MS CAi and Gas mileage
- Thread starter Pondo
- Start date
mazdaspeedster3
Member
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- Mazdaspeed3. 2008
Yea, you like hearing the turbo and BPV so you are on the gas more.
Exactly, the car will actually be capable of getting better gas mileage with a freer breathing intake but you will like the noise it makes more so you will get into the throttle just to hear it Unless you have really good self control and are that worried about gas mileage.
mazdaspeedster3
Member
- :
- Mazdaspeed3. 2008
MS3/Selfcontrol..... FAIL! 
I did not notice any signficant difference in gas mileage before or after my MS CAI. However, logically if it is making more power, it is likely using a little more fuel --- but nothing to worry about.
mazdaspeedster3
Member
- :
- Mazdaspeed3. 2008
How does power equate to fuel usage? It is creating power from better air flow. CAI does not cause more fuel usage does it?
It is clearly more complicated than just saying more power equals more fuel. That wasn’t what I was trying to convey. You are correct that A/F mixes, burn temperatures / pressures, friction, etc., all play roles in extracting the most power from fuels. However, all other things being equal, you can't get something for nothing. The CAI may allow the engine to act more efficiently, so that power gain does not equal an increase in fuel consumption. (Or only a minor one.) Still, you can only do so much to increase the power of an engine without consuming more fuel. Eventually, you can no longer increase the efficiency of the engine, and by the laws of physics, you have to increase your fuel usage.
mazdaspeedster3
Member
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- Mazdaspeed3. 2008
I was under the impression that the original idea of CAI's were for fuel efficiency gains.
It was my understanding that it was for power gains, not fuel efficiency. After all, a Cold Air Intake is specifically there to increase the density of the air in the cylinder, thereby creating more pressure during ignition and subsequently increasing power output. By adding more "air" to the mix, you would have to increase the fuel to maintain the same air / fuel mix.
Of course, it would all come down to how the computer handles the increased air density since A/F are constantly ajusted on modern vehicles.
I noticed a slight decrease in gas mileage after installing the CAI on both of my MS3s. I expected a minor decrease, and it has not been a problem.
I've actually noticed an increase in my gas mileage after installing a sri, then again my car had less than 3k miles when I put it on so it may have still been breaking in.
happy and angry
Member
More power generally involves burning more fuel. You can do a few things to improve power: you can burn more fuel, more efficiently burn the fuel you have available, or decrease mechanical resistance and thus mechanical power loss (think lightweight pulleys). Our turbo essentially allows us to burn more fuel by providing more air (oxygen) with which to burn more fuel.
So how does an intake provide more power? Two ways. You get colder (and thus more dense) air, which again means we can burn more fuel. It also allows air to move more freely. The motor works less to suck in the same volume of (now more dense) air, as there is less in the way to restrict air flow. This is why an SRI or a CAI provide such similar power gains on our car - Cobb tuning called our stock air box one of the most restrictive they have ever seen.
We have motors that run pretty rich stock. There is a lot of extra fuel in the cylinder each cycle, and we don't burn it all. An intake should provide more air (colder, more dense air) so we can burn more of it which produces more power, and allows air to flow more freely so we lose less power pulling in air.
All of this adds up to a more efficient engine. You make better use of the fuel you have available, you lose less power due to air restriction.
6
60181
Yes. The car is going to utilize the extra air and burn more efficiently but the ECU will adjust to the extra air and your car will still essentially run rich as it does from the factory. That's good on a turbo though. Lean runs will turn your pistons into ashtrays and your ECU knows that.
Bingo... What I was saying as well, but HappyandAngry gave a more lengthy explanation.
Who knows then... on both my MS3s, after the MS install, they MPG went down slightly. I am pretty meticulous about measuring my MPGs, so of course I was never using the trip computer to gage it. Clearly this could be explained by a myriad of factors. Driving styles, climate, HWY/CTY driving miles, etc.
