Please End The Madness: The Exhaust/intake/lift Kit Controversy!

[bb123]

Please end this controversy: Exhaust/K&N and gas/performance, + lift theory may apply!

 

OK, Ill make this as fast and short as possible.

 

I keep getting these debates with people and myself regarding exhausts and intakes.

 

OK, the various positions:

 

If i have a 2008 Silverado 5.3L:

 

 

 

 

What truly affects the gas mileage and performance?

 

 

 

Here we go and see where you stand:

 

A) Replace stock muffler with common flowmaster 40 series and replace stock filter with a K&N that fits inside the stock air box.

B) Replacing entire exhaust suystem

C) Replacing muffler and obtaining a cold air intake

D) Lift Kits; You can lift it, but so long as the wheels and tires are same appx size, you won't lose much, even to wind resistance if stock gearing is used.

 

The Angles:

 

-0) replacing the entire exhaust from header on you will destroy any gas mileage you ever planned on recieving. way too free flowing for a typical everyday application

 

-1) replacing the muffler and K&N filter (in stock box) will give you better gas mileage. The reason is bc its more free flowing. Its not having to strain to suck in air or expell it and is the best for everyday applications. Your gas will increase as well as power. Bottom line, less strain, less heat, more power and ease of operation.

 

-2): it will do nothing to gas mileage. If I am not running a new piping dimension or replacing the cats, headers, etc I am fine and will only get noise difference.

 

-3) It will affect gas mileage, more air is being expelled, more air is being inhaled, you will lose gas period. More air, more gas...

 

-4) Now, you need backpressure to create torque. With a free flowing exhaust do you eliminate that torque thus making your engine work harder and then actually dropping your gas mileage due to that reason? A camaro can get away with it, not a large vehicle.

 

-5) Lifts w/ stock gearing? You can lift it, but so long as the wheels and tires are same appx size, you won't lose much, even to wind resistance if stock gearing is used. But if you go higher than a two inch leveling ( such as a 4" on up), the decent gas will disappear as the wind resistance is equivalient to towing a 2000lb trailer.

 

-6) Cold Air intakes: Myth about all that cold air. It doesn't make sense. The stock air box sucks air from the fender. This means while driving you are getting the coolest air. Colder air means more dense air, which equals more horse power due to oxygen concentration. How can you possibly get better power and such if youre doing nothign but sucking hot engine compartment air into an already warm motor? It defeats the purpose. Your going backwards instead of forward. Why did they swtich from the old filter on top of the carb styel motor, and the first style of fuel injection where I think you had two main injecteors with a filter on top like a carburated. Its bc its more efficient pulling it from the sides. The only way your going to benefit by having it in the middle or near the motor is if you are running a supercharger with the big ol butterflies, but then again, its sticking out and recieving fresh cool rammed air. So cold air intake is a bogus myth. Your better off getting a K&N that will fit in the stock box.

[elcompalaline]

I can give a little input on the subject, my truck has the 4.8 so results will be different.

 

One week after purchase, I went with a 40 series Flowmaster with full 3" pipe all the way back. It sounded great but I did not know if it helped performance wise. Planning to do more like a CAI, tune, shift kit, etc... I figured I was prepping it for later mods. Well those mods never went on and my MPGs weren't that good. Looks like there was a lack of back pressure in the exhaust, I was giving it more gas to compensate so bad MPG. For a quick solution I had a muffler shop cut one foot off of the tailpipe and install a 2.5" pipe in its place. It helped! As soon as I drove home I noticed lower drone and better low end torque, not to mention way better MPG. As for the CAI, your right about it breathing hot air. I kept the stock air box in this truck and got a drop-in K&N, couldn't be happier with the results.

 

IMO unless you are going all out in the truck, you are doing more harm the good.

[hockeypro1411]

I have a drop-in K&N, a lift with bigger tires and stock gearing, and true dual exhaust with aftermarket mufflers. I think the only thing I missed was the CAI. Darn!

[uh6tdrvr]

IMO, 3 inch is good for High end power but the smaller pipe diameter does better for low end power....where most of us use our trucks. I have 3in cat back with a 40 series on my 94 suburban and i lost some low end power.....but it sounds good!

[marko]

I have all 3 - lift kit, k&N 77, and a Corsa Exhaust. I LOVE driving my truck now, and put my foot in it whenever possible.

 

And I don't give a $h!t about gas mileage. It may be a little worse, but my smileage is way better.

[usmc3529]

Its a truck, imo if you have a 5.3 or better and want to mod it out you are not worried about gas mileage.

 

If you want to keep your mileage at the 20 mpg mark keep the tiny stock wheels and tires on, throw in a k&n and a cat back exhaust.

 

Throwing on a cat back exhaust at 2.5 inch pipe is your best bet, you eliminate the huge garbage can stock exhaust, the new muffler alows the muffler to breath better andf not get nearly as hot

[Matt_]

if you want to save gas mileage then just put your tailgate down.............

[C. Charles Hahn]

There's no end to the "madness." There are several different options out there for exhausts, intakes, and lift kits, and for as many options as there are, there are just as many different opinions about them (most of which have been expressed previously on this board -- hence the existence of the search feature; please try it, it could blow your mind).

 

The best way to end the "madness" is to do a search, look at what's out there, and decide what you like.

[bb123]

if you want to save gas mileage then just put your tailgate down.............

 

I had THE WORST gas!!!!! According to te govt site www.fuelecono

y.com the Nissan Titan 4wd got the worst out of every full sized truck in it's class. I spent $550/mo in gas alone! Add a slight lift and you're gonna pay for it. Once my exhaust was replaced and an in box k&n placed in, I got around 45miles per 1/4 tank. I drive this chevy around and it's a blessing. I also had a 4x4 expedition and that drank like a whore as well. The chevy is known for good gas, period.

 

I’ll be the first to admit, I bought into the notion that by having your truck’s tailgate down while you’re driving down the road (especially the highway) you would greatly increase your truck’s fuel economy. Apparently that just isn’t true.

 

According to several sites (Ask Yahoo! for example) state that you get roughly the same gas mileage driving with your tailgate up as you do when your tailgate is down.

 

According to the Ask Yahoo! article, this is the reason why:

 

“When the tailgate is raised, a “separated bubble” of stagnant air is formed in the bed of the pickup. Wind tends to swoosh over this bubble as though it were part of the truck. Lower the tailgate, and the bubble disappears, which leads to increased wind resistance.”

 

Actually myth busters proved that tail gate down made it worse...

[Matt_]

if you want to save gas mileage then just put your tailgate down.............

 

I had THE WORST gas!!!!! According to te govt site www.fuelecono

y.com the Nissan Titan 4wd got the worst out of every full sized truck in it's class. I spent $550/mo in gas alone! Add a slight lift and you're gonna pay for it. Once my exhaust was replaced and an in box k&n placed in, I got around 45miles per 1/4 tank. I drive this chevy around and it's a blessing. I also had a 4x4 expedition and that drank like a whore as well. The chevy is known for good gas, period.

 

I’ll be the first to admit, I bought into the notion that by having your truck’s tailgate down while you’re driving down the road (especially the highway) you would greatly increase your truck’s fuel economy. Apparently that just isn’t true.

 

According to several sites (Ask Yahoo! for example) state that you get roughly the same gas mileage driving with your tailgate up as you do when your tailgate is down.

 

According to the Ask Yahoo! article, this is the reason why:

 

“When the tailgate is raised, a “separated bubble” of stagnant air is formed in the bed of the pickup. Wind tends to swoosh over this bubble as though it were part of the truck. Lower the tailgate, and the bubble disappears, which leads to increased wind resistance.”

 

Actually myth busters proved that tail gate down made it worse...

 

 

 

 

.... sorry to make you type all that... i was being sarcastic

[Visegrip117]

I have the 5.3 ext cab with 20' rims.

 

I installed a full cat back exhaust (gibson duals) and a drop in K&N filter.<---My volant CAI ships on monday

 

IF I drive it right and not try to pass every car I come up to, and not drag racing everyone I see at the red lights.

I still get 20 mpg on AVG after a tank of gas.... I've even gotten up to 22.5 mpg for a tank.

 

A decent exhaust isn't going to harm your MPG. Unless you keep your foot in it to listen to the pipes.

[bb123]

.... sorry to make you type all that... i was being sarcastic

 

 

[Visegrip117]

Please end this controversy: Exhaust/K&N and gas/performance, + lift theory may apply!

 

OK, Ill make this as fast and short as possible.

 

I keep getting these debates with people and myself regarding exhausts and intakes.

 

OK, the various positions:

 

If i have a 2008 Silverado 5.3L:

 

 

 

 

What truly affects the gas mileage and performance?

 

 

 

Here we go and see where you stand:

 

A) Replace stock muffler with common flowmaster 40 series and replace stock filter with a K&N that fits inside the stock air box.

B) Replacing entire exhaust suystem

C) Replacing muffler and obtaining a cold air intake

D) Lift Kits; You can lift it, but so long as the wheels and tires are same appx size, you won't lose much, even to wind resistance if stock gearing is used.

 

The Angles:

 

-0) replacing the entire exhaust from header on you will destroy any gas mileage you ever planned on recieving. way too free flowing for a typical everyday application

 

-1) replacing the muffler and K&N filter (in stock box) will give you better gas mileage. The reason is bc its more free flowing. Its not having to strain to suck in air or expell it and is the best for everyday applications. Your gas will increase as well as power. Bottom line, less strain, less heat, more power and ease of operation.

 

-2): it will do nothing to gas mileage. If I am not running a new piping dimension or replacing the cats, headers, etc I am fine and will only get noise difference.

 

-3) It will affect gas mileage, more air is being expelled, more air is being inhaled, you will lose gas period. More air, more gas...

 

-4) Now, you need backpressure to create torque. With a free flowing exhaust do you eliminate that torque thus making your engine work harder and then actually dropping your gas mileage due to that reason? A camaro can get away with it, not a large vehicle.

 

-5) Lifts w/ stock gearing? You can lift it, but so long as the wheels and tires are same appx size, you won't lose much, even to wind resistance if stock gearing is used. But if you go higher than a two inch leveling ( such as a 4" on up), the decent gas will disappear as the wind resistance is equivalient to towing a 2000lb trailer.

 

-6) Cold Air intakes: Myth about all that cold air. It doesn't make sense. The stock air box sucks air from the fender. This means while driving you are getting the coolest air. Colder air means more dense air, which equals more horse power due to oxygen concentration. How can you possibly get better power and such if youre doing nothign but sucking hot engine compartment air into an already warm motor? It defeats the purpose. Your going backwards instead of forward. Why did they swtich from the old filter on top of the carb styel motor, and the first style of fuel injection where I think you had two main injecteors with a filter on top like a carburated. Its bc its more efficient pulling it from the sides. The only way your going to benefit by having it in the middle or near the motor is if you are running a supercharger with the big ol butterflies, but then again, its sticking out and recieving fresh cool rammed air. So cold air intake is a bogus myth. Your better off getting a K&N that will fit in the stock box.

 

 

CAI isn't this great new invention that does something completely different than the stock filter and intake does.

 

The stock intake and filter is way better than the old ones that us to sit on top of the carb.

Because, as you stated above, it pulls cold air from the fender well.

 

Many CAI still pulls it's air from the fender. And many use a box and lid to separate the fender well air (cool) from the motor air (hot)

 

They didn't do anything but improve upon what the stock filter and intake tube does.

 

They use a better flowing filter to allow more air to pass freely and still stop debris.

They use a more stream line intake tube to allow air to flow with less disturbance.

They use a bigger Filter to allow for more air intake.

 

 

Basically they just improve upon a good thing.

[orlan85]

There's no end to the "madness." There are several different options out there for exhausts, intakes, and lift kits, and for as many options as there are, there are just as many different opinions about them (most of which have been expressed previously on this board -- hence the existence of the search feature; please try it, it could blow your mind).

 

The best way to end the "madness" is to do a search, look at what's out there, and decide what you like.

 

 

[blackout07]

I'm going mad reading all of this. I get 11-12mpg...so what the heck do I know? My mileage decreased slightly after adding a CAI and Flowmaster muffler. I didn't have my DIC in the truck before I added those mods and I didn't keep a close eye on the mileage, but I feel that these mods have hurt more than they have helped. I am considering going back to the stock intake for a while.