sprx3

Hey guys ive been looking at the emu for my avo kit but no one seems to want to touch them here in Australia (melbourne)

a few questions if i may,

how hard are they to tune?

can you get an autotune for them? (if so is this a true auto tune or will i still need to put it on the dyno)

is anyone running a 99 nb with a gt28 & 550cc injectors that i can use a base map from?

should i be using different o2 sensors or anything at all or will all the mazda gear handle the pressure, i will be running low boost no more then 10-12psi

please help
Zoran

IntrnlStorm

iTrader: (3)

I had one on my '92 and ran 550cc injectors just fine. Get yourself a Wideband O2 and the EMU and do an autotune. After the autotune is done you can fine tune it to get some better curves. It's not hard, just takes some research and tuning....

Joe Perez

iTrader: (8)

EMU? I thought all you blokes ran the Wolf.

The EMU certainly has a lot of buttons and ***** and can be intimidating at first, but I believe that of all the piggybacks it is probably the best.

You will want to use Greddy's official 4-bar MAP sensor, as opposed to a cheaper universal MAP sensor. Around here the Greddy sensor is about US$100, but it's worth it. Certain aspects of the software are scaled to the voltage range of this particular sensor and are not bypassable.

You'll also want a wideband exhaust O2 sensor package. The popular ones in the states are the AEM and Innovate units, the basic one sold by Wolf should also work if that's easier for you to obtain. (No need for fancy things like logging in the sensor- you'll be logging in the EMU itself).

As IntrnlStorm said, the EMU does include a rather good A/F Autotune, assuming you have the MAP sensor and Wideband mentioned above. Tuning on the street is possible, but difficult. I have been running on a street tune for more than six months now and while it's adequate I really need to book an hour or two on a dyno...

Marc D

iTrader: (7)

as soon as i get my car running back to its original condition, i will be turboing it. it is a 1999 NB, so ill keep you updated on how im running it. i will be using the EMU.

sprx3

so something like this?
http://wbo2.com/2j/default.htm

that sounds great what injectors are you running & how far off is it from seeing daylight again?

cheers
Zoran

Joe Perez

iTrader: (8)

Although I'm not familiar with that particular device, from the specifications it appears it would work. Purchasing the display would be optional. It's not technically necessary for operation, however I find it reassuring to see the afr displayed.

MX5Kuro

Well first of all I'd like to thank you guys for putting this site together. I was getting very excited so I'm building my DIY turbokit for my 1.8L NB 1998 MX-5. I got these parts for building it:

- HKS manifold
- Garret GT28R turbo
- 3" Custom made complete exhaust
- Goodridge braided hoses
- 550cc RX7 injectors (square connectors soldered)
- Turbosmart BOV
- V-mount FMIC
- eBay intercooler tubing and silicon couplers
- VDO instruments (oil temp, volt and turbopressure)
- Innovative LC-1 WB.
- Greddy e-Manage Ultimate with boomslang harness (knock and air temp)
- Greddy turbopressure sensor.

I'm fitting the kit within the next couple of weeks, but I aready have a question this time. It's regarding the JP8 on the EMU board. It's standard set to 5v but I read there were some issues with this setting. I can't find the right topics again. So should I use the 5v setting or the 12v setting? My engine is a BP-ZE(NB). And should I alter jumper settings for the boomslang harness?

And where can I find the autotune option build in the EMU software? Couldn't find it...

Joe Perez

iTrader: (8)

There was a wonderful thread about this a while back, but unfortunately all that was lost in the Great Accidental Purging of Two Weeks Ago.

The practical upshot was that I verified with an oscilloscope that the ignition trigger level on the 1.6 engine was in fact 5 volts, and have run my EMU at that setting for roughly a year with no problems. Someone else interjected that perhaps the 1.8 engine used a different signalling level owing to its different ignitor design, however nobody ever volunteered the use of their NB to me so that we could scope out the ignition on one of those. At the end of the whole thing, we all agreed that we had absolutely no idea what was going on, and so instead we got drunk.

There are several things you have to do to enable this.

First, go to Parameters, switch to the Throttle tab and set up your throttle position sensor. Ensure that it is working properly.

Next, still in Parameters, go to the A/F Target tab. Set the Affected Map to I/J 1, set Throttle Position to, say, 25% or so, and accept the defaults.

Next, still in Parameters, go to Map Select, and check the A/F Target box.

Next, still in Parameters, go to Front Panel, and ensure that your A/F Meter and Pressure sensor is properly configured. Also, examine the DIP SWITCH settings to see if I/J 1 is presently set on any of them. If it is, make sure that dip switch is on.

Close Parameters.

On the left side of the screen you now have an A/F Target map. I suggest that you scale this map the same as I/J 1. From the drop-down window, select Pressure Sensor.

The way this works is that anytime the conditions you set in the A/F Target tab of parameters are met (temperature, throttle position, time since start) the EMU will look at whatever AFR value you have put into a given cell, compare it to actual AFR, and adjust I/J 1 to try and achieve this value.

You DO NOT want A/F Target to be running while the ECU is in closed-loop mode. So for all pressure values below atmospheric, enter "-" (that's a hyphen or minus symbol, ASCII character 0x2D). On US keyboards, it's the non-shifted character between 0 and =. On a Dutch keyboard, I think it is the character all the way at the lower-right (next to the right-shift key) where = is the shifter character on the same key. DO NOT enter 14.7, zero, etc.

In the boosted cells, enter your target value. In my table, I start at 13.5 at atmo, and scale down to 11.5 at full boost.

Marc D

iTrader: (7)

i dont have the money for amazing injectors, but i will be using the non-turbo supra's green tops. i think they were rated at 310cc at 43.5 psi? since the stock fuel pressure is about 60-63, it should be more closely rated at 360 or somewhere at 80% duty i think.

MX5Kuro

Thanx man!

But on the hardware side it is correct that Autoune is only activated when using the knock & watertemp option (on my boomslang)? Because in that case I have to alter the wires of the harness.

Joe Perez

iTrader: (8)

I don't know very much about the Boomslang harness as I have never seen one. I much prefer to do my own wiring.

You must have the following sensor inputs to use the autotune:
Wideband AFR
MAP
TPS
Water temp

A knock sensor is not required. Unfortunately, the EMU still does not (as of 2.12) have the ability to retard timing on knock. It can only log knock events, and it is then up to the user to manually correct the affected cells.

Marc D

iTrader: (7)

^^^^ whew! good to know i wired it up correctly.

MX5Kuro

Okay, so I have to alter the harness...

This week I will be putting every together and hope to finish it. Let you guys know if it al works as it should, and if possible post some pics.

sprx3

sweet, get lots of pics oh & dont forget the pics

hey Joe you wrote
does this mean that the emu will not control fuel & ignition in closed loop (or am i reading it incorrectly) if that is the case how do larger injectors effect closed loop?

sorry i think im confused

Marc D

iTrader: (7)

ive decided to roll with 550 injectors, but the turbo i will be using is a GT2554, so im not sure how it could apply to you.

sprx3

sweet so theres a few of us trying to do the same thing, my turbo kit is due this week so as soon as i get the wide band & emu i'll be playing around with it as well, has anyone got any base maps as yet & what timing should we be running, im guessing about 15 deg at around 8-10psi? ive read that emu does not use the knock sensor as yet, is that true? meaning auto tune wont adjust timing as or is that something we can play with? is anyone else going wide band?


cheers
Zoran

Joe Perez

iTrader: (8)

The EMU will control fuel and ignition in closed-loop. That's actually the problem here- it has no way of knowing whether the ECU is in open-loop or closed-loop operation.

I believe that you may be considering several different EMU features together, which are in fact seperate. Here is a simple breakdown:

1- In the Parameters menu, under the I/J Tab, you can enter a "Before" and "After" value for fuel injector size. This will create a static correction value that is invisible to the user, but is applied all the time. It compensates only for the increased injector size, and not for the increase in airflow and manifold pressure due to a turbocharger.

So if you originally had 205cc injectors, and you replaced them with 440cc injectors, the EMU will always apply a correction factor of 0.47 to the final fuel calculation, since that is the ratio in size of the old injectors to the new injectors. This correction is active in all conditions, and is how, as you stated above, the EMU compensates for large injectors.


2- In the I/J Map tables, you can enter fuel correction values relative to RPM and MAP. These values are separate from (and in addition to) whatever correction is applied in step 1. Also, these cells are the ones affected by the A/F Target map.

Now, the problem with A/F Target in closed-loop operation is this: Let's assume you are cruising at a constant load, say -7.5 PSI at 3,000 RPM, and the ECU is in closed-loop mode. The ECU is constantly making small changes to the fuel, causing the mixture to oscillate back and forth between slightly rich and slightly lean. Given the limitations of the stock narrowband sensor, this is how stock ECUs verify that everything is working correctly and that the mixture is at stochiometric.

Now, imagine that your EMU is monitoring the mixture at this point, and trying to hold a specific value- we'll say 14.7:1 for example. As the stock ECU swings the mixture to slightly lean, the EMU will enter a larger number into the -7.5 @ 3000 cell in the I/J map, thus adding fuel to try to bring the mixture back to 14.7:1.

Depending on the rate at which this correction is taking place, the stock ECU will either sense that its command to go lean has not had any effect and continue pulling additional fuel (which the EMU will in turn try to correct again) or it will swing back in the other direction and start adding fuel, since it believes that it's time to oscillate rich. Since the EMU has already added fuel, this will cause an over-rich condition, and the EMU will immediate start decreasing the value of the -7.5 @ 3000 cell, trying to lean the mixture out.

So basically, no matter what value you enter into non-boosted cells, it will result in the EMU and the ECU fighting each other, which will result in all sorts of strange data in the I/J Map, and probably a CEL and poor driveability. Your A/F Target map should look something like this:


Since I have entered "-" in all the cells where MAP is less than atmospheric, I have told the EMU to do nothing in these cells. It does not start autotuning until MAP crosses the 0PSI threshold.

Incidentally, my Aux Output map is set up to engage my narrowband O2 sensor clamp at exactly 0PSI as well, which ensures that the stock ECU is not trying to oscillate at that point.

Joe Perez

iTrader: (8)

Knock sensor- the EMU has been demonstrated to have knock-logging ability, but as of 2.12 still does not have knock-retard.

Wideband- Pretty much everyone with an EMU (or any other higher-end piggyback or ECU) has gone wideband. Trying to tune fuel without one is like trying to sink the USS Eisenhower with a .22 rimfire. Technically it can be done, but there are better ways.

Timing seems to be greatly misunderstood. And there are several factors at play.

First, a lot of people will say that their timing is set to 10* BTDC, and think that it stays there at all times. In fact, the stock ECU has a 2D timing map built into it that applies different amounts of advance at different conditions of load and RPM. 10 degrees just happens to be the amount of advance applied at idle with the TEN jumper installed. So by setting the advance to 10 degrees under this particular condition, all we are doing is ensuring that the CAS is correctly aligned so that all the rest of the ignition timings will be where they should be.

In the EMU we have virtually no exposure to actual ignition timing. We are applying advance (positive numbers) or retard (negative numbers) in addition to whatever ignition timing the stock ECU is using at the moment. These are relative numbers, not absolutes.

Take a look at my EMU ignition map:


First off, know that this map assumes that the CAS is adjusted for a factory-stock base timing of 10* BTDC at TEN idle, and that this car has both a big FMIC and water-methanol injection. If you run these numbers on a non-intercooled, non-water-injected engine, you will blow it up.

So take a look at the -12.3 @ 1000 RPM cell. This is about where the engine idles. In this cell I have a value of 6, meaning that the EMU is to add six degrees of advance to whatever input signal it receives from the ECU. Since the ECU is outputting its ignition signal when the crank is at 10* BTDC, the EMU will output the ignition signal at 16* BTDC. (How is it possible to output a signal before you receive it? Well, technically the EMU is delaying the signal 354 degrees, which gives the same effect as advancing it six degrees.)

At 4.9PSI @ 3000 RPM, I have a zero entered. Let's say for the sake of argument that the stock ECU is programmed to give an ignition pulse at 14.4* BTDC at 3000 RPM at the highest load cell. Since there's a 0 on the EMU in this cell, it will simply pass this ignition pulse along directly and tha actual timing will be 14.4* BTDC.

Now go to 11.4PSI at 6000 RPM. I have a value of -2.5 in this cell. Let's say that the stock ECU is giving an ignition event at 22.9* BTDC at 6000 RPM at the highest load, then the EMU will delay this by 2.5 degrees, and wait until the crank comes over at 20.4* BTDC to fire the ignitor.

This ignition map, in my opinion, is extremely aggressive. In fact I have dialed it back slightly since that was generated, since I still heard an occasional ping every now and then.

Typically, the rule of thumb for turbocharged engines is one degree of retard from stock for every PSI of boost. When I first built my turbo system (before the water injection) I found that I needed even more retard than this. I think I wound up at around 1.5 degrees per PSI. Better safe than sorry.

MX5Kuro

Well I got everything ready today and I thought I would give it a try. But the car won't start, with or without the EMU. Probably the increased size of the injectors to 550cc is the problem. I could smell the gasoline, so I think the injectors work. The only thing is that I hear a high pitch comming from the area of the injectors. Don't know if that's normal. Didn't pay attention regarding such a sound with the 'old' injectors. Has anyone a working map for a 1999 with 550cc injectors?

Well I checked the partnumber off the injectors I used. They are RX-7 injectors with partnumber 195500-1370. Last time I checked they were hight imp injectors, but according to this tread https://www.miataturbo.net/showthrea...ht=195500-1370 there are high and low imp versions off the injectors with the same partnumber.

So I guess I have to measure the resistance of the injectors. (Was not the easiest part of the project, removing the fuelrail.) Can anyone tell me, if the injectors are low imp. How likely is it that I will have any damage to the electrical system (ECU/EMU)? I tried to start about 5 times and I had the ignition on for about 5 minutes for adjusting the EMU.

sprx3

Thanks Joe, i think i need all the help i can get

Just another quicky, ive bought the ultimate with a greddy pressure sensor but no harness so im looking at the boomslang plug & play only problem is it comes with a few different options, could you tell me what would be best suited for me???

choices are
air & water input
knock & water input
knock & air input
dual knock input.....

what the???