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Originally Posted by Poochie
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Originally Posted by The Nerd
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Originally Posted by Poochie
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Originally Posted by Weiner0123
Do you think I could have been tricked about this "environmental recall" I noticed a significant decrease in power after I serviced it for the recall.. I ordered the vehicle in February so I got a really early production model... I wonder if I got duped
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Thanks a lot for sharing this letter, it explains what all this hoopla about the 'power lost' is about.
Here in the US, there is no emission standards at full throttle (85%+). This exception was made so car manufactures could deliver maximum power when it is needed the most and the overall effect on emissions would be small, since people rarely drive at full throttle.
Thus, at high RPMs, the O2 sensors go into an "open loop" state and is taken out of the system so the fuel system can be enriched for maximum power, without the needed to abide by any federal emission standard, since it's exempt.
It seems in the early M340i, the ECU mapping was programmed in error to place the O2 sensor in a "open loop" state at lower power band, instead where it belong, at WOT.
This new software update places the power back in the higher RPM to meet allowed emission standards. So the addition power wasn't taken away, it was just move to higher band in the RPM.
This aftermarket tune just brings back original lower end power band. |
Thanks for the info....2 questions.
1) Where did you learn of the info you shared regarding this power loop, emissions standards, etc, etc? I'd like to read more about that as it pertains to the m340i.
2) If what you're saying is true (no power lost, it was just moved to lower rpm ranges)....then, wouldn't Mission Performance's peak WHP #s from their dyno remain relatively the same from earlier model to late model....albeit at different rpms? Because on their dyno, their was a 50-60 WHP LOSS....that sounds like actual power being robbed.
And by the way, I do understand that a car's performance is about the total area under the horsepower and torque curves, not just peak #s. However, a horsepower loss is a horsepower loss.....and it would be nice to truly get to the bottom of this. Thx again for sharing.... |
First of all, I gain nothing by coming here and making up a facts. Google is still free, anyone can search the subject on "open/close loop 02 sensor" to verify this, which is my source. That and a keen understanding of emission standards measurement. The subject would take pages of typing for me to break down.
The second I heard some random tuner is claiming a major auto manufacture is taking away almost 50hp, I knew it was nonsense. Had it been true, it would be a front-page headlines by now.
I just couldn't confirm it until I saw the official letter from BMW where it stated "this issue could cause emission to exceed the prescribed standard" that's when I figured out what they both meant because I understood how allowed emission standards are measured.
You ever wonder how a ULEV N20 motor could legally roams the streets same as a gas-guzzling, dinosaur-burning V12 Lamborghini? It's because said manufacture has demonstrated to the EPA that their motor doesn't effect allowed emission standards given today's federal testing procedures.
If it helps you sleep better at night believing that BMW took away your power and a tuner brought it back, that's fine. No disrespect to them but it's absolutely a false statement.
It's just BMW original tune was ignoring the original set standards and now it was corrected and moved to a higher band in the RPM, where it's allowed.
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http://www.autotap.com/techlibrary/u...en_sensors.asp |
Sorry Poochie, I wasn't trying to imply that you made up facts. I was genuinely asking where the specific information (as it pertains to the m340i) came from that yields this change in power from higher rpm to lower rpm bands. All that being said....I'm still not understanding how the PEAK numbers are so drastically different (on Mission Performance's dyno)between the early version and current version. If it's just a change of "where" the peak power hits (from higher band to lower band), why would the peak numbers be so different?
Regarding whether BMW "stole" horsepower back, or, just renormed the power due to the emmissions issue....that minutiae doesn't matter to me. What WOULD matter (if I were an m340i customer) is if I test drove a faster, earlier version....ordered a car based on that drive/feel, and then felt underwhelmed by a slower, less powerful vehicle when my order came in.