Speed3 Gas Mileage Question..

[Phaedrus409]

Alright... I've got a bit of a tricky question for you guys, with a lot of variables involved. I'm looking for some general feedback and any opinions on the situation you might have.. Here's the situation:

I recently through a roofrack on my Speed and it seemed my gas mileage dropped quite a bit. I was getting around 315m per tank, and suddenly I was around 270! Quite a difference.. Anyway, I attributed this all to the roofrack, but now I'm starting to question a few things.

Previously, I had been going to a no name gas station with cheap prices and using their premium..The othernight I filled up at a Sunoco and the stupid kid working there, put 89 in my tank rather than 93.. Strangely enough with this tank of gas, I'm back to 300+ miles per tank!?

Now on to the questions:

Is it possible that overall the Sunoco gas is just better and that is why I'm getting better mileage?

Does it have something to do with the 89 Octane??

I live in NJ, and the temps have gotten a bit warmer, this could in fact be part of it, but I have trouble believing it's that big of a difference... Thoughts?

I have probably driven a bit more on local roads with this tank. Is it possible that the drag of the roofrack has less of an effect at lower speeds?

I know there are a ton of variables at play here, but I'm just really curious what you all think. In general I just find it really interesting that I switched to a "Brand Name" gas station and now I'm back to 300+ miles to the tank. Any feedback at all on similar situations would be very helpful.

Thanks in advance guys..

 

[dread]

too many variables to guess, but drag will be less at lower speeds. The roof rack could knock of a couple mpg. Not sure about sunnoco gas but I wouldn't be complaining about gas mileage, I only get 230 per tank, mostly city driving for short distances. I cant believe you got over 300 that is amazing. How many miles do you have on your car and what kind of driving do you do.

 

[dcomiskey]

I think it's funny when people who buy a pocket rocket like the MS3 worry about gas mileage.

 

[Mspeed3]

yah u gotta pay to play! But I noticed with highway driving my mpg shoots up!

 

[Phaedrus409]

i'm not complaining about mileage, but simply making an observation that my mileage decreased quite a bit and now has seemed to go back up with a different brand of gas... if i can get more bang for my buck by going with a different blend of gas, i'm all for it..

 

[dcomiskey]

i'm not complaining about mileage, but simply making an observation that my mileage decreased quite a bit and now has seemed to go back up with a different brand of gas... if i can get more bang for my buck by going with a different blend of gas, i'm all for it..

I was just pulling your leg.

Do you have the Thuli faring (sp?) I would imagine that would help reduce the drag at least somewhat.

 

[redms3gt]

winter gas has a diffrent mix does't it? I think it usually produces worse gas mpg but less emissions.

 

[C-Bass]

winter gas has a diffrent mix does't it? I think it usually produces worse gas mpg but less emissions.

Yeah, especially up north they tend to put in additives during the winter months that do your mileage no justice.

I'm picking up my MS3 on Saturday, and I'm personally going to do everything in my power to maintain single digit gas mileage. I managed to get my MSP down to 8mpg ONCE...but that took 3 hours of beating the ever loving hell out of it at VIR (best road coarse evar!), haha.

 

[dread]

single digit that is awesome. Let us know how it goes. It shouldn't be hard considering I can see my gas gage go down everytime i floor it.

 

[AntimonyER]

I have noticed the MS3 is extremely sensitive to drag changes, so it is possible the roof rack is your problem.

I got 32.5 mpg going from Savannah to Orlando, and the mileage really jumps when you are drafting behind semis and SUVs. But 300 miles and I still had a quarter tank left over.

 

[benzo]

I do a ton of highway driving. I say about 80% highway 20% city. I average about 24.2 mpg per tank. Oh yeah I can go about 270 miles or so on a tank.

 

[DaveMS307]

I do a ton of highway driving. I say about 80% highway 20% city. I average about 24.2 mpg per tank. Oh yeah I can go about 270 miles or so on a tank.

I don't think I drive like a granny, but I seem to average around 27-28 mpg and that is a mix of highway driving and city -probably simliar 80% hwy 20 city. Even when I thrashed it a bit and let a few friend try a few drag type starts, I still averaged around 25mpg for the tank.

 

[shark77]

Bought the car with 6miles on it. Dealer topped it off.

Filled it up 12.5gal @ 304 miles - 6 miles = ~23.8mpg for the 1st tank

 

[got_titan]

getting 26.5 mostly city driving and many wot runs per tank......3000 miles on car.....

 

[dread]

are you guys using your trip computers to calculate or you actual mileage because the trip computers are not very accurate. Got titan was your gas mileage always that good or did it go up after break in?

 

[jheer]

trip computer

are you guys using your trip computers to calculate or you actual mileage because the trip computers are not very accurate. Got titan was your gas mileage always that good or did it go up after break in?

Yeah, the trip computer is about 2 mpg too high. I calculate my MPG by amount of fuel vs. mileage at every fill-up. I have averaged 24.7 mpg in mostly highway driving since I bought it 2,600 miles ago. The trip computer has me averaging 26.5 mpg.

 

[Phaedrus409]

Alright.. A little update.. Since I last posted I've probably been through three tanks of gas, and I'm on my fourth as we speak. I've been going to only "Brand Name" stations and I've been getting around 300+ to a tank, and driving the car pretty hard.. A few days ago, the temps here in jersey dropped quite a bit, and on this current tank (from exxon), it looks like i'll end up getting more like 260 to the tank..

I didn't realize cold air would have that much of an effect, but it seems to be the only thing that has changed in the past 4 tanks of gas..

Anyway, just figured I'd give you all an update..

Thanks for the replies.

-greg
-'07 speed, black

 

[RPI-Speed3]

I am personally getting great gas mileage on my MS3. I think my worst tank I averages 22.7mpg. I just completed a trip from Boston to Pittsburgh, 580 miles, avg 29.7mpg, avg speed 68mph over the 580 miles. My first fill up was after 301 miles and I had a quarter tank left. Plus, I was hauling a 30 inch Sony Wega HDTV (tube), 4 duffels, lots of xmas presents, myself, and my girlfriend and still got that great mileage. Can't really complain. My first tank was Mobil 93 octane from Boston area. Second tank was Sunoco 93 octane from Allentown PA. I'm currently on a tank of BP 93 octane from Pittsburgh, we'll see if there are any differences.

Roof racks kill you gas mileage for sure, especially on the highway. I would also stay away from those really cheap brands of gas.

 

[SwampAss]

Colder weather affects fuel mileage. If the temps are cold, your car takes longer to warm up. A cold engine requires more fuel. (think choke)

 

[RPI-Speed3]

Yeah, the trip computer is about 2 mpg too high. I calculate my MPG by amount of fuel vs. mileage at every fill-up. I have averaged 24.7 mpg in mostly highway driving since I bought it 2,600 miles ago. The trip computer has me averaging 26.5 mpg.

Remember though, this method of calculating is only effective if you fill up at the same gas station using the same pump each time. All pumps pump at different speeds. I've found the variance between some to be as much as 1.5 gallons before hitting the initial safety cutoff!

I would like to know the code logic Mazda is using in the ECU to calculate avg mpg. I've found mine to be fairly accurate.