Piggybacking with a Motec
11-17-2003, 11:49 AM
#1
Registered User
Thread Starter
Piggybacking with a Motec
OK... so I saw this article linked from another thread:
http://www.autospeed.com/A_0911/cms/article.html
In that article, they describe a setup where they piggyback a Motec M4 on top of the stock ECU. Basically, the Motec is doing the engine control (fuel/timing/etc), but the stock ECU is doing the menial work like dash display, OBD-II reporting, etc. Presumably, this means that the stock ECU would still be reporting appropriate values to the OBD-II port. This is important to me because I believe that in order to pass inspection in my area, it is required that the ECU report an "operational, non-error code" to the OBD-II port.
What are your thoughts? Do you think a setup like this could provide the best of both worlds: 1) the power that can be reaped with a Programmable ECU, and 2) the necessary hardware to pass emissions testing.
If this could be done with the Motec, I assume it would also work for an AEM EMS, etc. I wonder if the stock ECU would end up throwing a code because it would try to "correct" the a/f ratio to get it to its desired (conservative) values, however its changes would be ineffective (since it isn't actually controlling these things).
http://www.autospeed.com/A_0911/cms/article.html
In that article, they describe a setup where they piggyback a Motec M4 on top of the stock ECU. Basically, the Motec is doing the engine control (fuel/timing/etc), but the stock ECU is doing the menial work like dash display, OBD-II reporting, etc. Presumably, this means that the stock ECU would still be reporting appropriate values to the OBD-II port. This is important to me because I believe that in order to pass inspection in my area, it is required that the ECU report an "operational, non-error code" to the OBD-II port.
What are your thoughts? Do you think a setup like this could provide the best of both worlds: 1) the power that can be reaped with a Programmable ECU, and 2) the necessary hardware to pass emissions testing.
If this could be done with the Motec, I assume it would also work for an AEM EMS, etc. I wonder if the stock ECU would end up throwing a code because it would try to "correct" the a/f ratio to get it to its desired (conservative) values, however its changes would be ineffective (since it isn't actually controlling these things).
11-17-2003, 12:08 PM
#2
Exhausts and intakes haven't ever really shown the kind of gains he is talking about, yet they are much more significant in his mind than the computer tuning, I don't see why it is worth considering.
11-17-2003, 12:16 PM
#3
Registered User
Thread Starter
Originally posted by gernby
Exhausts and intakes haven't ever really shown the kind of gains he is talking about, yet they are much more significant in his mind than the computer tuning, I don't see why it is worth considering.
Exhausts and intakes haven't ever really shown the kind of gains he is talking about, yet they are much more significant in his mind than the computer tuning, I don't see why it is worth considering.
If that can be done while still preventing the stock ECU from throwing error codes, then it would be a worthwhile endeavor in my opinion.
11-17-2003, 12:54 PM
#4
Registered User
For two years this article was universally vilified on this board. I wish they would take this crap off their site so it wouldn't keep re-emerging.
If you want to have control over fuel and timing, buy a stand alone ECU like the AEM EMS. You can still pass emissions with a properly tuned engine, there is no vodoo magic required here.
If you want to have control over fuel and timing, buy a stand alone ECU like the AEM EMS. You can still pass emissions with a properly tuned engine, there is no vodoo magic required here.
11-17-2003, 01:22 PM
#7
I don't see how you could convince the OEM ECU that it has control. It would not ever see its changes take effect. Supposedly, the ECU periodically forces a lean condition so that it can verify that the O2 sensors are working properly.
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11-17-2003, 03:27 PM
#10
MXT_77,
I do lots of Motec installations on various cars. I've have not done one on a S2K but have looked at the possibility of doing so as I will be fitting quad throttle bodies to my F20C engined race car in the next year or so.
The factory ECU has a few special things it does which a Motec will not easily do such as the Honda 3 wire idle control valve, the alternator charging control, ODB2, Immobliser, RPM signal to the instrument panel.
I think this is the reason why people piggy back the Motec rather than replace the whole ECU. The Motec can be programmed for the idle control with another Motec compatible valve installed, it can also be programmed for the tacho output.
The standard ECU also has feedback from lots of sensors to check that things are working correctly. With a piggy back setup the injectors, vtec, igniters and possibly AF sensor would not be controlled by the honda ECU so the honda ECU may start to post CEL errors galore. You would probably pull the globe out of the instrument panel. The ODB2 data will not necessarily be valid.
The Motec does offer some nice things such as Launch and traction control, full throttle gearchanges, data logging, boost control, anti-lag. Make sure you get the Motec model with enough channels. The M800 is the pick at the moment as you have lots of i/o channels to play with.
If you wanted to make the car a racer I would suggest finding a work around on the alternator and using only the Motec M800 and ditch the Honda ECU, and do without the immobiliser, ODB2.
Look into the pricing. I think you will find an V-AFC or similar will be a much cheaper and simpler way to achieve easy mixture/ign trims on a roadgoing car.
Speedracer.
I do lots of Motec installations on various cars. I've have not done one on a S2K but have looked at the possibility of doing so as I will be fitting quad throttle bodies to my F20C engined race car in the next year or so.
The factory ECU has a few special things it does which a Motec will not easily do such as the Honda 3 wire idle control valve, the alternator charging control, ODB2, Immobliser, RPM signal to the instrument panel.
I think this is the reason why people piggy back the Motec rather than replace the whole ECU. The Motec can be programmed for the idle control with another Motec compatible valve installed, it can also be programmed for the tacho output.
The standard ECU also has feedback from lots of sensors to check that things are working correctly. With a piggy back setup the injectors, vtec, igniters and possibly AF sensor would not be controlled by the honda ECU so the honda ECU may start to post CEL errors galore. You would probably pull the globe out of the instrument panel. The ODB2 data will not necessarily be valid.
The Motec does offer some nice things such as Launch and traction control, full throttle gearchanges, data logging, boost control, anti-lag. Make sure you get the Motec model with enough channels. The M800 is the pick at the moment as you have lots of i/o channels to play with.
If you wanted to make the car a racer I would suggest finding a work around on the alternator and using only the Motec M800 and ditch the Honda ECU, and do without the immobiliser, ODB2.
Look into the pricing. I think you will find an V-AFC or similar will be a much cheaper and simpler way to achieve easy mixture/ign trims on a roadgoing car.
Speedracer.