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View Full Version : Rate of acceleration vs pumping loss (mpg)


enkeivette
08-01-2008, 03:38 PM
How many threads about mpg can someone with a carbed blown V8 start? :smack:

I was reading a post by someone that knows waaay more about engines than I do. He said that he gets the best mileage by "accelerating briskly" through 1st to 3rd gear staying below 3K rpm (4 cyl turbo) up to cruising speed, and short shifting into 5th.

Thinking about it, this makes sense. I average 25mpg in my Neon in the city, driving just this way (as I tend to do naturally). For one tank, I tried an experiment and stricly stuck to it. I accelerated slooowy though all of the gears, taking 2 to 3 times as long to reach cruising speed. Drove like a grandma all week, no joke. When I went to fill up and calculate my mpg, I was surprised to find that I averaged 22mpg. :eek: At the time I thought it was a fluke. Now I realize that staying in the lower gears longer at higher rpms (still below 3K) increases pumping losses to the point that I screwed up my gas mileage.

Although I'm not sure this would work the same if you tipped into the boost. As most cars will increase fuel pressure upon seeing boost.

enkeivette
08-01-2008, 03:56 PM
TTT

Don't miss this one. It's even more interesting IMO. And I won't be as defensive if someone wants to shoot it down, because it's far from an exact science theory.