Intake Effect On MPG

[imike929]

Hey Guys, need a little help here. I'm sick of reading Yahoo! answers probably from 13 yr olds trolling the web. I'm looking at installing a CAI or SRI on my Yaris. I'm not big into the mechanics of cars, so i'm wondering what kind of effect this will have on MPG? Increase? Decrease? I figured I'd ask ppl who actually have the same car and intakes I would be using. Thanks all!

[bebeelo]

Originally Posted by imike929

Hey Guys, need a little help here. I'm sick of reading Yahoo! answers probably from 13 yr olds trolling the web. I'm looking at installing a CAI or SRI on my Yaris. I'm not big into the mechanics of cars, so i'm wondering what kind of effect this will have on MPG? Increase? Decrease? I figured I'd ask ppl who actually have the same car and intakes I would be using. Thanks all!

i have a AEM CAI. my opinion is that your mpg may slightly decrease. once, you remove the MAF sensor(and reset the battery) the ecu will learn to dump a little more gas into the engine because of having more air flow. the faster you go, more gas to be used.

[tooter]

Originally Posted by imike929

Hey Guys, need a little help here. I'm sick of reading Yahoo! answers probably from 13 yr olds trolling the web.

I'm 14.

(just kidding...)

I'm looking at installing a CAI or SRI on my Yaris. I'm not big into the mechanics of cars, so i'm wondering what kind of effect this will have on MPG? Increase? Decrease? I figured I'd ask ppl who actually have the same car and intakes I would be using. Thanks all!

Colder air is denser so your computer will tell the injectors to provide more fuel which decreases your gas mileage. I run a short ram intake...



...and am logging decreased mileage in Winter due to the much colder ambient air temprature as well as slower engine warm ups.

[why?]

but Tooter's SRI is unique, especially with that massive filter/stack thingy.

A CAI will decrease gas mileage slighty, a sri it really depends. It also depends on how you drive, aka if you floor it all the time to hear the intake you will get worse gas mileage. But some people with more off the shelf sri systems have reported slight increases, however those people usually have everything else stock though.

The theory is that the stock box is ridiculous, if you free it up with a sri system that gets more air in, but doesn't really reach far to get colder air, gas mileage can go up slightly, or stay the same. If you get an sri that reaches for colder air, or get a cai, gas mileage will likely decrease. Some Eco modders have created systems to get the warmer air into the engine, which can increase gas mileage.

[david_827]

Originally Posted by why?

Some Eco modders have created systems to get the warmer air into the engine, which can increase gas mileage.

Do you have any other info on this? Sounds interesting,

[tooter]

Originally Posted by why?

A CAI will decrease gas mileage slighty, a sri it really depends.

I wasn't actually comparing an sri intake to either a cai or the stock box, but was only commenting on cold weather versus hot weather. Regardless of what intake is used, the same principle applies to all intakes. Cold weather reduces gas mileage for all intakes.

[tooter]

I put on the stock air box and am going to drive it around for a few fillups just to see how the gas mileage compares to an SRI, and will post the results...

[tooter]

Just did a Google search of the question: "Does warmer intake air increase gas mileage?" and found this answer on Yahoo Answers



"Your car has a computer which calculates the air/fuel ratio dynamically. Hot air is expanded (in volume), meaning the molecules are further apart. With less air going into the combustion chamber, the computer will tell the injectors to use less fuel, in order to maintain the correct ratio. The opposite is true with cold air intakes. With cold air, the molecules are closer together, meaning more air will fit into the same volume. So the computer injects more fuel into the combustion chamber, causing a larger explosion, and increasing horsepower at the expense of fuel economy."

[fnkngrv]

When I was running my AFE Stage 2 I could get either better or worse mileage depending on how I drove it. Even when driving it like I stole it however I never really dropped more than 2mpg which to me seemed like a fair trade off for the midrange performance bump it gave. When driving like a normal human being (insert chuckle) I would get the same as the OEM box or 1-3mpg better. It will also depend on the terrain around you since of course if you have much for hilly driving you could see different results as well.

[Bluevitz-rs]

so if colder air is more dense and is therefore able to use more fuel, you make the same amount of power with less throttle input to keep you car at the same speed while producing the same amount of power.

Only drawback is the air is MUCH colder in winter months so warming a cold engine takes longer and more fuel is used. To compensate for this, I install a lower grill block off panel so warm up times are greatly improved and it protects my condenser and rad from damage from road salt and rocks.

My millage increased after installing my AEM CAI.

[UberSilver]

Maybe too late? But dont waste the time and money on a CAI. I just bought my 08 a short time ago. It came with a K&N CAI. I drove it like that for two tank fulls, getting about 31 mpg mix driving. I put the stock box back in, and I'm into my second tank @ 33 mpg, same city 75%, freeway 25% driving. Today I ran 163 miles on the freeway at 70~72 mph, and used 4.2 gallons. The car feels 100% the same compared to the CAI setup(but less noise).

[Kaotic Lazagna]

I think it all depends on how you drive. I lost mpg's when I installed my exhaust system (too large of piping). I regained what I lost with the exhaust when I installed my K&N SRI. However it'll chug more gas if I go WOT. If I'm traveling 35-40 mph, I'll be getting 50-60 mpg (according to my Scan Gauge II, which I calibrated to read worse than what I'm actually getting).

[Kaotic Lazagna]

UberSilver, I believe your intake filter needs a cleaning and a "recharge" (oil) and your MAF sensor and throttle body needs some cleaning. I'm assuming the previous owner drove in a dusty area, and probably over oiled the filter.

[why?]

Originally Posted by david_827

Do you have any other info on this? Sounds interesting,

if you go to ecomodder.com and search for hot air intake you'll see people that do this and claim much better gas mileage with it. Some of them went to crazy extremes, like putting a tube that gets the air from right behind the engine to get as warm air as possible.

As Tooter's quote mentioned, it kills power.