: Gas Mileage after exhaust



tbss08
04-02-10, 09:41 PM
I've been tracking my mileage since I put the Corsa's on and have noticed I've gained about 2.3 MPG, even playing a little harder. Has anyone else noticed an increase in mileage after changing exhaust systems?

dvandentop
04-03-10, 01:57 AM
waiting to hear on the borla systems but that is good to hear about mileage increase!

Mike 09 V
04-03-10, 11:04 AM
You're probably driving it a little easier because it is making so much noise! LOL. Since the gas is already burned up before it gets to your new muffs it shouldn't make any difference unless there was so much back pressure from the stockers that the engine wasn't as efficient. Since I took mine off and looked at them I found that they are a straight through design, like a glasspack, from the factory. I don't see where they could have any back pressure. Maybe you did the pipes as well as the mufflers? That might make some difference. It is not too hard to believe that if the factory could have avoided the gas guzzler tax simply by changing the muffler design that they would have done so.

6speeder
04-03-10, 03:39 PM
I would guess the mileage change is due to going back to real gasoline Vs. winter E-10 gas.

tbss08
04-04-10, 08:27 AM
The exhaust has been on since late February. I've compared gas usage between this time last year and now. I used to use a half tank of gas a week going back and forth to work. If I took a trip into the big city of Evansville from out here, about a 15 mile trip, I could use 1/8th of a tank easy. Since the mufflers were put on I noticed the gauge moving slower. At first I thought it was just my imagination but I started monitoring the fuel economy. I have a heavy right foot when it comes to driving the car. I'll venture to say the normal 12 minute commute to work easily has a few minutes shaved off it each day. :cool2:
My average mileage before the mufflers was 12.9 - 13.1 MPG. Since the mufflers my average is now 15.2 MPG. Playing around a little I set the cruise at 65 and with the instant mileage in the DIC, I maintain around 20-22 MPG. Before with the cruise at this setting on the same road I would barely pull 17-18 MPG. I'm not sure if it is the mufflers or what but it is nice to have a few more MPG's.

Nine Ball
04-04-10, 09:48 AM
It could be possible. On 4th gen Camaros/Firebirds, I always saw a gain in mpg with the addition of longtube headers and a catback. Seemed to let the engine work more efficiently at cruising speeds.

neuronbob
04-04-10, 11:02 AM
I have tracked every tank of gas since I purchased my car. I have noted absolutely no, repeat, no significant change in my gas mileage since putting on the Corsas.

Here are my results for fillups around the time the exhaust was installed last May:

5/3 233.2 14.8
5/9 200.0 13.4
5-15 219.7 14.5--->Corsas installed during this tank of gas
5/24 290.5 11.9--->WOOOOT! having fun immediately after install
6/6 218.6 14.6----->back to normal driving
6/14 241.2 14.9
6/21 229.0 15.2
6/27 225.1 15.4
7/2 209.1 13.8

Gary Wells
04-04-10, 12:40 PM
I have tracked every tank of gas since I purchased my car. I have noted absolutely no, repeat, no significant change in my gas mileage since putting on the Corsas.
Here are my results for fillups around the time the exhaust was installed last May:
5/3 233.2 14.8
5/9 200.0 13.4
5-15 219.7 14.5--->Corsas installed during this tank of gas
5/24 290.5 11.9--->WOOOOT! having fun immediately after install
6/6 218.6 14.6----->back to normal driving
6/14 241.2 14.9
6/21 229.0 15.2
6/27 225.1 15.4
7/2 209.1 13.8
Ah, I don't know, Bob, I think that there is a positive difference there, not significant enough to detect without averaging out the #'s, but I would not totally discount it either.
If you average the 1st 2 tanks of gas: 14.8 & 13.4=28.2/2=14.1 average.
Discount the next 3 tanks due to changes, fun factor, & back to normal driving.
Using the next 4 tanks: 14.9, 15.2, 15.4, & 13.8= 59.3/4= 14.825, or 14.8 average, and if you were to discount the 13.8 as an isolated incident, that would give you 45.5/3=15.16, or rounded off to 15.2.
I think that the 14.9, 15.2, & 15.4 are close enough together to be considered statistically sound #.s, and maybe even the 13.8.
I think that you gained about 1 MPG average and time will tell.
HTH
I know that you know your car better than I do, but I think that you are overlooking the #'s for what they actually represent and the consequent change & improvement.

jimbo1320
04-04-10, 09:48 PM
Seems that way to me to. In any case it sounds cool a? Touring or sport?

neuronbob
04-07-10, 08:03 PM
OK, a little more data for you, Gary. :D Every other month I rotate at a hospital that is further from me, and I spend longer on the freeway.

4/5 14.2 --->More freeway driving for work, average for April 14.6 mpg
4/12 221.4 15.0
4/18 228.5 14.7 2.18
5/3 233.2 14.8 --->Less freeway driving for work, 14.1 mpg avg for 5/3 and 5/9
5/9 200.0 13.4
5-15 219.7 14.5 --->Corsas installed here.
5/24 290.5 11.9 --->Having fun with Corsas on
6/6 218.6 14.6 ---->all of June, more highway miles for work, comparable to April, 15.02 mpg avg in June
6/14 241.2 14.9
6/21 229.0 15.2
6/27 225.1 15.4
7/2 209.1 13.8 --->all of July, less freeway driving, comparable to May driving, 14.3 mpg av for July
7/11 218.4 13.9
7/18 206.2 13.9
7/24 236.4 15.0
7/31 203.2 14.7

So it looks like there is a small increase in gas mileage. During my months with more city driving, it is 0.2 mpg. During my months with more freeway driving, it is 0.4 mpg.

JFJr
04-07-10, 08:23 PM
I don't have the "cool sounds" since my car is bone stock, and no tunes wanted or needed, but I get close to 21 mpg at 2,100 rpm cruising on the highway. If I set my cruise control to 65 mph I would expect the mid 20's mpg. I also have been known to put my foot into it. Why else would one buy a high performance sports sedan? Couldn't speculate why your mileage was so poor before, but all of us should expect better mpg at around 25,000-30,000 miles based on my experience with the LS_ engines.