M button and horsepower, revisited:

[ozinaldo]

Originally Posted by buckeyegirl

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?

Please do. Nothing bad happens.

Seriously, it just doesn't harm.

[Dan Parker]

Don't do it! I heard a salesman say it would void the warranty immediately.

[Artemis]

Originally Posted by buckeyegirl

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?

No harm at all, well on the contrary, it will get you hooked.

One might consider the break-in period as the first date. Up to you to decide whether you want to go all the way.

Alfie reaching for the M button ("In a flash I have my New Year's resolution - aim higher"):

[johnnyb84]

I was wondering how this topic could possible go to two pages. Now I know.

[RPM90]

Originally Posted by Pete_vB

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...

That is the claim, but without torque there is no HP.
Since HP is calculated from torque, then if torque goes up so will HP.
I don't know why BMW chose to advertise the over boost as greater torque without saying it has greater HP as well? Maybe they figured people who want this car would already know that?

Here's another dyno:
http://www.bimmerpost.com/2011/05/26...331whp362rwtq/

They too claim the "M" button doesn't do anything for power, just throttle response.

Does over boost come on during a dyno run?
In street driving, when do you feel over boost coming?
Is it during a downshift at speed?
Does it do it in gear and you smack the loud pedal all the way down?
I've not driven a 1M or BMW with over boost so I don't know.

[RPM90]

Originally Posted by Franklin Joseph

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.

I believe stock boost should be around 11.6psi, and over boost can get up to 14.5psi.

Stock N54 boost is about 8.7psi.
With the JB+ set to near maximum, not set to full "max", boost pressure shows a bit over 12psi.
That's about right as the JB+ at "max" setting can give up to a 4.75psi increase.
The claimed wheel power increase is 40hp and 50lb ft. at the "max" setting, which should be about 13.5psi, about 1psi less than
the 1M's 14.5psi at max over boost.

This dyno does show a low boost on the first run, and the second run is close to over boost levels for a short duration as it should be.
Seems the second run is normal for a 1M.

[Pete_vB]

Originally Posted by RPM90

That is the claim, but without torque there is no HP.
Since HP is calculated from torque, then if torque goes up so will HP.

At any given point HP and Torque are directly related, but peak hp and peak torque don't occur at the same RPM. What BMW claimed they did was what they had done for the 335is, which also has overboost. There you see a big increase in torque, but this rolls off at high RPM, so you see almost no increase in peak hp, as seen in these dynos:





With the evidence at hand, however, it looks like BMW held the peak boost longer for our 1M, so overboost effects peak hp as well as peak torque (though not as much).

Originally Posted by RPM90

In street driving, when do you feel over boost coming?
Is it during a downshift at speed?
Does it do it in gear and you smack the loud pedal all the way down?
I've not driven a 1M or BMW with over boost so I don't know.

It's difficult to tell for sure, but personally I sometimes notice when overboost doesn't kick in. I'm never exactly sure when this will occur; clearly overboost is limited when the car is warming up, but I try not to push it all the way during warm-up anyway. Outside of that I do find that occasionally, probably less than 5% of the time, when I ask for maximum warp the engine bay doesn't fully respond. I have not been able to determine the pattern yet- maybe it's stating higher in the rev range, maybe it's a misfire caused by poor 91 octane CA gas, I don't know... Generally overboost is seamless- you go for the full beans and they are there when you call.

[HP Autosport]

There is no difference in power as confirmed by GIAC with my 1M on the dyno througout the software development process.

[LotusBoy]

Originally Posted by Pete_vB

At any given point HP and Torque are directly related, but peak hp and peak torque don't occur at the same RPM. What BMW claimed they did was what they had done for the 335is, which also has overboost. There you see a big increase in torque, but this rolls off at high RPM, so you see almost no increase in peak hp, as seen in these dynos:





With the evidence at hand, however, it looks like BMW held the peak boost longer for our 1M, so overboost effects peak hp as well as peak torque (though not as much).


It's difficult to tell for sure, but personally I sometimes notice when overboost doesn't kick in. I'm never exactly sure when this will occur; clearly overboost is limited when the car is warming up, but I try not to push it all the way during warm-up anyway. Outside of that I do find that occasionally, probably less than 5% of the time, when I ask for maximum warp the engine bay doesn't fully respond. I have not been able to determine the pattern yet- maybe it's stating higher in the rev range, maybe it's a misfire caused by poor 91 octane CA gas, I don't know... Generally overboost is seamless- you go for the full beans and they are there when you call.

+1, sometimes, overboost doesn't kick in, and this using 98 octane fuel (EU).

[bdaddylo]

For the most part your butt dyno can detect overboost, but there's no substitute for a boost gauge. I can't understand why BMW left this out.

Everytime I fill out the BMW after service survey, I comment on the lack of an engine oil dipstick and boost gauge. Maybe one day they will listen.

On my baseline dynos the tech wasn't able to engage sport mode with traction control off, but my numbers were consistent with everyone elses.
I'm heading to the dyno tomorrow to see if I gained anything from the Helix intake and Berk midpipes.

[Franklin Joseph]

u should ask the tech to press the sports mode button first then traction off.

Basically when u turn traction off then click on sports, sports is on, but it just doesnt show up on the dash.

[-cj-]

Why wouldn't it run on the dyno with M-Mode?

[///M1]

I just had another set of dyno runs with and without the M button. No difference.

[ozinaldo]

Originally Posted by ianf

Another member's dyno two runs with 1M. No M-button=243kW, with M-button=252kW.

My car would not run on dyno in M-mode, but in normal mode did 248kW (mid pipes)

Numbers are at the wheels?

[PSYMON81]

when you press the M button....the horse....is getting a BEAST!!! is TERRIBLE!!! aahahahahah

[v1k0d3n]

oh not this topic again! lol

hp is completely overrated these days...i think car manufacturers should look at neodymium propulsion. that's where it's at.