What did you put down on the dyno again? lol :P

 

I get about 15mpg or so

 

i get about 25-27mpg when i'm not driving like an ***.

 

damet I need a DD

Even though I only drive about 200miles a week, thats still $50/weekly

 

I used to get 27-29mpg mostly highway (it was crazy looking at 380+ mi on the trip). It has gone down a lot with my new tires (225s). Also might be because gas stations switched to winter formula. Anyone know?

 

^^Sticky summer tires reduce mileage noticeably, especially if they are not properly inflated. Check your tire pressure. I would expect a 5% hit in fuel economy switching from RE92's to Bridgestone RE01R's, for example.

 

They are all-seasons inflated to 34F/31R. I can imagine the extra grip and weight of the tires are to blame.

 

2004 STi + tbe + turbo inlet + tgv deletes + fuel pump + custom tune X driving like a monkey on pcp = 12-14mpg

 

i got 400 plus to every tank of gas an no one believes me i had almost got 500 once (475) before the light came on.. and i do not drive conservatively nor am i stock

 

when i was stock, i can get 400 miles to the tank all freeway. and in the city if i drive slow and shift early i can get about 300 mile to the tank.

after stage 2, and 235 tires i barely see 300 in the cities. freeway gets about the 350 to the tank. when im not in a rush, i always drive 65-70 mph on the freeway. i can get some really good numbers

 

A 5% hit to fuel economy is almost negligible. At, let's say, 25 mpg, we're talking 1.25 mpg. Driving habits can easily effect mpg a lot more than 1-2 mpg.

Don't get me wrong, I totally agree with your point, but I think there's a much greater difference than 5%. With sport tires, you have to consider rolling friction, but also, most likely a larger contact patch (a lot of sport tires are slightly wider, but also, less water channeling means more rubber touching) which includes not only increased friction, but less aerodynamic as well.

On another note, if you're really paranoid about MPG, you can do what one of the guys does on the Yaris forums (yeah, my roommate has a Yaris). The guy shuts his car off whenever he's going down a hill, shuts it off at every light, overfills his RE-92s to 60 PSI to get the smallest contact patch, and probably some other stuff I don't know.

 

my 2.5RS never gets better than 23...avg is 21 lowest 19

1/2 Highway 1/2 Mtns

 

-Good points overall.

-Agreed on driving habits matter more than 1-2 mpg. Hence why some guys are getting 14mpg and others are getting 28.

-Are we talking about differences in rolling friction or total mileage? I think a 5% difference is a good assessment for the difference in total mileage between a Michelin Pilot Sport and Michelin Pilot all season in 75mph steady state cruising at the same PSI and in the same size. It might be slightly more, but I can't imagine that it would be more than 10% because rolling friction is not more than 25% of the total overall friction that needs to be overcome by a car (wind and having to stop due to traffic and street layouts). I'm factoring wind resistance into the equation as well. On the streets, you don't roll till you stop either you usually hit the brakes to stop. Comparing the rolling friction between the two tires, you are right there will probably be a larger than 5% difference.

-Agreed that heavier wheels and tires with wider footprint will make a difference as well.

-Agreed that the Yaris dude who shuts his car off going down hills is taking it to the extreme.

 

^ lol i put it in neutral on 280 downhills...i can go up to 1.5 mile sometimes.
Ive gone like 6 miles before coming down 80 without being a traffic hazard.

ok this thread needs some spark:
going downhill at 4K rpms the same amount of gas as idling down the hill? since the engine is being turned by gravity and the hill, and the throttle is closed while going 4K rpms? ive always wondered if coasting was worth it

if you go up a steep hill for a mile you'll average for example 10 mpg, but coming down that same hill youll get 100's+ mpg right? i need to drive a car with a mpg guage

 

I know I was watching top gear once, and Clarkson said some cars' fuel injectors completely shut off when you're coasting down a hill in gear. Your wheels are turning your transmission which cause your motor to be at that RPM, so there's no need for the fuel to keep it running. Dunno if it's true though, can someone prove it?