What are you automatic LT1 guys gettin as far as gas mileage goes? After my rebuild I am getting about 11 MPG and that was a week i did not get on it. Just seems like I should be gettin better than that with a 3:23 rear-end. The M6 is going in this summer. What are the LT1 with M6 getting as far as mileage? Thanks.

94' Z28, 350 LT1, forged pistons and rods, ported and polished heads with larger valves, comp 218/224 cam, 1.6:1 roller rockers, hooker headers and catback, custom tune from madZ28.com, B&M shift kit.

 

Fuel mileage depends on a whole bunch of things. From your siggy list, the power adders and the tune might be be part of the "problem". Also, short trips in a cold climate screws overall fuel mileage. My (A4) C5 has a fuel mileage computer which shows an instantaneous 3-6 mpg for the first mile or so driving out of my subdivision on a below freezing day. When I get to the 55-65 mph highway and plug in cruise instantaneous mpg slowly improves as the engine warms up. It may be 11-13 mpg with the coolant at 120* but by the time it gets to 140* and the converter locks up it's closer to 20 and when it get to 195*, it's more like 25 mpg, unless of course the road is wet or snowy where it drops significantly.

Check overall fuel mileage for a few fillups and 500 miles or more.

Unless you top off the tank the same each time you fill it, you really don't know how much fuel you used between fillups.

 

My LT1 is getting 3.73's in a few weeks, but other than that, all I have is a CAI. Nowhere near your mods, but FWIW, I get high teens to 20 in town (if I shave a little lead of my foot) and upper 20s on the interstate.

 

I would recommend getting new ACDELCO o2 sensors. They will help quite a bit most of the times.

 

what would you guys try to get my gas mileage up?

 

MY car is all tuned up with 2.73s and i get 11mpg as well averaged on my tank. I also have an a4. Recently i took it on the highway and was getting near 25 without even having cruise control on. My problem is short trips with long warm up time.

Any point in changing o2s if you dont get any errors and can get 25 on the highway? They aren't cheap so i don't want to di it if it wont help anything and will just wait until headers.

 

I have been getting a consistent 17mpg. Probably about 70% city-30% highway. Oh, and I have a M6.

 

17mpg in town and 25mpg on the freeway avg. 75mph

 

like Ion said, new O2 sensors from ACDELCO will make huge difference

 

mines a 95 Z, A4 136Kmiles all stock 3.23 rear stock.
19-20 in town, 27-28 highway. usually pretty consitent. sometimes i get about 18 in town depending on how much i hit that pedal

 

I get ~15mpg in town and 25mpg highway trips. 131k miles w/1.6rr, cc305, hooker long tubes and 2.73 gears. But I know I need a better tune for my car then what I currently have.

 

My gas mileage usually stays around 20-24 and my driving is usually about 80% highway and 20% city. But I need new 02 sensors so it probably could be better.

 

My highway mileage is good but I just want to boost my town mileage. Thanks guys and I'll talk to ya. Kill those MUSTANGS!!!

 

'95 Z28 M6 with 131k and averaging 19.5 with about %50 interstate and %50 city.

I think my car has a 160 thermostat, if I were to put in a stock thermo would that help mpg any? Also what is the stock one rated?

 

93 3:23 M6 here, i get about 14 MPG overall, 99% in town, 1 % highway....the thing that makes it that bad is that my car never warms up in time to get into closed loop