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-   -   Gas mileage with gen III intake (http://www.the370z.com/engine-drivetrain/12694-gas-mileage-gen-iii-intake.html)

HellfighterZ 12-26-2009 06:16 PM

Gas mileage with gen III intake
 
I'm planning on purchasing this system, but so far I have not do anything to my car completly stock, will installing this kit decrease/increase gas mileage or pretty much just stay the same. I do alot of highway driving and short drive to work, an I'm pretty happy with the mileage I'm getting , I plan on getting exhuast and HFCs in the future but I'm opting for intakes first.

I just wanna know what you guys/gals have experienced after installing you intakes. Gas mileage wise

G37Sam 12-26-2009 06:25 PM

So you want to get a performance mod but are concerned with mileage? That's a first.

Your gas mileage will definitely drop due to your foot becoming heavier to listen to that sound ;)

SilverBullet 12-26-2009 06:26 PM

There won't be any difference really in mpg, unless you start driving the car harder.

HellfighterZ 12-26-2009 06:50 PM

There is times to play around, none the less when I am not playing I do stay aware I my gas mileage, and drive moderatly slow(obey the speed limit). Let me rephrase my question.

Under regular/casual driving will there be a loss on milage.

HellfighterZ 12-26-2009 06:51 PM

Quote:

Originally Posted by SilverBullet (Post 343016)
There won't be any difference really in mpg, unless you start driving the car harder.

Thank you silverbullet, I had a 06 frontier and i put intakes on it and the mpg dropped slightly and I was concerned

SilverBullet 12-26-2009 06:54 PM

I have had my intakes on for a while and my gas mileage has not dropped noticeably. I don't think that it will drop.

HellfighterZ 12-26-2009 07:05 PM

Cool, did it sound good, with just the intakes?

SilverBullet 12-26-2009 07:06 PM

I don't have the 3g. But it will sound good. It sounded good when I switched to JWT. I have Injen now.

G37Sam 12-26-2009 07:09 PM

Even if it did, it won't be anything noticable IMO

I seem to get more or less the same milage on the highway, never paid attention to exact numbers.. but then again it's really hard to tell since there are so many factors involved, weather, altitude, in city driving, highway, car mileage etc..

HellfighterZ 12-26-2009 07:11 PM

Cool,

G37Sam 12-26-2009 08:15 PM

Did some researching for you

Quote:

If modifications cause the engine to run moderately lean, there will be a slight increase in fuel economy, sometimes at the expense of increased NOx emissions, much higher exhaust gas temperatures, and sometimes a slight increase in power that can quickly turn into misfires and a drastic loss of power, as well as potential engine damage, at ultra-lean air-to-fuel ratios
Oxygen sensor - Wikipedia, the free encyclopedia

SilverBullet 12-26-2009 08:15 PM

Thanks Sam. Getting a tune after doing modifications can help with mpg.

Z eliminator 12-27-2009 08:18 AM

Intake + Cats + CBE = a little better mpg. Now add 4.08 gears 700 rpm more at 100km and your milage drops, 2800 vs 2100 in 7th. 4.5 mpg at least. 37 mpg to 32 mpg, but it does the 1/4 in 12.800.
Small price to pay for performance.

Modshack 12-27-2009 01:06 PM

More horsepower takes more fuel (part of the "no free lunch" axiom)...Though the differences should be minimal under less than WOT condidtions....

kannibul 12-27-2009 02:54 PM

Quote:

Originally Posted by HellfighterZ (Post 343098)
There is times to play around, none the less when I am not playing I do stay aware I my gas mileage, and drive moderatly slow(obey the speed limit). Let me rephrase my question.

Under regular/casual driving will there be a loss on milage.

In theory, gas mileage will go up a bit due to the car running a bit fat in the fuel/air mix, so you get more HP out of the deal.

But, the end result is that you will probably not notice much, if any, increase or decrease, given the same driver input.

370Zsteve 12-27-2009 03:45 PM

No, that is incorrect. See Modshack's comment above. More HP = more fuel consumed. There is no free lunch.

Rps13.jw 12-27-2009 03:49 PM

More Air means more fuel. The Maf will compensate.

kannibul 12-27-2009 04:23 PM

Quote:

Originally Posted by 370Zsteve (Post 344399)
No, that is incorrect. See Modshack's comment above. More HP = more fuel consumed. There is no free lunch.

Not the case if you're running rich, as documented....

The Gen3 intake helps lean the A/F Ratio a bit, which in turn DOES add HP and lead to a bit better efficiency, which translates into a bit better MPG.

If the A/F ratio was the same, then you (and modshack) would be correct. You can't generate HP without increasing air AND fuel. Technically, we have too much fuel going in, which in effect causes us to lose power. The G3 intake is such that it lets more air in than the stock intake, and the positioning of the MAF sensor doesn't see the additional air flow (or as much of the improved air flow)...

Resulting in a leaning effect, which in turn does give a bit better efficency/MPG.


There's that's 2 ways to explain the same point! :)

Modshack 12-27-2009 06:43 PM

Quote:

Originally Posted by kannibul (Post 344426)
Not the case if you're running rich, as documented....

:)


Welll....You're not "really" running rich under everyday partial throttle driving conditions. While the ECU is calibrated slightly rich, the O2 sensors, in concert with the MAF are constantly adjusting the fueling to maintain a stochiometric 14.7:1 ratio no matter what intake you have. This is Multiplicative adaptation otherwise known as long term fuel trims or closed loop. The sensors determine the Correction (injector duration) that needs to be applied to maintain the correct A/F ratio. The "Rich" 370 typically runs at -9 to -12% rich correction which means the fuel is dialed back to keep A/F's good. An efficient intake will result in lower numbers here but they are still "Corrections" with the desired goal of a Stochiometric A/F. The end result remains the same. These numbers (fuel trims) are easily read with a Scangauge or equivalent. When you go to WOT, you leave 02 fuel controls behind and go to pre-built fuel maps. These are typically a bit rich, but with the right intake you'll flow a bit more air to so it balances well. YOu're still using X amount of fuel, but with more air and a slightly leaner WOT mix you make more power. The real HP gains are made at high RPMS under WOT open loop conditions where More flow tells the MAF to deliver more fuel ...So technially, even though you are a bit leaner at WOT, you're really burning more fuel due to flow improvements read by the MAF. This is where the Dyno'd improvements are coming from. More air + more fuel + slightly leaner mix = more HP. Still no free lunch. Anyone who spends much tme with their foot in it can verify that.. You really have 2 distinct fuel usage profiles here. If you never step into it and make that transition from closed to open loop (determined by RPM, Engine load and throttle position) it should be a wash mileage wise, but you're not making any more HP in those ranges either.

http://images51.fotki.com/v747/photo...ueltrim-vi.jpg


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