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What is the best mileage you all have gotten on the highway? My car has issues and I want to see if I can get 40+ mpg on the highway by driving 55 and doing a bunch of maintenance and maybe minor modifications.
40 mpg highway
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78 Posts
i never checked
I was getting low 30s at one point. I think doing 55 would have made my mpg worse though.
I got about 42 highway peak back when my GS was 9.5:1 compression, with my turbo setup. It's a very efficient turbo setup though, lowered, has some skirts and a lip.
Does about 35mpg peak now at 8.7:1. Measured at ~120km/h.
Efficient tuning, small-medium turbo, aero mods, low rolling resistance tires, light wheels, and I see no reason 45+mpg can't happen
Does about 35mpg peak now at 8.7:1. Measured at ~120km/h.
Efficient tuning, small-medium turbo, aero mods, low rolling resistance tires, light wheels, and I see no reason 45+mpg can't happen
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17 Posts
If I just got a fastworks tune and specified I want it to focus on peak mpg what kinda gains would you expect?
I got about 32mpg highway on my GS with bolt ons and a 91 octane tune with Fastworks.
The only difference between an economy tune and a power tune would be that I stop making adjustments after a certain RPM. Power and fuel economy both come from making the engine run more efficiently. The volume of air is unchanged, but adjusting timing and fueling, more power can be made on that same volume of air. The big gains are on catless cars, as the requirements in tuning to keep cats hot involves extra fuel, and ignition retarding. That puts more heat into the exhaust, and so that heat is lost energy which could have instead gone to powering the engine.
The only difference between an economy tune and a power tune would be that I stop making adjustments after a certain RPM. Power and fuel economy both come from making the engine run more efficiently. The volume of air is unchanged, but adjusting timing and fueling, more power can be made on that same volume of air. The big gains are on catless cars, as the requirements in tuning to keep cats hot involves extra fuel, and ignition retarding. That puts more heat into the exhaust, and so that heat is lost energy which could have instead gone to powering the engine.
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so let’s assume I gut my cats and get a eco tune on e-15 what kinda mpg am I looking at
Poor. Very very poor. Gutted cats are awful and your O2 sensor data will be inconsistent. Probably worse than stock
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I’m
how well could I do with just a new exhaust manifold from eBay? 35+ or no? I’m really concerned about mileage and I wanna find the cheapest ways to improve it.
Depends on the manifold. A lot of the cheap OEM replacements have poor pipe fit-up inside, and block flow.
If you're looking like a DNA Motoring 4-1 header (catless), and have access to a welder to weld an O2 bung onto runner #1 for your bank 1 upstream sensor (they're designed wrong), that's your biggest NA gain from a header. Quality control is terrible on them however.
If you're looking like a DNA Motoring 4-1 header (catless), and have access to a welder to weld an O2 bung onto runner #1 for your bank 1 upstream sensor (they're designed wrong), that's your biggest NA gain from a header. Quality control is terrible on them however.
You only get 300 km per tank on a gs? That is roughly 187 miles on 18 gallons of fuel. That is like 10.4 mpg. On the highway I start to look for a gas station around 450 miles. In a mixed situation I go about 300 - 350 miles. Either you have some serious issues or you need to change your driving style.
That's likely clogged cats or hard driving
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263 Posts
I drive a little more aggressive but i get anywhere from 20-25mpg... City/Mountain daily driving. 2006 2.4
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