Increased MPG or HP anyone????

[slvryaris]

Was curious if anyone was experiencing an increase in miles per gallon or horsepower with an aftermarket Intake or exhaust. I was curious to know if an intake or exhaust would benefit other then looking/sounding better. Let me know what you all are using and your thoughts on the product.

[Violin]

Give me a couple of weeks and I'll let you know about the AEM cold air intake.

[eco]

Not so true Yaris TTe,I have a TRD CAI,And I noticed a 3-5% increase in milage,no bull.Actually if you are easy on the throttle at all times,you will get an improvment,but ofcourse when you get the CAI or exhaust,you always want to accelarate faster,because now you can.With the CAI,it actually is like compressed/denser air,which will cause your car to use less gas.zthink of it this way,if its real hot out side,air is less dense,so your car replaces lost air with more gas,so when the air is cooler via cold day or CAI system,them you will have better combustion using less gas,its that simple.As for exhaust,it helps reduce back pressure,and at the right rpm will increase the pulse performance,it like it creates a outward vacum that actually helps pull the exhaust out.If you have both CAI and intake,you will get good improvment if you are easy on the throttle,but can you resist when you get those new performance parts.And you cant compare a ferrari with a 4 banger,you dont even want me to start and explain why a ferrari uses more gas!!!

[Black Yaris]

I have a TRD cold air and have noticed some MPG improvment, but, as eco stated, I romp on her a little bit more so it is only like 15-20 more miles per tank. hey even rompin on her hard I am gettin 30-33 MPG

[swng]

When my OEM tires expire, I may buy a set of tires with lower rolling resistance and I believe I will get slightly better acceleration and slightly better fuel economy as a result.

[KSIbucky]

Originally Posted by swng

When my OEM tires expire, I may buy a set of tires with lower rolling resistance and I believe I will get slightly better acceleration and slightly better fuel economy as a result.

be care full with tire pressure because I guess that mean they have tighter rubber and it lowers mpg a lot compared to stock

[ItsMyDaily]

The only way adding an intake will decrease your mpg is if your busy gunning it all the time to hear the noise of it. When You add these bolt ons such as intake, header, exhaust, it only improves fuel efficiency. Adding more power to the vehicle only makes it easier for the vehicle to move itself. Meaning the engine has less struggle getting the car moving, and also means you are able to apply less gas to get to your desired speed at the right amount of time.

Yes you are adding more air into the engine which helps increase combustion, but you are not adding more fuel to it unless your running an aftermarket ecu. Adding an intake will not make your ecu send more fel into your engine to compensate for the "extra" air. It's set to what it is, and that's that.
If anything with all bolt-ons most cars end up running lean if they don't have an ecu to tune with because the factory ecu will not automatical ajust itself and send more fuel. While this is good for gas, going to lean is not good for the motor on the long run....especially if your always pushing it.

[ItsMyDaily]

and if you need an example.....
when I had my S bone stock I was averages with calm driving around 200-210 on a full tank. After adding my intake/header/test pipe/exhaust/flywheel I was making close to 230whp(this was all on the stock ecu). After all those mods I was averaging with calm driving 235-245 on a full tank.

[bulldogs2k]

Originally Posted by ItsMyDaily

and if you need an example.....
when I had my S bone stock I was averages with calm driving around 200-210 on a full tank. After adding my intake/header/test pipe/exhaust/flywheel I was making close to 230whp(this was all on the stock ecu). After all those mods I was averaging with calm driving 235-245 on a full tank.

I need to get a header and emanage! my goal is 230 to the wheels, but i want to get there with my cats still in place. I will probably buy a test pipe and put my exhaust back on for a quick dyno run.

Get the intake!

[Violin]

Basic thermodynamics tells you that all other things being equal, when you lower the intake temp, you'll increase effeciency.

[riceboy]

Hey Jcove, long time no see!!! Glad to see that you got things worked out with Vibrant, can't wait to see the pics!!! Hey let me know if you're coming out to the fall tour this Sunday....

[eco]

Your wrong Ron.Even when Im behind a trailer,I notice a diffrence in rpm's at a set speed.I have a ScangaugeII and a tach,I know what Im talking about.Laws are made to be broken,and I know for sure thats not a law.

[hasher22]

Wow there is gonna be a great debate here.

My yaris - gained some Hp with my new muffler, but i dont take that much notice with my MPG

[spkrman]

same here, small gain with muffler only, nothing measurable mpg wise though, if there is a difference its not big.

[hasher22]

Ya its always good to get something out of your mods, emotionally or performance wise.

Like i always say "better than nothing"

[Violin]

With the AEM CAI and TRD exhaust I'm getting 1 or 2 more mpg based upon a decent number of fill ups.

Also its more fun to drive, sounds great and looks better.

Win/win.

[spkrman]

yep I did it just for the sound, really.

[07WYarisRS]

FWIW if you know how a transmission works AUTO or MANUAL a gear ratio CAN NOT CHANGE ON ITS OWN. RPM MUST be the same. Ron is 100% correct
Adding any component to the intake or exhaust CAN NOT lower or raise your gear ratio or cruise speed RPM. It's impossible.
If you say it can please by all means explain this mechanical phenomenon to us

Man I love it when people that have no idea how fuel injection or carburetion works post in threads like these. Gives me something to laugh at and makes my day.

As for more HP = less MPG
Yes, usually

An engine is basically a big air pump the more air you let in and out the bigger the combustion. BUT in order to maintain reliability the fuel injection system will always maintain a PROPER fuel/air mixture (stoich) 14.7:1
That's 14.7 parts oxygen to 1 part fuel
That's what oxygen sensors are for. They read the mixture levels and send the info back to the ECU so it can correct the fuel trims and injector timing to maintain the 14:1 mixture.
Regardless if you lower the air temps or even force air in via a turbo or supercharger the STOCK ECU can alter the fuel injection over a WIDE range to maintain the proper fuel mixture. If the car is run higher or lower then this fuel mixture it will cause serious engine problems. And NO matter what you do as far as bolt on the ECU and FI system and the dozens of sensors on this car will maintain the perfect fuel mixture.
If you add more air or colder air it MUST ADD MORE FUEL.
Saying the EFI will not add extra fuel for more oxygen is just silly. That means nobody here can drive their car from here to Florida then up into the high mountains of Colorado with out serious tuning issues? Give me phuckin break. The ECU and EFI system will compensate for air temps, humidity, intake air volume and YES altitude. It has to compensate otherwise you car would run like ass.

If you allow more air into the engine buy either changing the intake or exhaust or both the engine MUST add more fuel. If it does not you run lean and even a little bit lean will cause DETONATION, PRE-IGNITION, and both will destroy your engine. Most engines also use a knock sensor that listens for any signs of detonation or pre-ignition and will alter the ignition timing to compensate (none of which adds power but infact greatly reduces it to prevent engine damage)


The reason people don't often see a MPG difference is because under normal driving conditions or at cruise speed there is no HP gain
Look at the latest dyno results posted in the WR secret weapon short ram intake thread.
There is no noticeable HP gain until after 4500 rpm. The intake or exhaust don't do a damn thing before that rpm range and as long as you drive in this rpm range your mileage will remain the same.
At 2000-3500 there is no big gain BUT drive in the power curve 4500rpm + and you will see a loss of MPG because with more air, there is a need for more fuel.

Anyone that says they feel a difference in power 1hp at normal cruise speeds is completely full of shit.

That's why colder weather/air temps make every FI engine harder on fuel. Colder air temps mean more dense air = more oxygen and more oxygen means the car must inject more fuel to maintain the proper fuel/air ratio (stoich)

Plain and simple
Colder the air temp = more oxygen= more fuel (to maintain stoich) = more hp
More air volume = more oxygen = more fuel (to maintain stoich) = more HP