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      11-10-2012, 09:35 PM   #23
kwike92
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Originally Posted by 808@702 View Post
Feeling more power and seeming to get better gas mileage to boot.
haha i was thinking the same thing this morning... i woke up real early to go fishing, and the temp was 42 in south orange county, and my car pulled hard..
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      11-10-2012, 09:47 PM   #24
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Between the temps and a less restrictive exhaust, my car was absolutely phenomenal today.
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      11-10-2012, 10:00 PM   #25
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Okay people, I had a brain fart, lay off. While the boost pressure is constant, the reduced temperature of the charge dictates an increase in density (ideal gas law) meaning more oxygen and power.
Are you referring to a SC M3 or turbo cars in general?

Take for the moment turbos, depending on which car you are referring to, and whether the ECU is torque targeting or boost targeting can mean two scenarios

1) Torque targeting, in cold weather setup, car makes less boost because its able to reach its torque target faster

2) Boost targeting you will make more power for every added amount of boost. This ECU setup is great for cold weather but sucks for hot weather as the car will pull timing to prevent detonantion.

The answers are not as simple as just referencing the ideal gas law, there are many variables involved the most important being the ECU logic
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      11-12-2012, 01:32 PM   #26
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Originally Posted by Amri215 View Post
Are you referring to a SC M3 or turbo cars in general?

Take for the moment turbos, depending on which car you are referring to, and whether the ECU is torque targeting or boost targeting can mean two scenarios

1) Torque targeting, in cold weather setup, car makes less boost because its able to reach its torque target faster

2) Boost targeting you will make more power for every added amount of boost. This ECU setup is great for cold weather but sucks for hot weather as the car will pull timing to prevent detonantion.

The answers are not as simple as just referencing the ideal gas law, there are many variables involved the most important being the ECU logic
If it's boost targeting, there isn't any additional boost. That's the definition of boost targeting. But a quick look at the ideal gas law tells you that if pressure is held constant (boost targeting) and the temperature is lower, the density must be higher.

I thought that it was pretty clear that I was referring to the basics of a boost targeting type setup. It would have been pretty simple for you to just add a note about torque targeting instead of trying to "call me out".
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      11-12-2012, 01:44 PM   #27
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Something I miss about my 'ol E36 Supercharged M3. Used to drive on PCH, around this time, car felt so fast and so strong.
I haven't tried it in the E90 yet.
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      11-12-2012, 02:35 PM   #28
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Quote:
Originally Posted by M3PO View Post
If it's boost targeting, there isn't any additional boost. That's the definition of boost targeting. But a quick look at the ideal gas law tells you that if pressure is held constant (boost targeting) and the temperature is lower, the density must be higher.

I thought that it was pretty clear that I was referring to the basics of a boost targeting type setup. It would have been pretty simple for you to just add a note about torque targeting instead of trying to "call me out".

all you guys type like the engineers you prob are and just sound silly. Stop with "ideal gas laws" blah blah blah.. your vocab exceeds your mech know how obvi.

Truth is, many turbo cars can induce an (unrelated) boost creep with the cold weather that will cause a fuel cut from the "better" air.
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      11-12-2012, 02:47 PM   #29
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Originally Posted by m3an View Post
all you guys type like the engineers you prob are and just sound silly. Stop with "ideal gas laws" blah blah blah.. your vocab exceeds your mech know how obvi.

Truth is, many turbo cars can induce an (unrelated) boost creep with the cold weather that will cause a fuel cut from the "better" air.
And you type like a 15 year old girl on FaceBook.

I am an engineer and you know nothing about my "mech know how". Thanks for the unrelated post though.

Boost creep is a function of wastegate design. If you are at the limit of the wastegate's ability to bypass exhaust during warm weather, it won't be able to bypass the additional exhaust during cold weather and the boost will creep. That leads to a dangerous lean condition, not a fuel cut.
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      11-12-2012, 02:48 PM   #30
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      11-12-2012, 02:55 PM   #31
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And you type like a 15 year old girl on FaceBook.

I am an engineer and you know nothing about my "mech know how". Thanks for the unrelated post though.

Boost creep is a function of wastegate design. If you are at the limit of the wastegate's ability to bypass exhaust during warm weather, it won't be able to bypass the additional exhaust during cold weather and the boost will creep. That leads to a dangerous lean condition, not a fuel cut.
ok; as said by my () unrelated meaning yes boost creep is related to the wastegate essentially being overrun, however; it is amplified in colder weather and yes, this will induce a fuel cut as the car is seeing too much air to correlate with a lean condition being present.

15 y/o girl. OK man, good for you; you engineers are the best!
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