Increased MPG or HP anyone????

[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

[Violin]

I guess that Carnot guy was full of crap then.

[07WYarisRS]

Originally Posted by Violin

I guess that Carnot guy was full of crap then.

Yeah in guess so.

Do you reall think at car cruising at 20% throttle is allowing the same amount of air into the engine as a car running 80% throttle.
NO WAY...
The fuel injection system must accurately and constantly change the fuel trims to provide the propera mount of fuel for the right amount of air.
it does this with mass air flow sensors and oxygen sensors that read air volumes and oxygen levels.
Saying a FI system is set and can not or will not change its setting for more air or less is retarded. That's why carburetors were fazed out because that's how they operate and with out the ability to change the fuel mixtuyre for changing air temps/weather etc it's extremely hard for them to meet EPA standards.


For anyone that still thinks they know how fi sytems work and that they are a set metered fuel system like a carburetor... Please read this
http://auto.howstuffworks.com/fuel-injection.htm

[Violin]

That all sounds great.

However - my car was consistently getting about 30 mpg. With the CAI and exhaust upgrades I'm getting 31-32 mpg driving the same routes with the same driving style.

Go figure.

[Yarii]

Your gains in power or mileage with exhaust/intake bolt-on's both come from making the engine waste less of the power it is making on keeping itself operating.

An engine is basically just an air pump, it sucks it in, burns some fuel with it, then pushes all the waste gas out. If it can pull air in and push exhaust out with less engery, that energy can be applied to the flywheel instead. Those gains in power translate to less air/fuel needed to maintain a cruising speed. The chemistry doesn't change, you still need to have a correct fuel mixture, but because your engine isn't working as hard to breathe, you can maintain a certain rpm with less throttle than a stock motor. Car manufacturers design first with ease of manufacture/assembly and noise in mind, which is why the stock equipment isn't as efficient as it could be.

Don't think of bolt-on's as adding power, you're just taking power the engine is already making, and moving a little bit of it to the wheels.

[07WYarisRS]

Originally Posted by Violin

That all sounds great.

However - my car was consistently getting about 30 mpg. With the CAI and exhaust upgrades I'm getting 31-32 mpg driving the same routes with the same driving style.

Go figure.

There is a difference between cruising and accelerating. A BIG difference.

Unless your revving the engine over 4500 rpm you have added little to no HP and very little torque. So regular driving MPG won't usually see a difference in performance or mileage in fact changing component that add top end power like header often take away a lot of low end power/torque is not designed correctly.

The difference is this. Accelerate your engine in the now stronger power curve over 4500rpm and there will be a loss of MPG. More air=more fuel
Cruise at the rpm of your new power curve and mileage will drop or reamin the same.

A cold air intake or high flow exhaust does not help off the line up to about 3000 rpm because at such low air intake volumes and exhaust volumes there is no restrictions. The restriction is at HIGH rpm operation where the engine has trouble pulling in or letting out air fast enough. That's why you only see a HP gain over 4500 rpm

The same will apply for a turbo or supercharged car if the compressor is not pushing any positive boost. If you added a big turbo to the Yaris and it did not spool up until after 4500 rpm you would not see any perfromance increase below 4500rpm and your mileage would not change, but once it starts spool up, and force air in the ECU compensates by adding more fuel.

With the high flow muffler and a short ram intake the engine is allowed to breath better above 4500 rpm that's why you only see notciable gains over that rpm.

1hp at 2500 rpm will no = 2-3 mpg
10hp maybe but your not getting at 10hp gain from muffler and intake at 2500 rpm while on the highway infact there may be no HP gain at all at such low RPM's . The 10hp gain is only at 5000-5500.
Basically that kind of HP is only good for drag racing because under normal driving conditions your engine will not see these rpms.

That's where CAMS, twin loop muffler or superchargers comes in because these component help move the power curve lower to where you would use it for everyday driving. On a stock engine set up you have a window of only 1000rpm (4500~5500 rpm) where you can use the HP gain, with about a 200rpm range with higher torque.

Don't get me wrong 10ft.lbs and 10 hp gain is HUGE for such a little engine but it does come at a price of more fuel USED while accelerating (not cruising) but unless you see a noticable HP gain at cruise speeds it's not going to help your fuel mileage much if at all.
And from what I've seen of most dyno's on any I4 engine under 2L you don't gain HP unitl HIGH in the rpm range.


Remember one other thing
TORQUE is what gets you up to speed. It's the force that accelerates you. The more torque you have the faster you accelerate.

HP keeps you there. The higher the HP the easier it is for the engine to maintain speed. The more HP you have the less throttle you need to maintain speeds.

BTW did anyone notice the intake in that thread and how it's damn near the same length as the STOCK intake...
Toyota did their research on this car. The intake was designed with good performance and best mileage over all for normal operationg conditions.

[Violin]

You obviously feel very strongly about this. I guess my mileage increase is an illusion. This must be wrong too:

[07WYarisRS]

You don't listen do you!
I was talking about the dyno info in the secret wepon thread. Where an intake shows NO GAINS or and exhaust shows NO GAINS before 4500 rpm
I then went to say if you change the power at cruise speed for which you operate mileage may go down or stay the same. More HP at cruise allows you to drive with less throttle.

Comparing the two intakes..... While the AEM does not make as much over all PEAK HP
It does yeild higher low-midrange RPM powercurve so the AEM would be the better overall intake for daily driving and steady cruise speeds
But accelerating it's going to use more fuel if the intake allows more air in.
PLAIN AND SIMPLE it HAS TO. You can't get around it...

[Violin]

So I really am getting better mileage with my AEM CAI and TRD exhaust (the only ones I ever commented about on this thread), or am I just holding the calculator upside down?

[the_saint]

Is it me, or is it getting hot in here?

Better play it safe...

[07WYarisRS]

It is possible
If you drive at fairly steady speeds and there is a noticable torque/hp gain in the rpm range you are operating at YES it's possible.
The AEM charts show the best gains are below 5000rpm and a MUCH wider power curve of over 300rpm (2000-5000rpm) where the other intake the gains are above 4500. (4500-5500)

That's why I like the twin loop style mufflers, strait through pipes for great top end gains but provide a wider power curve then any single strait through pipe design due to the heat retention and needed back pressure.

But if your driving conditions call for constant acceleration/stop and go etc the result is usually lower mpg.

Same as if you were installing a cam if you want to keep you fuel mileage you buy a can that has a high torque and lower rpm range then a racing cam. this puts the power where you need it.

I would buy the AEM intake LONG before I bought that WR intake. Actually i would never consider buying an intake where the gains are over 5000 rpm in a 100rpm window.
PEAK HP means nothing
More usuable power and torque will make you faster overall.
for instane

Lets say the AEM and WR cars were to race and both are automatics..
By the time the WR car got up to 4500 rpm the AEM car would already be a car length ahead because it's power pand/power curve starts sooner and carries on longer. Its a lot like a car with turbo lag.That's why supercharged cars are usually quicker off the line because they produce more HPand torque at lower rpms.

With my truck when i first got it got rock solid 24mpg (low KM and like new)
I change the oil, trans and differential fluid to Amsoil synthetics
I made my own high flow foam air filter, and modified the air intake system. I used the OEM air box but remove the inlet and made one 3X larger and directed in cold air only. For the exhaust I made my own stainless cat back system using a large glass pack muffler with dual inlet and dual outlets and piped it to works like a twin loop with single in/out.
Just that alone boosted my MPG to 27 on the hwy, and HP overall was probably around 10-15hp gain. Very noticable around 2500-3500 rpm.
But in town there was a loss of mpg not much but it did show up on paper and the pocket book. Because I drive mostly hwy it worked out great for me because over all my mileage went up. Hardly any s-10 owners believe I was getting 27MPG except the few that did the same thing.

[Violin]

Thanks - You provided quite a bit of info there and it was fun messing with you.

[07WYarisRS]

kept me busy for a while too

[hasher22]

Originally Posted by the_saint

Is it me, or is it getting hot in here?

Better play it safe...

OMG that cracked me up for some odd reason......

[Snake]

Originally Posted by Yaris TTE JWRC

if u increase th HP u are going to lose MPG, the same thing to Increse MPG = lose HP, u cant get it all, the Farrais only get 8-10 MPG, but the got mass HP. so if the intake give u good HP, then u will lose good MPG.

this was the dumbest thing ive ever read before thank you for sharing

[Black Yaris]

ok this may sound a bit funny... or is is just a coincdence.... after switching to mobile one 5w30 synth i have been getting 3-4 MPG better gas miles..... I am thinking of switching over to amsoil 15w90 gearlube in my trans as well, maybe add a couple more MPG