Such bad mileage!!

[Norinradd]

Originally Posted by ScoobsMcGee

If you think 24 mpg out of a 2.0 liter engine is bad: http://www.fuelly.com/car/mazda/rx-8...arakawa/392021

There is a lot more to consider than the amount it costs to fill the tank and the distance driven between fuel ups to determine how efficiently an engine makes power. There are also some flaws in using only that, unless the driving environment and cost of gas per liter were identical in both situations. That's not even getting into power output or fuel delivery, as well as countless other variables I'm too lazy to list.

If you're not happy with the current efficiency in your FRS, flash it back to stock and be sure to keep the Primacy (or comparable low rolling resistance) tires. If you're still not getting comparable efficiency to others with a stock car, there may be an issue with either the car or driving technique. If you're not happy with the average fuel efficiency others are getting for the engine displacement and power, research your next vehicle more carefully prior to purchase.

I have done my research prior and post. Im aware of all that. I probably read every article on this car and watched every youtube video. Atleast 200+ hrs obsessing over it before i eventually bought one. So i assure you im well aware of its tendencies. I just feel i get shit mileage is all. I woulda kept my jeep. Big reason i bought this car was to save on gas.

And stfu up before u start tcoat, you dyslexic asshole. Its not a jet fueled drag car that burns a tank in 2 passes. Its a 4cyl economy poor mans race car with 150 hp to the wheels.

[PMPB]

Your jeep gets 12-14 and the frs gets 24mpg? That sounds to be roughly double the mileage, like you wanted. I understand the FR-s uses more expensive fuel, in order to make 200hp from 2L, you kinda have to. However, you could run 87.... I wouldn't recommend it though.

Also, contrary to popular opiniong shifting at low RPM and low engine load doesn't save gas. There is a concept known as volumetric efficiency, and most engines maximize volumetric efficiency in at higher loads and middling RPM (near the torque peak). It's best to accelerate up to speed rather quickly and then shift to the gear that drops the RPM to the lowest to maintain your speed.

Good Luck.

BTW, I have an 8km commute, including a 5km run on the highway. So the engine isn't even up to temp by the time I get to work. After 40,000km, I have a combined 8.4L/100 (28MPG). Car is stock, and I run E10 (Petro Canada 94)

[everythingsablur]

TLDR version: Long story short, the math is a lot more complex than "half the displacement should be double the fuel economy".

Long version: I think the important point here to make is that the OP's base concept that there is a directly linear relationship between engine displacement and fuel consumption is what is fundamentally at fault. Just because engine A is 4.0L and engine B is 2.0L does not mean that engine B will consume half as much fuel as engine A; there are just way too many other factors at play, not the least of which is that these are completely different cars with different purposes.

An 86 weighs roughly 2750 lbs (give or take), and a mid-90's Jeep YK weighs between 3100 to 3800 lbs. Some quick math here, but the Jeep weighs between 12-40% more than an 86. If we assume that lighter end of the Jeep weight scale is the I4 engine, you have two cars that are roughly within earshot of each other's weight (12%), and 20% apart in displacement, but the fuel economy difference is dramatically about 47% (17mpg for the 2.4L I4 Jeep to 25mpg for the 2.0L H4). If we go with the original premise on its own that there is a direct correlation between displacement and fuel economy and nothing else, then the YJ should get much better fuel economy then it does. The weights are similar, the engines are similar displacement, yet it is way off in fuel economy. Why? They're different cars with different purposes, so pretty much everything else is not equal. Gearing, how the torque and hp is designed to be delivered, aerodynamics, vehicle mass/weight, volumetric efficiency, you name it. So at this point I'm going to throw out the displacement theory because there is clearly more to fuel economy than engine size alone.

Looking more specifically at the 4.0L I6 the OP brings up, assuming the I6 is going to be the heavier end of the weight scale, we have a 40% heavier vehicle with 100% more displacement. Stated fuel economy differences are 15mpg for the 4.0L I6 vs 25mpg for the 2.0L H4, or 66%. Assuming you are using a 19 gallon fuel tank in the YJ, your estimated range is about 285 miles vs 330 of the 13.2 gallon 86 fuel tank; so your 86 should get you about 14% more range per tank. Now if we assume that the two engines used the same fuel (to eliminate the cost argument), the average US cost for a gallon of regular gas is $2.15, each car would cost you $40.85 and $28.38 respectively (44% more to fill up the Jeep). Now readjusting for reality, the 86's run on premium, so that tank actually costs $34.61 based on the current US average price on premium ($2.622). The I6 now only costs you 18% more for 14% less range.

Hypothetically if we drive both cars 1000 miles, the Jeep will use 66.66 gallons of fuel and cost $143.33. The 86 will use 40 gallons of fuel, and cost you $104.88. That's a savings of 37%.

I'm really not sure what the complaint is anymore. From all angles the FR-S/BRZ are doing better fuel wise than his Jeep, but being double the economy is a bit of a pipe dream if you are basing that solely on displacement. You are getting much better fuel economy, but you are also having to use more expensive gas, so while there is a lot of fuel efficiency gained, the increase in per gallon fuel costs negates the straight dollar savings if apples were really comparable to apples. Still, you are saving 37% of your money by driving the 86 over the same distance in your Jeep.

If that alone isn't worth it to you, feel free to send me that 37%.

[everythingsablur]

Darn. Didn't realize the OP was Canadian. And here I was doing all the conversions into Imperial...

All vehicle weights and fuel economies were based on published statistics for each vehicle, so not totally pulling numbers out of my posterior.

[Tcoat]

Originally Posted by Norinradd

You really need to get a life tcoat. Get your veteran bum ass off the couch, stop feeling sorry for yourself. Its your fault you went to fight a bullshit war for your corrupt owners. Youre on these forums 160 hrs a week.

Or stop trolling my posts. I could give a fuck about your opinions let alone this clear aching you have inside you to belittle people from behind a screen. Get the fuck out.

I am not the one that does not understand simple math or concepts. This is a public forum and I will post where I wish. Not trolling a thing and will continue to point out asinine statements when they are presented.

I am not sure what my military service or time spent helping people here that actually can understand what is being said have to do with you?

[everythingsablur]

Originally Posted by humfrz

Well, I wasn't surprised at my FR-S's gas mileage ........ since my Miata got about the same mileage ......

Same. Coming over from an older MINI Cooper S (1.6L supercharged), I'm not terribly surprised. It's a little worse, but it's also a lot more fun (and assuming reliable, and cheaper to maintain).

Mind you, my sample size is all of one tank of gas, so I'm sure things will change over time as I get used to the gearing and whatnot of the car, but I'm getting maybe 450 km per tank in mostly city driving. Travelling the same route, with the same frequency, my MCS was getting maybe 500-550. On paper their fuel economies are really close, so I think it (my anecdotal fuel economy) will improve.

[nikitopo]

Originally Posted by Norinradd

You really need to get a life tcoat. Get your veteran bum ass off the couch, stop feeling sorry for yourself. Its your fault you went to fight a bullshit war for your corrupt owners. Youre on these forums 160 hrs a week.

Or stop trolling my posts. I could give a fuck about your opinions let alone this clear aching you have inside you to belittle people from behind a screen. Get the fuck out.

[Dadhawk]

Originally Posted by Norinradd

I dont expect to get 1000 miles to a tank but i expect to double the kms for dollars..

On the flip side, apparently I was able to accomplish this with my FRS. Reviewing my fuel expenses I paid $46.05 for a tank (around 10 gallons) on 8/28/2012. Earlier this year I paid $22.69 for the same 10 gallon tank. Net effect, I got double the miles for the same amount of money.

(and yes, I realize you said in your post "if prices are the same", but my interpretation is more amusing)

More seriously, I'm not sure why your car is in the low/mid 20's for mileage. It may be the tune, it may be your driving habits, it may be your standard driving situation (all cars get the same MPG when sitting still in traffic, although the Minutes Per Gallon will vary). It could be a combination of all of it.

Mine has averaged 33.01MPG over 86,000 miles since new. Over time, the fuel economy has actually improved a bit. Most of my miles are in the 45 to 60MPH range commuting. (You can see my builder's log for a tank by tank numbers).

The absolute worse I've gotten out of a single tank was 27.6 and that involves being stuck in bumper to bumper traffic for 4 hours.

And, no, I do not drive like a Grandma. I've never been beaten off the line by a Soccer Mom Van, and have never met a curve that I don't see the "recommended speed" as a challenge to double it.

[jvincent]

I feel I must post this here.

[humfrz]

Originally Posted by Norinradd

You really need to get a life tcoat. Get your veteran bum ass off the couch, stop feeling sorry for yourself. Its your fault you went to fight a bullshit war for your corrupt owners. Youre on these forums 160 hrs a week.

Or stop trolling my posts. I could give a fuck about your opinions let alone this clear aching you have inside you to belittle people from behind a screen. Get the fuck out.

DANG! ....... @Norinadd ....... those are harsh words ...... and IMHO completely uncalled for ......


humfrz

[humfrz]

Originally Posted by Norinradd

I have done my research prior and post. Im aware of all that. I probably read every article on this car and watched every youtube video. Atleast 200+ hrs obsessing over it before i eventually bought one. So i assure you im well aware of its tendencies. I just feel i get shit mileage is all. I woulda kept my jeep. Big reason i bought this car was to save on gas.

And stfu up before u start tcoat, you dyslexic asshole. Its not a jet fueled drag car that burns a tank in 2 passes. Its a 4cyl economy poor mans race car with 150 hp to the wheels.

Well now, Norinradd, the estimated gas mileage on this vehicle is published .....

As far as @Tcoat being a "dyslexic asshole" ....... I don't think he is dyslexic ......

(I jest couldn't pass that up ...... )


humfrz

[Songha]

160 hours a week leaves an hour and seven and a half minutes of sleep a day.

I feel like our cars should get better gas mileage too, my mom's 2015 accord sport v6 gets better gas mileage than me if you think about displacement.

[Tcoat]

Originally Posted by Songha

160 hours a week leaves an hour and seven and a half minutes of sleep a day.

I feel like our cars should get better gas mileage too, my mom's 2015 accord sport v6 gets better gas mileage than me if you think about displacement.

Does the Acord get driven in exactly the same places and in exactly the same manner as your car? If the answer is no then what mileage it gets is totally irrelevant as a comparison.

[ajcarson11]

Yeah... have to be honest, my car is averaging 23-26mpg city, and 32-35highway. I don't understand how you could get your AVERAGE across highway/city combined under 26mpg in this car. It gets great gas mileage, and I have 18x9.5 wheels that aren't light.

Granted... I don't like in areas with fun roads, so I don't put my foot into it as much as some, but I don't drive like a granny either.