MPG tuning?

GuitsBoy · 01-28-2008, 01:44 PM

Hi all -

Ive been tuning cars in the GM / LSx world for a few years, and now im ready to start playing around with the tuning on my daily driver (2006 WRX). I just ordered my tactrix cable, I downloaded ecuflash and enginuity. I found the latest stock hex files and poked around and found a few popular examples of some stage 1 modified bins. Im leaning towards starting with Gabe's r29 to start with.

Im wondering if anyones been tweaking their fueling in order to get a couple more MPG out of these cars. I see there looks to be plenty of room to work with the open loop fueling tables on the low end, however I dont see any way to adjust the O2 sensor switchpoints for closed loop fueling. Is there some other method of adjusting closed loop fueling? Or will it always shoot for stoich no matter what? I dont think im ready to run an openloop tune in my daily driver.

In the LSx world, ive got my 430 RWHP heads+cam '02 camaro doing about 28MPG through 4'10s, big injectors and heavy tires, not to mention a laundry list of other mods, all through a very conservative tune. With a little more aggressive open loop + MAF tune, i brush up against 30 MPH on the highway. If I can get that big 'ol motor doing that kind of mileage, I really hope I can get a little turbo motor to hit similar marks even through the AWD.

Thanks,
-Tony

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rkramer · 01-28-2008, 02:02 PM

You can set stoich, as well as timing. (increase stoich within limits, and then advance timing to back the EGT's down) Keep doing that until you are comfortable with the numbers and aren't running on the edge of 1 bad tank of gas.

rkramer · 01-28-2008, 02:06 PM

Quote:

Originally Posted by GuitsBoy

In the LSx world, ive got my 430 RWHP heads+cam '02 camaro doing about 28MPG through 4'10s,

Thanks,
-Tony

Also, keep in mind wrx's/sti's have a horrible drag coeffecient, no matter what you do to them, they never will generate great MPG. The camaro already has that going for it.

GuitsBoy · 01-28-2008, 03:37 PM

Ill make sure im not running it on the ragged edge by any means...

Where can stoich be set? I dont see a table or option for it in Enginuity. Also, does DFCO (decel fuel cutoff) exist in this world? I think I feel it kick in during decel, although not as pronounced as in other cars.

I had assumed that coefficient of drag had played some role in gas maileage, but after looking into it, it seems that the Cd is very similar to one another. The 2007 WRX is stated as having a Cd of .33 while the 2002 Camaro was stated as having a Cd of .34. If anything that puts the scoobie at an advantage. In real world experience, though, the camaro certainly seems to cut through the air more easily. Its not nearly as battered about by the wind. It also coasts much longer at higher speeds before slowing, although that could also be attributed to the higher parasitic drivetrain loss.

bucket7788 · 01-28-2008, 05:45 PM

Under "Fuel"

-Closed Loop Base Fueling Target

GuitsBoy · 01-28-2008, 05:59 PM

Quote:

Originally Posted by bucket7788

Under "Fuel"

-Closed Loop Base Fueling Target

Apparently 32 bit O/S's dont have this. I dont know if that will change once they discover all the vars and tables in the rom and update the definition files. I guess im out of luck until that happens.

bucket7788 · 01-29-2008, 12:40 PM

Bummer. Wasn't aware of that. Hopefully new defs will help you out.

Good Luck,

Buck

01-28-2008, 01:44 PM	#1
GuitsBoy Scooby Newbie Member#: 61721 Join Date: May 2004 Vehicle: 2006 WRX Steel Grey Metallic	MPG tuning? Hi all - Ive been tuning cars in the GM / LSx world for a few years, and now im ready to start playing around with the tuning on my daily driver (2006 WRX). I just ordered my tactrix cable, I downloaded ecuflash and enginuity. I found the latest stock hex files and poked around and found a few popular examples of some stage 1 modified bins. Im leaning towards starting with Gabe's r29 to start with. Im wondering if anyones been tweaking their fueling in order to get a couple more MPG out of these cars. I see there looks to be plenty of room to work with the open loop fueling tables on the low end, however I dont see any way to adjust the O2 sensor switchpoints for closed loop fueling. Is there some other method of adjusting closed loop fueling? Or will it always shoot for stoich no matter what? I dont think im ready to run an openloop tune in my daily driver. In the LSx world, ive got my 430 RWHP heads+cam '02 camaro doing about 28MPG through 4'10s, big injectors and heavy tires, not to mention a laundry list of other mods, all through a very conservative tune. With a little more aggressive open loop + MAF tune, i brush up against 30 MPH on the highway. If I can get that big 'ol motor doing that kind of mileage, I really hope I can get a little turbo motor to hit similar marks even through the AWD. Thanks, -Tony * Registered users of the site do not see these ads.

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01-28-2008, 02:02 PM	#2
rkramer Scooby Guru Member#: 118209 Join Date: Jun 2006 Chapter/Region: MWSOC Location: North Dakota Vehicle: 2002 WRX Sedan	You can set stoich, as well as timing. (increase stoich within limits, and then advance timing to back the EGT's down) Keep doing that until you are comfortable with the numbers and aren't running on the edge of 1 bad tank of gas.

01-28-2008, 03:37 PM	#4
GuitsBoy Scooby Newbie Member#: 61721 Join Date: May 2004 Vehicle: 2006 WRX Steel Grey Metallic	Ill make sure im not running it on the ragged edge by any means... Where can stoich be set? I dont see a table or option for it in Enginuity. Also, does DFCO (decel fuel cutoff) exist in this world? I think I feel it kick in during decel, although not as pronounced as in other cars. I had assumed that coefficient of drag had played some role in gas maileage, but after looking into it, it seems that the Cd is very similar to one another. The 2007 WRX is stated as having a Cd of .33 while the 2002 Camaro was stated as having a Cd of .34. If anything that puts the scoobie at an advantage. In real world experience, though, the camaro certainly seems to cut through the air more easily. Its not nearly as battered about by the wind. It also coasts much longer at higher speeds before slowing, although that could also be attributed to the higher parasitic drivetrain loss.

01-28-2008, 05:45 PM	#5
bucket7788 Scooby Specialist Member#: 124263 Join Date: Aug 2006 Chapter/Region: MAIC Location: Now with DB Super 16g and WI! Vehicle: 2004 WRX Wagon RomRaider + UTEC Tuned	Under "Fuel" -Closed Loop Base Fueling Target

01-29-2008, 12:40 PM	#7
bucket7788 Scooby Specialist Member#: 124263 Join Date: Aug 2006 Chapter/Region: MAIC Location: Now with DB Super 16g and WI! Vehicle: 2004 WRX Wagon RomRaider + UTEC Tuned	Bummer. Wasn't aware of that. Hopefully new defs will help you out. Good Luck, Buck