon to be replaced by 310cc ones).

The problem I'm facing is a very rich AFR (10.0 - 10.5) at low rpm (while the AFR is perfect above 3000rpm, around 12) in spite of keeping the relevant PC-Pro fuel adjustment to minimum (zero). I've been told that the 2001+ MX-5 (Euro spec) has very aggressive closed loop fuel control up to ~3000rpm and the way the PC-Pro handles this is to chuck in huge amounts of fuel, so the stock ECU gives up trying to compensate - which results is an AFR range of ~10.0:1. I've also been told that I shall not be able to improve the situation if I stick with the PC-Pro and that the solution would be another piggyback (EMB/EMU) + an O2 clamp or a replacement ECU.

So, let me ask this: Which one would you suggest? EMB or EMU? The thing is that I'm aware of some unsatissfied FI miata owners here in Greece running on EMU. They all finally switched over to EMB! Do you think it was just an issue of bad EMU programming or is something really wrong with EMUs ???

And something else: Could I possibly use an O2 clamp with the PC-Pro? Or is EMB/EMU my only way forward?

Many thanks in advance!

Don't limit yourself to EMB/EMU. Check out other options, as well, such as Megasquirt.

What he said, deffinately go MS.
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Hi Dimitris,

I've been running the EMU for 4 years or so, my advice is to pay slightly extra and go for a standalone.

I would recommend the Adaptronic over the Megasquirt though, it is more expensive but it has, sequential injection and ignition control, is a lot easier to tune and adjust and has full VVT support.

Are you in the Greek mx5 club?
Reverant is THE guy to talk to for the MS over here, so it would be worth having a chat with him to see how he got around VVT support.

If you want more info on the Adaptronic, they have their own forum.
Adaptronic - Index

Or mx5nutz has several Adap users with NB's.
MX5Nutz (Powered by Invision Power Board)


Cheers
Mark

Thanks for your answers!
Unfortunately I cannot afford a standalone...So, if I have to stick with a piggyback, which one would you recommend? EMB or EMU? A friend of mine sells his EMU&Boomslang (which worked fine on his FI miata, he has now sold the car) for less than a new EMB (without boomslang), so should I grab this opportunity or not? Every miata owner in Greece says "keep away from EMU, buy an EMB instead". What's your opinion about that?
Or should I perhaps buy an AEM FIC as my tuner proposed?

Too many questions, I know, but I'm really confused...

i am running a EMU with no problems. i would grab it if it is cheap but standalone has more options than the emu it is not a bad piggy back

Well, the Megasquirt is considerably less expensive than either an EMU or an EMB, but I understand the unwillingness to jump into something so new.

Between the EMU and the EMB, there is no comparison- the EMU is far superior in its fuel control mechanism. Whereas the EMB is limited to merely tweaking the airflow signal, the EMU takes control of the injectors directly.

I completely agree with EMU's superiority-the issue is if the EMB is more "co-operative" with the stock ECU as I've heard (an experienced tuner told me that "EMU and miata ECU are fighting with each other")...And probably more reliable as a piggyback solution ???

Joe,
Does MS support VVT or will he need to do a parallel install?

Did i also read somewhere there is a problem with MS with the later cars alternator?


Dimitris,
The EMB and EMU are great bits of kit, the problem is the cars stock ECU is shite.
My car runs extremely stable in boost and have never had any problem tuning it and running it in boost.

The problem comes out of boost, the stock ECU has so many parameters it's constantly changing.
As an example i can tune my car on the way into work and it will absolutely perfectly.
I save the info and go to work.
Then on the drive home the tune has completely changed, i'll be running very lean or very rich (off boost).

I've tried adjusting every possible setting from temp adjustments to Inj lag times, but still i cannot get a consistent excellent state of tune.

Right now it's not too bad as i seem to be at the mid point of the adjustments, but it's a right pain in the foooooookin arse.

As i say though in boost when the EMU is in it's element it's stable and consistent.


I know a fair few guys in Greece have had a lot of problems with the EMU on NB's.
I've heard that the EMU brings down the various sensor voltages and ignition outputs to the point where it becomes inconsistent.

Sounds good in theory, but there's a fair few guys in the UK running EMU on NB's without any probs so it cannot be that.


Honestly, i'd save up a little longer or if the MS can run on a 02 with VVT i'd go that way.
A standalone is just soooooooooo much more controllable and stable than even the best piggyback systems.


Cheers
Mark

Thats not actually true. the EMB can lessen the injector duty cycle through the air flow meter signal and INCREASE the duty cycle DIRECTLY by holding on the injector pulse. to say that the EMB can only adjust by airflow is a gross untruth and implies that it is in the same family as the SAFC, WHICH IT AINT!

THE EMB can do 90% of what the EMU can do with a bit of thought put into its tuning and setup.

with my EMB setup i can auto tune if i want, i can data log, i can switch an aux output, and im NOT using a pressure switch for my O2 clamp.

its all about how much you know about tuning and electronics. The emu i feel is a lazy mans piggyback with plug and play stuff but a real tuner/dyno session needed to actually get it right. ( I.E chequebook hotrodder)

I asked myself and others this same question when I was researching my options as I planned out my turbo build.

The more research I did, the more I could not ignore the resounding answer that I came across: NEITHER.

Honestly, I get where you're coming from. I was (and still am) there too - I wanted something affordable that gets the job done easily for low boost. I didn't want to spend big bucks for fancy stuff I didn't need and couldn't really afford. But trust me, do not get an E-manage. Research your options and add up the true cost of going that route. I found that after getting an Emanage plus the 02 clamp plus the necessary harnesses etc. I was easily around $500.

Now, fancy ECU's cost $1500. I would have never spent that kind of dough and neither should you for a mild supercharger setup like yours. But when you consider that Megasquirt is only a couple hundred dollars more for a completely standalone ECU that can control spark, fuel, etc. to a level that E-manage owners only dream plus with wayyyy more ease of use and tuning, suddenly it seems crazy to buy an E-manage.

You'll find LOTS of people on here who will say to go megasquirt. At first you'll probably just assume as I did that most everyone has only tried this one product and so they blindly recommend it because it's all they know. This is not the case. It just happens that megasquirt (especially the DIY MSPNP) fits a niche that no other ECU out there does - amazing control ability over every function of the motor you need for an astoundingly low price compared to all the competition. A lot of guys have had EMB, EMU, FM Link, Voodoo boxes, PC Pros, Mechanical fuel controls, etc. and almost all of them have come to the same conclusion: they now run MS.

But seriously, research it and find out for yourself. Look into how you tune with EMB and compare that with other systems out there, and with Megasquirt. Look at what factors it can control, how well it can control them, what its limitation are, etc. I'm sure you'll come to the same conclusion I did.
-Ryan

Your stock ECU wasn't designed to run a turbocharger. Get an ECU that is. You can try and bandaid the solution with piggybacks and O2 clamps and other junk, or you can bite the bullet and do it right the first time. The car will run more smoothly, be easier to drive, and make more power. Standalones are the only way to go.

Of course by the time you've purchased the EMB plus the Autotune plus the serial cable you could have bought a EMU.

The datalogging, available ports, Autotune, Ignition adjustment and ability to remove the AFM/MAF are all worthy extra's the EMU has over the EMB.

The biggest problem with the EMB is exactly as Joe says.
Is exactly correct, try removing fuel with the EMB.



Thing is though it's sort of like arguing which is better, being punched in the face or being punched in the stomach.



Piggybacks are a compromise, a standalone is as far better solution.



Cheers
Mark

Considering you've never used a MegaSquirt or Adaptronic how do you know ;)

BTW the MegaSquirt is a piece of piss to tune...

Downloaded both software versions and installed them on me comp though.

As far as i'm aware the software is exactly the same no matter if the unit is connected or not.


Also done a fair bit of research on most the standalones available, i wouldn't say i''m knowledgeable but i have a good basic understanding of what's involved.

So the fact that.
1/ I'm interested.
2/ I can read
3/ Am able to install software.

I believe gives me enough basic experience (software wise) and knowledge to at least comment on the basics.

Lastly in 5 years of mx5 ownership and various reading through the forums i've got a fairly limited group of people who when they say summet i read, as they have been correct so many times i've come to respect their opinions.

One of those is Joe on here.




Cheers
Mark

Does the MS support VVT or will a parallel install be needed?

While it is true that the "EMU and ECU are fighting" when the ECU is trying to be closed-loop and the EMU is trying to add fuel, this is a basic shortcoming of all piggyback systems, and the solution is to use an O2 sensor clamp to prevent the stock ECU from noticing that the mixture is going rich. This is the reason that the Voodoo box, for instance, connects to the factory O2 line- it clamps that line (limits it to a certain voltage) whenever it is adding fuel.

Between the EMB and the EMU, I'd posit that the EMB is actually "fighting" a bit more. It's sole means for negative fuel trim is to artificially decrease the AFM/MAF signal. This is problematic in a number of ways:

First, there is a limit to how far (and how accurately) you can trim the airflow signal at very low loads such as idle. Thus, there is a practical upper limit to the size of the injector which can be used- 330cc is generally agreed upon as a safe maximum if you still want to be able to idle like a normal car.

Second, modifying the airflow signal affects not only the ECU's fuel table selection, but also its spark table selection. Remember, the principle variable with AFM/MAF inside the ECU is the load calculation, and load is a variable in damn near everything.

With the EMU, the injector signals travel through the EMU itself and are delayed by exactly 1 cycle. Because of this, the EMU can directly reduce the duration of the injector output pulse without having to feed any bogus information into the ECU. In other words, you can perform precise and exact trim on fuel and spark independently without having to "fool" the ECU about anything.


Presently, '01-'05 cars with VVT are best served by a parallel install. Open-loop VVT control has been done "on paper" and there was an effort to achieve closed-loop VVT with the MS2, however neither have borne fruit and further effort has been largely derailed by the OpenEFI effort.

Having now done both parallel and standalone installs on a couple of NBs, I've eased up slightly on my damnation of the parallel install as a "cop out" solution. Although it does add somewhat to the amount of wiring that you have to do initially (the build the boomslang harness) I did not find parallel operation to be problematic in the one NB I've done it on. Idle control was spot-on the first time (perhaps a bit more stable than mine, even) and the ECU did not throw any codes, despite being disconnected from the injectors and coils.

For the OBD-I cars I still suggest that standalone is the simplest method, however for the OBD-II cars, I can condone the parallel build as its advantages seem to justify the extra work required.

On the NB, the alternator's field coil is controlled by the ECU. To run the alternator without the ECU requires the purchase of about $25 worth of parts from NAPA to add an external alternator controller, as outlined in This Thread


I understand how the EMB/EMG works, and see above for some related commentary. It's not my intention to class it entirely with the S/AFC, I would deem it equivalent (in terms of fuel control) to an S/AFC plus a PowerCardPro.

The limiting factor with the EMB is that because it cannot perform direct negative fuel trim, there is an upper limit to the size of the injectors which can be used and still maintain a reasonable idle (meaning 850 RPM @ 14.7:1 AFR, not 1100 RPM @ 12:1 AFR.)

If we use the "common wisdom" of a 330cc injector, assume a rather generous 0.60 BSFC, and fuel rail pressure at the median of NA factory specs (42 PSI differential over manifold) then the system will support 165 crank HP at 80% duty cycle, and 185 crank HP at a ludicrous 90% duty cycle. (This is crank HP; wheel HP will be somewhat less.) And in such a configuration, headroom is reduced to virtually nothing. Any small overshoot in boost will result in an immediate lean condition.

Thus, to achieve "real" power on the Miata engine with an EMB, it will be necessary to also run an old-school rising rate fuel pressure regulator. Not only does this erase the cost difference between the units, but it further complicates fuel tuning by adding an additional variable.

Obviously, this is not within 90% of the functionality of an EMU.


Obviously you are wrong, however it is your right to be wrong without the fear of being killed in any way. :bigtu:

Also, see further discussion of chequebook hotrodding at the very end of this post.

Obviously none of us have actually worked with every possible engine management solution out there. The best you can expect is to find people who have collectively worked with a broad enough section of those systems which are popular on the Miata, and derive experiences from this.

Personally, I've owned an EMU and an MS1, and I've worked with the EMB, the Link Piggyback, the VooDoo box, and the MS2 as well. I have not worked with the Hydra, the Zoom3, the Xede, or the Motec, however based upon my considerable experience with engine management systems on Miatas, and the fact that the specs and documentation for all of these units are freely available, it is easy to draw comparative conclusions about these other devices. The Hydra looks like an awesome unit, however it is overpriced relative to the few additional functions it provides over the MS2. Ditto the various Motec boxes out there- they have proven themselves worth in the crucible of motorsport, however not only are they shockingly expensive, but entirely too closed-architecture for the DIY enthusiast. I went through the entire distributors list at Motec.com.au and I couldn't find a single place in al of the US that's willing to sell me just a plan ole' M400. They all want to sell me a complete solutions package, including a state of tune. Shade's of 4sfed5's chequebook hotrodder comments.

i am having positive experiences with the EMU and for simplicity reasons would recommend it. initially i was going to go with the Megasquirt but due to inspection reasons decided against it. i might try running it in parallel with the stock ECU if Joe offers to help me again. lol.
Ive gotten really good help on this forum especially from Joe. I think after running the EMU for a while you want to explore other frontiers. Absorb all the knowledge on this forum and make a decision. i don't think anyone had regrets with the EMU i really like the unit, good luck well help if we can.

I've been trying to tune EMU on a stocker for a while, but have been held up due to laptop problems. It seems to work ok - definitely use an OBDII reader to see the LTFT so you have an idea of what the EMU and ECU is trying to do. I live in a place that requires OBDII for inspections, so this was the easiest solution for me.

I've been using the EMB on my 1999 for over a year without any trouble,
I'am running 360cc injectors p/n #195500-2130 (420cc at the higher NB fuel pressure) I guess the NB's have more room to play on injector upgrades. Using the EMB my A/F is 11.04 wot @ 70% duty cycle, on 10psi boost. Idle A/F is 14.5@ 850 rpm base timing 12 deg. ( modifided crank angle sensor).
I know people say the EMB is a dated system, but so is the car. The stock ecu is still a 1999 , the way I look at it any Emanage system is still a upgrade.

As far as I have understood, there isn't a plug-n-play Megasquirt version for 01-05 MX-5s. Is it really so? What exactly do you mean by DIY - it comes as bits and pieces which need to be assembled? I do not have any experience with electronics, if I buy an MS I suppose I shall need an expert to set up the hardware and then another expert to tune the software!
Which exactly type of MS should I be looking for ('02 1.8 VVT)?

Maybe I'll proceed with EMU, it isn't such a bad idea after all...

Your first premise, that you can get the EMU and harnesses for less than the cost of an EMB is the kicker.

I have been running EMB with my own version of "Autotune" because that is where I started years ago.

I wish that the EMU had been available when I first got into it for the versatility that it offers that others have pointed out(Most especially getting rid of the AFM on early NA's and reducing injection directly)

All things being equal, I think you would be best served with an EMU modified with an O2 clamp to keep the ECU from fighting it.

I went for the Emu from Bipes/Powercard/Aquamist at 200flywheel bhp because the a/f's were leaning out at the top end.

Certainly out of my comfort zone but I wanted to try 'proper' tuning. As has been said above you will need a clamp - though I am told some cars don't - and a wideband. I've recieved a lot of help, encouragement and advice from fellow enthusiasts on the forums. I would really recommend a boomslang harness as it eliminated the worry of iffy leccy connections. There are still hook-ups to be made and I am getting quite good at it now. Also some form of knock detection, I have the pigging great knocklite (Eunos1800 will tell you all about them) Really looking forward to fitting a set of 450 blue tops and an smaller pulley. This will be after I've been to the dyno to see if better fueling has given more power without spinning the blower even faster.

In short I am happy with an Emu though I did think long and hard about getting either an Adaptronic or Megasquirt. It's all a lot to get the old head round and I've made some classic mistakes but - ahem - ultimately worth it.

I'll finally proceed with EMU, it's now in my trunk and soon to be wired! Let me ask you guys something else: I've read that EMU can cope with idle droop (I have a TDR-like A/A I/C in front), could someone briefly explain to me how is this done?

Do not forget the custom solutions with piggybacks like mine.

The 8 injector set up with EMB. https://www.miataturbo.net/forum/t4097/


1)VERY EASY to tune
2)perfect driveability-almost like stock
3)low price-value for money

and 4) I handle over 400whp with this setup, I use it 3 years with no problems and 2 bar (30 psi) boost pressures.

Think it again sometimes.;)

I installed yesterday the E-manage Ultimate combined with an O2 clamp from Olderguy (thanks Bruce!).

Everything seems to work fine and AFRs I saw on the dyno are pretty good, except from the fact that my (narrowband) AFR gauge doesn’t move at all (!!!) while off-boost (looks as though the ECU isn’t cycling the injectors at all, is that possible???) but works fine while on-boost. Moreover, I have now a CEL after I drove for 50-60kms. Do you have any idea what’s going on ?? Just for your reference, the clamp was installed with the voltage provided by Olderguy (I think 0,32Volts)

I connected to OBDII reader yesterday and saw a Fault Code P0153 - O2 Sensor Circuit Slow Response (Sensor 1).

For your reference, I have connected the clamp to ECU pin 4W (Front O2 sensor) and to pin 4AF (+12Volts switched). My Miata is MK2.5 (2002).
The question (apart from the CEL) is why doesn't the AFR gauge have any indication while off-boost? Is the O2 sensor dead?

Do you see something wrong regarding the connections?

Answered your email question. The narrowband wire must be attached to the wrong wire if it was working before. It should be attached to the wire coming FROM the O2 sensor which is going to the Normally Closed switch connection.

If the gauge is not connected correctly since the beggining, how did it work in the first place? And something else...The AFR gauge DID work for some time after I connected the clamp/EMU and during the tuning on dyno, it just stopped working off-boost after 1-2 hours. Something happened in the meantime...But surely we didn't change anything with regards to connections, wires, etc. The only thing we did was placing the ECU cover back on.

If the gauge worked for a little while, then there is something amiss with the O2 sensor; Or; there is a possibility that the pressure switch is defective and is remaining activated all of the time.

Hook a continuity tester to the switch and blow into it to see if it is operating correctly.

Refer, please to my second email which asks why you have the white wire connected to a wire other than the switch.

I think you should decide which communication route you want to pursue and stick to it.

We can do it here for others to learn, or we can do it by email. But; both will cause confusion.

The wiring diagram for the O2 circuit is here:

https://www.miataturbo.net/forum/t2572/


The internal part of the diagram has been changed in the product itself, but externally, that is where the wires go to the power supply and switch.

The "problem" was solved: The wire carrying the front O2 signal towards the ECU had been caught by one of the 4 screws that hold the ECU cap on the co-driver's floor (remember, mine is Euro spec), thus acting as ground and sending out zero signal:bang:. So nothing was wrong with either the O2 clamp or the wiring layout (Olderguy, sorry for the trouble...). Now the signal towards the ECU is correct and the AFR gauge is alive again-with one exception: For the first 1-2 minutes after cold start it's dead, then it starts working again. Any ideas???

Let me add that it's not an AFR gauge issue (it works 100% fine), it seems like the front O2 sensor is "dead" for this short period of time after cold start, is this possible?