Mods that are good or bad for mpg?

[Quinton Exler]

I think it would look sexy as hell, and lower the frontal CD and drag. With my seating position I've got atleast 4" of headroom

Yes Completely full until the fuel light came on! See If I achieved 50 average I'd think at LEAST 55 could be doable with an eco tune VS. a heavily aggressive 93 octane 42lber tune?

 

[sx sonic]

Yes Completely full until the fuel light came on! See If I achieved 50 average I'd think at LEAST 55 could be doable with an eco tune VS. a heavily aggressive 93 octane 42lber tune?

It may sound counterintuitive it won't make much, if any difference. If your staying out of the throttle most of the time then fuel trims and all that is the same or near identical in both modes.

 

[Quinton Exler]

I will be more than glad to hand calculate and see! Crossing my fingers for at least a few MPG gain... But you must also remember, my car is Automatic transmission so when I get the MPG tune the shift points will change a good bit.

 

[Swordsmith]

I have yet to hear anyone report that they got better mpg with the eco tune instead of the performance tune, in a blind test. It's human nature to alter your behavior in line with your expectations, and then misinterpret the results as confirmation. So you'll want to design your test in a way that removes that bias as much as possible. The simplest way to do this is to get to a set speed on a highway where you can set CC and drive a long distance over the same stretch with no human input... but that's not really informative, since a lot of the difference between the two tunes would lie in how they behave while accelerating.

If you can arrange for someone to go to your car, flip a coin, and set one of the two tunes, while covering any telltales so you can't tell which is which, and then go away without you seeing them, then do your best to repeat everything, with nice long swaths of test data (5 miles is not informative). A tank, two tanks, per setting, if you have routine driving.

Driver behavior affects mpg so much that detecting a 2 or 3 mpg change due to any given mod (including a different tune) requires some serious rigor.

 

[trollbait]

Just hire Wayne Gerdes for your chauffer.

 

[Quinton Exler]

I have yet to hear anyone report that they got better mpg with the eco tune instead of the performance tune, in a blind test. It's human nature to alter your behavior in line with your expectations, and then misinterpret the results as confirmation. So you'll want to design your test in a way that removes that bias as much as possible. The simplest way to do this is to get to a set speed on a highway where you can set CC and drive a long distance over the same stretch with no human input... but that's not really informative, since a lot of the difference between the two tunes would lie in how they behave while accelerating.

If you can arrange for someone to go to your car, flip a coin, and set one of the two tunes, while covering any telltales so you can't tell which is which, and then go away without you seeing them, then do your best to repeat everything, with nice long swaths of test data (5 miles is not informative). A tank, two tanks, per setting, if you have routine driving.



Driver behavior affects mpg so much that detecting a 2 or 3 mpg change due to any given mod (including a different tune) requires some serious rigor.

I could probably put it to rest forever... I have a drive coming up that is 75 MPH highway the entire way, literally right onto and off the highway in both locations in multiple spots are gas stations ready! All of which are shell stations quality 93 octane gas. I could cruise control 75 MPH in both directions doing each direction with a different tune to compare the eco 42 lb tune to the 42lb injector performance tune. it may not be 100% absolutely accurate however it could def. show a difference in the highway MPG between these two tunes. City would be a different ball game.

 

[Swordsmith]

While that's a start, it's not really as refined as it should be. Problems with your plan:

1) You'll know which tune you are using. This is bigger than it sounds, because driver behavior is such a large factor. Smaller than it sounds, with your plan, because CC will eliminate driver behavior for most of the trip. But getting on and off the highway is one area where I'd expect to see a difference between the two tunes, if any.

2) You won't be repeating the same drive. I know it will be the same road, the same distance... but one direction may be uphill, the other down, one may be with the wind, the other into the wind.

3) Temperature may vary. The problem with long drives is that you start out in cold air, and the day warms up, so even though you are going through tank after tank, which is good, you aren't doing it all in the same conditions. Gains or losses, if any, tend to be pretty small for most changes, so you can lose or overestimate them in the clutter.

You will still be able to take a look... and that's exactly the sort of thing that lead me to believe the eco tune doesn't make any difference; I drove to Texas and back, alternating tunes, and when I averaged all the "eco" and all the "performance" the numbers came out pretty much the same.

On a different note, following up on a lead elsewhere in the forum, I looked around the ecomodder forum and found this really detailed post on a whole range of possible eco mods you could look into:

 

[Quinton Exler]

Thanks for that page, a lot of it kills functionality but some is very helpful! It has been 6 days total since my request for the 42lb eco tune, so I should be seeing it pretty soon and play around some to see what I can make out with it.