What happens to MPG when you Modify?

[surfinflorida]

I like how my MSP gets 32 MPG (Unlike my Mustang that gets 16). What happens if I start doing minor modifications. I.e. Cold air intake, Up the boost, change spak plugs. I can't see how changing the intake would decrease my MPG but I'm not sure about the boost. Any thoughts?

 

[Notorious]

more air = more fuel depending on the ecu

just about any mod is reduce gas mileage.

 

[Replica]

Just stay out of boost for daily driving. No biggie

 

[jersey_emt]

Any performance mod is going to decrease gas mileage. Even an intake. More air is being put into the engine, so more fuel has to be put in as well.

 

[Swerny]

Don't forget, the more mods, the more time you will be spending at WOT.
Therefore, worse mileage.

 

[marashka]

mileage defiantely goes down, but depending on your driving habits you might not even notice it that much. i still mod my car a bit who cares about gas milage when you can kill 330ci for less then half the price?

 

[MSPinVA]

I disagree with jersey_emt here, an intake will only suck more air in if you ask it to. In my experience, a free-flowing exhaust and intake makes the engine not work as hard, thereby increasing gas mileage, like on my 97 camaro (went from 19 mpg mixed driving to 21.5 mixed driving), especially if you drive a lot on the highway.

Now, granted, if you have all these go-fast goodies and don't go fast, what's the point?

 

[iluvmacs]

More air doesn't mean more gas, it means more A/F ratio, which means better gas mileage (unless you mod your ECU to push more fuel).

If you mod the car to make more boost, you need more fuel to run safe, and that's less mileage. If you tune the car to breath more air, you can shift your torque curve to the right, which means less torque at low RPM, which depending on your driving style, can mean better mileage.

Mileage is related to torque at the average RPM you use (neglecting stop lights etc). Higher torque peak means more hp, and more mileage (only at low rpm). Mileage will decrease if you rev higher or push the gas harder. This is why most people experience a decrease, because they push the car more when they mod it.

 

[MSPinVA]

Well said. That's what I was trying to get at as well.

 

[pip7441622]

I like how my MSP gets 32 MPG

Lucky, I can't ever get that(uhm)

 

[Notorious]

Not in our case. The maf reads more air getting through and at a lower temperature. The ECU adjusts the only way it knows how and thats add more fuel. That's why on a dyno a/f with a cold air isn't drastically higher, and it'll still pull less than 10:1 a/f.

More air doesn't mean more gas, it means more A/F ratio, which means better gas mileage (unless you mod your ECU to push more fuel).

 

[MSPinVA]

So then why aren't the horsepower gains that noticeable with just an intake if that much more fuel is being dumped to change the gas mileage? That doesn't make sense.

 

[marashka]

there are gains, they r just spread through the powerband, you will not notice a gain in regular street driving unless its 20+ hp, but if you take it to the track you might see the diff.

 

[MSPinVA]

Yeah, you're probably right. I also heard that an intake combined with a FMIC upgrade really makes the nice bottom end HP numbers.

I would imagine your MPG really all depends, no matter what mods you have, on your driving habits. If you floor it all the time, gas mileage sucks. If you take it easy, gas mileage goes up. They might just be magnified one way or the other.

 

[srtchick]

Just stay out of boost for daily driving. No biggie

YEAH DEF if i get on the car alot i get about 200mi or less per tank! (shocked) thats what happens when u mod a car !

 

[DiscreetSpeed]

i got 345 miles on a tank...driving hard i got a little under 300....and im somewhat modded haha

 

[03MSP]

I always get 330 or more to a tank, without completely draining it, oh and I drive "spirited". I am at 9.5 psi and have a custom CAI. My mileage might have gone down a bit since I was stock, but that's just because I like to play more when driving.

 

[jesse]

i get about 22 mpg and no mods.. terrible...

 

[bored132]

265mpg per tank in fl with a couple mods

i think more gas goes out of the tailpipe than its used in the combustion chamber

 

[mspdfreak]

30mpg city, 34-36mpg hwy. Oh, and my only mod is an Injen.