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I've debated posting this in the normal tech or performance section, I've decided to go with the performance section since it involves some of the performance aspects of these cars engines.
As you all know I drive a Solstice and not a Sky, but for this informative bit that matters not at all since this was a test of the engine and not the exterior of the car.
For a while the 20/28 MPG values were a highly debated value especially compared to some V6/V8 engines that get nearly comparable fuel economy values (on non-roadsters of course though). Why should these more powerful large displacement engines get better fuel economy values then this brand new tech smaller displacement i4 engine get? Well some of that can be chalked up to this being a Roadster (other cars using this engine do get much better fuel economy values) but it doesn't explain it all.
I decided to do a little experiment to test an idea I had. So ok the city/highway values are best case scenarios for someone driving economicaly. How many Mustang GT/GTO/Corvette owners do you know who can get the real rated values on their cars without driving like a grandma all the time (what's the point of owning a car like that then)? Reading a lot of info on various boards for the other cars once you get your foot on the go pedal with a car like that your fuel economy greatly dips down well into the mid to low 10's range. There's a price to pay for high displacement engines under full load of course.
What about our car, what happens when you drive it under load all the time? Well I decided to find out and drove everywhere at 4000 RPM or higher (very few times I was at 3500 for more then a minute due to gearing and traffic flow) which is where most of the cars power is really coming on. I was usually in the RPM range of 4000~5500 during this experiment. I was only under WOT during initial acceleration from stoplights or when passing on the highway. I jack-rabbited every start and drove like a crazyman everywhere I went during this timeframe. To work, to the store, on the highway, etc. I filled up with a new tank of 93 octane, reset the fuel eocnomy in the DIC and zoomed off from the gas station.
As some of you know I also auto-x my Solstice. I've reset my fuel economy DIC several times and recorded values from 6mpg to 9mpg depending on track design. This is usually WOT most of the time with high RPMs also. I was personally expecting to see values at or under 15 mpg for this experiment.
All said and done I drove 212.9 miles on 11.5 gallons of 93 octane fuel.
212.9 / 11.5 == 18.5 MPG
The DIC read 18.3 MPG and was amasingly close to my calculated values. I was very shocked that after driving that hard for that long I maintained a value only 1.5 MPG off the estimated city "economy" driving estimate.
Like a good engineer I decided to double check my values by doing this experiment again. Suffice to say I got 18.4 MPG the second time around.
Our engines might not have the best top end economy numbers for our car types, but I'm defintely glad to say I can get good fuel economy values while still driving like a mad man. :thumbs:
As you all know I drive a Solstice and not a Sky, but for this informative bit that matters not at all since this was a test of the engine and not the exterior of the car.
For a while the 20/28 MPG values were a highly debated value especially compared to some V6/V8 engines that get nearly comparable fuel economy values (on non-roadsters of course though). Why should these more powerful large displacement engines get better fuel economy values then this brand new tech smaller displacement i4 engine get? Well some of that can be chalked up to this being a Roadster (other cars using this engine do get much better fuel economy values) but it doesn't explain it all.
I decided to do a little experiment to test an idea I had. So ok the city/highway values are best case scenarios for someone driving economicaly. How many Mustang GT/GTO/Corvette owners do you know who can get the real rated values on their cars without driving like a grandma all the time (what's the point of owning a car like that then)? Reading a lot of info on various boards for the other cars once you get your foot on the go pedal with a car like that your fuel economy greatly dips down well into the mid to low 10's range. There's a price to pay for high displacement engines under full load of course.
What about our car, what happens when you drive it under load all the time? Well I decided to find out and drove everywhere at 4000 RPM or higher (very few times I was at 3500 for more then a minute due to gearing and traffic flow) which is where most of the cars power is really coming on. I was usually in the RPM range of 4000~5500 during this experiment. I was only under WOT during initial acceleration from stoplights or when passing on the highway. I jack-rabbited every start and drove like a crazyman everywhere I went during this timeframe. To work, to the store, on the highway, etc. I filled up with a new tank of 93 octane, reset the fuel eocnomy in the DIC and zoomed off from the gas station.
As some of you know I also auto-x my Solstice. I've reset my fuel economy DIC several times and recorded values from 6mpg to 9mpg depending on track design. This is usually WOT most of the time with high RPMs also. I was personally expecting to see values at or under 15 mpg for this experiment.
All said and done I drove 212.9 miles on 11.5 gallons of 93 octane fuel.
212.9 / 11.5 == 18.5 MPG
The DIC read 18.3 MPG and was amasingly close to my calculated values. I was very shocked that after driving that hard for that long I maintained a value only 1.5 MPG off the estimated city "economy" driving estimate.
Like a good engineer I decided to double check my values by doing this experiment again. Suffice to say I got 18.4 MPG the second time around.
Our engines might not have the best top end economy numbers for our car types, but I'm defintely glad to say I can get good fuel economy values while still driving like a mad man. :thumbs:
