whitelx1

We just bought a 08 SS with 90,000 miles. The only thing done to it is a K&N and Flowmasters. We are located in Chicago and my wife does a lot of stop and go driving. The question is what is the actual mileage you guys are seeing with stop and go driving, driving normal. And what is the actual mileage on the highway. This car seems like it is getting terrible gas mileage and she is driving normal..Also is there anyway that you can take the car out of the 4 CYL mode. Also is there anything else I can do to it to get better MPG. Thanks in Advance.

Cory1750

I just did a 650 mile drive in my car and got 23.5 mpg without 4 cylinder mode, which doesn't help you with mpg anyway. My car isn't the best example though. In city stop and go you can expect it to be a decent amount under 20. When I go cruise I get 14-15 mpg, even back when I was stock. It's a V8 dude, it's not gonna get good mpg.

To get rid of 4 cylinder mode is going to cost around 550 bucks because it needs a custom tune to do so.

lVloses

iTrader: (1)

I did a 500 mile round trip a few months back and netted 23mpg on the way there, 24mpg on the way back going 75mph. No DoD and with my list of mods. Just the other day I went on a smaller trip going 80mph I got 20 even. When I had DoD I used to get 26-28mpg at 75mph.

In town I used to get 16.5 when I was mainly stock. That was with stop and go traffic.

91parkave

iTrader: (4)

I was avg 82mph seeing 25-27mpg on a 2 hour rd trip no dod. And I'm running on a maf only open loop tune.

whitelx1

Thanks guys. The car runs great, buy do you think it might need a tuneup or something like that. From what I understand it has not had one done yet. As far as goin in 4 CYL mode, I was told from someone that that makes it worse. Any input on that would be helpful . And as far as a tune, I am not worried about the performnce end of it but by getting one done would it help with the MPG. Thanks

smoooth

Mileage with a tune will typically increase a little. Most tuners won't guarantee it though because they have no control over the right foot. If you want to keep it out of 4 cy mode, you can get it tuned out or just put the car in 3rd.

I have a Diablo canned tune in mine MCSS and my year long average is 19.4 with about half city, half highway. The tune is for 91 and I've been running 89. This month I started running 91 just to see if it made a differance and have been seeing 23. From what the tuner told me if you run lower octane than the tune it retarts the timing a ton so it definitely pays for me to run the more expensive fuel.

whitelx1

The reason I am questioning the gas mileage so much is because I have a 02 Tahoe with a 5.3 and it seems to get better gas mileage than the wife's SS.

BuffaloSS

iTrader: (3)

I had an '06 SS, purchased new in '05, and rarely got better than 14mpg in the city...and unfortunately, most of my driving was in the city. My wife and I admittedly drove her hard, though.

Cory1750

It's a very different 5.3.

Dom87SS

iTrader: (3)

After my non DOD tune I get worse mileage around town and highway. I average 19-20.5 for daily driving of Chicago suburbs and some highway.

Kazmaniac

167k, average 20.2 My car seems to lose most of it's mileage driving less than 5 miles a day in city traffic.

4EVER3

I got just over 28mpg driving 73mph. I did a Hogan DP with cat plus used chevron injector cleaner for a few tanks now. I drove 250 miles total and it was a windless day.

smokin06impala ss

iTrader: (2)

With DOD disabled and the mods on my sig , I get 22 hwy and 16 city .

LS1 Racing

iTrader: (15)

10-15 MPG is very common in town and the only way to help that is to (a) Get DoD disabled, which will cost you 2 MPG on the highway, or (b) get a tighter torque converter.

As for highway driving, after getting a catless DP and having Lew remove the cat over-temp routine from my tune, I got an honest 31 MPG over 330 miles from LA to Vegas. And this wasn't the number on the DIC, but was actually calculated from fill-up to fill-up.

The gist is, these cars can and will get great highway MPG, but they suck *** in the city.