RaWarrior
Well-Known Member
You're not being a dick, I welcome an intelligent discussion....in 5 minutes I google-found around a dozen dyno charts on as many forums (for anything from civic tuners to jeeps to sportbikes) that say the same thing. The "regular vs premium", much like the "which oil is best" thread is hardly an exclusive to VMF.
For example on the Civic, it produced 128hp on regular and 122 on "premium". Same car, same temp, sequential pulls. Most of the ones I found put it anywhere between a 4-8% difference, and the biggest lost seemed to be in the middle on the rev range, with smaller losses up top.
Have I personally done this test? No. But others have and proven it again and again, not to mention it just makes sense that it would if you think about it.
The high octane burns slower at a "regular" compression than regular fuel would. The explosion is much slower, spreading out force on the piston over a longer period of time. Problem is, it takes too long. The exhaust valve opens before it's done, releasing the remaining energy.
Another result of that is that the motor doesn't burn as hot as it should. Again, a subtle change with no immediate or noticeable effects. But over the life of the engine, this will encourage additional carbon buildup. I have personally seen this in snowmobile motors. One of my friends was convinced that premium would make it faster and be "better" for the motor. After cleaning the exhaust valves for like the 5th time in 2 years, I convinced him to use regular instead. Now 2 years later, I pulled them and they're not half as bad as they were after a couple months on premium. Yes, this is much more of a problem in 2 strokes than 4, but the point stands.
In the real world such differences would be difficult if not impossible to detect.
But at the same time, why would you pay extra for less power?
Ethanol sucks, it shouldn't be in fuel, and it's a farce cooked up by special interest groups with absolutely no future. That said, it's not the disaster everyone makes it out to be. At 10%, it's just not that much of a difference.
1 gal of straight gas: 125k BTU of energy
1 gal of E10 blended: 120k BTU
Or around a 4% difference. Considering an internal combustion engine is only about 1/3 "efficient" (only ~30% of that energy is converted into motion, rest is wasted as heat), that's down to a bit more than 1%.
The stoich difference is bigger, but not much. Gas is 14.7:1 for an ideal burn. E10 is around 14.2:1, or around a 3.5% difference. I programmed an EFI control unit on the school's "clean snowmobile" for a variety of ethanol concentrations. In testing, no appreciable difference could be determined in real-world mileage between straight gas and e10, differences were so small as to be well within the margin of error. On E85, we noticed on average about a 25% loss in mileage, and on E100, it was around 30%.
For example on the Civic, it produced 128hp on regular and 122 on "premium". Same car, same temp, sequential pulls. Most of the ones I found put it anywhere between a 4-8% difference, and the biggest lost seemed to be in the middle on the rev range, with smaller losses up top.
Have I personally done this test? No. But others have and proven it again and again, not to mention it just makes sense that it would if you think about it.
The high octane burns slower at a "regular" compression than regular fuel would. The explosion is much slower, spreading out force on the piston over a longer period of time. Problem is, it takes too long. The exhaust valve opens before it's done, releasing the remaining energy.
Another result of that is that the motor doesn't burn as hot as it should. Again, a subtle change with no immediate or noticeable effects. But over the life of the engine, this will encourage additional carbon buildup. I have personally seen this in snowmobile motors. One of my friends was convinced that premium would make it faster and be "better" for the motor. After cleaning the exhaust valves for like the 5th time in 2 years, I convinced him to use regular instead. Now 2 years later, I pulled them and they're not half as bad as they were after a couple months on premium. Yes, this is much more of a problem in 2 strokes than 4, but the point stands.
In the real world such differences would be difficult if not impossible to detect.
But at the same time, why would you pay extra for less power?
Ethanol sucks, it shouldn't be in fuel, and it's a farce cooked up by special interest groups with absolutely no future. That said, it's not the disaster everyone makes it out to be. At 10%, it's just not that much of a difference.
1 gal of straight gas: 125k BTU of energy
1 gal of E10 blended: 120k BTU
Or around a 4% difference. Considering an internal combustion engine is only about 1/3 "efficient" (only ~30% of that energy is converted into motion, rest is wasted as heat), that's down to a bit more than 1%.
The stoich difference is bigger, but not much. Gas is 14.7:1 for an ideal burn. E10 is around 14.2:1, or around a 3.5% difference. I programmed an EFI control unit on the school's "clean snowmobile" for a variety of ethanol concentrations. In testing, no appreciable difference could be determined in real-world mileage between straight gas and e10, differences were so small as to be well within the margin of error. On E85, we noticed on average about a 25% loss in mileage, and on E100, it was around 30%.
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