29.5 mpg @ 84mph
 

Got to do a nice road trip this weekend to whyoming wish i wouldnt have ben in a hurry hence the 84mph but pretty happy with almost hitting 30 mpg with a full highway tank.

I love that about my second gen. When I'm in a blazing rush I don't get good numbers... until I look at the numbers and reflect that I got them while going really fast!

30 in a fit is ridiculous, but so is 30 when you're doing over 80. :)

it's hard to feel guilty about speeding at 30 mpg!!!!

I know, but I'm trying to get back up into the 50s. Saying "well, I'll still get in the high 30s for the trip" is a tank killer.

When you're spending the winter struggling to get above 40, it takes a lot of discipline to not say "screw it" and get there a bit sooner at the cost of just a few mpg.

I've had a tank avg 32mpg in my 2010 Prius
we were running 75-80mph the whole time, very windy out
and we had a Thule cargo box on top the whole time
as well as very loaded for the road trip

Nice! Throw on some aero mods and at that speed your MPG will go up pretty quick. I get about 33-35 highway in my B5 Passat at that speed, ~45 MPG at 55. Gotta love good aero and mods.

Don't want to hijack the thread, but I have been really curious about this exact thing lately.

The EPA highway mileage estimates are taken at what, 55? Is that right?

And here on Ecomodder we see really high MPG figures, but typically these are accomplished at speeds lower than I see on my daily commute.

I'm wondering how I can compare these mileage numbers I see to the fact that I can currently average 30.5 mpg on my commute through mountainous terrain at an average speed of 75-76 mph to keep up with interstate traffic and not drag my commute out any longer than necessary.

If I were inclined to buy a car like a Prius or a Metro, which advertise and are capable of much higher MPG figures, is there any way of knowing how they would perform driving how I do currently?

It's hard for me to calculate the potential fuel savings if I don't know how the contemplated car would perform under those circumstances, and is therefore difficult for me to determine how much, if anything, I would end up saving over my current setup.

My car has some aero mods (grill block, extended air dam, side skirts, some underbody smoothing) and some engine mods (no AC, aggressively leaned mixture, and advanced timing, etc.) I know it has a lot of room for improvement as well, it's getting an electric water pump, deleting power steering, I need LRR tires, it has lots of weight to shed, etc. I'm hoping that if I get really aggressive with the ecomodding that it may hit 35 or more MPG on my same commute. If so, how efficient must any replacement car be in order to exceed this?

The best way to find out is to ask. You're right to think that you can't compare EPA figures to your own driving style, but they're good for getting a rough relative comparison of one vehicle to another.

My Insight is rated for 70mpg highway / 61 city by the EPA. Cruising at 55 down a flat road on a warm day, I get around 100mpg. When it's 25 below zero and the roads are covered in deep snow, I might get 45-50mpg until it's warmed up, after which it's more in the range of 55-65mpg at the same speeds. At 75mph, economy is in the 60mpg range on flat roads, and probably a little lower in the mountains, but I never drive at those speeds.