is it true do you really get more mpg i love more power but its hard to get more power without burning more gas

 

yes and no,

yes you theoretically can get better gas mileage with better throttle response and making your engine a more efficient air pump.

No, you won't be able to keep foot out of it.

 

really better mpg;if you got 1-2mpg it would be tottlly worth it;you u have one aim4sqlls;do u have a 360 52mm tell me is it really worth it more powwer really or a placebo

 

More than 95% of daily driving is done with the throttle blades partially closed creating a restriction. This 'normal' restriction is about 10 times greater than the typical 0.3 inches Hg improvement you get with a larger throttle body... only when you are at wide open throttle.

The larger throttle body will not improve MPG in a careful test,
but if all you do is check the next few tanks of gasoline
you have a 50% chance of getting
EITHER higher or lower MPG,
because 'normal' MPG jumps around.

If the throttle body gets too large...especially with the huge plenum of the standard 'beer barrel' Magnum 5.2/5.9 V8 intake manifold, there will be a slight 'bog' as the accelerator is pressed very fast.

 

No, I have the 5.2 and the 50mm fastman. And HankL is abosutely right about the bog down effect. Think this is what Modding the TPS does, it reads the plates a little more open than what they really are.

 

i went with the 70mm on my 4.7 dak when i had my cam kit installed and it was a great improvement over stock weel worth the investment. here is a pic of the factory tb and then the fastman.

[IMG]local://upfiles/31284/9D6065D51E504A08ADF583F15E33C716.jpg[/IMG]

 

it is worth making note of
that Chrysler went to a very large 90 mm single bore
throttle body on the Hemi 5.7 v8 (more than 900 cfm capacity)
but then took care of the 'bog'
by making the throttle blade movement 'fly by wire' with computer control
so the driver could not press the accelerator too fast

in the new 2009 5.7 Hemi
Chrysler apparently has increased the compression ratio
but let the 'fly by wire' throttle partially shut
when the knock sensors detect pinging
and maybe also vary the valve timing and lift

this gave a total of a 4% improvement in engine fuel efficiency

so, the moral of the story is;
a throttle body can be part of a fuel economy improvement
but it takes a lot more
than just the big throttle body