First Post Here!

I bought a 05' G35 6MT with 65k miles, about 6 months ago and made some mods.

Mods: Lower Plenum, 5/16 spacer, z-tube, K&N drop in, Stillen sways.

Yesterday, I changed the spark plugs, which was much needed, as before I changed the plugs I was getting some cracking sounds at 5,500-6,500rpm, but now it is firing with no problems, and runs like a champ.

My question is: I am headed to Portland in 2 weeks and trying to calculate my MPGs. Typical MPGs for this car are 28 highway. I am wondering if anyone has hard evidence and clear data that their MPGs have increased with these mods, or some of them. I am figuring about 30-35 MPGs should be expected with my current setup? Does anyone have any knowledge with this?

Appreciate the help, and thanks in advance.

 

Bro I get maybe 16 miles on the highway.

 

30-35 MPG?

If you can manage 24-25MPG even after the mods...you are way ahead of the game. Even if you manage that, the minute you hit surface streets your combined fuel economy will be somewhere in the teens.

Not trying to knock you or the car...but these cars are not that fuel efficient. You're probably looking mid to high 20's at best when at cruise on the highway.

 

I have an '04 MT sedan and average over 23 in mixed driving. I baby mine most of the time with an occasional run to redline. I think the MT's can get more mpg's than autos.

However, I don't think any of the mods you made will make any measurable difference.

 

Thank you for the responses. This is a lot of mixed information lol. I will say, I am far from babying this thing, but thought the intake and more air would make a bit of difference. If babied I figured it would increase over rated MPGs.

I totally agree, Mustang. It is a fun car, and most fun cars, besides electric sports cars, are NOT fuel efficient.

I guess the only way to find out how mine reacts, is to test it out!

Anyone got a recommended radar scanner!? I live in CA.

 

The engine was designed pretty efficiently from the factory. There really isn't much in terms of N/A mods that you could do to it to really squeak out more HP and fuel efficiency. You could throw several thousands of dollars in N/A mods at it and not really generate a whole lot of additional HP and MPG's, so don't get hung up on that. Just enjoy the car.

 

Willcliff, you should easily get 300 miles per tank on the open road, use your cruise control when ever possible! Surprised your plugs were breaking down with only 65K miles on your G! Your mods should only help your MPG! Check your belts/hoses and do an oil change before heading to Portland. Love that town, it's so clean compared to other large cities...maybe cause it's constantly taking a bath!
Gary

 

+1.

What will give you better mileage are just basic efficient driving habits and good overall maintenance. E.g. fresh oil change, proper tire pressures, reduced weight, driving/shifting at lower rpm's, etc.

I can consistently get around 20/21mpg city when I drive easy (shifting around 2.5K rpm's or less).

 

I did cross-country in mine, averaged about 28mpg in both my 5AT and 6MT, mostly 75mph.

I drive mostly highway to and from work for my commute, and 400 per tank is average, but speed is split between 75 and 63, about 15 miles at each speed.

 

This is great information. Although I do love the 4500-6000 rpm range, I will baby it, and run around 3k at 80mph. Hopefully that will help, or maybe stay below 3k rpm on cruise control. I will let you all know my results, if you are curious.

Appreciate the help!

 

Just an FYI to everyone...cruise control at 80mph and got 20.53mpg. Not bad at 2950 rpm. Made it to Oregon in 7.5hrs.

Thanks everyone for the posts.

 

20.53 mpg? Lots of hills? Or romping on it to get around trucks? Even my 4AT Maxima got 24-27 mpg on road trips.

Guess I'll take my Accord on longer trips, get close to 30 mpg at those speeds, 80 mph is just under 2500 rpm.

 

Well yes there were hills/passes. Of course I had to romp it around the trucks. Had 92 octane in there, but I don't like how 80mph is almost 3k rpm. Wish it was less.

I bet if I did 65 I would get a loooottt better, however it would have been an 8.5 hour drive.

 

You can increase your MPG by 1-3 MPG by not using cruise control.

Didn't you notice the vehicle braking on long downgrades when using cruise control?

I get excellent mileage on round trips between NJ and Florida.
Short trips while in Florida not so much



BTW using a higher octane only empties your wallet.
It does not increase your MPG

Telcoman

 

When the transmission in my son's Prelude went out (4 speed automatic) while we were both driving our cars to Arizona, we were limited to about 60-65 since 4th gear was toasted on his car. I was getting 34-35 mph with a V6 Accord. But it sucked going that slow. I'll pay more to go fast! And I certainly didn't buy a 6 speed G35 to go 65 in the right lane.

I do the same on trips, I kind of look for trucks that are closing in on other trucks and get on it to get around them before they can move into the passing lane.