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      03-03-2012, 06:20 PM   #1
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M button and horsepower, revisited:

So the conventional wisdom seems to be that the M button changes the throttle mapping and builds boost faster, but does not change peak boost or power output.

Forum member Zuzu has posted dyno results here that seem to contradict this. The following dyno show his 1M with and without the M button pushed, all stock including software except for an N55 midpipe:
Multiply by 1.34 to get HP, so this is 325 WHP without M and 346 whp with, or 21 HP difference...

Given this, it would seem the M button really does unlock more power. Has anyone else taken the pepsi challenge, or have supporting/ contradictory evidence?

The original thread where this came up is here:
http://www.1addicts.com/forums/showt...=651547&page=2
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      03-03-2012, 06:32 PM   #2
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Very interesting.

Don't believe the M button triggers a different map but that it changes the wastegate setting for quicker response.

Neil
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      03-03-2012, 06:45 PM   #3
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Is that lower line, your boost? Doesn't look like a torque line.

Did you swap the mid pipes recently? Was the car learning?
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      03-03-2012, 06:55 PM   #4
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The lower line does appear to be boost, in PSI (don't know why they don't stick with metric?). Appears to show ~4 psi more boost until the very top end. Almost looks like overboost, but the claim is that effects torque but not HP.

No idea how long it had to learn, I think he'll chime in here soon...
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      03-03-2012, 06:56 PM   #5
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all i know is first thing i do after starting the car is push the M button
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      03-03-2012, 07:01 PM   #6
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It's possible with the mid pipes, that you're over boosting since you're removing exhaust restrictions. Just a guess though.

From what I hear, the over boost is only affecting midrange power and doesn't carry over into the upper RPMs, thus your peak HP never increases. It would be really nice to test the M button on a completely stock car (I"m surprised no one has done this?)
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      03-03-2012, 07:02 PM   #7
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Anything is possible - when I press mine, the ride seems to stiffen up as well (yea, I know, impossible, but still).
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      03-03-2012, 07:04 PM   #8
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Quote:
Originally Posted by -cj- View Post
Is that lower line, your boost? Doesn't look like a torque line.

Did you swap the mid pipes recently? Was the car learning?
Hi.. Yep lower line is boost..Peaked at exactly 14 psi.

Mid pipes have been 14 days before the dyno and probably on covered about 80 kms since install. So yes, the car was learning on the dyno and it explains why after 5 runs it probably adapted..
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      03-03-2012, 07:08 PM   #9
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Quote:
Originally Posted by -cj- View Post
It's possible with the mid pipes, that you're over boosting since you're removing exhaust restrictions. Just a guess though.

From what I hear, the over boost is only affecting midrange power and doesn't carry over into the upper RPMs, thus your peak HP never increases. It would be really nice to test the M button on a completely stock car (I"m surprised no one has done this?)
I did do 4 runs on stock with no mid pipes before install 2 weeks earlier.

In this case the car kept malfunctioning on dyno and throwing codes when M button was pressed..

This time the operator persisited and there seem to be more adaption to the new mids and no probs with the electronics throwing codes..
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      03-03-2012, 08:02 PM   #10
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I'd put my money on the idea that we're seeing the difference between overboost and non overboost. 10 psi is too low for stock boost without The question is, did the M button somehow make the car go into (or make it more likely to go into) overboost?
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      03-03-2012, 09:18 PM   #11
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I've dynoed my car a few times, both mustang and dynojet, both stock and with mods, and everytime i'd ask the operator to dyno with and without the M button...everytime the difference was within 1-2hp.

10psi is way too low.
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      03-03-2012, 09:28 PM   #12
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Quote:
Originally Posted by Franklin Joseph View Post
I've dynoed my car a few times, both mustang and dynojet, both stock and with mods, and everytime i'd ask the operator to dyno with and without the M button...everytime the difference was within 1-2hp.

10psi is way too low.
+1. Here is what I posted in the other thread, which confirms your findings:

1. I have dynoed the car with M button on, and with it off (in consecutive runs). No change in observed peak HP numbers.
2. I have a boost gauge (get's physical readings through DV lines as opposed to the CANbus version). No observed difference in peak boost between M and non-M mode (15psi peak on stock tune regardless if M button is engaged).
3. I have also logged the car in multiple parameters, peak included, through the AccessPort. Again no difference in peak boost was noticed whether M button was activated or not (via ECU readings this time).
4. Tuners like COBB have maps which disable the M button all-together (e.g. their 91 and 93 Linear Throttle maps where there is no difference if you depress the M button or not). This results in no change in recorded peak power as compared to there Non-Linear Throttle maps (where the M button is allowed to work). All it changes is sensitivity on throttle response, not peak power (nor boost).
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      03-03-2012, 09:48 PM   #13
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Quote:
Originally Posted by Franklin Joseph View Post
I've dynoed my car a few times, both mustang and dynojet, both stock and with mods, and everytime i'd ask the operator to dyno with and without the M button...everytime the difference was within 1-2hp.

10psi is way too low.
Hypothesis: The car was cold when non-M button was pressed and didn't go into overboost, until the later runs when the engine is up to temp?
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      03-03-2012, 10:06 PM   #14
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Quote:
Originally Posted by sparoz View Post
Hypothesis: The car was cold when non-M button was pressed and didn't go into overboost, until the later runs when the engine is up to temp?

This could be the reason...engine oil has to be over 160 degrees to produce full boost.
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      03-04-2012, 06:11 AM   #15
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I saw no difference between the 2.
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      03-05-2012, 09:41 PM   #16
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Quote:
Originally Posted by doug_999 View Post
Anything is possible - when I press mine, the ride seems to stiffen up as well (yea, I know, impossible, but still).
I'd swear by this too!
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      03-05-2012, 10:49 PM   #17
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Quote:
Originally Posted by M3 Adjuster View Post
I'd swear by this too!
Maybe I'm not completely crazy
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      03-06-2012, 07:57 AM   #18
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Quote:
Originally Posted by doug_999 View Post
Anything is possible - when I press mine, the ride seems to stiffen up as well (yea, I know, impossible, but still).
You sure something else is not stiffening?

Neil
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      03-06-2012, 09:06 AM   #19
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Quote:
Originally Posted by Franklin Joseph View Post
This could be the reason...engine oil has to be over 160 degrees to produce full boost.
Well this would explain why sometimes my car feels slower... lol
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      03-06-2012, 10:13 AM   #20
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Quote:
Originally Posted by MDORPHN View Post
You sure something else is not stiffening?

Neil
Stranger things have happened when driving the 1M...
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      03-06-2012, 01:35 PM   #21
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Quote:
Originally Posted by MDORPHN View Post
You sure something else is not stiffening?
Quote:
Originally Posted by doug_999 View Post
Stranger things have happened when driving the 1M...
M button...

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      03-06-2012, 04:30 PM   #22
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Question

Quote:
Originally Posted by MDORPHN View Post
You sure something else is not stiffening?

Neil
LOL, Mines not broken in yet. Can I push the button??? Seriously, will it be bad for me to push the button at 700 miles?
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