I had my 2007 g35s 6speed since 2009. First thing I did was change out my stock air box to takeda SRI, then Invidia catback exhaust. Smog day finally came for me so I had to swap back to factory box. First thing I noticed was the sound of my exhaust. It became noticeably quieter. Then today on my normal 50 mile commute, I reset my average mpg once I got onto the freeway to see if it will make a difference. To my surprise, it did. I averaged between 28.5 to 29.5 the whole way from sacramento to fairfield, averaging 70mph. By the time I exited, for the first time, I got 30.5 on my display!! Temp was around 80 today with some light traffic. I driven this same route with this car many times with the same condition and speed, but I never came close to anything like today. The most with the SRI was 27.5 but usually 25-26 depending on traffic and weather. Now I'm debating if I should stick with stock or if I should swap it back out. I will do more testing to see if it will yield the same result. With gas prices staying near $4, I might have to stay with stock.

 

i reckon the reason was that you reset the mpg after getting on to the highway so if you reset it while cruising the average will always be higher. Iv done that before and averaged around that through my highway drive but after getting into stop n go city traffic is plummets down to 22-21 after a few days

 

Yeah, that doesn't seem that odd since you are resetting it on the freeway. I do that to my wife's car to "prove" that I can get better gas mileage than she can.

 

Nice! Sadly I will never achieve this with my 5AT, need more gears!!!

 

Yep, limited samples are of limited use.

I've had mine indicate over 50mpg before. It was a result of freshly filling the tank at a gas station right off Highway 4 in the Sierras, then resetting the gauge, then basically driving downhill for the next 40 miles or so.

Of course by the time I finished the trip back down to the bay area, I was at 26 or so. Bottom line is, it's the average you want to look at, not the sweet spots.

 

^ yup but i used to average a solid 21.5 mixed (mostly city) which i was happy with for quite some time but recently it has dropped to 19 with all city driving which i think is great given its rated at 18mpg by EPA in city... now try to figure out how spirited i drive

On the other hand i used to average around 12-14 the first few years when i used to be a more 'spirited driver' signs of aging i guess

 

^^ that's alright kool, I won't tell anybody.







besides, it happens to the best of us, right?

 

That is good. Seems like that 6 is a big deal breaker for the better MPG then the 5. I know the G37 gets better MPG then the G35 for there 7AT. WOuld be nice to see 30+. One reason why i try to drive the scion a little more b/c i see 33 on the highway.

 

Mine since the day I bought has read 18.1 all round average driving. On highways, seen it hit 21-22

 

Yeah I do about 50/50 city/highway driving and can't seem to break above 20 mpg average ever. No matter how delicately I drive. Even if I really push the car I don't seem to get any worse than 18, so it's almost not even worth it for me to be too gentle.

 

When I drove my G35 full time I averaged about 18.1, now my wife drives it about 75/25 and she is pretty calm, and she gets 19.7... these cars are not very gas efficient that is for sure.

 

Even if its freeway only, 30mpg with about 70mph average is quite good.

 

i get 22mpg 30 city / 70 highway with 91 octane

 

30 mpg?? was there a 70 mph tailwind?

 

No, but the route he described is primarily a slight downhill grade overall.