Real world MPG increase from aftermarket

[Mr. Hyde]

Recently I purchased a K&N cold air filter system for my 2008 5.3 V8 Silverado, this is the engine with the ability to shut down 4 cylinders by the way.
Afterwards, I puchased a Borla catback system that happens to change it from a single dump to duals.
I did my own little real world MPG test and thought I'd tell you guys what the results were for no apparent reason at all. This was a 25 mile test strictly on the highway on my way to work in the morning (at 2am) so no traffic at all.
During all of the tests the tank was topped off (same weight) before the test, the tires were properly inflated to the same lbs. too.

1.) Stock = 18.6 MPG

2.) K&N cold air alone = 21.3 MPG (2.7 increase per gallon)

3.) K&N + Borla = 21.7 MPG (.4 increase per gallon)

So there you have it boys, a total of 3.1 MPG increase for a total investment of $880.00 for the Borla and K&N. Not to mention the little bump in HP.
Was it worth it? Hell yea! The truck sounds much better, and that alone was worth it. Not to mention that when I see the lil Colorado trucks getting 22 MPG I'm thinking to myself, that's fine, you go ahead and drive your little trucks with a 6 banger, I've got close to 350HP, a full sized truck, AND I'm getting a REAL WORLD 21.7 MPG...and that's close enough to 22 MPG for me.

(The test was at 60MPH steady)

[GULLETT17]

awesome! good info!!

[FORD RECOVERY EXPERT]

Thanks for the good info....

[gd1996]

I have a ram, by swapping to a high flow cat I picked up 2mpg... but no where near 20+, thats impressive.

[Shermanator86]

I have a ram, by swapping to a high flow cat I picked up 2mpg... but no where near 20+, thats impressive.

ha my ram gets 13-14mpg on the highway, but its got the old 360 in it so can't expect much out of it

o and to the OP Colorado's have an inline 5 not a 6
but that great that they are finally making full size trucks that will get reasonable mileage now

[00z28bubba]

ha my ram gets 13-14mpg on the highway, but its got the old 360 in it so can't expect much out of it

o and to the OP Colorado's have an inline 5 not a 6
but that great that they are finally making full size trucks that will get reasonable mileage now

they got lm7s now too. the 5.3 v8. but they also have a z51 w/o 4wd. thats odd.

[Zapper2003]

I currently drive two 4wd dodge rams. ones std. cab long box with utility cap and loaded, the other is my quadcab. both auto hemis. ones an 04, ones an 05. 04 has 3.55 LSD rear, 05 had 3.92 LSD rear. Best ive gotten (with a calculator) with my quadcab was 16.5 highway, loaded to the top of the box with firewood. Same trip home, unloaded, 16 flat. So far with the worktruck, 12.8 is the best ive mustered (when it was warm last week). Average between both is around 11.

[third_shift|studios]

Recently I purchased a K&N cold air filter system for my 2008 5.3 V8 Silverado, this is the engine with the ability to shut down 4 cylinders by the way.
Afterwards, I puchased a Borla catback system that happens to change it from a single dump to duals.
I did my own little real world MPG test and thought I'd tell you guys what the results were for no apparent reason at all. This was a 25 mile test strictly on the highway on my way to work in the morning (at 2am) so no traffic at all.
During all of the tests the tank was topped off (same weight) before the test, the tires were properly inflated to the same lbs. too.

1.) Stock = 18.6 MPG

2.) K&N cold air alone = 21.3 MPG (2.7 increase per gallon)

3.) K&N + Borla = 21.7 MPG (.4 increase per gallon)

So there you have it boys, a total of 3.1 MPG increase for a total investment of $880.00 for the Borla and K&N. Not to mention the little bump in HP.
Was it worth it? Hell yea! The truck sounds much better, and that alone was worth it. Not to mention that when I see the lil Colorado trucks getting 22 MPG I'm thinking to myself, that's fine, you go ahead and drive your little trucks with a 6 banger, I've got close to 350HP, a full sized truck, AND I'm getting a REAL WORLD 21.7 MPG...and that's close enough to 22 MPG for me.

(The test was at 60MPH steady)

screw the truck, tell us more about the VETTE!

[02cetransam]

now thats good info! Thanks

[Red on Red WS6]

Those are really big gains for those mods. Great job and good detailed info. I am a MPG freak and been tracking mine on all my cars for the last 5 years. In your case I would be curious if it stays averaging like that for the next couple tanks of gas.
To add to the thread, this is what I have noticed on my TA for milage.
Stock I was only getting around 15.5 MPG City, after my hot cam and a mail order tune right around 14. Adding the stall converter dropped to 12 to 13. Then did my own PMC tunning and added LT headers rather then shortys. MPG went up to 16. Lastly stepped down to a colder plug and been at 18 MPG city for the last 3 years. When Tulsa went to 10% ethanol in there gas I did not really see much of a change.
In my Kia Ethanol drops the mileage by about 3 to 4 MPG.

[Mr. Hyde]

I installed a K&N cold air on the Vette as well, and with the tires overinflated to 35PSI, actually the Owners Manual tells you that if you are going to exceed 175MPH for an extended time, to inflate the tires to 35PSI, the correct pressure is 30PSI. In addition, on Corvettes, if you're not familiar with the Z06 in particular, and the 436hp option on the regular model, there are 4 pipes in the back as I'm sure you've seen, but only 2 are working or "open" below 3500RPM or unless you floor it.
I overode this by disconnecting the vacuum line that closed the "flaps", hence giving me a more aggressive sound, a bit more grunt below that 3500RPM threshold, and a lil more MPG as well.
I also lowered my Z06 by 1.5" in the front (more to come later with coilovers all around) and 1" in the rear. This helps a tiny bit, but wasn't done for anything more than asthetics really, and to lower the car's center of gravity to aid handling.
I have not done the same extensive testing on my Z06 as I've done on my Silverado, because honestly I didn't buy the Corvette with ANY gas mileage expectations in mind, and the cold air was a performance mod more than a MPG mod. Whereas I bought the mods for the Silverado to squeeeeeeze more out of each gallon.
Neither of these cars are my daily drivers though, I have a Miata that gets high 30's for that. My wife drives the Silverado a whopping 14 miles daily. I have the 50 mile commute, hence the one way (25 mile) test for the truck.
Anyway, with those mods to the Vette it has actually returned close to 30 MPG on a 300 mile trip we took it on recently at a steady 65MPH. Remember that it has the 427 in it, big mouth to feed. Wide tires too, lots of friction, not too bad for a car that's intended for racing.

Again....not what I bought it for....130MPH in 3rd gear...that's what I bought it for!