RX-Hachi

Most people seem to get just fine mpg with highway driving, it's city driving where there seems to be a great deal of difference. Some getting as low as 13, others around the EPA claimed 18.

But I'm also curious about the definition of "City" driving. As the island I live on (Oahu) is pretty small, I could classify 100% of my driving as "City". However, when I'm on a freeway for about 20-30 minutes, I think of it as "Highway" driving. Yet, when I used to live in California and Washington, I could easily drive for 20-30 minutes on the freeway and still be in the "City". A long "Highway" drive from say San Francisco to Portland is probably the kind of "Highway" mpg that the EPA is based on. But this kind of highway driving simply can't be done in Hawaii.

So I wondered, could people's varying mpg be based on their definition of "City" driving? Would you classify a 30 minute inner city highway drive (without traffic lights) as "City" or "Highway"?

mysql101

You could get highway miles in a city...

I consider any situation where you're able to go over 55 mph without stop lights highway.

Anything with stop and go is city - so you could be on the freeway in traffic and that would count as city.

TRZ750

The EPA City milage come from California LA4 emiission test that was to be like a standard comuter in LA. It has a cold engine start and drive from a "home' to the freeway and then a few miles on the freeway in trafic with a top speed of 55~65 (don't really remember the details) then a drive from the freeway to a downtown work spot. There actually is a route in LA that I drove many years ago (~74) for Mazda testing.

Actuall city or freeway milage depends most on three things: Accelleration, top speed, and idle time (stops). The harder the accelleration and the higher to top speed and the longer and frequency of the stops will determine the milage. The ones that are concerned about when injectors turn on or what gear to be in at 2000 rpm are really small, very small, contributors to ones overall milage. I remember when the rotary PU came out that some street ice cream vendor tried it and he got like 4 mpg or some horrible city milage.

I suspect the RX8s that get 13 mpg have a lot of stops and jump on the throttle. I get 18~19 going back and forth to work. But I have 35~45 speed limits. Mostly steady trafic, and only 4~7 stops for 9 miles. No freeway or extreem city. Hard starts are a waist since most is two lane and no way to pass or other advantage.

mysql101

People are reporting driving highway at 50 mph, with granny shifting (under 4k) and getting 12 mpg. There are RX-8's out there with serious mileage issues.

I am almost always 100% city, I shift at 5-8k rpm, and accelerate hard, and worse I've been able to get was 16.5 mpg.

RX-Hachi

Yes there are a very few who have some serious mpg problems, but they are the exceptions not the rule. I'm not discounting their problems, but I'm interested in the average car which seems to get something like 15-17 mpg in the "city". I would classify myself in that category.

I've noticed if I take routes where I'm on the freeway for about 20-30 minutes at a stretch and then stop and go traffic in city blocks, I'll net around 18-19 mpg. If I'm 100% stop and go with traffic lights to contend with, I'll end up around 15-17 mpg. If I drive it like I stole it, 14-16 mpg. I'll bet those that claim to get around 18-19 mpg in their city driving have daily commutes which include a good stretch of freeway time, as per TRZ750's definition of "City" driving. While others who are getting around 14-16 mpg, are probably all stop and go with lots of traffic lights or drive with a lead foot all of the time. If I'm right, this whole mpg concern (for the majority of folks, not the exceptions) is probably much to do about nothing.

Old Rotor

Thats my feelings exactly RX..

Rxdriftingaction

city driving mpg = 200 bucks/month