rom tuning for improved gas milage
 

My goal is to create a rom that will give 10%-15% mileage increase.
Im not looking for performance here I just want to see if it is possible to achieve that. Dont care if the car is slow as a Prius.

Anyone have a clue how to achieve better gas mileage?
What tables should I start looking into?

What tuning method, ECUtek or RomRaider?


I guess you could change the O2 sensor scale to read richer and therefore make closed loop operation be leaner. Having not looked into mileage tuning I wouldn't know how to adjust the timing although from memory you'd advance the timing a little.

Don't expect any big gains for improving fuel economy without hurting performance. The factory a pretty good job in this respect. The problem with leaning the AFR target at cruise is that you will also see a loss in engine torque which will require more throttle which will then meter more fuel and you are back to square one. You can problem get some minor gains by leaning AFR slightly and then adding a small amount of advance (2-3 deg) at cruise conditions. The factory couldn't get away with these changes due to emission constraints (primarily NOx emissions concerns). But the effects on mpg would be small and take some very controlled testing to quantify. Probably too controlled to street driving.

Romraider is my tuning method.
I have a stock car.
Ill try both of your suggestions and go from there.

You 'll Have better luck with a 3.7final drive swap if you want that 10~15% mpg increase

I got slightly better milage after installing OFH catless header suspect due better low end torque, but you have to drive very sedatly to achieve good economy in city.

@shif7i7down, I was going to swap out to a 3.7 final drive in a couple of years from now once I had a turbo installed. It seems like a good option to do it now and don't worry about the tune and just flash OFT rom files.

I got better mileage with the OFT Stage 1 tune 29.2 (without tune) 29.6 (With tune).

Could possibly play with the drive by wire setup so it's not possible to full throttle.


Electronic equivalent of putting a block under the gas pedal.

hate to be 'that guy' to question the OP or suggest something contrary to what you're asking, BUUUT

is that ~2-3mpg increase really worth cutting the nuts off this car? One doesn't die with their money. Memories and experiences are all we really got at the end of the day.. just some food for thought.

I feel your pain though man. I drive 130 miles a day. Everett to Kent, WA.

Over 51,000+ miles I have averaged 32.65MPG, as documented in my owner's journal thread. An increase of 10 to 15% would mean an increase in mileage of 3.2 to 4.8MPG.

Given the current focus on fuel economy requirements, I just don't see any way that Toyota/Subaru would have left that on the table if a simple ROM change would have upped it, even if it meant sacrificing performance a bit particularly given that straight-line, top speed performance was not their focus with the 86 platform.

You'll get far better gains by changing your driving patterns than by re-tuning for economy.

Choke your intake so it can't flow enough air for 100hp. Redo MAF scale, retard some cam timing, done.

Step 3:???
step 4: drive slower than a prius