My 2 Cents

[RIZNOSS]

Since the weather has got very warm up in MI, I have been seeing insane gas mileage. I drove from Cincinnati to Ann Arbor yesterday, ave speed 67.5 mph, 4 hour trip all highway with approximately 7.5 gallons of Mid grade and 4.5 premium.

49.5mpg! Just last weekend I got 47.1 mpg with an average speed of 72.1 on a full trip from Ann Arbor to Milwaukee.

I use a mix of Shell gasoline for the non stop long trips of 75/25 mid/premium since I don't really get on it, and I have the Trifecta tune. I run the low boost tune for these trips.

I'm a happy camper, and I was still getting 41mpg 2 months and 10000 miles ago. I'm at 18,300 and I've had the car since 12-29-11. Trifecta tune, drop in KN filter. And this thing romps pretty good with premium and the boost jacked up. I have to admit, I'm a powertrain engineer and I have been working on downsizing and turbocharging applications for the last 3 years and I think the Sonic is a very solidly engineered package compared to any other carmaker.

Remember, tire pressures are key!!!!! And don't coast in neutral (manual), take your foot off the gas and let your momentum turn the engine, downshifting to make sure you are keeping the r's above ~1100-1200. This way the fuel system is in full shut off.

 

[dvn]

Since the weather has got very warm up in MI, I have been seeing insane gas mileage. I drove from Cincinnati to Ann Arbor yesterday, ave speed 67.5 mph, 4 hour trip all highway with approximately 7.5 gallons of Mid grade and 4.5 premium.

49.5mpg! Just last weekend I got 47.1 mpg with an average speed of 72.1 on a full trip from Ann Arbor to Milwaukee.

I use a mix of Shell gasoline for the non stop long trips of 75/25 mid/premium since I don't really get on it, and I have the Trifecta tune. I run the low boost tune for these trips.

I'm a happy camper, and I was still getting 41mpg 2 months and 10000 miles ago. I'm at 18,300 and I've had the car since 12-29-11. Trifecta tune, drop in KN filter. And this thing romps pretty good with premium and the boost jacked up. I have to admit, I'm a powertrain engineer and I have been working on downsizing and turbocharging applications for the last 3 years and I think the Sonic is a very solidly engineered package compared to any other carmaker.

Remember, tire pressures are key!!!!! And don't coast in neutral (manual), take your foot off the gas and let your momentum turn the engine, downshifting to make sure you are keeping the r's above ~1100-1200. This way the fuel system is in full shut off.

What tire pressure are you running? I know the 17's on my LTZ ride like crap at anything over 36 psi. Also, is the "low boost" on the tune still higher than stock boost?

 

[laborsmith]

Low boost is 14, stock is 16 and tune is 20-22.

Laborsmith

 

[RIZNOSS]

Rollin Deep

I had some weight in the car so I icked up the tire pressures to around 36-37psi for that trip.

The low boost version seems to really do well on the highway, but thanks for the info LB. You have any more info on the price of your coils or updated pics since the car has setled please pm me, i'm really interested.

 

[TIEfighter]

Nice MPG with that tune and tire pressure.

 

[wingman]

Very impressive and I totally agree with keeping it in gear while decelerating.

 

[mister2d]

Remember, tire pressures are key!!!!! And don't coast in neutral (manual), take your foot off the gas and let your momentum turn the engine, downshifting to make sure you are keeping the r's above ~1100-1200. This way the fuel system is in full shut off.

Why not let it coast in neutral? The engine turns at lower RPMs this way as opposed to being in gear.

Although, I've noticed that the Sonic isn't all that aerodynamic. If I let it coast in neutral I lose speed.

 

[Eric Smit]

Why not let it coast in neutral? The engine turns at lower RPMs this way as opposed to being in gear.

Although, I've noticed that the Sonic isn't all that aerodynamic. If I let it coast in neutral I lose speed.

The idea being if you coast in neutral you're using fuel to keep the engine spinning; if you coast in gear, the momentum of the vehicle transferred through the transmission to the engine will keep it spinning.


-Eric Smit

 

[mister2d]

Thanks. That makes sense now.

 

[mister2d]

The idea being if you coast in neutral you're using fuel to keep the engine spinning; if you coast in gear, the momentum of the vehicle transferred through the transmission to the engine will keep it spinning.


-Eric Smit

So I got my Ultra Gauge yesterday and did some tests.

Letting off the gas and coasting in neutral revealed a significant MPG spike. Coasting just above 1200 RPMs showed higher numbers, but not as significant as coasting in neutral.

How do you guys come to your conclusions about the fuel pump shutoff?

 

[RichieRocket]

mister2d, yeah I agree, I have been trying to get the fuel cut, but don't see it on the UG. I have tried throttle off coasting in gear at various rpms for 5-10 seconds, but I couldn't get the gallons per hour to 0.0

Someone said the cut-off was only between 1000-1500 rpms, so I've been trying that, but no cut...

 

[SooperSonic]

My SG II indicates fuel shut off between 1200 and 1900 RPM, but only when the engine is relatively warm

 

[mister2d]

My SG II indicates fuel shut off between 1200 and 1900 RPM, but only when the engine is relatively warm

How does it indicate this? Does it have something like Fuel Pump: Off?