14 mpg no matter what!

[M5280RCR]

Originally Posted by Dr. George

Came from an E46 M3. Gas mileage was not bad. Got this 2011 E9x last week. Runs like a bat out of hell. No matter how I drive it, it gets 14 mpg. I'm gonna have to get used to this gas mileage. Everyone get the same or worse?

I added a super charger and my mpg increased from an average of 16 to 19 mpg; 20% improvement. I'm not a techy so can't explain why, but strongly suggest you consider installing an ESS 625!

PS. When gas was close to $5 per gallon I calculated the sc'er would pay for itself in 9 years,

[V8FunNaturally]

Originally Posted by M5280RCR

I added a super charger and my mpg increased from an average of 16 to 19 mpg; 20% improvement. I'm not a techy so can't explain why, but strongly suggest you consider installing an ESS 625!

PS. When gas was close to $5 per gallon I calculated the sc'er would pay for itself in 9 years,

Isn't the electronics wrong when calculating mpg for an engine that is no longer stock with a SC ? I could be wrong but read this before.

[M5280RCR]

Originally Posted by V8FunNaturally

Isn't the electronics wrong when calculating mpg for an engine that is no longer stock with a SC ? I could be wrong but read this before.

Not sure I understand the question, but I don't use the obc to calculate mpg, but rather the old fashion way dividing number of miles on trip odometer by number of gallons to fill up (the obc overcalculates quite a bit, 5% plus or minus)

[Helmsman]

Originally Posted by M5280RCR

Not sure I understand the question, but I don't use the obc to calculate mpg, but rather the old fashion way dividing number of miles on trip odometer by number of gallons to fill up (the obc overcalculates quite a bit, 5% plus or minus)

Better do guys because the M3 OBC calculater is proven to be wrong by a good number of MPG. The non M cars OBC do make the calculations fairly spot on (how hard can it be), so this bit is less than good by BMW.

Cheers

[1MOREMOD]

Originally Posted by Helmsman

Better do guys because the M3 OBC calculater is proven to be wrong by a good number of MPG. The non M cars OBC do make the calculations fairly spot on (how hard can it be), so this bit is less than good by BMW.

Cheers

Not an accident.

[V8FunNaturally]

Originally Posted by M5280RCR

Not sure I understand the question, but I don't use the obc to calculate mpg, but rather the old fashion way dividing number of miles on trip odometer by number of gallons to fill up (the obc overcalculates quite a bit, 5% plus or minus)

interesting. It's in line with the better mpg i observe with power mode on the stock engine. Frictions losses seem to play a significant role in the s65. More torque over a shorter time (SC case) seems to incur less Energy losses to friction over that acceleration than using less torque over a longer time (stock case) to reach same final speed . That's odd as the former case should result in similar (at best or worse) friction losses but not better !

Except... if the the friction force evolves over the time spend under acceleration due to a reduction of the oil film thickness in some engine surfaces (rod bearings ?). If that's the case it could explain the better mpg with shorter stronger accelerations.

There is a dry sump conversion available for the s65, i think that might be the best engine mod for the s65. The wet sump is something of a let down for a high rev engine.

I also wonder if bhp can reflect how much frictions (due to RB) a particular engine has.

[Amirsm3]

Originally Posted by OhSoCal

Are you in normal mode or power mode? Wondering if that even makes a difference in mileage.

It just changes throttle response. You can turn on "power" and lighten up on the pedal pushing and still achieve "optimal" mileage.

[V8FunNaturally]

Originally Posted by Amirsm3

It just changes throttle response. You can turn on "power" and lighten up on the pedal pushing and still achieve "optimal" mileage.

true but it changes the response in a non linear fashion. Steeper initially and rolling off after. It's not a linear multiplication especially in the first few inches of the pedal.

[Amirsm3]

Originally Posted by V8FunNaturally

true but it changes the response in a non linear fashion. Steeper initially and rolling off after. It's not a linear multiplication especially in the first few inches of the pedal.

But technically, it shouldn't alter fuel economy, though, since nothing is being altered with the timing, etc etc.

For instance, pressing the button then setting my cruise control to 75mph should do nothing to negatively impact my mileage.

If the person I quoted meant something different and it went over my head, I apologize

[V8FunNaturally]

Originally Posted by Amirsm3

But technically, it shouldn't alter fuel economy, though, since nothing is being altered with the timing, etc etc.

For instance, pressing the button then setting my cruise control to 75mph should do nothing to negatively impact my mileage.

If the person I quoted meant something different and it went over my head, I apologize

All you said is correct but I am talking about something different. How mpg is impacted in dynamic driving (bouts of accelerations) reaching the same speed but using different torque to get to that speed. Obviously in constant speed with cruise control on flat terrain the throttle butterflies opening is going to be the same with power mode on or off. What i am getting to is how friction losses change if driving with a slighlty more aggressive style (which power mode indirectly promotes and SC even more). Using more couple shortens the time during which the car is under acceleration until it reaches the wanted speed (say 60 mph). That seems to reduce loss to friction in a car where oil film is getting brushed away if the car is under prolonged acceleration even if that acceleration is less.
I'm wondering if the engine gets enough oil. Two things might play a negative role : wet sump oil pump, and of course RB clearance..