Mods in sig: I get only 11mph highway. I've seen guys putting down 400+rwhp getting close to 20mph highway. I'm only at 375rwhp max. Any ideas?

 

11 mph on the hwy is SLOOOOOW! JK, I know what you meant.

11 mpg sounds pretty awful. I'm getting 12 city with my new 383, so I think something is wrong there. With your 3600 stall, is there a converter clutch? If so, does it lock during cruising? If your converter is open (spinning freely) when highway cruising, that can kill gas mileage and cook trans fluid.

Pressing the brake just enough to turn the brake lights on while cruising, with steady throttle position, should unlock the converter clutch and cause revs to increase slightly. When cruising with TC clutch locked, minor throttle input should not change revs.

 

Dayyumm!!! I just got over 300 miles on a tank with my LT1. Thats over 20MPG.

 

damnit! I totally f'ed up this thread. I meant to say 11MPG city, not hwy. I probably get 18 or 19mpg hwy. Anyway, does 11mpg city still seem low?

 

Wow, my 375rwhp Corvette with 4.10's gets 28 mpg's on the highway. May be the ZF6 with two overdrives.

It sounds like you are deperate need of a good tune.

 

My dyno #s are high for my mods, so is it a "bad tune" or possibly an "aggressive tune"???

 

WOT and part-throttle tuning are two different things. It sounds like you have a good WOT tune. But, your part-throttle tune may need tweaking. Your high stall converter is also not helping gas mileage.

 

11 isn't horrible, but I was a bit dissapointed to take like a 30% mpg hit.

 

I get 17ish in town. And thats getting on it to atleast 3 grand each light.

 

I only get 10ish in the city... but I am loading a new tune in to the car tomorrow, so we will see then.


Before when my car was just bolt-ons I never got anything less than 16mpg no matter how hard I beat on the car.

 

11mpg even in the city w/ a hotcam is awful. Tune needs to be checked.

 

Tc is definitely locking up at cruise speeds. I guess its something else with the tune. How much will it cost to have the tune checked? And should I get a speed shop to do it or just a regular shop?

 

So you get at worst 240 Miles per tank in the city?

 

You can't really use your milage to figure out his MPG, he might fill up at a different indication on the fuel gauge than you, he might only put in 10 gallons every time he fills up, and that would only be 170 miler per tank, but still 17mpg.

 

I agree, I guess I should have rephrased that as per full tank. I guess what I really want to see is how many miles he got and how many gallons were used. 20 MPG seems really really high for agressive city driving, 3.73 gears, A4 and a stall. I know i don't get anywhere close to that with 3.23 gears on the best of days (100% city). On the highway I do hit that fairly easily and the car is running very well with every sensor checking out properly. Perhaps its my engine, although I did put a new engine in at one point too