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Discussion Starter #1
Here's a simple math question that I would like to know the answer to if anyone finds the time to answer it.

My K&N intake is going to cost me about $290.90. I was told it will get me about 2-3 MPG more. On top of that I am going to do a custom catback exhaust from muffler tech running me $300.00 +, say $350.00 max. I was told that this will additionally get me 2-3 MPG more aswell. So here lies my question: If i spend the $650.00 to get a max of 6 MPG more. How long will it take until it starts paying me back. Additional information: 13.0 Gallon Tank Gas High avg $3.00/Gallon Car avg MPG 26.0 City and highway

Also if any of this info I have been given is false..please tell me, because i trust this forum and the people no it more than a business out to make money.
 

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The K&N deal is false. K&N filters increase the amount of air going into your engine by reducing the resistance. Any time the amount of going into your engine increases the car will increase the amount of fuel to compensate.

My average mpg is 42 with NO engine or exhaust mods at all. Believe me that you are looking in the wrong place for added mpg. You must address the way you are driving your car. I would suggest looking at the forum front page and going to the "all about mpg" section. I would read everything in this section and really address the way I drive the car. This will give you your biggest gains.

Is you balt auto or 5 speed? Year? mileage? SS or not?

---------- Post added at 09:53 PM ---------- Previous post was at 09:47 PM ----------

One more thing. Something that is for HP will NEVER add mpg and vice versa. There is no way around it. You must choose one or the other.
 

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ok I did your math anyway even though i agree with will
at 26 mpg going 15000 miles a year at $3 a gallon=roughly $1730 a year on fuel
at 32 mpg going 15000 miles a year at $3 a gallon=roughly $1406 a year on fuel so there you go
 

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I barley hit 25 MPG AVG with city and highway and i keep my foot out of it too and crusing at like 56 down the freeway i get only about 32-34. and barley 24 city...
 

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I've been more concious recently and watch the Instantaneous MPG Meter and keep it at about 32 MPG highway and keep it in the high 20's low 30's crusing in the city, but my car still reads 24.3 after a week.
I read that excessive idling will hurt, there are a lot of traffic lights where I live and have to stop and sit for about 2-5 min on end at each. I also noticed that when sitting my car reads 0 MPG Instant.
 

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well yeah city driving is hard, honestly I can make my car get 24 or make it get 44 depending on how I drive and how much I care about economy that day, try a tune up, google hypermilling, check your tires
 

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How much is a tune up? Also my oil life is down to about 19% (tight on money) would this effect it at all, also i put in 91 octane gas, bad, good, dosent matter?
 

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I have a 08 LT and a little over 33000 miles. I also just take my car to the GM dealership to change my oil.
 

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The K&N deal is false. K&N filters increase the amount of air going into your engine by reducing the resistance. Any time the amount of going into your engine increases the car will increase the amount of fuel to compensate.

My average mpg is 42 with NO engine or exhaust mods at all. Believe me that you are looking in the wrong place for added mpg. You must address the way you are driving your car. I would suggest looking at the forum front page and going to the "all about mpg" section. I would read everything in this section and really address the way I drive the car. This will give you your biggest gains.

Is you balt auto or 5 speed? Year? mileage? SS or not?

---------- Post added at 09:53 PM ---------- Previous post was at 09:47 PM ----------

One more thing. Something that is for HP will NEVER add mpg and vice versa. There is no way around it. You must choose one or the other.
that's not true i used to get 18mpg city when i was stock. best i've seen so far was 23 and it comes easy now compared to when i was stock. but now that its winter i'm getting 16
 

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that's not true i used to get 18mpg city when i was stock. best i've seen so far was 23 and it comes easy now compared to when i was stock. but now that its winter i'm getting 16
Something else had to change adding more air to an engine will always cause the engine to add more fuel. Are you sure the weather (air density) did not change? Did you get a tune up? Your own driving habits? A tune? New plugs? Just sayin something else had to have changed.

---------- Post added at 01:44 AM ---------- Previous post was at 01:43 AM ----------

yeah I feel as if I got some better MPG with all my mods plus the tune though
Tune for better mpg maybe? You have any data? I know you like to collect data, and I would be interested in a tune that helped mpg...
 

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that's not true i used to get 18mpg city when i was stock. best i've seen so far was 23 and it comes easy now compared to when i was stock. but now that its winter i'm getting 16
True but mine was getting an overall average of 32 or so last sping/summer/fall... but I lived in the middle of nowhere and had to drive 30 min to get anywhere. You probably live too close to everything to get it to really go up.
 

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Your biggest fuel savings come from driving habits. My TC can stretch to 40mpg easily, I just have to keep my foot out of it and the boost gauge out of the positive pressure.

Remember that winter blend gasolines kill your mileage. In traffic I'm lucky to break 20mpg these days, which is bad even for an SS.

As for the fuel octane, don't waste your money. For a car to gain a benefit from high octane fuel, it has to be tuned as such. Your 2.2L is tuned for 87 Unleaded, so put that in. Anything else is just a waste of your money. Also, change your oil. It's not worth gunking up your engine.

that's not true i used to get 18mpg city when i was stock. best i've seen so far was 23 and it comes easy now compared to when i was stock. but now that its winter i'm getting 16
Weird saying this, but CC08 is right. I suspect his mileage increase is more from driving habits than his mods, which add very little power, but that's neither here nor there.

Increasing power can certainly increase mileage. There's a reason my TC can get the same highway mileage you 2.2 guys can despite the massive power gap. A car which is more powerful, if geared properly, doesn't need to work as hard to achieve or maintain highway speeds. For a turbocharged car, good city mileage can also be achieved, since we can keep the car out of the boost and get similar results to a regular old 2.0L inline four.

A lot of the bolted and tuned TC guys, pushing north of 330whp and 350wtq, have seen increases in fuel economy - THAT I believe.
 

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My assertion that nothing increasing HP will ever increase mpg is only for N/A vehicles. There are a lot of differences in cars that have forced induction.

There is also research out there suggesting that if you have two vehicles the same in every way except one is forced induction it will get better mpg. I have not done enough research to believe this to be fact, but I certainly do not doubt it.
 

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i asked him if they could do a dual tuning one mode or HP the other for MPG and he said no because when they tune they tune for both MPG and max HP at the same time, the tune really does work wonders, and I wouldn't say that mods like an intake and exhaust hurt mpg either, they may not help by 6 mpg but maybe a few
 
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