December 16, 2006^Yep.
Thats the main reason why I was running it. It has higher octane and was cheaper so I figured why not.
|Chevy Truck World - Chevy Trucks and GMC Trucks, Chevy Truck Photos, Chevy Truck Forums, GMC Truck Photos, GMC Truck Forums||Congratulations Texas Chapter!||
|1 |||2 |||3 |||4 |||5|
December 16, 2006^Yep.
December 17, 2006Yeah but Octane is just a measurement of a fuel's resistance to detonation. It is not a measurement of the engergy or BTUs available in the fuel and adding Ethanol to Gasoline lowers the BTU output of the fuel and engine power and efficiency will go down unless the engine is optimized to the fuel. A gallon of 91 Octane pure Gasoline has about 126,000 BTUs and Ethanol at about 129 Octane, only has about 85,000 BTUs; so as a fuel, Gasoline is more efficent and will make more power and economy. Now since Ethanol has such a high Octane rating, you can tune and build your engine accordingly with increased compression and different timing and get back most if not all of the losses inherent with the Ethanol fuel. Since our engines are not optimized to run on Ethanol, we see these losses, but a purpose built race car engine can run just as well or better on Ethanol. GM has acknowledged the power and MPG losses when running Ethanol but has said over time that these problems will be overcome and as they go along the trucks will perform better and get the same MPG as the straight gasoline trucks. If they can get the new Active Engine Management system to increase the compression ratio during reduced load situations, the MPG will go up. We don't have much if any Ethanol down here now, but hear it is coming. We used to have E10 years ago but haven't seen any Ethanol at all lately.
December 17, 2006I've been buying gas in Mass on occasion lately and I see on their pumps that it has Ethanol.
December 17, 2006ever heard the saying "you get what you pay for?"
December 17, 2006ditto on what 92 WT said. if a car is optimized to run E85 then it'll run great, get good mileage, and be pretty darn fast. the problem is chevy wanted to make it so it could run both E85 and regular gas, which basically means the rubber seals and lines won't corrode and it can run a little more timing, but there is no performance gain or gas mileage gain; its just a "green" fuel and they wanted to show the world they want to make the world a better place. its possble to convert our older trucks to run e85 and get good performance out of it, new fuel lines, fuel pump, injector seals, and programming, then we could run high compression pistons, more timing and more lope... but with how scarce E85 gas stations are (right now) it won't be happening for a while.
December 17, 2006i thought even with the ethanol/gas mix you couldn't raise compression because you'd detonate the gas? least that's what i got out of the pop mechanics article.
December 18, 2006One other thing that they don't tell you about ethanol is that it binds with water very easily. The more humid it is or the longer it is left out in the open the more water it absorbs hence the worse it makes your engine run. Houston has converted to E10 and depending on how old the gas is can make a pretty significant change in the way my engine ran and MPG. That is going to be another factor in the price is how difficult it is to transport and keep "fresh".
December 18, 2006our local Wawa (like a Sheetz or other mini mart/gas station) had a little trivia contest about that. whether it works or not i don't know, but apparently there's an alarm that goes off and there isn't supposed to be any water allowed. it's a pretty popular stop, so i doubt the gas gets stale though.
December 18, 2006with ethonal you can run higher compression because it is less volital (129 octane) higher octane does not mean the gas contains more potential power, it means it is less likely to explode just because there is a lot of compression. (hence why running 93 octane in a 87 octane car won't gain any performance)
December 18, 200692 WT summed it up very nicely. Octane doesnt mean squat when youre talking power, it only pertains to resistence to auto-ignition. Like stated before, you can change the timing dramatically with a higher octane alcohol (ethanol), but it still doesnt have the power or the BTUs. Alcohol also runs cooler which is another reason it is often used in race applications.
December 18, 2006One other thing no one has touched on yet.
December 18, 2006Actually alot of the reason that higher octane is useless in most car's is because the timing won't compensate to enough degree to show the power and mileage difference's.
|1 |||2 |||3 |||4 |||5|