Pretty sure this will be around the same as the 3.4 guys, but just wanna see. On the free way I was getting around 20, but then I discoverd I had a clogged cat, so I gotta check and see what I am getting now. Also, what grade gas are you guys using. Thanks Jason

 

i have a 03 Monte Carlo SS, and on the freeway, i'm getting somewhere between 25-29mpg. around town, i'm getting like 19-22mpg. the Monte Carlo has the 3800 V6 also, so i'm guessing you could see similar mpg. i've been running just regular unleaded too.

matt

 

93 octane, get about 20mpg city and the godliness of the highway I get about 35mpg

 

3800 series 2 engine is designed for 87 octane, and thats what u should use...

i get prolly 25 or so mpg w. mixed (75 city/25 highway) driving

 

87 Octane getting anywhere from 23-26 MPG on mixed driving.

 

y on earth would u put high grade gas then what you are told to put in there, in runs best on what they say to use, anything else is just a waste of money, and yea um on long drives going about 70 with no stops i get high 20s mpg, but around my town i usually get low 20s maybe even less

 

The manual for my 2000 camaro says to use premium for the 3.8. I used to use it for pizza delivery as well and I noticed a significant (2-4MPG) improvement when I moved from regular to premium.

 

2-4 seems a bit much, but whatever.

I've gotten everything from 17-31

 

Before the turbo, using 89 octane (CO only has 87,89, and 91 at most gas stations), i got up to 36mpg highway. Not sure what i was getting in the city. After the turbo install, i switched to premium, and now i get in the neighborhood of 34 somewhere.

 

I am the proud new owner of a 2002 Camaro with a 3.8 after trading in my 92 (miss you girl) anyway I am getting around 20-25 per gallon highway and city. I do a lot of city driving (Atlantic City NJ) but even on the country roads I get the same mpg. I usually run super 93 octane and only use chevron gas ( which includes techron in the pump) .

 

If I drive like a grandpa, I can get almost 30mpg out of my car, with about a 50 50 mix of Highway and City driving. Otherwise, I guess I see somewhere between 23 and 27mpg.

I use 87

 

I think I have been getting 20mpg highway or could be a bit worse and that's good compared to when my O2 sensor was doing bad and I was wasting more gas and it was the O2 sensor behind the cat that went bad. So do you guys think my cat is bad like his was and where should I get one? A decent one at least nothing insane since I ain't got much money.

 

If you live somewhere where there are no emissions tests like Florida I'd say get an o2 sim and gut or get rid of the cat, if you do I'd say get a Mangaflow/Carsound hi flow cat. My Magnaflow was $60 shipped. (EBAY)

 

I have emissions or that thing would of been gone when I got the car. What size diameter is it? I have a 99 3.8 How much you get it installed for also?

 

I had a friend weld it in for free , shouldn't cost much though.