mpg

[usmcagg02]

with the rising gas prices i'd like to get some better fuel efficiency out of my truck with out payin a sh** load of money. what is the best way to improve mileage on a 5.3L vortec? its pretty much stock, only has a new air filter on it.

[Graystroke]

what's a **** load of money? You can try running synthetics in everything. Axles, trans, engine, and t-case if you got one. You probably will pic up a mile or two. Free-flow exhaust and intake. Bed cover will give you the most mpg. get rid of the bug deflector if you have one.

[uglyota]

Don't get a whole replacement intake, because you'll start sucking hot air out of your engine bay. Just get a drop-in K&N for fuel efficiency. I agree with the exhaust stuff too. DO NOT waste your money on throttle body spacer like the Helix Power Tower or the PowerAid. Total waste of $100.
Don't chip or cam your truck if you're sincerely concerned about fuel economy, and for god's sake don't lift it!
Staying off the skinny pedal (or buying Honda Steve) is really the only economical thing that you can do to make a difference. None of the other improvements will "pay for themselves" over time with increased economy.

[Chadnutz]

Or get a diesel. $.18 cheaper per gallon.

[BigRedFord04]

best way i've ever heard it put is that an engine is like a big air pump, the easier air can get in and out the more efficient it will be.

my suggestions would be a K&N filter (not a full kit), good exhaust, TB spacer (contrary to popular belief, i saw a bit of an improvment when i put mine on about a month ago), and synthetic fluids. i've also read that wrapping your air intake hoses w/ insulation to keep heat out helps keep the air cooler, i.e. more dense > more O2 > more efficient. i know its no fun but stay off the skinny pedal. i know the newer motors dont need spark plugs very often so replacing them might not do much for you. if you've got a bunch of miles on it run some fuel system cleaner thru the gas tank and get the berryman's fuel system cleaner thru the vacuum system, i've always found that stuff does great.

[BMFScout]

I thought that K&N assembly cut off that whole corner of the engine compartment in those models? I'm gettting one, I think it would definitely help even if it is slightly hotter. Have you looked at the resonator on the stock intake tube? Way restrictive.

[uglyota]

okay, then research the TB spacer on your engine before doing it, and if they're worth anything, find one on Ebay. I think you can get the name brand ones for $30 or so. but it didn't help me any

and I still say drop in filter, so you keep pulling air from the fender and not from the engine bay (the kits improve throttle response, but definitely not any more economy than a drop in)

my resonator wasn't restrictive at all, but I still got rid of it

(btw mine's a 5.7 not a 5.3 though)

[stx4wheeler]

i mean simple as that you not gonna be able to get a mile or two per galln better even if you do all that stuff to your truck. But if you think it is worth it when you go to true dual exhuast have and h-pipe put in before the mufflers and also get the cats hollowed out. i noticed like a mile or two per gallon if i am not hauling ass once i got the above exhaust work done.

[AgDieseler]

85% of what goes through a naturally aspirated engine is air, and like Austin said, any addition that lets the engine pump air easier removes the amount of work that has to come from burnt fuel.

An ample supply of fresh cool air for the intake, and the ability to expell spent gasses easily is the first step in making an engine a mpg monster.

Here's the wierd thing that I have yet to understand:

I just finished taking thermodynamics, and I learned that the typical thermal efficiency of a spark engine is 15-20%. That comes from an equation that says you want the energy that leaves the engine (like exhaust gas temperatures) to be as low as possible, and the energy that enters the engine (like the intake air) to be as high as possible.

But as common sense has told us, we try to keep the intake temp as low as possible. It makes sense that high EGTs mean an engine is being inefficient since that comes from unburnt exhaust gases.

Engineering aside, get cooler intake air, let the exhaust breath easier, run the lowest octane rating you can (higher isn't always better; it just costs more), run the AC as little as possible, idle as little as possible, and keep off the skinny pedal.

[robertf03]

4 barrel with vacuum secondaries

[Fredo]

Originally posted by uglyota
and I still say drop in filter, so you keep pulling air from the fender and not from the engine bay (the kits improve throttle response, but definitely not any more economy than a drop in)

No, the full K&N kit for the chevy LS based motors blocks off the corner of the engine bay and draws cold air from behind the headlight. Much much better air flow than the stock setup too. A buddy of mine has had 3 of those trucks and had the k&n on all of them.

[Fredo]

Originally posted by stx4wheeler
But if you think it is worth it when you go to true dual exhuast have and h-pipe put in before the mufflers and also get the cats hollowed out.

This....this idea is Horrible Peter. You're telling me it's a good idea to hollow out all FOUR cats on a 5.3L chevy? You're also saying that the computer won't figure it out and trip the check engine light, or even pass inspection?
I always get a kick out of people who say catalytic converters stop up an exhaust system. I saw a dyno test in Hot Rod a few years back that tested a 650hp big block with and without cats. The motor put out 654hp without cats, and ripped out 653hp with them. That motor was really straining due to the cats huh?

[uglyota]

Originally posted by Fredo
No, the full K&N kit for the chevy LS based motors blocks off the corner of the engine bay and draws cold air from behind the headlight. Much much better air flow than the stock setup too. A buddy of mine has had 3 of those trucks and had the k&n on all of them.

Didn't know this. In that case, just make sure and drop $$$ on the K&N brand, the cheap airaid or pro-crap kit that I got doesn't block off the area like freddy described

[stx4wheeler]

Originally posted by Fredo
This....this idea is Horrible Peter. You're telling me it's a good idea to hollow out all FOUR cats on a 5.3L chevy? You're also saying that the computer won't figure it out and trip the check engine light, or even pass inspection?
I always get a kick out of people who say catalytic converters stop up an exhaust system. I saw a dyno test in Hot Rod a few years back that tested a 650hp big block with and without cats. The motor put out 654hp without cats, and ripped out 653hp with them. That motor was really straining due to the cats huh?

ok not all of us drive chevy products with four cats. i got my one stock cat hollowed out on my, 95 bronco 351w and and had them put in another hollowed out cat in when they did my dual exhaust, and the reason for the hollowed out cats was more for the price than anything else because seriously there farva a ford bronco with a 351 is just a real power monster, as we all know. it was gonna cost me like an extra 80 bucks to get cats, and hey i maybe got one hp yeeeeah!! Also i have never had a probelm throwing check engine light or any codes. i simply stated the no cats thing to relate what my pos has, to give him a better idea. Let any further flaming begin now ***.

[mark]

My advice to get better mileage: Get your friends to drive you around.

I'm with freddy on the cat thing. With the OBD2 system on the 5.3, there are 4 o2 sensors, one before each cat and one after. The one before provides feedback to the PCU keeping the mixture in line, while the one after monitors the performance of the cat. All 1996 and after gasoline powered vehicles have this (all though not all have two cats), so hollowing out the cat on anything reletivly new will throw a code.

-Mark