AEM V1 vs Flash ECU? Which should I have?

[Intropy]

I hear ya, and that's even more true for more recent ECUs, but the problem is once you mod your 3S you fall right into that "dozen different cars" category. Can anyone explain how is he supposed to tune his ignition timing without live tuning on a brake dyno?

[J. Fast]

It's $1000 (more like $1500) because it's a generic system meant to fit a dozen different cars and sold in small quantities. It's got no comparison to an OEM quality system tailored to a specific car and specific sensors, one which has hundreds of hours of tuning by professional calibration engineers and is built with emissions compliance, warranty needs and the ability to keep an engine alive despite some ham fisted idiot who never changes the oil and only uses the 'cheap' gas.

Last time I checked, the AEM used a very coarse knock feedback system which wasn't half as complex as Mitsu's patented factory system, to say nothing of the fact that the Mitsu system is actually tailored specifically to our engine.

I'm not saying the AEM isn't a damned nice piece of equipment. But there is precious little that makes it 'better' than the OEM ECU, and quite a bit that makes it worse. Starting off with Mitsubishi's factory developed calibrations will put you at a drivability point where you're far ahead of all but the absolute best AEM tuners out there, and you're getting there for a fraction of the price.

If you keep the engine stock, sure. If you don't, they're the same. I give the edge to EMS for another 5-10 years because there's a support base. Try putting double the air density and 1000+ cc injectors in there and get it to run like stock. The drivability and starting issues will be the same. What exactly can the stock ECU do that you can't bend an EMS around, or that hasn't already been improved upon by carefully developed standalones?

[Intropy]

And just so I'm clear and it doesn't sound like I'm bashing the flash ECU, my big crusade is for real tuning. Not for AEM vs flash ECU. I could care less what you use.

In this case and any like it, I will recommend the EMS because he:
1) has serious mods
2) is going for big power
3) doesn't know much about tuning
4) therefore needs a professional tune

I'd rather see the car get a flash ECU and go to the dyno than an AEM and wing it.

[Greg E]

If you keep the engine stock, sure. If you don't, they're the same. I give the edge to EMS for another 5-10 years because there's a support base. Try putting double the air density and 1000+ cc injectors in there and get it to run like stock. The drivability and starting issues will be the same. What exactly can the stock ECU do that you can't bend an EMS around, or that hasn't already been improved upon by carefully developed standalones?

Give it time. The stock ECU will get to those levels. It's still too new of a development.

You really want to know what the stock ECU can do that the AEM can't do and never will be able to? Drive legally on the street....

[Greg E]

Didn't know about logging on the tactrix cable, that's cool.

Comparing fuel trims to the AEM's O2 feedback is like comparing a BB gun to a cruise missile though. The feedback driver on the EMS is a configurable PID controller with two wideband inputs. A narrowband-based system is mainly for maintaining stoich (narrowbands would be inaccurate for any other purpose). The EMS has a full AFR target map (just like a fuel map) and can make corrections to each bank to maintain the target for each cell. How these per-cell trims are stored and cleared is also configurable. It's the same for boost control. With the AEM it's easy to implement things like "Don't go over 10psi if I'm in 6th gear".

I dig the flash ECU, I'm just saying... there's a reason the EMS is $1k. If they could be matched by a 14-year old re-purposed stock ECU, they should all kill themselves.

Gear based boost control is Something I'd love to implement soon. It's fairly simple. Just too busy working on other things ATM.

I figured out how to adjust the target voltage of the narrowbands. Chrome V2 will be able to adjust this for use with a WB and it wouldn't take much even to implement a table look up to change the target AFR based on any condition. Just tell me what you'd like to see and I'll make the code do it.

See unlike an AEM, I have the source code. I can implement anything given time. The hardware on the stock board is my only limitation. Something else I've briefly looked into is Ion Knock detection. Hardware wise, I don't know if I could make this work. Software-wise, it'd require a complete rewrite of the code, but it can happen.

I've already posted about my setup which implements a GM ethanol sensor to make the car a true flex fuel vehicle. The code is already written and the sensor is sitting on my coffee table. Just waiting for me to test...

[Greg E]

I'd rather see the car get a flash ECU and go to the dyno

Hans, are you reading this?

[J. Fast]

Give it time. The stock ECU will get to those levels. It's still too new of a development.

You really want to know what the stock ECU can do that the AEM can't do and never will be able to? Drive legally on the street....

You can run a standalone EMS and be street legal. In 2010 DOT passed a regulation that said all DOT registered alternative fuel vehicles Fed Tier I and II, category 3 or greater (which is ethanol, meth, propane, and etc) are emission and OBD test port exempt and street legal. A lot of people don't know that, but it true!

[Intropy]

Chrome V2 will be able to adjust this for use with a WB and it wouldn't take much even to implement a table look up to change the target AFR based on any condition. Just tell me what you'd like to see and I'll make the code do it.

If you seriously have the ability to do this on the stock ECU, I'm impressed. It sounds like a LOT of work though. You'd basically be implementing your own PID on the stock ECU hardware, and tying this into the injection controls. Is that possible?

All you need to do to get me to try one is get speed density working.

[Greg E]

You can run a standalone EMS and be street legal. In 2010 DOT passed a regulation that said all DOT registered alternative fuel vehicles Fed Tier I and II, category 3 or greater (which is ethanol, meth, propane, and etc) are emission and OBD test port exempt and street legal. A lot of people don't know that, but it true!

I didn't know that! I was just hoping to get the tax break like you mentioned in your other thread. So glad there's an E85 pump within 10 minutes from here.

If you seriously have the ability to do this on the stock ECU, I'm impressed. It sounds like a LOT of work though. You'd basically be implementing your own PID on the stock ECU hardware, and tying this into the injection controls. Is that possible?

All you need to do to get me to try one is get speed density working.

The mods in chrome V2 are written with a simple hex editor. The most time consuming part was learning the language & syntax. Seems I'm getting over that curve finally though! The disassembly part is never ending...

The closed loop feature of the ECU simply checks the NB voltage and compares it to half a volt before deciding which branch to step next. If you plugged in a 5V wideband sensor, then changed this value to be 2.5 volts, you're essentially doing the same thing as stock. Drop this target value and closed loop is targeting a leaner AFR thus giving you better mileage. (already been tested)

I also found the table the ECU uses to switch into open loop. Say you wanted a full autotune. First I'd extend this table so the ECU is always in closed loop. Next, I'd adjust the high/med/low trims with larger airflow switch points. Next I'd replace the target NB memory address (.5 a volt) with a static address. Moving on, the harder part is to create a sub which would have a 2D table look up which would have an RPM (or airflow) axis (hell, I could have a 3D table with both rpm and airflow like the fuel and timing maps) with various target voltages populated within. The table would populate this temporary axis with whatever conditions are met in the lookup. This wouldn't be too hard to add to the code at all to be honest.

Damn, now I got a new excuse to stay awake till 3am for a week straight....

[Jeff V.]

In 2010 DOT passed a regulation that said all DOT registered alternative fuel vehicles Fed Tier I and II, category 3 or greater (which is ethanol, meth, propane, and etc) are emission and OBD test port exempt and street legal.

DOT doesn't pass emission rules.

EPA does.

Link to relevant section of the CFR?