I am trying to understand ECU aftermarket stuff from the IT perspective. I've gathered the following, please correct me if I got something wrong.

Basically, the ECU is just a chip, some input (sensors), some output (e.g., A/F ratio), and a data base (i.e., info on the car). There seems to be two ways to spoof the ECU.

The first method is the piggyback method (e.g., Unichip). A secondary chip (HW) seems to send spoofed input (sensor data) to the real ECU in order to have it do what the piggyback wants it to do. One advantage of this is to go stock, you just unplug it before hitting the MINI dealer and the original ECU isn't touched.

Second method actually goes into the ECU's data base and replaces the ECU's data files with its own (e.g., MTH, Shark). This seems much more dangerous and more inconvenient in that before going back to MINI dealer, you need to upload the original ECU files. Lose those original ECU files and your in trouble.

Does that about sum it up or am I way off base?

 

you're right about there "piggy-back" systems intercepting and changing some sensor inputs [crank angle, manifold pressure (boost/vac), rpm, intake air temp] to change engine running parameters [ignition timing, injector pulse width, throttle position]

piggy back systems for the most part are only fooling the ecu into reacting with a desired result, for example the apexi- AFC intercepts and changes how the ecu "sees" engine load (through the map sensor) to richen or lean the current mixture. one of the downsides to a piggyback (as far as i know) is that tricking the ecu into providing parameters/database values for what would be a false state, changes other outputs as well. for example if the engine load is higher than what is being reported to the ecu, not only do we get the (desired?) leaner fuel mixture (controlled by injector pulse width), but the spark timing is affected as well.

Ecu "flashes" are probably the best way to change the engine's parameters. If i'm not mistaken (it happens ) our cars use what is reffered to as a speed-density system to control the engine's activity. MAP (density) and RPM (speed) are the x-y axis' on a table that has injector pulse widths (how much fuel is delivered). There is at least one other table that uses the same two variables to look up ignition spark timing. And various other tables that are used in correction factors (intake air temp, what gear is in use,etc.)

most of the time the engine is running in "closed loop" meaning that the table values are being referenced, but are also being trimmed/adjusted by what the ecu is recieving from the oxygen sensors, the speed sensor, and who knows what else.

when you floor it (WOT) the ecu reverts to what is called "open loop", the table values are used (almost?) exclusively. These parameters tend to be on the safe side, and generally do not pay any attention to the oxygen sensor.

the third option is a fully standalone engine management system, like AEM/haltech/motec/F.A.S.T. they have thier own wiring harenesses, sensors, coils, etc. As far as i know there aren't any stand alone ems's for the mini, probably because the car's ibus is too complex to interface with.

but what do i know?

 

Both of you guys are spot-on.

 

Bingo.

Piggyback systems also introduce 200 (or so, andy has the real number) points of failure.

 

Flashing (like a BIOS) is probably the same as changing the original SW and its database (map)

As to points of failure, your talking the pins? True but unless your really clumsy bending them, whats the odds of that? On the other hand, messing with the "database" is inherently dangerous unless your safely backed up

I guess both methods have their pros and cons. Spoofing the inputs, as mentioned above, could have downroad difficulties unless ALL the parameters have been sorted out.

Wow, I actually got it from just reading Now to decide which method is good for me

THANK YOU for responses

 

I love this arguement....data travels a lot faster than 7000 rpm. I don't know what the delay/propogation time of piggy back systems are but it would be interesting to see what the potential for things like "jitter" and "wander" have on our cars. 7000 RPM is pretty slow in the electronic world..... I don't know how the data is transfered....is it packets? I know that my car runs very well with a Unichip,piggy back system..... any data guys out there want to chime in

 

You really think he's talking about losing data? Very doubtful. Any decent chip has got to be sitting their idling most of the time, even if reading the data in real-time. I thought he was talking about the pins failing (e.g., corrosion?). Arguing about data loss is probably pointless (unless its running windows)

 

I agree but I keep hearing this business about "tricking the ECU" being a problem and frankly I don't get it. What is the gist of that arguement?

 

I too have a UNICHIP without adverse effects ...BUT

With the level of MODS I have, i wish I could bump up the redline and the piggyback ECUs won't

I have to shift when my car is really pulling hard as I hit the Rev Limiter zone !!!

 

First let me say that I don't have actual numbers on "data delay" nor do I know how the unichip is piggybacked on the ecu. I have however worked as a hardware designer and a software programmer. If the unichip is working in conjunction with the ecu (data being combined) there will be data delay, allbeit very small, but also the possibility of incorrect information that's being interpreted. Just the fact of piggybacking hardware will cause data delay. By flashing the ecu the actual program is replaced and therefore no delay as compared to the original program.

So, even though the delay is miniscule and most likely doesn't affect the performance; it's there.

 

I wonder if anyone here has considered MegaSquirt to build and program you own. A buddy of mine has started on this quest on a turbo car he's building. To bad it is not a MINI.
It's worth a look:
http://www.msefi.com/msinfo/MS%20FAQ.htm#whatis

 

Remap or piggyback? Both have pros and cons.
Standalone would drive the motor, but the ABS system wouldn't work any more..... And maybe the car wouldn't start.... But you could yank all that crap and drive around... BIG JOB HERE!

7000 RPM is just shy of 120 RPS. the crank sensor is 58 teeth, with 2 missing to find "home", so the crank sensors goes at 7 KHz at redline. This isn't baby data acquisition, but it sure aint fast.

As far as propogation delays, it's surely not more than a few clock cycles of the piggyback computer, and at 40 MHz (just a guess, but lots of microcontrollers run off of these clocks), calculation propogation delays is for all intensive perposes pretty much negligable.

Going back to stock can be easy for re-maps (MTH lets you up-and download at will). The biggest risk for piggybacks is the actual connection, this is when pins bend...

I wish we could get this for Minis.....
http://www.shonutperformance.com/TwEECer.htm
www.tweecer.com
Anyone up to the task?

Matt

 

I have put my Unichip on and off several times.......that is a very robust connection and I do not fear bending the pins. As far as latency in the program......I was not concerned and i totally agree with you but I have heard this arguement and I wanted to flush it out......It is a bummer that we can't change the redline because my car is still pulling like mad at redline and I 'm sure I could go another 500 -750rpm easy.(SC be damned)

 

Just to give you an idea, there is someone running an 8500 redline.

 

If your in a rush to get to the dealer or the car is dead and needs to be towed, Uploaded/Downloaded via a laptop, especially if the car is dead, would seem to be a terrible pain in the butt. IT would seem much simpler to just unplug the plug and play. BTW, that would mean you would HAVE to have a laptop lying around just to maintain the car.

BTW, thanks for all the responses, I've read nothing here that tells me the principles I explained were wrong. As to the chip speed between the piggyback and the ECU, well we all know those little itty bits move at the speed of light and I'm sure, that CPU is idling a lot.

 

EVOTECH sets the rev limiter to 7500 in higher modded car maps ....

For the small sum of 720$

 

But it helps. And you won't change red-line until you go into the stock programming. Like I said, pros and cons. But you do get the added benefit of being able to upload/download at will, on your own schedual, without having to send something through the mail.

so pain of having to use a computer (BTW, what are you typing your posts on?), but you reliev your self of the pain, and cost, and time of shipping for getting reprogramming, or the like.

As someone who has laptops and UPS shipping labels lieing around, I really wish that we had better iterative tools that allow for hackiing the ECU maps. I have a wideband and logging, and would love to change my own maps.

The Ford EEC-VI is a nice unit. It allows for you to have maps read instead of the stock programming (If it's hooked up to the diagnostic port, that CAN override the stock programming) so you don't have to change anyting in the stock map. That Tweecer is only $550, and gives you access to 5 maps! (Stock, and four modded ones). The web support for tons of other peoples maps as starting points is nearly endless. How I yearn for tools like that for our cars.....

Propoagation in wires is not at all the speed of light. It's many, many, many times slower. Those are electrons, not photons. (Damn, more bonus point on the nerd test!)

For as deep as you got, you did well. But each system has it's own issues and specifics. You did a pretty high level description, and as far as it goes, its pretty much right on. But very, very incomplete.

And not one hundred percent right. A/F is an INPUT from a sensor, injector pulse width is an OUTPUT of the ECU. But this is just picking nits.

I also find the word "dangerous" in your original post interesting. Seems like you've already decided which way is best for you (and this is fine, to each his or her own). But be happy with the stock red-line, as that's all you'll ever get. Pros and cons....

Matt

ps, I've looked for more technical information on what actually happens inside out ECU, and it sure isn't written down anywhere easy to find! Seimens won't even give it out, even when I pretended to be making custom cars!

 

I've used "CROME" and "Uberdata" to tune my honda's ecu, the two programs are hobbyist/enthusiast developed and work amazingly well for a being reverse-engineered. We can only wish for something with that level of adjustability/control for our cars.

From what I understand, MTH, GIAC, and Evotech are the only companies (other than oem updates) that can create and edit maps. Are there any chips/flashes/what-have-you that are truely 100% customizable, like while the car is sitting strapped to a dyno? or in the case of my honda, edit the maps while sitting in the passenger seat of the car (street-tuning)?

when we wish upon a star

 

My point about the hundreds of possible points of failure is due to the Unichip's use of an additional set of male and female ECU connectors so it can be "plug and play". Every time you introduce a new set of connections in series with the factory ones, it increases the likelyhood of electrical issues - witness the M7 AGS complaints about the throttle body wiring harness extensions, and the Unichip complaints about ABS/DSC lights and faults. See this post for more info:

https://www.northamericanmotoring.co...0&postcount=42

There are advantages and disadvantages to both piggybacks and flashing. However, IMHO, flashing is the way to go for reliability, simplicity, and expense. User-tuneability is unfortunately not an option at the present time for flashing, but I predict it will be available in the MINI marketplace in the not-too-distant future (and no, it will not have anything to do with my company :smile.

 

Not a laptop. I though you needed a laptop to upload the MTH files. I ain't dragging the big old beast and monitor out to the CAR

I said that wrong. I meant to say that a CORRECT A/F ratio is the result of the output. thanks

NO, i haven't decided anything. I used the word "dangerous" in the IT sense. No backups and you lose the primary, and you ar screwed. I consider that "dangerous"

Thanks!

 

The routines that allow reading and writing data into the ECU are not public information, but they also don't seem to be a very well-kept secret. MTH sells their program to allow users to read the files and to write whatever you'd like into the ECU. Of course, having a pen and paper doesn't mean you have the ability to write a Pulitzer-winning book.

Other companies using flash technology include:

Dealer installed only:
GIAC
Evotech
Powerchip

User installed but limited to the stock and one tuned file:
Conforti (through their handheld flasher, no laptop needed)
AmD (through their handheld flasher, no laptop needed)

There are probably others too, but they all use the same methods as far as the ECU is concerned.

 

The other thing about a flash like MTH. The only way the dealer will ever know you have it unless you tell them is if they run it up to redline and see 7.2k instead of 6.7k . Just food for thought.

 

Thank YOU. ALL GOOD INFO ... I'm Learning and your all so good and sharing

 

Stock redline is 6750 correct? But the rev limit is still 7250 isn't it? I know my car revs up over redline and into the 7000s, not chipped or anything.

 

Can I get MTH just to raise my rev limit?