I saw in the BR 1680WHP thread that one of the cars was getting 30mpg. Do the larger turbos do better with fuel mileage because they are more efficient? They run higher boost due to size but why the better mpg at the high WHP levels. 500+whp and 30mpg?!?

 

If the turbo is nowhere near spooling up at highway speeds in 5th gear, I think that's where some of that gas mileage is coming from.

 

yeap i agree with what you are saying....it takes the bigger turbos longer to spool so normal drying you wont come into boost as much as with the smaller turbos.

 

but wouldn't you say that 30 mpg came when the turbo was no where near working.

iow you'd get that same "30" if you left your foot off the throttle, even with a teeny tiny turbo.

 

I know what you mean, I've noticed a drastic change in fuel economy on mine as a result of how fast I go on the highway.... I also noticed that if I watch the vacuum gauge I can see it get closer to "0" the gauge as the cruise rpm's go up (say 85 mph)... I'm not 100% positive on this but I think that might be a result of the turbo starting to come to life

 

stock evo at a 70mph highway cruising speed will get 22 to 24mpg typically. The 500 whp cars are doing 30, neither would be on boost at this point, I am still not seeing where the 20%+ increase in mpg comes from. Is it because of overall increase in engine efficiency with the engine mods?

 

With a standalone you can make the car do anything you want. On the stock ecu there are ways but its not common. So the car is going to do what it wants while cruising pretty much.

Cheers!

 

I didn't read the original thread, but there is no way the 2 liter in lancer body is getting 30 mpg unless its drafting a semi at 45 mph.

 

ask VWJEFF about that

 

the larger exhaust housing of the large turbos is less of a restriction which contributes to increased MPG. also never going into boost helps.

Ive hit 27MPG on the stock turbo on a long highway trip.

also, when driving, the less vacuum you pull the more gas you are using

 

That's what I was noticing on mine...

 

yeah, and they said they got 270 to a tank. You do the math.

Running pretty lean on my car I can average about 28 if I'm running 80-90mph. Thats roughly 270-280 before the light comes on. It tends to come on after using ~10 gal of fuel in my car.