I have spent an entire day in vtec with the top down on a group run and I still observed 23mpg. I probably spent 80% of the time over 6k. I'd say thats pretty good.

 

Along the same lines, I have a question about the sun-roof as well (obviously not on the S2000 ). How does using the sun-roof affect gas mileage? I'd assume that opening up the sun-roof all the way will use more gas, but what about tilting up the back? On hot days, I like to just tilt up the back to vent out the hot air. Does it help to put one of those plastic thingies that fit on the leading edge of the sun-roof to deflect the air?

Oh, and since we are discussing what affects gas mileage, does anyone have any info on the effect of a dirty car on gas usage? Everyone knows that a clean/waxed car gets better mileage, but is there a quantitative study? Also how dirty must a car be for mileage to suffer? Thanks.

 

[QUOTE]Originally posted by Intrepid175
[B]

STL,

You're right in that the difference in gas mileage between winter and summer driving has to do with the fuel mixture.

 

Question Saab9-3

What was your average throttle opening? I'm sure you were "on it" much of the time but I'd almost be willing to bet that a lot of the time, even though you were in vtec rpm's, you weren't that hard into the throttle. Higher rpm's don't necessarily come with lower fuel consumption although that's the usual assumption. It's not an absolute.

Just wondering,
Drive Safe,
Steve R.

 

[QUOTE]Originally posted by Intrepid175
[B]Funny, STL, I don't see you posting a bunch of links in support of your position either.

 

I do not believe I ever made that claim. Anyhow, thanks for the link.

 

Intrepid175 and Road Rage,

I am under the impression that during the winter months gas stations (at least in the St. Louis area) are required to use a different type of reformulated (oxygenated) gas that is "suppose" to burn cleaner -- which in turn means slighlty less MPG.

 

[QUOTE]Originally posted by WhiteS2k
[B]Along the same lines, I have a question about the sun-roof as well (obviously not on the S2000 ).

 

[QUOTE]Originally posted by lanbrown
[B]The dirt hurts the vehicle in two ways.

 

I've heard this too. Here on the Texas Gulf Coast, we don't see oxygenated fuels like they in in the midwest. At least I've never noticed it. I have family in the St Louis area and in central Illinois that I ususally visit during the Thanksgiving season and I have filled up my car with "gasohol"(sp?) a number of times. If it effected my fuel mileage, it wasn't much. Then again, I'm only talking a tank or two and most of the running is a mixture of freeway and local driving so my fuel mileage was lower than strictly highway driving and higher than it would be with strictly in town driving so it's really hard for me to tell if I'm being adversely effected by the different fuel or not.

As for the "burn cleaner -- which in turn means slightly less mpg" part of your comment quoted above, the lower potential fuel mileage has nothing to do with the fuel burning cleaner. The problem is that ethanol (alcohol), that they mix with the gasoline, does not have the same energy potential as straight gasoline does. Ethanol does burn more cleanly but it doesn't make as much power per gallon burned. The end result is that you've got to push that gas peddle a little farther down to achieve the came acceleration (or to simply maintain speed) and "that" accounts for the lower fuel mileage. As long as you drive conservatively, I don't see that a fuel mileage drop will be that much of a problem. At least that's been my observation on the few tanks of gasohol I've run through my personal vehicles.

The post I made on this subject that Road Rage responded to was just talking in generalities. I was speaking on the assumption that all things were equal except the season (and thus the temps) involved. Since we don't see the fuel formulations changes where I live like the folks in the midwest do (at least they're not as obvious), I wasn't considering that. Oxygenated fuels do change the equation a bit.

FWIW,
Drive Safe,
Steve R.