ok so I'm sure this question has been asked somehow somewhere before on this forum but i searched and couldn't find anything so i'm gonna ask it again anyway. What mods have been proven (if any) to positively impact gas mileage on the sedan? I picked up a k&n filter but haven't put it in yet. I'm skeptical on how much gas that might actually save me but we'll see. Just wanted to see if there is anything else that people have done and seen better results.

 

None...

Driving style changes are your only real hope.

 

thats the thing. From everything i'm reading it sounds like this is not a car that responds particularly well to be extremely gentle on the throttle. Obviously if I'm not constantly rompin on it then that helps but so far I've been driving the car very conservatively in an effort to gauge the gas mileage.

P.S. Do you have any vids of your car? I've been checking it out thoroughly. I'm coming from a single turbo z.

 

Light weight wheels/tires. I've noticed a small change in mpg when I swap out my coupe 19s w/ rock weighed RE050 to my oem 17s. About 1.5 mpg or so.

Keeping your tires inflated and driving conservatively are two other good ones.

Mods that improve engine efficency would in theory work but you have to avoid the tendency to push your right foot down!

 

Dyno tune with something like the Osiris or Cobb. Playing with timing can work wonders here.

Keep your car clean. The less weight in your car, the better.

Any breather mod (i/h/e, etc...) can be great if you get a proper tune for that set-up.

MREV2 will actually help mileage (with a tune)

I've also seen better mileage without the stock cats (also tuned)

Motor mounts, clutch, lightweight flywheel, etc will help efficiency and like Jeff stated, will help you get better mileage if you don't gun it.

I barely need to touch the gas pedal, and I can get more than 30mpg... I've seen over 35mpg on long freeway drives before. And no, I don't go by the GPS bs gauge (or whatever that leaf thing is).

Oh, one more thing - cruise control. Use it.

 

The geo metro mod adds mpg.

 

Believe it or not, boost was originally used to improve fuel economy... it can still work great depending on the build and tune.

One more mod - Hydrogen conversion. It works, just not as great as advertised. I'm actually thinking the tune did more than the hydrogen, but the cars we've been testing those things on are getting slightly better mileage than before with just a tune.

 

Sell it and by an economy car. This is a vehicle that recommends/requires (depending on year) premium fuel and is built and tuned from the factory with an emphasis on enthusiastic driving. Not saying improved mileage is not possible...it should just be a factor when choosing the car. I hate when people purchase a vehicle knowing what it does from the factory and decide they want to change certain characteristics like the fuel economy. Drive the car like it was mean to be driven!!!!! sorry for the rant guess I am on a soap box today.

 

Cars come from the factory with a very conservative and "safe" tune for liability reasons. Get a real tune and see how wrong you are! You won't gain physical power on the revups, but response and everything else will be much better. That's where you'll be getting the better mileage from. You can see a gain of up to about 20hp (depending on the motor and the dyno) with just a tune. Most stock non-revup G35s can see a gain of about 5-10 hp with much more improved throttle response.

 

I bet a 2.0 final drive would net you some killer mpg

 

Actually, I'd stick with stock gearing... you still would want to get up to speed without being on the gas that long... the longer your foot is on the gas to accelerate up to speed, the more gas you are wasting. Then again, if you gun it too much, you're wasting more gas too.

The best way to get more efficiency with these cars is to tune for more torque. The closer the torque and hp lines are to each other on the dyno chart, the better efficiency your motor is putting out.

 

Actually you don't burn more gas if you open the throttle. Only if the engine takes in more air.

 

ok. I like the Idea of tuning. I did a little with the utec on my Z and would like to try my hand at something a little more sophisticated like the haltec down the road.


And BTW I have an economy car. good ole ford focus hatchback.

 

has anyone tried tuning the stock motor to 87 or 89 octane? would that save money at the pump? just a wild idea. btw i have a beater maxima that i drive daily to work. has better mileage.

 

-Try to shift below 2k rpm and hold as high gear as possible without lugging the engine. 5 th is fine at 50 km/h and 6th at 60 km/h. You can always drop a gear or 2 for quick pass.
-Do not coast in neutral(if you have manual), let it be in 5th or 6th. Let wheels spin the engine, not the idle control, which is on the rich side.
-Premium gas is a must in city traffic. Difference in consumption is staggering, at least for my car. On the highway it doesn't make much difference.
-Properly sized exhaust will improve low end(modest piping diameter for N/A). I just love my single Tanabe, it definitely added to low end. I think it is only 2.5" diameter.

And the usual stuff about fluids/tire pressure etc