Fuel Economy.....LOL

[rocket69GTP]

I am only asking this because I have had luck in the past but I understand these cars were not exactly built with fuel economy at the top of the priority list. How much of a difference would I get if I did an intake, exhaust, and custom tune on my G? I was able to pull an extra 3 mpg on my last Grand Prix with these simple mods so how feasible is it with these cars? Any input is greatly appreciated.

[biggie]

The money for those parts will probably negate the mpg increase. And 'go fast' parts will cause the right foot to be heavier.

[tboudre]

When I signed the lease/purchase agreement on my G37, gas mileage was the furthest thing from my mind. Today, I had to take a job with a 160 mile/day round trip commute. Fortunately, I drove a lot less miles than I signed up for, and I'll use them in the last 10 month of the lease, but I'm stuck burning 8 gallons/day until then. Is there any modification I can do to increase my MPG? I'd love to keep the car at the end of the lease, but I can't justify it unless I can get better mileage.

[audtatious]

I have a cat-back and slight tune today and have not noticed any mpg increase. Will have to see what happens with HFC's and a real "tune". When it happens I'll obviously document it.

[SavG35]

First thing first, its simple but key. Tire pressure, check it constantly, or as most of have,make sure your tire gauges that are inside the tire are correct. I also replaced all my tires with Nitrogen and got 1 or 2 more miles. Anything that will lighten the load on the engine and return power to your the wheels would help. I am about to install all new UD light weight pulleys on my 04 g35 coupe, I'll let you know what I get from that. Also I have been looking all through this forum and others to figure out my best intake upgrade. What I have come up with is that the G's intake system really is not bad, other then a Z-tube you won't get much if any from that. I am heavily thinking on getting the Kinedix V+ plenum, it seems to give the most power and MPG results.

Now really no matter what you upgrade it all comes down to how you drive. Now if you upgrade everything and drive easy then yes you can see some more MPGs. So there you go thats what I got. I 'll let you know what I get when I add the pulleys, and the plenum.

[Sentientbydesign]

First thing first, its simple but key. Tire pressure, check it constantly, or as most of have,make sure your tire gauges that are inside the tire are correct. I also replaced all my tires with Nitrogen and got 1 or 2 more miles. Anything that will lighten the load on the engine and return power to your the wheels would help. I am about to install all new UD light weight pulleys on my 04 g35 coupe, I'll let you know what I get from that. Also I have been looking all through this forum and others to figure out my best intake upgrade. What I have come up with is that the G's intake system really is not bad, other then a Z-tube you won't get much if any from that. I am heavily thinking on getting the Kinedix V+ plenum, it seems to give the most power and MPG results.

Now really no matter what you upgrade it all comes down to how you drive. Now if you upgrade everything and drive easy then yes you can see some more MPGs. So there you go thats what I got. I 'll let you know what I get when I add the pulleys, and the plenum.

You guys have two completely different cars. Comparing MPG mods isn't going to work.

Probably the most effective way to increase MPG in the G would be a different final drive ratio to bring the RPM back down at cruise.

It's possible to have the target closed loop values to be a little higher than stoic to shave a little more, but you'd have to be gentle with it and not drive in high gear with a load. Then again, it would probably go out of closed loop if enough load was present.

[tollboothwilley]

I increased my hwy MPG from 23/24 up to 27/28 but when I swapped gears in the FD I went back down.

You won't increase it that much for around town. It never changed.

You should just expect intake/exhaust mods NOT helping with MPG. Especially not enough to justify the cost.