gained a coupple mpg's

Due to the technical nature of calculating MPG average in the U.S.-Based Prius models I expect you have more detailed information on how you went about measuring the MPG change?

Excuse me for being VERY skeptical here but no one else has measured such gains so it would be interesting to see how you accomplished such a feat and took driving style out of the equation.

 

I had a feeling you might have done that, which is why I asked.

The Prius (U.S. and Canadian models) use a bladder fuel tank system which is somewhat felxible so the amount of fuel you put in on one day may be different than the amount you are able to put in the next day. Therefore, you cannot do the type of "hand" calculation you performed and expect any accuracy without creating an average over at least 10+ tanks of fuel and more likely 20+ to get a good average sample.

There are numerous threads on the subject of hand calculations and computer calculations and they explain how you need to average over many tanks to get any accurate #s. If you look through the first few pages in this forum you'll find at least a few. It's a good idea to read those to gain a better understanding of the Prius fuel system.

Then you can go on to learn about how small changes in driving conditions and driving style can make large changes in MPG. We must understand these basics before we can attribute any MPG changes to a new part. I hope this helps out.

 

LOL

It's a double-edged sword for me. I wish it was a regular tank so I could get the full 11.9ga worth of fuel in it and be able to better calculate my MPG BUT they do this for emissions reasons so I end up polluting peoples lungs and the environment less than if it was a regular style tank. I'll settle with the finicky tank if it means less pollution. I do ray: that they will make it better on the next Prius though.

 

might wanna invest in a scangaugeII for better mpg guess-timation

 

There is a whole lot of ignorance in that post so I'll just let it go. If you would like to learn more about why you are wrong I invite you into the environmental forum where there are threads on the subject and we can field any specific questions you may have. My 3rd job is a student of Ecology/Biodiversity and environmental science.

 

Actually now is the best time to get that V8. With so many people leaving their V8's and trying to get a more fuel efficient car, the demand on V8's is low and the supply is very high. That means the best time to negotiate a very favorable price for yourself.

If you can't afford it at this time, you can sell off your Prius, probably for a profit from what you initially paid for it (high demand for Prius vs low current supply) and get one helluva V8.

If we do start drilling off the coast and gas drops to $2/gallon, people will abandon the "slow footed" Prius and go back to their V8's, thus you won't be able to sell your Prius for as much and the cost of the car you want will increase.

I say, strike while the iron is hot!

 

So how far off is the estimate the Prius itself provides? I'll look for these threads you mentioned but I think I've seen them before and couldn't quite sort out the best way to track mpg.

 

The Prius MFD is the most accurate way of tracking milage if you do so over a large number of tanks. The same can be said for hand calcs. They tend to be within 1-3% of each other after 20+ tanks of fuel.