Why isn't the fuel economy better?

[Photonic]

Not reading through all 30 pages but heres a nifty fact.

You can put an LS1 into an s13 and get 30MPG. Happens all the time. Volumetric efficiency and less mass to move with less throttle.

Thats right, a gas hungry V8 designed for a 3400 pound car with an easy 250 wheel horsepower will stick into your 2800lb chassis and give you damn close to 30 mpg.

So theoretically speaking why shouldnt I be able to take the engine from a nissan titan and stick it into my 240 also and get 40mpg since it weighs half as much and I can get around the same using 1/8th throttle ?

Hmm ..why indeed.

[Luis_GT]

I got 18MPG out of my last tank... FUCK MPG! lol

[Vracer111]

Still getting consistent 21-22 mpg....car is too much fun to care about fuel mileage. Dance chassis - dance I say! Once up to temp I keep the revs up whether needing to speed up or slow down (and downshifting along the way...). Plus I'm sure heavier weight 5-W30 oil robs a little MPG as well...

[incubus1995]

honestly, if anyone wanted better mpg they could just replace the 4.10s with 3.73s or 3.35s in the rear end, yea acceleration would suck but mpg would be better haha-anyways.....am i the only one that wants to get a steeper gear ratio ?

[Dadhawk]

Originally Posted by keithgold

seriously i keep seeing people getting 30+ mpg on their fr-s. I have no idea if they are mostly auto drivers or drives only freeway. My car is a MT currently on 740 miles. I average about 25.8 mpg granted i do drive mostly in the city.

It's most likely a combination of the two, at least it is for me. Over 30,000 miles, I've averaged 32.54MPG calculated. Most of my driving is commuting where my average speed around 50MPH when I've timed it. (40 mile commute, normally takes 45 minutes). I do see a drop when I have to tool around town for a more significant portion of my time but the lowest I've had for a tank is 28.9MPG.

I'm usually fast and first off the line, and not afraid of a little fun but I do normally go no more than 9MPH over the speed limit with a few rare exceptions.

By the way, I have read studies that show you use less fuel by accelerating to speed quickly then getting there gradually. That's one of those facts I find too good to check so I just go with it.

I've documented every tank on the first post in my builder's log and a description of the conditions, if you are really bored.

[chrisl]

Originally Posted by Dadhawk

By the way, I have read studies that show you use less fuel by accelerating to speed quickly then getting there gradually. That's one of those facts I find too good to check so I just go with it.

I suspect it is dependent pretty heavily on the car. My Outback's gas mileage seems best if I nearly floor it away from the line, and shift at 3500-4000rpm or so (which still leads to pretty brisk acceleration). It also doesn't seem to change much regardless of acceleration style, unless I'm driving like a complete jerk. My Cayman though definitely drinks the gas if I accelerate quickly, even if I short shift, and it gets very noticeably better mileage if I am gentle away from the line (which doesn't stop me from stepping on it anyways - it's more fun that way )

[UnOvertime]

Originally Posted by Dadhawk

It's most likely a combination of the two, at least it is for me. Over 30,000 miles, I've averaged 32.54MPG calculated. Most of my driving is commuting where my average speed around 50MPH when I've timed it. (40 mile commute, normally takes 45 minutes). I do see a drop when I have to tool around town for a more significant portion of my time but the lowest I've had for a tank is 28.9MPG.

I'm usually fast and first off the line, and not afraid of a little fun but I do normally go no more than 9MPH over the speed limit with a few rare exceptions.

I am in the exact same boat, I am just shy of 27,000 miles and my signature shows 31.1mpg. I averaged closer to 33mpg before I switched to my new wheels and tires, now I am hovering around 30mpg give or take.

I commute 40 miles each way to work and the average speed is probably 55. I have an auto, but I do not drive extremely slowly and I do have fun while driving. 95% of my driving is "highway" or at least highway speeds.

[cycleboy]

I've got 13K on mine and still averaging about 31mpg.

It's mostly because my daily driving is: 1 mile local roads @ 35mph, 33 miles highway @ 65-75mph, 1 mile local roads @ 45mph, then the opposite in the afternoon.

I also don't leave the revs up when not accelerating. I shift it at 5-6K, but if I'm cruising along steadily I use the gears like overdrive and put it in something where it sits at ~3500 or less. Need to pass, downshift!

[paiceyfan]

I am in the break-in period of the MT BRZ and its getting 28.5mpg, with revs less than 4k at all times, not sure what I will get when I start opening her up!

My 2007 Civic SI gave 29 consistently until the VTEC kicked in, then it was 22mpg.

[DC2R]

Readout says 25. I'm at 700 miles and been through 2 tanks of gas since owning. Just calculated on last fill up and got 19 mpg. Keeping revs under 4k. I'm at 0 altitude and warm weather in Miami. What gives?

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[93cc]

I dont care too much about mpg but it would be nice to get in the upper 20's or higher like some of you are... Im only getting like 21 mpg but part of that is probably cuz I pretty much just drive around in town and very little Hwy and I might have a heavy foot

[DC2R]

Took into dealer and they got 34 plus MPG when they hooked up TechStream and rode around. They pretty much did all highway at like 55 though. I pretty much drive all city.

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[Tromatic]

People claiming upwards of 30MPG are FOS.

[DC2R]

Originally Posted by Tromatic

People claiming upwards of 30MPG are FOS.

I got 30 once all highway but that was from dash so probably 28

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