Is this cheating?

[trikkonceptz]

My work commute is as unchanging as they get, 50 miles each way, same path same traffic patterns unless there is an accident.

My one way commute using driving techniques usually yields 46mpg by the time I get out of the vehicle. This happens driving 55mph, 40mph in the city. I have 2 highway segments divided by 2 city segments.

Now last night I drove home @ 65mph, 40mph city commute, 55mph on 2nd highway stretch & 40mph in the 2nd city stretch and when I got home the scangauge still read 46mpg.

Is this possible because of the distance I cover? 46mpg seems to be the limit currently with mods, technique and weather. I just do not know what 46mpg avg means. I would think that my average would be lower considering the higher speed on one leg of the commute.

Chime in please.

[Ford Man]

The best way to check this for accuracy is to try these speeds everyday for 2 or 3 tanks and figure it using the miles divided by gallons method then go back to your old speeds and check it the same way. The scan gauge is a good tool, but it's not always perfectly accurate. It does seem that you would have lost some FE by driving faster, but I have read of others claiming to get better mileage at 60-65 than at 55 although it's never been the case with me.

[trikkonceptz]

Nor me, my best FE is @ 55mph unless drafting ... I'm just curious if the distance I drive is a factor? Knowing that no matter how much farther than the 50 miles I drive will not result in better FE, I wonder if there is a distance where I reach optimal FE then after that its all maintenance.

[IndyIan]

Do you mean that your first 5 miles has, for example, a trip average of 32 mpg, and then the trip average gets better as you go?
I guess the best trip average you could hope for is slightly less than your best 55mph instantaneous MPG if you don't pulse and glide and are driving on a flat plane.
I like the trip MPG function as it shows how bad your mileage is on short trips, and the cost per trip function. Costs me a dime to get out of my driveway!
Ian

[TestDrive]

A couple of things that may contribute.

Maybe the ECU's open loop fuel map leans out enough at the higher rpms to give better FE?

In any case, the engine is bound to warm up sooner at higher rpms allowing the ECU to go into closed loop sooner. And you're bound to get better FE in closed loop.

[PaleMelanesian]

I find that after 10-15 miles, it levels off. The first 5 miles are bad, 5-10 is ok, and 10+ is cruising time.

[BlackDeuceCoupe]

I guess I don't get it, trikkonceptz

What are you asking? Cheating at what?!?!?

I imagine my commute is very similar to yours. I drive 3 miles from my house to the freeway. Then 40 miles of pulse n' glide freeway driving to the turnoff for work. Then 3 miles from the freeway to work. I usually take the same route, yada, yada, yada.

I seem to get better FE @ 70 mph (4400 rpm) than I do @ 55-60 mph (3000-3500 rpm). And, I'm strictly going by raw numbers, if you will, e.g. not using a SG or whatever - just topping off my tank every two days and using the trip meter, a wristwatch calculator, and the EM fuel log, to compute my mileage.

The thing is, I don't like to drive that fast, even if it gives me better FE!

My dumped rice rocket *looks* fast. Driving fast is just asking for a speeding ticket!

Anyway, what is your concern? I don't get it...

Do you *feel* like you're cheating by driving too fast - too far - doing too much freeway driving - not enough city driving?

LoL!

I don't *feel* guilty because I get world-class FE, nor *believe* I'm cheating...

Is THAT what this is about - you *think* you're inadvertently rigging the results?

[trikkonceptz]

Here is my question, I gues in SAT test format .. LOL

My drive is comprised of 4 legs;
-Home to Hwy - Seg A
-Hwy to Crossroad - Seg B
-Crossroad to Hwy - Seg C
-Hwy to Wok - Seg D

I tested this on two nights heading home; Usually the distance Seg D to Seg A results in my Scangauge reading a 46mpg Avg.

The other night I drove Seg C @ 65mph, by the time I exited the Hwy I was at 40mpg. The crossroad segment added on another 2mpg, then I got on to seg B which netted me 45.8 by the time I exited. Once home I had 46.1mpg.

Looks like I can cheat on one segment, make up for it on another segment and still net the same mileage. But is it really?

[BlackDeuceCoupe]

Originally Posted by trikkonceptz

Looks like I can cheat on one segment, make up for it on another segment and still net the same mileage. But is it really?

Why do you *feel* that you're cheating on one segment?

Who/what are you cheating - cheating death by driving too fast?

That's what I don't get...

[trikkonceptz]

No .. hehe .. cheating my overall tank average ... if now I do 55hwy 40city and get 46mpg, and I can achieve the same results by doing 65mph for a time then 55mph for a time and still get the same read out on the scangauge, is the scangauge accurate? Or am I using more fuel?