PatsSoxfan

OK, I will state up front that I can afford it, but it is much more of a "principal of the thing" type of deal. I want to know your opinions on the type of fuel one can use on the new LS. At least here in the Midwest 10% ethanol (89 octane) is quite prevalent. For my LS430, I tried premium (at least 91 octane) for a while when I bought the car 4 years ago. However, I decided to then try 10% ethanol. I did not detect any significant difference in gas mileage between the two. Also, the engine ran just fine for 4 years. Ethanol also is better for the environment. I asked the dealer if I can use ethanol on the new LS. They said that I probably could but I would notice a drop in performance and that the gas mileage would not be as good as with premium. That is also what they told me when I purchased the LS430, but I think they were dead wrong. Obviously, this is a different, more powerful engine on the new LS, but what do you people think? Has anyone been trying 10% ethanol on the 2007/2008 LS? BTW, the difference in cost between ethanol and premium here is about 22 cents per gallon. Again, it is not a matter of affordability (although the price differential is nice psychologically). I am going to at least try it out unless you folks tell me under no circumstances should I do such a thing.

19psi

it's not really the concentration of ethanol that you need to think about. the LS is a high compression engine which requires premium for maximum performance. without the benefit of a high octane fuel, the engine will pre ignite, which will be picked up by the knock sensors and then the ecu will retard timing to prevent future preignition. as long as the same low octane fuel is used continually, the timing will remain retarded, which means less acceleration and possibly less mpg. over time you'll never notice the loss of performance as the car will always run that way. you would notice if you filled up with premium for a few tanks. the ecu will then give back the timing it pulled after it sees no knock overa period of time.
that being said, if you're not the type of person who floors your car regularly and doesn't need much acceleration, you can use the lower octane fuel. just don't expect to have the promised power available should you need to floor the car to get out of harms way.

PatsSoxfan

Thank you 19psi. Will the use of 10% ethanol harm the engine at all? I obviously would never want to do anything like that. If it does not harm the engine then I would at least want to give ethanol a try just to make a comparison for myself.

19psi

The 10% concentration is fine. ethanol is actually very high octane but it's corrosive in large concentrations.

19psi

here's more info on ethanol. it's a topic of debate in the high performance community due to it's high octane rating.
of course the high octane comes from the E85 mixture, which is different from what you're talking about. however, these links will give you more info than you thought you needed!
http://www.dsmtuners.com/forums/redi...Fnewsid%3D6980

http://www.dsmtuners.com/forums/tuni...59040-e85.html

http://www.dsmtuners.com/forums/newb...asoline-s.html

vollandt

[QUOTE=PatsSoxfan;3134902] Ethanol also is better for the environment. QUOTE]

I am not onboard with this statement. This article outlines some good arguments for and against ethanol.
http://auto.howstuffworks.com/ethanol-facts.htm

PatsSoxfan

Thanks again 19psi. That is a lot of good information and some misinformation as well. It appears that I can go ahead and at least try it out.

vollandt, I guess there are two sides to every story, but it appears from reading your linked article that ethanol use leans toward the side of helping rather than hurting the environment. Obviously, there is some controversy here, but there is no arguing the fact that it burns cleaner than gasoline.