[JimKing]

I recently purchased a 92 Civic VX, the forerunner of the Insight. Needing an expensize long distance commuter, I remembered the VX caused quite a stir when it came out, with it's new at the time lean burn engine. It's EPA rating was 44 city / 55 hwy - pretty amazing for the day.

I'm disappointed to find that the car is "only" getting 35-37 mpg on the highway at 70-75mph. I've done a tune-up, and checked tire pressures. It has 134k miles. Nothing seems wrong, but the mileage is way down from what I'd expect, even at the higher speeds than what the EPA probably based their estimates on 10 years ago.

Any chance someone here is familiar with the 92-95 VX hatchback and can tell me what kind of mileage you used to see?

Thanks!

 

[Will M]

Your speed is almost certainly the biggest cause of your low MPG. Most people fail to respect how much work it takes to push against the wind. The power needed to push against the wind progresses exponentially with speed, so if you take the added power needed to go from 60 to 65 and add that much again, you won't make it to 70. It takes quite a bit more power (and gas) to make that difference between 70 and 75.

If you consciously keep your speed at 70 and never go to 75, you'll probably see a bigger difference in gas mileage than you expect. If you start going 65-70, you'll get another level of savings.

What's important to you? Minutes or gallons? You have to decide. Likely, you can't have both.

Better oil, better tires, care about tire inflation and even washing and waxing the car can help, but nothing is likely to affect mpg as much as your right foot.

 

[Rick Reece]

I have a 94 VX with 220K miles and routinely drive it 70-75 and get 50 mpg consistently. I will be using it to teach my son to drive this summer (he's not driving the Insight anytime soon). My window sticker (when the car was new) said the EPA rating was 57 on the highway but perhaps that's because I don't have air. I would have the alignment checked and what type of tire are you using. The orginal LRR tires are hard to find so you probably have the wrong size and some soft rubber also holding back the fuel economy. Have fun, Rick

 

[Tim Maddux]

The power needed to push against the wind progresses exponentially with speed...

It goes up as the square of your speed, so it takes four times as much power to go 40mph as it did to go 20mph. It would take four times as much power to go 80mph as it did to go 40mph and SIXTEEN times as much as it did to go 20mph.

Put another way, going only 40% faster will burn twice as much gas.

Slow down cowboy!

 

[sno779]

Jim
Back in the olden days when the speed limit was 55 I was driving a Subaru Justy 150 miles a day and averaging 40 mpg. Several times I drove the trip at 45 mph and the mpg would go up to 56. 16 mpg for 10 mph is quite a lot.

Louis

 

[Delta Flyer]

Even Worse Above Mach One

The power needed to push against the wind progresses exponentially with speed...

It goes up even more once you exceed the sonic barrier. That's one of the reasons the Concorde will be retired this year. :mrgreen: :mrgreen: :mrgreen: