[Shovelman]

Mileage and power are excellent. The turbo is lackadaisical.

Just returned from a 5,000 mile road trip.

Highway mileage is 42 at 70 mph. That's outstanding for a 250 hp car!

Mixed driving is 32 mpg (US gallons)

From coast to full throttle leaves you waiting about 1.5 seconds for the power surge (in comfort mode) it is only a little better in Sport+ mode.

A different engine might keep the turbo spinning faster at low demand for faster response. That would make it more thirsty.

These are just my observations. Any other ideas?

[jase2addict]

A tune can take away some of the delay. But may increase gas consumption. There is a product called pedal box which some people swear by.

[crabu2]

42 at 70? Maybe I should slow down.. I'm either flying or rush hour traffic and I'm getting 28-31 mpg... But 42 at 70? Was this trip all down hill?

[3rdcoast228i]

I got 38.8 mpg on a 35 mile trip the other day. (N26)

If it had been all freeway I could see getting 40mpg at 70 mph

B46 must be a little more fuel efficient than the n26

[USA-RET]

Lag is electronic throttle, not turbo IMO. Tune does help. Dinan Stage 1 eliminates any hesitation from a dead stop in Comfort and Sport, Still just a touch in Comfort if you go from a slow roll (1-2 mph) to gas, Have not tried it in Sport.

I have the M240i, so not sure how much of a variance there will be w/ a tune on your car. However, the electronic throttle seems to be the issue across models and brands.

[crabu2]

Originally Posted by USA-RET

Lag is electronic throttle, not turbo IMO.

You might be right on this... because if I ease into the go peddle, there's no lag. This is exactly what happens on my Cummins Ram. In the case of my diesel, the reason they have it tuned like this is because of emissions. They don't want too much fuel dumped into the engine at once, causing unburned fuel. I wonder if this might be true with these gas engines too....