I've read a good bit about this on some other forums and I just wondered if anyone had any luck here. I've got a Chevy 5.3L V8 in a Silverado 4x4, and was wondering if putting a better air intake and a flowmaster exhaust on it would actually buy me anything. Not too concerned about improved HP or anything, but wouldn't mind it.

I've never really had a reason to care about engine performance before now, as all I've had previously were 4 bangers, and I'm certainly a neophyte when it comes to these things. I think this is my first garage post.

And I'm not complaining about the gas mileage I'm getting - I knew what it was before buying it, but if I can improve it, I would like to.

[Edited on July 4, 2012 at 7:11 PM. Reason : asdfa]

7/4/2012 7:10:36 PM

let's say these mods get you 1mpg
let's say you get 15mpg currently
let's say they cost ~$500
it would take you 533 gallons of fuel, or 21.33 25gal tanks to break even, before it became a positive

[Edited on July 4, 2012 at 7:25 PM. Reason : assuming regular gas at $3.30/gal]

7/4/2012 7:25:19 PM

wouldn't even take 6 mos. for me to break even

but my 5.3L Z71 chevy gets 17-18 mpg with a mix of highway and country roads

[Edited on July 4, 2012 at 7:50 PM. Reason : adv]

7/4/2012 7:48:12 PM

EFI Live is going to be your best possibility for fuel economy, apparrently guys with 6.0 chevy's are getting +2 or so mpg with nothing but a change of tune. Add some 'worthy' bolt-on mods and you may gain 1-2mpg more.


as far as I am concerned the standard bolt-on intake/exhaust do nothing for 'felt' performance and mpg's


noteworthy enough, the cost of owning my honda civic in addition to my dakota (15mpg avg) saves me money over actually selling civic and driving dakota alone.

7/5/2012 8:11:11 AM

http://ststurbo.com/gm_trucks

Bahahhahaha

7/5/2012 9:21:37 AM

I gained a few mpg when I gave the Integra an aftermarket cold air intake, header and exhaust system. Granted those parts cost around $1000 altogether but I wasn't doing the mods for a fuel mileage gain, so it was really just icing on the cake.

So I would say it's possible. Whether it's a good move from a financial standpoint isn't as clear.

7/5/2012 10:13:25 AM

If the truck is your only vehicle then go for it. If not, then only drive it when you actually NEED to drive a truck. (just make sure that you drive it often enough to keep the battery up)

7/5/2012 10:26:27 AM

i seriously gained 4mpg mixed use on the roo with the hta 20g... (bigger turbo) mostly because it's possible to keep her out of boost now if i want to.

[Edited on July 5, 2012 at 10:44 AM. Reason : .]

7/5/2012 10:44:14 AM

i still like the civic mod....


you know... buy a civic & drive it 80% of the time

7/5/2012 11:39:07 AM

^ I installed that mod a few years ago. Works pretty well until you have to pull a boat.

7/5/2012 12:32:49 PM

^hence why i said 80% of the time (assumed truck ownership there)

7/5/2012 1:22:22 PM

Changing the way you drive costs no money, saves on wear and tear, keeps tickets away, makes you more safe, and will get more mpg improvement than any parts out there.

[Edited on July 6, 2012 at 8:18 PM. Reason : a]

7/6/2012 8:18:24 PM

Doubling the VWs HP gave me 5-8 mpg, while not changing the way I drove.

7/6/2012 9:06:16 PM

You'll notice that doesn't contradict what I said.

7/6/2012 9:12:57 PM

For a truck, would a bed cover or camper shell help any? I would think improving the aerodynamics on a vehicle that large could increase the mpg.

Also, I noticed a difference when I cleaned out the tool box in my truck. I probably took out 300lbs of tools I never used.

7/6/2012 10:09:55 PM

your driving technique and tire pressure would make a bigger difference than bolt on mods and are free

7/7/2012 10:38:19 AM

Quote :

"your driving technique and tire pressure would make a bigger difference than bolt on mods and are free"

if dude is getting in the 16mpg range from a v8 pickup, other than 'hypermiling' there's not really any benefit from driving technique.


FWIW, generally speaking regarding fuel economy stats:

- 4.x - 5.x V8 pickups - 15-17mpg
- 6.x-8.x v8 pickups - 11-14mpg
- cummins diesel pickups - 12V & 24V- 19-21mpg, 4x4's sometimes dip to the 17mpg range.
- new diesel trucks do 14-17 with the DPF & Regen equipment
- IIRC the newest fords may be in the 18mpg range?

7/7/2012 1:40:34 PM

7/7/2012 2:52:28 PM

+1 for the civic mod

7/7/2012 4:51:08 PM

^^

7/7/2012 6:31:37 PM

+1 for the Civic mod

Quote :

"FWIW, generally speaking regarding fuel economy stats: - 4.x - 5.x V8 pickups - 15-17mpg - 6.x-8.x v8 pickups - 11-14mpg - cummins diesel pickups - 12V & 24V- 19-21mpg, 4x4's sometimes dip to the 17mpg range. - new diesel trucks do 14-17 with the DPF & Regen equipment - IIRC the newest fords may be in the 18mpg range?"

I've been going to industry events and looking at a lot of materials on this subject. If you look toward the future, say about 2016 when the next big jump in fuel economy standards arrives, expect combined MPG to get to around 20 for naturally aspired V8 gas trucks, along with generally lower sales volume of them.

Below are some new technologies to look out for besides the obvious downsizing (fewer cylinders) + weight reduction. These are already being introduced on higher end passenger cars, but gas powered naturally aspirated V8 trucks typically run on a long development cycle with a focus on keeping costs down:

1) friction reduction--for example, lower friction valvetrain and better materials technology
2) smart alternator regeneration--only charging the battery during deceleration
3) transmission improvements--7 to 9 speed automatics with lower internal friction and smarter controls
4) increased use of variable valve timing and valve lift systems
5) gasoline direct injection with an emphasis on low end torque for "downspeeding"
6) reduction in displacement
7) improved knock resistance and knock control logic to allow more aggressive spark timing
9) cylinder deactivation or start-stop technology (maybe both in the same engine)
10) throttling of water pumps, oil pumps

for diesels, look for the following technologies in addition to some of the applicable technology mentioned above. Because of the heavy use of aftertreatment and regeneration strategies, fuel economy and emissions go hand-in-hand. The more you can reduce engine-out emissions the less you have to do fuel-consuming regenerations:

1) higher fuel pressure. Currently about 180 MPa (26,000psi) is standard, but 200 MPa is coming in and it's only going to go higher.
2) more injections per cycle--about 5 is common right now, but it will increase. This means more expensive injectors and more development effort.
3) perhaps even more of an aftertreatment clusterfuck than we have right now (emission converters & traps, etc)
4) even more aggressive use of cooled EGR (exhaust gas recirculation)
5) exotic turbocharger configurations--EGR requires a very wide compressor map to have good part and full load performance.
6) swirl control valves

I really expect the cost gap between gas and diesel to get greater over the next decade. It's really expensive to make a clean diesel, and all these boosted gas engines are now getting close to diesel-like torque characteristics.

[Edited on July 7, 2012 at 9:14 PM. Reason : .]

7/7/2012 9:10:51 PM

Quote :

"and all these boosted gas engines are now getting close to diesel-like torque characteristics. "

BAH!

7/7/2012 10:26:41 PM

ok... close enough to diesel torque for your average Joe customer (middle class family) and small business owner.

7/8/2012 10:00:34 AM

haha, twas just trying to make a funnay.



Thought on EFI live, anyone?

7/8/2012 3:24:41 PM

my 5.3L z71 gets 19-20 mpg

7/8/2012 3:39:47 PM

^well, go on....

7/8/2012 8:10:38 PM

I swapped my v8 SS Camaro for my wife's civic becuse drive a lot more than here at work. Best thing we could have done, saving 50+ bucks a month.

7/8/2012 8:46:27 PM

+1 for the Civic mod
Hell, get a used one from the 90's for $2500. It'll still get double your current MPG, and at that price the insurance will be $Rhode Island and you can keep the truck for weekend/hauling duty without paying a huge extra penalty.

Quote :

"For a truck, would a bed cover or camper shell help any? I would think improving the aerodynamics on a vehicle that large could increase the mpg. "

I don't have any hard data but I'd think it would.

[Edited on July 9, 2012 at 12:13 PM. Reason : d]

7/9/2012 12:12:28 PM

Quote :

"^well, go on...."

i mean i haven't done shit to it other than routine maintenance.

7/9/2012 2:22:31 PM

then you must have some magic smurfs in that shit kicking in a few extra mpg.

7/9/2012 3:42:40 PM

probably going by the MPG reading on the dash, which is about 1.5 mpg high on my truck. his claims are still reasonable for highway mpg. my dad's '05 2wd silverado gets 20-21 on the highway.

man told me once that a man will lie about 3 things: money, pussy, and gas mileage

[Edited on July 9, 2012 at 8:32 PM. Reason : adf]

7/9/2012 8:28:25 PM