Do you have an SS? If so, I don't know how you could possibly be getting 30 mpg in the city. I can only get that high when I'm on the open road on long trips. I can get as high as 32 MPG, but any trip averaging over 65 MPH decreases the SS to about 28 MPG.

 

i posted here and asked trifecta if they had tune for mpg , or if it was only for performance. i also asked if not mpg tune , would the performance tune help with mpg. i am pretty sure i got no reply.

 

Mine is an SS, cruisin' around town my car does 7-8 liters per 100kms (29mpg +). We have very hilly roads out here, so i'm only getting 30 on the highway.

 

It seems that each mod I have made for performance, has also helped mpg at steady 65 mph a bit. Despite others being able to get claimed 34 mpg with their SS at 65, the best I could get (stock) on a perfectly level coastal freeway at steady 65 mph was 29.5 mpg and that was an average of 2 weeks of 80 miles (roundtrip)commute, resetting the DIC as soon as I reached 65. and just before exiting. Now that I have installed Hahn/PPC tune, K&N filter, Hahn CAT downpipe, Hahn CATback, and insulated the airbox, I get just under 33 MPG at 65. Lifetime average after 25,000 miles is 26.2 MPG and avg speed (never reset) of 49 mph.

 

I found 30-33 at 65 mph flat road....but at 80..it actually goes up!! 35-38...past 80 it drops again....75 being a good overall speed for consistency.( with stg kit ) Have lots of flat road here in the slower lower,,,

 

The past few tanks (50 liters) i've gotten 600-630 kilometers. Thats mixed city and highway.

 

I have the gm tune and just returned from a round trip drive from Chicago to Indianapolis and averaged 31.7mpg and 74mph. I am very happy with these numbers, but I cannot compare it to any pre-tune trips since I did not take any.

SPPD

 

Try slowing down. Oh wait... That's not possible!

Trade it for an LS or LT then.

 

My sweet spot is 60 MPH (32-34 MPG). At 65 MPH and up, the MPG goes down significantly (27-28 MPG).

 

With 3,500 miles on the clock, the long-term average shows 26.5 mpg.

I have a feeling this will improve when the engine loosens up a bit.

Of course, I went 108 mph the other day. That CAN'T help mpg's.

(And at 108, the engine wasn't even breathing hard.)