I'd be ecstatic with 15mpg!

 

You know what - I'd like to respond, but I'm not - its not worth getting into a heated debate about it. Good luck selling your intakes.

For everyone else, I suggest doing your own research and decide for yourselves what makes sense to you. In the end that's all that matters. Besides, when you do make changes to your engine, the gas gauge will not lie.

 

Hummers get a bad rap for fuel economy... well let me be specific.. at least our truck, the H3, gets a bad rap considering what fuel economy its capable of.
I'm getting 22-23mpg hwy in comfortable temps which is far better than most other SUV's that are fairly comparable. My brothers 07' Grand Cherokee (V6 auto) has trouble coming close to 20mpg despite it weighing nearly 1200lbs less than my truck. My dad's 2010 M-Class has a 6cyl. 7-speed auto and still can't beat my truck in terms of fuel economy. Taking a look at new car lineups (again within somewhat of a comparable class to the H3) and the fuel economy isn't that much better. I'm getting better fuel economy than what the 2011 Tahoe's are rated at and that truck is in a larger class. Not to mention that when it comes to offroad, the H3 will do circles around any of those vehicles I'm using for comparison... well the Jeep might be able to keep up for a little while but that's a whole different thread. Oh, let's also not forget how our truck is as aerodynamic as a brick wall and doesn't have the ability to switch the transfer case into 2wd which would be an additional help.
Now, I have done some mods which allows me to achieve the fuel economy I'm getting. I didn't do those just to get better fuel economy. Some I did to improve performance/reliabilty/preventative maintenance b/c I do a lot of towing and the rest I did just b/c of what Doc said above. I like tinkering and doing stuff to my truck and if better fuel economy is a side effect of that, well then all the more better.
Just my .02

 

and here i thot they put computers in cars to monitor air temp,flow,mass,throttle demand,load,exhaust gas ingredients,and make adjustments instantly to precise levels with electronic fuel unjection. and u can beat that by lettin more air in and it never notices,just burns more air,less gas. wow,ill be darned. i bet when the worlds auto enginners get wind of this the'll get in there and mess it all up with some silly ecu or an automatic choke or,,or sumpthin. my guess is a oval 8 in intake with 6 big air filters,,no 5, and a platinum gas saver to boot,,,

 

Did that "thot" hurt yourself???



All those adjustments........... are within FIXED parameters. In the case of fuel mixture, the amount is FIXED by the fuel trim tables in the OEM tune.

Air fuel ratio - 14.7:1 for best fuel economy and lowest emissions. 12.6 - 13:1 for maximum power at WOT, but dependant upon MANY variables including altitude (air temp/volume being only 2).

The amounts of fuel is dependant upon two tables. Short term fuel trim (Strim): moves swiftly in response to precat O2 values to make part throttle A/F 14.7:1
Long term fuel trim (Ltrim): moves slowly to bring the Strim to zero - the total fuel added or deleated is the sum total of Strim and Ltrim.

The tables themselves cannot change unless the programm is changed [ie. tuned].

 

I think you need to go back and reread what he wrote until you figure out what he actually said. lol

He stated quite clearly:
When you're done reading and feel the need to reply, don't be scared to use that fancy spell check feature.

 

ko
soe itz not the air thet berns,but, if u put more in you get betr mpg, now i get it

 

hey Doc,

This is how I understand it:

The default fuel maps/tables are fixed, and these are what are changed when you "tune" or program the ECU.

The Short and Long Term fuel trims are trims used modified as required by the ECU to adjust the fuel map in those default tables, based on those conditions you mention, but have a fixed range that they can vary, meaning that the ECU can only do so much and cannot infinitely adjust the fuel for extreme conditions or modifications....

But I think the point drtom is trying to make is: if you add something that increases air flow, the ECU will attempt to compensate for the lean condition and bring the A/F back to 14.7, in this case, adding fuel.

Also everyone should realize that in most modern ECU's, the cruising fuel maps (partial throttle) and Wide Open Throttle fuel maps are separate. The cruising fuel maps use the O2 sensor to monitor A/F ratio and adjust using the trims mentioned above. At WOT the ECU relies on the MAF or MAP sensors to meter air flow into the engine and determine where on the map it should be. The WOT fuel maps add considerably more fuel to make the mixture rich, which adds a good level of safety to protect against detonation as you put the engine to the test. WOT maps are generally fixed in OEM ECUs, and if things get out of kilter the ECU uses other things like timing to adjust according to the situation. So as you can see, attempting to increase flow into the engine can produce different results based on which map the ECU is using and where you are in that map.

 

I follow that. Thank you.

My point is along the lines of: If 2 asprins are good, you don't need to take 20 to make it more gooder.

More O2 in the combustion chamber can make a more efficient burn creating additional power with the same fuel, but.... only up to a known maximum. In some vehicles with poorly designed intake systems it has been measured as high as 5-7%. Realistically, far less for most.

Just sayin at hypothetically the same exact part throttle position (OEM vs less restrictive intake) the PCM will always shoot for 14.7, but your power output may and can be different. You can see this with live tune software, making the same or more power at different points on the tables while testing performance add ons. You can also monitor fuel used at the same time.

Some may sarcastically joke around like a horse with blinders if that floats their boat, but it is what it is.

 

If money is no issue a dm conversion will help!