Focus Fanatics Forum banner

1 - 20 of 37 Posts

·
Registered
Joined
·
875 Posts
Discussion Starter #1
Ever since I hit a combined 27 mpg with my first tank of gas, I've been chasing reasonable gas numbers. I've been getting ~20mpg ever since, and I've noticed a lot of others on the forum have the same issue. This last tank I've been shifting @ 2-2.5 grand religiously, and I've eeked out 50 more miles to the same point in the tank [1/2 used] than before, which equates to 200 miles/half tank vs. my usual 150, where I was shifting ~3k. I'll update on what the end result is, but it looks like you really have to almost dog the motor to get respectable numbers. The odometer reads 5,1xx miles btw. Is this pretty much what every one else is experiencing?
 

·
Registered
Joined
·
1,236 Posts
knightm3 said:
Ever since I hit a combined 27 mpg with my first tank of gas, I've been chasing reasonable gas numbers. I've been getting ~20mpg ever since, and I've noticed a lot of others on the forum have the same issue. This last tank I've been shifting @ 2-2.5 grand religiously, and I've eeked out 50 more miles to the same point in the tank [1/2 used] than before, which equates to 200 miles/half tank vs. my usual 150, where I was shifting ~3k. I'll update on what the end result is, but it looks like you really have to almost dog the motor to get respectable numbers. The odometer reads 5,1xx miles btw. Is this pretty much what every one else is experiencing?
Here are all of my numbers since Day One. Overall average is 27.7MPG right now with about 6500 miles. I include temperature numbers (taken off a National Weather Service website) because, in general, MPG should fall off in colder temperatures and you can see that it does.

I use the car mostly for commuting, with a mix of about 20% city, 20% rural backroads, about 40% secondary roads (55-60mph in 5th) and 20% highway (75-80mph). I usually shift, depending on mood and situation, between 3K and 4K. In general I am at 125 miles at the 3/4 mark; 200 miles at the 1/2 mark; 275 miles at the 1/4 mark.

Calculating fuel economy can be slightly tricky. I have noticed different gas pumps shut off at very different times. The best bet is to always use the same gas pump. You will wash out differences in fillup levels if you take an MPG reading across several full tanks in a row. Take the total miles driven and divide by the total gallons from those several tanks to get your number.

Another thing I would suggest is to watch tire pressures. The Pirelli P6 205/50-16 spec's 34psi front and rear (check inside your driver's door or gas cap). My car was delivered to me with 26 psi. And when it got real cold, the 34psi fell to about 30. This is not to say low tire pressure is going to suck 7mpg, but it's worth a bit.


Code:
date		trip	gal	MPG	avg temp
09/04/03	308.3	11.255	27.4	67.5
09/10/03	341.3	11.940	28.6	65.9
09/18/03	367.1	12.111	30.3	67.6
09/29/03	360.5	12.219	29.5	67.3
10/04/03	338.4	12.222	27.7	54.2
10/12/03	343.7	11.855	29.0	55.1
10/22/03	352.6	12.206	28.9	51.4
10/29/03	327.4	11.601	28.2	49.6
11/10/03	257.4	9.438	27.3	51.4
11/14/03	234.8	8.598	27.3	43
11/20/03	328.3	11.956	27.5	43.3
12/03/03	324.7	12.036	27.0	42.7
12/12/03	293.9	10.163	28.9	31.3
12/17/03	310.5	12.507	24.8	34
12/23/03	343.3	12.506	27.5	38.6
12/26/03	322.3	11.153	28.9	44.5
01/04/04	344.1	12.344	27.9	40.8
01/10/04	300.8	12.042	25.0	24
01/20/04	270.9	10.916	24.8	17.3
 

·
Registered
Joined
·
13,065 Posts
I haven't been quite so good at recording my mileage as religiously as Soffiler, but I'm trying. Here's a quick rundown of some numbers: (Automatic)

Average since October = 25 mpg
Best = 28.9 (~3300 miles on car)
Worst = 21.6 (most recent, 60xx)

I think it's pretty respectable, my driving is all over the board. I notice it plummets when I do most of my driving in the streets of Worcester, where there are lights every like 10 feet (go figure)! On the highway I try not to go over 80, for several reasons...[:p]
 

·
Registered
Joined
·
875 Posts
Discussion Starter #4
soffiler: Thanks very much for the mileage numbers! Mine are starting to look like that as well. I think the main problem is our average temperature for the past 2 months has been in the teens, as we've had several days of near and below zero.

Question though: I noticed you got < 10 gallons a few times -- are you waiting until the Reserve light comes on to fill up each time to fill up? If not, how can you record accurate data?
 

·
Registered
Joined
·
1,236 Posts
knightm3 said:
soffiler: Thanks very much for the mileage numbers! Mine are starting to look like that as well. I think the main problem is our average temperature for the past 2 months has been in the teens, as we've had several days of near and below zero.

Question though: I noticed you got < 10 gallons a few times -- are you waiting until the Reserve light comes on to fill up each time to fill up? If not, how can you record accurate data?
The couple times I have filled up with < 10 gallons, it was on a trip. I wanted a full tank to begin the trip so I filled up the night before leaving; ditto the return leg. I didn't pay much attention to the numbers but looking at it now I see I got 27.3 on both legs of that trip. It was a lot of highway, so you might expect closer to 30mpg or better, BUT! I was travelling with someone else in another car who was an absolute leadfoot. We were going 85mph the whole time. If you've ever driven the Mass Pike you'll know it is quite possible to run at those speeds out there - heck that's the center lane; people are still going by you in the left!

I rarely wait for the low fuel light before a fillup. My commute is 30 miles each way and a lot of it is pretty rural, no convenient gas stations. So, once it gets down to 1/4 or slightly below I will get gas whenever I'm near a station, generally, when I'm close to work. If I don't get gas then, it'll be like 40-50 miles (home and then back toward work again) before I'm near a convenient station again, and if I was waiting for the light to come on, that might be just too long.

How can I record accurate data, you ask. Well, that has nothing to do with the low fuel light. Just pull in and get gas - FULL. The gas pump tells you how much you just bought and the odometer (assuming you reset at every fillup) tells you how far you went. Those are the only numbers you need. The only problem with these numbers is that different pumps kick off at different times which adds some variability. Using the same pump every time can help. Taking the average over several tanks helps even more.

If there's some confusion about how to calculate fuel economy, here is a basic description: you begin with a chuck-full tank and an odometer reset to 0.0. Then you drive. You're using gas and piling up miles. Then you fill the tank again. This puts the tank right back where it started, full, so you can see how much gas you just used by the amount it took to bring it back to full. The mileage on the odo is easy.
 

·
Registered
Joined
·
875 Posts
Discussion Starter #6
Yeah, I hear you on the Mass Pike, it's easy to get a visit from the speed squad up there. Thanks for the info. on your calculations. [thumb]
 

·
Registered
Joined
·
65 Posts
i shall tell you a great why to get better mpg DRIVE ON THE FREEWAY MORE thats a good way to bring it up
 

·
Registered
Joined
·
875 Posts
Discussion Starter #8
Update: Just pegged 26mpg combined on my last tank. Probably due to the warmer [40s] temps. we've been having. For a while I thought the car was just being retarded.
 

·
Registered
Joined
·
386 Posts
Best I have ever gotten was about 355 to the tank. But that was before all the mods. Now I seem to get rather close to 300...strange I always thought an intake and exaust will boost up my MPG >_<
 

·
Registered
Joined
·
170 Posts
Use synthetic oil and lose friction and gain hp and mpg. Shift at low rpm under 2500 and gain more mpg. Boring. Rever up and have fun. You only go around one.
 

·
Registered
Joined
·
875 Posts
Discussion Starter #12
Infra3sv said:
You guys will get better mpg if you don't fill the whole tank. If you upgrade the suspension you can get better mpg.
I'm going to go ahead and assume you're joking.
 

·
Registered
Joined
·
875 Posts
Discussion Starter #13

·
Registered
Joined
·
2,719 Posts
Do you know the saying about assuming? It never fails me. The suspension will help you keep speed around corners. It might seem overkill to get suspension upgrades for gas mileage since most mpg enhtusiasts aren't taking corners at high speeds but it holds true in theory. Gasoline weighs 6.17 pounds per gallon @ 60 degrees fahrenheit. It doesn't save much weight but it also holds true in theory.
 

·
Registered
Joined
·
3,368 Posts
Here are all of my numbers since Day One. Overall average is 27.7MPG right now with about 6500 miles. I include temperature numbers (taken off a National Weather Service website) because, in general, MPG should fall off in colder temperatures and you can see that it does.

I use the car mostly for commuting, with a mix of about 20% city, 20% rural backroads, about 40% secondary roads (55-60mph in 5th) and 20% highway (75-80mph). I usually shift, depending on mood and situation, between 3K and 4K. In general I am at 125 miles at the 3/4 mark; 200 miles at the 1/2 mark; 275 miles at the 1/4 mark.

Calculating fuel economy can be slightly tricky. I have noticed different gas pumps shut off at very different times. The best bet is to always use the same gas pump. You will wash out differences in fillup levels if you take an MPG reading across several full tanks in a row. Take the total miles driven and divide by the total gallons from those several tanks to get your number.



No.. the milage will go up in cold weather. The air is more dense and is more efficiant. You will loose milage in the cold by 1) letting the car sit and idle to warm up 2) If your state requires "oxeginated" gas. If you get in your car and drive without warm up, colder temperatures will give you more power and better milage. Cold air intake? remember that one?


Slow down!! high speeds make the drag go up expotenialy.


stop saying what miles you get at 3/4 tank, 1/2 tank.... That is so inacurate, and has nothing to do with nothing. For example I get less than 100 miles at 3/4 tank, but I get nearly 30 mpg in mixed driving. Every car is a little different in the fuel gauge reading and is not an accurate indicator.



Maybe where you are, the pump shuts off and you can't top off.. but most of us can, so the pump doesn't matter to most of us. I just fill it up untill I feel it is full.. but the same pump is a good idea for accurate checking because of the different slopes of the gas station, affecting angle of the car at fill up.
 

·
Registered
Joined
·
875 Posts
Discussion Starter #17
Seems more like an opinion than actual theory. I can't fathom any relation between keeping speed in a corner and saving gas.
 

·
Registered
Joined
·
1,236 Posts
vanace said:
No.. the milage will go up in cold weather. The air is more dense and is more efficiant. You will loose milage in the cold by 1) letting the car sit and idle to warm up 2) If your state requires "oxeginated" gas. If you get in your car and drive without warm up, colder temperatures will give you more power and better milage. Cold air intake? remember that one?
Where to begin, where to begin?

Okay, first of all it's spelled "mileage" and "efficient" and "oxygenated".

Second of all, a cold car uses more fuel for several reasons... one is that the entire driveline is stiffer - tranny lube, axle bearings are harder to spin when cold. Another is that the air is denser, so it takes more energy to push through it. Another is that a cold engine runs enrichment longer (used to be a choke back in the old days).

Third, you aren't even correct about the oxygenated gas. Yes, the EPA admits that it causes a fuel economy hit of 2-4% but that is YEAR-ROUND.

Fourth, while cold air does give better power, it does not change combustion efficiency at ALL. ZERO. Nice cold air will give you better HP numbers at full throttle simply because the air is more dense, hence you get more oxygen with each intake stroke, and to take advantage of this, the computer will inject MORE fuel... hence more power. That's how CAI works, dude. It does NOT improve efficiency. It makes more power, and it takes more fuel to make more power. When you aren't at the racetrack, you are not driving full-throttle, and you are only using as much power as you need to overcome mechanical friction and aero drag... so whether the air is warm or cold or whatever means literally nothing.

Fifth, I don't let the car sit and warm up.
 

·
Registered
Joined
·
875 Posts
Discussion Starter #19
^ Agreed.
 

·
Registered
Joined
·
2,719 Posts
knightm3 said:
Seems more like an opinion than actual theory. I can't fathom any relation between keeping speed in a corner and saving gas.
Hypothetical situation (before suspension modifications)
You're cruising along at 25 mph
you take a corner
you're now going 15 mph
you accelerate to 25 mph

Same situation (after suspension modifications)
You're going 25 mph
you take a corner
you're now going 20 mph
you accelerate to 25 mph

less acceleration = more mpg
 
1 - 20 of 37 Posts
Top