igetgreens

iTrader: (4)

As the title states it gave me from 18.5 avg (before the installation of intake) to 17.2 avg (after). It seems everytime i disconnect the battery for 5 hours and connect it again the gas mileage goes back up for a week or two but then it starts going back down. Anyone else have a problem with this? I've searched for this about gas mileage and almost everyone seems to say intake increases gas mileage. Whats up with mine?

Thanks

Cux350z

iTrader: (162)

maybe its cause your intake is providing a colder, denser intake charge that the stock ecu tunes for. When you reset the ecu, it has to relearn a/f. You start out lean, making good power but then the ecu adds more fuel to richen you up.

maybe?
any other mods?

or could it be you like hearing the sound of the intake that you nail the gas?

igetgreens

iTrader: (4)

No all I have is this intake right now and I don't gas it anymore than I used to before the intake. I have to reset the ECU like every 2 weeks.

Zexy

iTrader: (55)

I don't think it has anything to do with a CAI.

If fuel economy is your concern, simply don't mod your car guy..

chimmike

iTrader: (7)

don't rely on the multi-gauge.

don't reset the ecu because it has to relearn and adjust to how you drive each time.

Wired 24/7

iTrader: (2)

You're kidding right?

1. More power = more fuel burned
2. The primary reason for increased or decreased fuel economy is DRIVING HABITS.

igetgreens

iTrader: (4)

but like i said before my driving habits have not changed from before i installed the intake and i have read on the forums that intake should increase gas mileage. Also after I reset my ECU i actually get more miles around 320 miles before I have to fill up and after about two weeks I have to fill up @ like 270

chimmike

iTrader: (7)

why should it? Where does it say this? Is it even advertised to increase mileage? And again. Don't pay attention to the multi gauge. It's not accurate.

btw: Newsflash. This isn't a Prius. If you're getting concerned about gas mileage, sell your Z.

97supratt

iTrader: (61)

+1 Our 6 cylinders get drunk off the gasoline.

igetgreens

iTrader: (4)

i was just wondering why i was getting worse gas mileage when others on this forum say u should be getting better gas mileage than before

post #2, 5, 22, 23
https://my350z.com/forum/showthread....ht=gas+mileage

post#5, 6
https://my350z.com/forum/showthread....ht=gas+mileage

also maybe it can be my driving habits, I've been trying to normally shift @ 2500 (sometimes i just have to gun it though) and my avg mpg is 17.2-18ish with 50% highway 50% city driving. How about you guys? When do you shift and what is your mpg?

also i know i didn't get the z to save gas but it would be good have a higher gas mileage and still have some fun

Thanks

Wired 24/7

iTrader: (2)

no offense dude, but I think I speak for 99% of forum members when I say this thread is completely rediculous.

myZter

iTrader: (7)

ur probably driving crazy with it cuz u wanna hear the sound, feel some what power it gives, or anyother reason. drive normal speed and accerlation

igetgreens

iTrader: (4)

non taken and for myZter i don't drive any different than i did before the intake

s2kphil

iTrader: (10)

The added roar from the intake vibrated the gasket loose on your gas tank seal and your leaky fuel. same thing happen to me. i just poured some stop leak in my gas tank and it cleared right up. im actually getting around 42 miles to the gallon now. i think stop leak is kinda like the turbonator. i add it everytime i fill up now.

myZter

iTrader: (7)

most people drive more faster after new mod but guess ur not one of them

undrgnd

iTrader: (2)

Several things jump out at the reader: 1. Stop resetting the ECU. If you want to reset the MPG, reset the MPG gage or odometer. 2. The difference you noted between the BEFORE MOD and AFTER MOD is so small, and your city driving is so high (50%), as to be statistically insignificant. If you want to make a fair comparison, take it on the highway. 3. If you care about gas mileage in your Z, there ARE things you can do as far as mods, but primarily it IS driving style.

Machupo

iTrader: (6)

I actively try to see how low I can get my gas mileage...

Average on the street is 12mpg when i'm doing all city driving, 28mpg when i'm in 6th gear for long periods of time (16mpg when i'm at the autobahn >150mph)... personal best? 2.5mpg when I was on the track -- went through a quarter tank in something like 12 minutes

chimmike

iTrader: (7)

but who's to say you drove like grandma before the CAI install?

sry110

iTrader: (17)

I don't think this thread is completely ridiculous. I went through the same thing when I installed a Cold Air Intake on my previous car two years ago. At that time I was new to 'tuning' cars and I didn't know what to expect. Before doing much research I figured that the Cold Air Intake makes the engine system (intake to engine to exhaust) more efficient due to the inner diameter and contour of the intake pipe and the shape and area of the cone-shaped air filter. So then I figured if system efficiency goes up, then surely fuel consumption should go down.

But I think the reality is that the Cold Air Intake gets air into the cylinders more efficiently (i.e. more air per intake stroke than the stock system allows). So therefore each time your engine sucks in this increased amount of air the computer adds a proportionally increased amount of fuel in effort to keep the Air to Fuel ratio as close to stoichiometric as possible. So as a dummy example using dummy numbers: Let's assume your stock system allows 14 'units' of air to enter the engine and it adds 1 'unit' of fuel to the air for proper operation. When you add your CAI it might allow 15 'units' of air which would require the computer to add 1.071 'units' of air in order to maintain the 14:1 air to fuel ratio. The extra air is free, the extra fuel is not.

The first guy who responded to this thread hinted on this topic. I agree that you should not be constantly resetting your ECU, and I also think that decreased gas mileage is characteristic of a cold air intake system even when making the assumption, however unrealistic it may be, that your driving habits before and after the modification are identical.

I might be wrong.

EDIT: Like you, at first I was irked buy the slight decrease in fuel efficiency. But then I realize that hearing the roar of the intake above 4500 RPM was worth the extra few dollars each month in my gasoline budget. Also as a general rule, and I think someone else already mentioned it, it always takes more fuel to make more power. You can't create energy, you can only convert it from one form to another, and this case you need more fuel to burn to create a more powerful stroke. You can also look at guys who have turbos on their cars....their gas mileage is pretty decent at low RPMs before the turbo spools up, but once they are in the boost range and throwing a whole bunch of air into the engine the same prinicipal applies. There is of course some variation due to how each particular system is tuned (i.e. some engines are tuned so that the mixture is 'leaned' so that the air-fuel ratio is higher than the theoretical stoichiometric ratio).

In my opinion your observations are typical.

igetgreens

iTrader: (4)

thanks and what makes me think that it isn't my driving habits that are effecting my MPG is that after I first set my ECU i have to fill up after like 320 miles but as the weeks progress I have to start filling up sooner like @ (290 then 270).