Just bought my 2008 G35 Journey and love it. I have a 22 mile commute each way for work, so I'm looking for a few mods to help with the gas mileage. However, I don't want to hurt performance (improving it would be a plus) and I don't want to void my warranty. I'm also concerned about reliability in the long run. What would you recommend?

I also have the slight hesitation from stop and wouldn't mind getting rid of that as well.

Great car!

 

What are you averaging right now? The only way to improve mileage without hindering performance is to drive like a grandma, keep your tires inflated to theproper pressure and make sure all of your filters are clean. You may wantto look into swapping your air filters for some k&n filters or even looking into the bullydog tuner. After installiing it and bumping the timing by 2 degrees I gained about 2mpg average, I also really woke the car up as well. If you are experiencing hesitation I would take it to the dealer. They can fix it under warranty.

 

Thanks for the response. I'm getting about 21 averaging 25% city and 75% highway (with hills). I get about 25 on flat highway with cruise. I read a little about a new intake adding 1-2 and the bulldog another 1-2. Both would be worth it for me. Any issues with warranty for these?

I also read a little hesitation from zero was normal for this car, but if it's not, I'll take it in.

 

Exhaust and intake are said to improve MPG a tiny bit (if you can resist the urge to get on the gas, that is). Bullydog ECU owners have also ~2 mpg increase. That being said, it'll take you many tens of thousands of miles to make up for the cost of these mods.

...but the most noticable mod is changing one's driving style. It's free, too. =)

 

I'd say 21 is decent. I get mid-19s with about the same commute. Then again, I have 20" wheels that slow me down.

Futhermore, I'm sorry, but mpg gains don't simply add up like that. Just like how hp gains don't simply add up (ricer math).

 

A 2 MPG increase would pay for itself in about 3 years. Seeing as I keep my cars longer than that, aside from the performance boost, the MPG improvement would be worth it. But seeing as I keep my cars for a long time, I want to make sure reliability and warranty aren't affected.

I agree about the driving style suggestion. But if I wanted to drive conservatively, I wouldn't have bought this car!

Sorry. Poorly written. I wasn't suggesting simple addition for the two, just examples of mods that could improve MPG.

 

What about tires? I got Goodyear Assurance tires on them from the dealer, but man they're loud. I'm thinking about swapping them out for something else, but what to do with 4 almost new tires?

 

If you want to get a single product, $/mpg-wise, I think just the Bullydog ECU would work best for you. About the same price as an intake and tons cheaper than an exhaust, and if the reviews are true, it should give you more mpg than an intake or an exhaust. I believe it gives you the option of reverting back to stock programming if you ever need the take the car into the dealer for ECU/engine warranty work, too.

However, it appears to be not completely refined yet and there have been some installation issues with it. Read the Bullydog thread for a lot of info and see if you want to make the investment. You can always resell it if you don't like it, though.

 

21mpg is great lol. i get 10mpg

 

I gained pretty much nothing from the exhaust and again.. nothing with the intakes.
The Bullydog gave me a solid 2-3 MPG gain with absolutely no change to my driving style. In fact, I'm probably more aggressive now.
I'm currently sitting at 19 MPG with a heavy foot and 50/50 City/Highway driving. If I put it in drive, get her up on the highway, set the cruise to 65 and behave, I'm very easily at 29-30 MPG.

The Bullydog is your answer. Gains are fantastic considering the price and with the better efficiency, well worth the price of admission.

 

I average 22.5 mpg with 80% interstate/20% city, going on 26,000 miles. I run Falken FK452's 19" on A34 19" Rays Nismo rims....and Bully Dog standard tune with 89 octane gas, stock intakes with K&N filters. Doubt I can get much better mileage since I enjoy WOT every chance I get....not to mention 90mph+ on the interstate to work when the cops aren't looking

 

Bolt ons did nothing for me as far as mpg, but my car was running very lean for some reason. Once tuned with Osiris, I was seeing over 30 on the freeway, and about 25 on the streets. Now with a new exhaust and back to stock cats, I'm in need of a retune, but I'm still seeing over 30 on the freeways.

 

You have the Injen SRI now, don't you? Interesting about the lack of MPG benefits in your case.

I used to average 21.4 mpg over 34 samples, whereas with the SRI i'm averaging 22.26 mpg over 11 samples, and i'm quite a bit more aggressive with it, and this includes the time the car saw track duty. Otherwise, same roads and distances as always. Granted, 11 samples may not yield as accurate a number as 34.

 

Yeah, I've been looking at the Bullydog. Maybe this is a question for the Bullydog thread, but if there's no warranty issue, and no issues with tranny or engine reliability, why wouldn't Infiniti offer this tune as stock?

Wow! That is a big difference. I'd be very happy with 2-3 MPG gain with zero loss in performance and only ~$350.

How are the K&N filters working for you? Think I'd notice a difference between them and stock?

Why did you pick SRI over the alternatives?

 

Mostly due to ease of installation/maintenance and price. I'm not really sure if i gained any power with it but at least it doesn't feel like i've lost any either. The sound at WOT is just icing.