gas mileage

Quoting mitsuturbo:
On a long freeway trip, i managed to get over 450 miles out of 14.5 gallons of 91 octane. Of course, this is because i tuned for economy and stayed completely out of boost.

SLC UT to Baker City OR on one tank of fuel.



Wow 450 miles out of a 14.5 gallons you know that breaks down to about 31mpg even with the best driving or cruising ability I cant see this happening the car is not even rated anywhere near 31mpg unless your car is running extremly lean I cant see this happening /ubbthreads/images/graemlins/dunno.gif /ubbthreads/images/graemlins/dunno.gif

 

[Lonewolf64]

I can see it happening. I got 28mpg going an average of 78mph in a fully loaded vr4 on my 700 mile trip from school back home.

 

[dmj]

Mileage depends a lot on the tune. I have gotten better mileage going to larger 650 cc injectors with Evo 8 mas and Keydiver chip from 22/23 per gallon stock to 27 mpg with mods.

 

I understand that the car comes from the factory tuned pig rich but its still rated at 19/25 city highway bone stock and thats when its brand new do you know how hard it is to pick up a combined 6/7 mpg more on a car a turbocharged one at that. As I stated before unless this thing was bone stock and in perfect running order and lean as hell I just cant see getting 450 miles out of 14.5 gallons just my two cents.If he did then damn I want that tune in that car most guys here dont even get 20mpg and thats not even beating on the car 31mpg no way was the turbo still there?

 

[Struc]

Typically, a turbo will actually help gas mileage if you stay out of the boost. Makes the engine more effecient, since the turbo spins and helps airflow even at highway loads. I picked up 4mpg with my Spyder when I put the turbo on it.

 

[SouthCaliVR4]

Trip on sat mostly freeway I netted 27mpg. I think a larger turbo helps, I know I picked up mpg's when I swapped to the 16g & larger exhaust. My average cruising speed was 75-80. And I am not dangerously lean. I do have higher than stock compression as well, which definitely helps.

 

[fuel]

Quoting Struc:
Typically, a turbo will actually help gas mileage if you stay out of the boost. Makes the engine more effecient, since the turbo spins and helps airflow even at highway loads. I picked up 4mpg with my Spyder when I put the turbo on it.



I would say on a factory turbo engine that would be negated by the significantly lower compression ratio, which makes the engine less efficient when off boost. If you didn't alter the comp ratio on your Spyder I would say that's why you had an improvement in fuel economy when off boost. However if the turbo is still spinning at lower rpms the ECU will still sense an increased flow of fuel and inject in more fuel as a result.