Bad mileage after tune, headers and exhaust - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

khanh · 07-24-2013, 09:54 AM

Hi,

I have a very bad mileage after tune, headers and exhaust.
Before that a have about 15-16 in the city with very light foot. Now I have 13 with very light foot. The same route. And when I stop the car for a while, mpg decrease very quickly by not moving. For example I have 14 at the moment and after 3 minutes of not moving it drops to 13. Does it mean that car has worst mileage when idle than when it moves?
What could be wrong?

Thank you.

2012 SS M6

vroomapunk · 07-24-2013, 10:01 AM

I averaged 22 before my headers and tune. I added headers and afm disabler (auto's only) and it dropped to 20. After the tune, im at 19.6 avg.

My car is running like a champ with absolutely no issues, I have to assume that the mods caused me to lose 1 mpg, and disabling afm lost me 1 mpg. That and I drive more aggressively now, cause its more fun with the tune and headers

daveagogo1 · 07-24-2013, 10:08 AM

I have made the exact same DD trip for 2 1/2 years. I used to avg 17mpg every fillup. After mods and tunes I avg 16.7 on same daily trip. It has only seen the highway a couple times other than the trips to the dragstrip.

litle88 · 07-24-2013, 10:14 AM

Quote:

Originally Posted by khanh

Hi,

I have a very bad mileage after tune, headers and exhaust.
Before that a have about 15-16 in the city with very light foot. Now I have 13 with very light foot. The same route. And when I stop the car for a while, mpg decrease very quickly by not moving. For example I have 14 at the moment and after 3 minutes of not moving it drops to 13. Does it mean that car has worst mileage when idle than when it moves?
What could be wrong?

Thank you.

2012 SS M6

Cause RACECAR!!
That's ok! MURICA baby!

khanh · 07-24-2013, 11:27 AM

Yeah, I know. Who cares about mileage when have V8. I love the new sound of retro chambered exhaust, LT headers, HF cats and CAI. The performance is great too. But I read that your mileage will get better with tune and these mods. So thats why I'm asking, because mine is worse. Even with a light foot.

45thAnniversary2SS · 07-24-2013, 12:02 PM

All depends on the tune.

thahemp · 07-24-2013, 12:13 PM

Quote:

Originally Posted by khanh

Yeah, I know. Who cares about mileage when have V8. I love the new sound of retro chambered exhaust, LT headers, HF cats and CAI. The performance is great too. But I read that your mileage will get better with tune and these mods. So thats why I'm asking, because mine is worse. Even with a light foot.

How light of a foot? Reset the MPG average at a stoplight and come up to speed with a "light foot". You'll see how crappy even grandma driving is. Then consider all the times you put a little more foot in it so you can hear that rumble... re-figure your math and stop worrying about it! Even thinking about MPG in my car takes the fun out of driving it.

If your average hasn't had much time running, then yes, your MPG will drop steadily at a stop light. After all.. you're burning gas and going nowhere... that's 0 MPG averaged over the total time since reset.

Synner · 07-24-2013, 12:13 PM

Post your dyno sheet with AFR.

JANNETTYRACING · 07-24-2013, 12:22 PM

Quote:

Originally Posted by khanh

Hi,

I have a very bad mileage after tune, headers and exhaust.
Before that a have about 15-16 in the city with very light foot. Now I have 13 with very light foot. The same route. And when I stop the car for a while, mpg decrease very quickly by not moving. For example I have 14 at the moment and after 3 minutes of not moving it drops to 13. Does it mean that car has worst mileage when idle than when it moves?
What could be wrong?

Thank you.

2012 SS M6

This is completely normal after resetting MPG as it takes an average over however long and however your driving.

You will get ZERO MPG Stopped Idling, this pulls your average down very quickly especially after a reset.

Not so much after several tanks of fuel without a reset.

The MPG is AVERAGE not INSTANT.

Ted.

vroomapunk · 07-24-2013, 12:36 PM

Quote:

Originally Posted by JANNETTYRACING

This is completely normal after resetting MPG as it takes an average over however long and however your driving.

You will get ZERO MPG Stopped Idling, this pulls your average down very quickly especially after a reset.

Not so much after several tanks of fuel without a reset.

The MPG is AVERAGE not INSTANT.

Ted.

This too

CamaroFemme · 07-24-2013, 12:42 PM

Disabling AFM will cost you 1-2 mpg, but I'd think the lighter exhaust, better breathe-ability (is that a word?) and overall streamlining with the tune should gain that back, if not give you slightly better mpg. Of course, for the first few months you'll be smack in the middle of trying out your new mods, so you won't be driving it the same way.

VR Baron · 07-24-2013, 02:24 PM

I had shorites, hiflows, cooler plugs and a tune. Tune cleaned up the curve, got rid of the timing being crazy all over the place and leaned the full throttle A/F to better ratio. MPG city is the same, freeway short test run about the same but not conclusive.Mpg should be o.k. unless they richened up the part throttle cruise, mine was nt messed with to keep mpg and smog o.k.

SStodo8 · 07-24-2013, 02:41 PM

LOL! So than litle88 must have a "Magic" Tuner

. After install of headers and AFM disabled, i went from 17.8 to 18.9 MPG. Same drive, probably stepping on it more to hear my exhaust, but same drive when I had AFM.

Will update you when its been a full week, but so far better ,mileage

litle88 · 07-24-2013, 02:44 PM

Quote:

Originally Posted by SStodo8

LOL! So than litle88 must have a "Magic" Tuner

. After install of headers and AFM disabled, i went from 17.8 to 18.9 MPG. Same drive, probably stepping on it more to hear my exhaust, but same drive when I had AFM.

Will update you when its been a full week, but so far better ,mileage

SHHHHHHHHH,

07-24-2013, 09:54 AM	#1
khanh Drives: 2012 45th anniversary V8 LS3 Join Date: Jul 2013 Location: Prague Posts: 32	Bad mileage after tune, headers and exhaust Hi, I have a very bad mileage after tune, headers and exhaust. Before that a have about 15-16 in the city with very light foot. Now I have 13 with very light foot. The same route. And when I stop the car for a while, mpg decrease very quickly by not moving. For example I have 14 at the moment and after 3 minutes of not moving it drops to 13. Does it mean that car has worst mileage when idle than when it moves? What could be wrong? Thank you. 2012 SS M6

07-24-2013, 10:01 AM	#2
vroomapunk [COTW 5/12/14] Drives: 2012 CRT NF Cammed 2SS/RS For Sale Join Date: Oct 2011 Location: NOLA Posts: 6,115 View My Garage	I averaged 22 before my headers and tune. I added headers and afm disabler (auto's only) and it dropped to 20. After the tune, im at 19.6 avg. My car is running like a champ with absolutely no issues, I have to assume that the mods caused me to lose 1 mpg, and disabling afm lost me 1 mpg. That and I drive more aggressively now, cause its more fun with the tune and headers __________________

07-24-2013, 12:02 PM	#6
45thAnniversary2SS Drives: 2012 45th Anniversary 2SS LS3 Join Date: Feb 2012 Location: Charlotte, NC Posts: 2,812 View My Garage	All depends on the tune. __________________

07-24-2013, 12:42 PM	#11
CamaroFemme Drives: 2010 Black Camaro 2SS/RS Join Date: Aug 2009 Location: USA Posts: 1,879	Disabling AFM will cost you 1-2 mpg, but I'd think the lighter exhaust, better breathe-ability (is that a word?) and overall streamlining with the tune should gain that back, if not give you slightly better mpg. Of course, for the first few months you'll be smack in the middle of trying out your new mods, so you won't be driving it the same way. __________________ -- My boyfriend don't mind it.

07-24-2013, 02:41 PM	#13
SStodo8 Drives: Summit White 2SS Join Date: Apr 2010 Location: Oak Brook, IL Posts: 117	LOL! So than litle88 must have a "Magic" Tuner. After install of headers and AFM disabled, i went from 17.8 to 18.9 MPG. Same drive, probably stepping on it more to hear my exhaust, but same drive when I had AFM. Will update you when its been a full week, but so far better ,mileage __________________ I am a SHOWSTOPPER! www.showstopperaccessories.com Be a fan of Showstopper Accessories on Facebook!

07-24-2013, 11:27 AM	#5
khanh Drives: 2012 45th anniversary V8 LS3 Join Date: Jul 2013 Location: Prague Posts: 32	Yeah, I know. Who cares about mileage when have V8. I love the new sound of retro chambered exhaust, LT headers, HF cats and CAI. The performance is great too. But I read that your mileage will get better with tune and these mods. So thats why I'm asking, because mine is worse. Even with a light foot.

07-24-2013, 12:13 PM	#8
Synner Drives: cars Join Date: May 2011 Location: Oversneeze Posts: 4,544	Post your dyno sheet with AFR.

07-24-2013, 02:24 PM	#12
VR Baron SoCal Camaro5 Race Team Drives: 2021 Shadow Grey Camaro 2SS 1LE Join Date: Mar 2010 Location: SO CAL Posts: 14,288	I had shorites, hiflows, cooler plugs and a tune. Tune cleaned up the curve, got rid of the timing being crazy all over the place and leaned the full throttle A/F to better ratio. MPG city is the same, freeway short test run about the same but not conclusive.Mpg should be o.k. unless they richened up the part throttle cruise, mine was nt messed with to keep mpg and smog o.k.