Okay so i know the 350z usually has a relatively low gas mileage than other cars but mine is just getting ridiculous now, the car is stored for the winter so i want to try to see what i can do to make my mileage better. First ill list off the mods i have on the car that may affect my mileage, but the gas mileage was always horrible on this car even before i started modding it(from bone stock). Then ill show you some numbers of my mileage. Then ill ask for some advice if there is any for me. And i understand that a heavy foot will bring the numbers down, but on the weeks that i tested the gas mileage i was certain to drive as civilized as i possibly could.

2004 350z roadster 60.0xx kms
JWT Popcharger
Motordyne 5/16 plenum spacer
Strup Test Pipes
Stoptech Rotors
Tire/rim Setup: rims weigh less than oem rims
front: 9 inch rim wrapped in a 225 (stretched)
rear : 10 inch rim wrapped in a 245 (stretched)

Car is up to date on all service and maintenance.
No CEL's
A/c is Usually off

Gas Mileage
Week 1:
Distance: 230km
Litres Used : 36.364
Km/L: 6.33 (thats 14.89 MPG for the americans)
L/100 km:15.81

Week 2:
Distance:277km
Litres Used:45.530
Km/L: 6.08 14.3 MPG
L/100 km: 16.44


So far i have planned to:

Clean my JWT Popcharger
Sea foam the car
ECU reset for A/f ratio

However i was hoping some of the experienced members could chime in here. Do you guys think if i got an Osiris Uprev tune done, it may help increase my gas mileage?


Any other ideas would also be appreciated. I have 3 months to figure this out. So i think ill try any idea good ideas you guys have. Thanks

 

try a fuel system cleaner, i am not sure what type of fuel stabilizer/knock retardant they use up there, but here they use ethanol, use to be mtb. Basically is highly corrosive and destroyed the injectors. 44k by BG usually helps. Worst comes to worst try an OHM check on the injectors, we see it all the time on cars that are driven in the winter or cold since fuel additives change from seasons.

 

Hmmmmm... I wonder if this subject has ever come up before????


https://my350z.com/forum/2003-2009-n...intenance.html

https://my350z.com/forum/2003-2009-n...s-mileage.html

https://my350z.com/forum/2003-2009-n...-z-owners.html

https://my350z.com/forum/2003-2009-n...s-mileage.html

https://my350z.com/forum/2003-2009-n...-your-mpg.html

https://my350z.com/forum/engine-and-...s-mileage.html

https://my350z.com/forum/engine-and-...lese-help.html

https://my350z.com/forum/engine-and-...s-mileage.html


Yeap, looks like is has.

 

Please dear lord not another MPG thread.

 

im getting 11 MPG with jwt pop chager, headers, test pipes, kinetix v+..i think u should be happy...14 is awesome...if u cant live with it sell it get a camry end of thread

 

Not really. My brothers vette is getting 20 MPG and thats a 6 litre V8. So if my 3.5 litre v6 is getting less than that, thats pathetic.

 

Thanks Dave, ill look into those when i get a chance.

And qqqqball, im gonna do a fuel injector cleaner (sea foam). Thanks though. And i use 94 octane gas, no ethanol from chevron. it has techron in it.

 

im getting 27mpg on my 04. that's horrible advise if i ever saw one.

try to get an alignment OP. maybe get a tuneup could be it imo.

 

Wow, I get that much on my H2 running around town. I can get 14 on the highway if I keep it under 70

 

keep us updated on any fix op

 

booey- got an alignment done twice. And thats what i was wondering, if i get an osiris tune up, do you think that would/could have any effect on it?

porschett- i bet you can get more out of your H2. And thats why its driving me mad, i understand its a sports car and all, i shouldnt expect it to be as efficient as a camry (like some smart *** suggested) but like i said earlier, my brothers 6.2 litre v8 is way more efficient than mine.

shawz- will do.

thanks guys.

 

Perhaps something OTHER than a rwd sports car would have been a wiser investment... like a huffy.

These threads make my work nights go by so much faster.... thanks, op!!

 

Your welcome douchebag. And i invested in a car, not something that pisses out gas faster than you can pump it in. If my car was in proper working order, i wouldnt be writing this up for your amusement. hence the post.

 

Oh, I totally get it... just seems that maybe if gas mileage was a top priority for you, you'd have invested in something a little more, uh, "Sentra" like... good luck in your search, hope you come to a quick resolution/fix.

 

what's your average mpH?
that's usually pretty telling..

 

Arvin, my first obvious guesses would be to check/replace the O2 sensors and things along the ignition and fuel injection system.

Less obvious things would be to check for seized calipers, brake drag, proper transmission and differential oil viscosity. I know the gear oil definately made a huge difference on my car. If you haven't changed it recently, try using Nissan MTF or Redline MT-85 for the trans and castrol hypoy C 80W-90 in the diff. This combination definetely works for me. I noticed that using a slightly thicker MT-90 (75W-90) in my transmission immediately lowered my mpg to low 16s. For several consecutive tanks I was stumped. Installing the proper viscosity instantly solved my mpg issues. Now my car sees mid-high 19mpg mixed driving all day even in sub 30deg F temps which is what it always got from when it was new.

A fuel system cleaner that has no ill effects for me was Redline Fuel System cleaner.

 

i get 24ish and play with mine, i can get low 30s if i cut my right foot off. (done it a few times). but wow. that is really bad. tuneup all around is my guess.

 

I am always impressed with the people who post mid 20s and even 30mpg gas mileage. Is your car a manual transmission? Do you do a lot of highway driving under 70mph? Also what fluids do you use in your car and what modifications, if any, do you have?

 

Not as bad as u, my 04 will get 17 if I play with her hard around town. 20 if I'm nice to her. I'll get about 26-28 on the highway. I have all most all the mods u have listed. Try cleaning out ur injectors?

 

I don't think I would call your gas mileage "horrendous". I believe the EPA rating for the 350Z is 17 city and 21 highway with a combined average of 19mpg. You aren't that far below the government totals.