@Andrei_ierdnA

Thanks for the tips. Per your suggestion, I've set my tires to 40/38psi as an experiment. I have a couple long trips coming up next week including another drive down to LA from SF. I'm taking the same route so it'll be interesting to compare milage with higher tire pressure this time. I can already tell the car feels better and I like it. 33/32 is definitely more mushy and always looked under inflated to me. No idea why Honda specs it that low when the tires are rated all the way up to 51psi.

Re: Hills - Yes, that's intuitively how I've been driving, with an eye towards using momentum as much as possible. It's kinda like an iOS game I used to play called Tiny Wings. The idea was to use hills and energy at just the right time to build momentum and glide the bird as far as possible. It's a great model for hyper-mileing

Tiny Wings by Andreas Illiger

 

Most manufacturers of regular cars spec around 32 psi on the door stickers.
I believe this is partly due to comfort, but also due to the fact that there are many different types of tires out there. Car manufacturers need to cover themselves from the liability of some people using the cheapest tires they can find.

El Cheapo tires (Made in China / no-names) are typically only rated for max cold pressure of 35 psi. The rubber in these type of tires is usually inferior to name-brand tires. Running these at high pressures will likely result in uneven faster thread wear, missing chunks and bulges from potholes, possibly even blowouts.

That's definitely helping you get better mileage. The problem you are facing is still the hills and short trips, I highly doubt there anything wrong with your car or your driving style.
Most hypermilers out there that have epic MPG are also long commuters driving in low traffic at the sweet spot of 50-60mph. So your best bet in getting better city mileage would be to stop all short trips, especially those under 5 min.

One other tip since you mentioned you're easy on the throttle. Many hypermilers advise it's better to accelerate quicker at about 75-80% throttle or engine load until reaching desired speed (a Scanguage really helps here), rather than the opposite approach of accelerating slowly since it will take longer to reach your speed and the car actually ends up burning slightly more gas that way.

Also turning off your AC climbing large hills and turning it back ON for the descent while coasting helps too.

 

Back from LA and logged my best and second best mileage to date! 44.5mpg driving down and 43.4 driving back.

Maybe it was the higher tire pressure or maybe it was near perfect driving conditions (no traffic delays either way) or maybe a combination... whatever it was, I'm keeping the tire pressure higher (40/38) and will probably try going up to 42/40.

I don't see any downside - better mileage as well as better handling and a nicer feeling ride... what's not to like?

Happy Holidays, All!

 

It's exciting to get better fuel economy and if you don't mind slightly harsher ride and wear on your struts and other suspension parts. But keep in mind that higher pressure in the tire, e.g. 44 vs 32 will result in lower traction and high speed grip. Personally, I wouldn't do it, I wouldn't want to risk crashing and dying trying to squeeze out 1 or 2 mpg especially at the cost of the increased wear of the suspension.

Why do you think manufacturers who purse fuel efficiency, like in a new prius don't recommend the high pressures you are suggesting?

Because they do see something serious "not to like about it". There is no free lunch. If there was, we would all be rolling on blocks of wood, fiberglass, or have train wheels, they have very low rolling resistance.

 

Another way to save gas is to buy a 87 Tercel M/T which yields 30 mpg city if you don't mind adding a quart of oil every 200 mi.
I am getting 27 mpg now and about 29 mpg at best

 

Usually 28.5-32 mpg. I have a light foot and usually keep my tires around 38-40 psi. Never had any issues with faster wear, ride quality is a little harsher (nobody ever mentions it when they ride with me). MPG is usually much better as a result. Pulling away from an intersection slowly is generally what makes the largest difference in MPG.

 

I've never seen less than 39 mpg on my meter and never calculated less than 39. Highest ever had was in the high 50s. Gravity is my brake pedal.