Gas Mileage Changes With Exhaust & Intake Mods
Same here. I do think, in my case at least, that the decrease in mpg has a LOT to do with the fact that my right foot has gotten an awful lot heavier since I installed the intakes and cat-back exhaust! 
Whenever I fill up my tank I think to myself "alright, it's time to start driving rationally", and I actually do...for the first 10 miles maybe
I then just get bored of driving at that pace (switching gears at lower RPM, not making the exhaust roar, etc, etc...) so I go back to "race mode" which ends up with my G getting ~15mpg. At some point I find myself pumping gas in the car and going through the same ritual...it's a vicious circle 
Whenever I fill up my tank I think to myself "alright, it's time to start driving rationally", and I actually do...for the first 10 miles maybe
I then just get bored of driving at that pace (switching gears at lower RPM, not making the exhaust roar, etc, etc...) so I go back to "race mode" which ends up with my G getting ~15mpg. At some point I find myself pumping gas in the car and going through the same ritual...it's a vicious circle
You and me both expect when I fill up that's when I justify punching it. I only drive slow when I near empty. Just installed a new catback that has made it even more challenging to not dump on the pedal.
Same here. I do think, in my case at least, that the decrease in mpg has a LOT to do with the fact that my right foot has gotten an awful lot heavier since I installed the intakes and cat-back exhaust!
Whenever I fill up my tank I think to myself "alright, it's time to start driving rationally", and I actually do...for the first 10 miles maybe I then just get bored of driving at that pace (switching gears at lower RPM, not making the exhaust roar, etc, etc...) so I go back to "race mode" which ends up with my G getting ~15mpg. At some point I find myself pumping gas in the car and going through the same ritual...it's a vicious circle
Whenever I fill up my tank I think to myself "alright, it's time to start driving rationally", and I actually do...for the first 10 miles maybe
I then just get bored of driving at that pace (switching gears at lower RPM, not making the exhaust roar, etc, etc...) so I go back to "race mode" which ends up with my G getting ~15mpg. At some point I find myself pumping gas in the car and going through the same ritual...it's a vicious circle 
Registered User
Joined: Feb 2013
Posts: 128
Likes: 7
From: Central Illinois
I manage to get 15/16 mpg driving hard and I'm stock. FWIW, maybe it's not so bad for you after all.
Oh, and I was in Canada last weekend and found gas costing $2.60 more per gallon. Keeping that in mind helps you get over the poor gas mileage we get.
Oh, and I was in Canada last weekend and found gas costing $2.60 more per gallon. Keeping that in mind helps you get over the poor gas mileage we get.
Registered User
Joined: Jul 2011
Posts: 16
Likes: 0
From: mississippi
I purchased my 09 G37S with 14,000 miles. I was getting 24 miles / gal. combined driving. Recently had dealer run diagnostic on transmission @ 41,000 miles because no pep when punched at low RPM's. Now I really like the power off the line and quick down shifting but mileage has dropped to 21 - 22. I like the auto transmission performance so much I am willing to give up the lost mileage.
I've always been one of those people who monitor their MPG manually every fill and I can honestly say it all depends on your right foot regardless of your mods. I was getting 18-21 mpg combined when I was stock and still the same today. I have stillen gen3, MD artpipes, MD E370, MD M370, and untuned.
does a new flywheel make that much of a difference? whats a good one to get? and to what type of tune are you referring? do I need an after market computer or can it be done with a stock one (or is it even worth it?)
I just got the tune from church automotive. The flywheel is lighter and you probable wont notice it but i am working on a CF driveshaft that will free up more HP and i am hoping to see some better MPG w/ that since the engine don't have to work so hard to spin the 30lb driveshaft. Would be nice if that really makes the difference to go beyond 24mpg
Our last 1600 mile roundtrip from Vegas w/ Injen SRI avg 28.5 hwy.
Our same trip prior to this w/out Intake I got identical mpg. I know my city mpg has gone down a couple, like everyone says it's too hard not to want to hear the "angry" VQ now
Our same trip prior to this w/out Intake I got identical mpg. I know my city mpg has gone down a couple, like everyone says it's too hard not to want to hear the "angry" VQ now
Registered User
Joined: Jul 2011
Posts: 207
Likes: 5
From: Upstate NY
The one tank with just the intake is useless statistically. No one should be reading anything into that.
As another stock reference point, I get 19-20 in daily driving. We drove 650 miles on the highway last weekend and only averaged about 22.5, but we were taking advantage of the minimal traffic... One leg was 295 miles in 4:15.
As another stock reference point, I get 19-20 in daily driving. We drove 650 miles on the highway last weekend and only averaged about 22.5, but we were taking advantage of the minimal traffic... One leg was 295 miles in 4:15.
Stock Intakes are the best! Look at my post I started!
You are going to burn more Gas because when you added the aftermarket intake you lost lowend and now you are having to put your foot into the flow more then before!
Just food for thought!
You are going to burn more Gas because when you added the aftermarket intake you lost lowend and now you are having to put your foot into the flow more then before!
Just food for thought!
I recently drove a stock 08 g37s about 250 miles and got almost 30 a gallon because I couldn't go over 55 the entire time due to a bent rim. once I got new rims on it, right back to the regular 19-20 a gallon. put the intakes and exhaust back on. same mileage as stock.