slant911

Chuck,

Yes in my case on my drive home with new car it was just 1200 miles of cruise control (and a few blasts )

For the first 12 hours of the drive I barely saw 100 cars in either direction. It was the backwoods of Oregon and Northern California. I'll have to write a book sometime about my adventure. It was pretty fun and memorable.

MidnighTT

I believe that, if you change injector size, the calculated fuel mileage display will be wrong. The ECU is commanding shorter fuel injector pulses (injector pulse = time period during which the injector is flowing fuel) during cruise with your larger injectors than it would with stock injectors. I believe it calculates fuel mileage by "adding up" the injector pulses. Larger injectors -> shorter pulses -> "better" fuel economy.

If you haven't changed cams or compression ratio, your cruising mpg should be very close to stock. It's fun to dream, though!

Jeff

John D II

That explains it...the computer says over 20 mpg when I am actually getting 15-16 mpg based on physical calculations...

Chuck Jones

Dennis: I know that at any time during a trip, you can reset your mpg function to zero and it will start over again at whatever rate of consumption is going on at the time....so you can actually get high mpg displays if you were to reset while on a long straight stretch and set it on cruise at say 70....but overall it will eventually drop down as you climb hills, go thru towns etc. In my 99 996 I did that reset function and got over 31 mpg for a stretch...but it was under absolute optimum circumstances while holding steady and already rolling at a given speed. I didn't even get that sort of mileage out of my motorcycle.

sechsgang

thats ridic...I never get over 9 mpg in my turbo other than in the pits!


and my M5 I fear is even worse!

Chuck Jones

Sechgang: Nice lift on the inside tire!!!

Mr C

Some tuners out there can reprogam the ECU so the trip computer fuel mileage display remains accurate, even with large injectors, at least I know UMW can, but probably not many others in the USA. Good European tuners can do this too, I have friends running Sportec 600+ conversions and their actual gas mileage vs. trip computer displayed gas mileage is 100% accurate, even with VERY BIG injectors.

Just my 0.02.

BuddyG

what kind of mpg's are they getting?

Mr C

More around low 20s if calculated back to mpg when they drive the cars sensibly. 28 MPG at 87mph is definitely not feasible, next time you fill up, reset your daily mileage counter and when the tank is empty, check how many gallons you put in for how many miles, easy enough to work out MPG from there

lightguy

Any up date here ?
I was shoping for an economy car for the wife, Mini Cooper was up on the list when I found this thread.
700 HP twin Turbo Porsche would be prefered

VRAlexander

Nice.... You cant beat that giving the car it is!!!



http://www.youtube.com/watch?v=Jt0KhGJyayM