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Anyone using regular gasoline lower than 90 octane in their Endeavor versus using the premium grade which is recommended? Just wondering if they notice any difference in performance, particularly engine knocking?
 

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Welll,...you know,...I have only ever used 87 octane,...and a fill up last me almost a full 7 days and I guess the engine feels alright. I guess when the gas becomes better priced if ever I might try premium but until then my budget only leaves me with about $100 every two weeks for gas, lucky for me my wife and I both work for The Hartford and have the same schedule!!
 

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I have tried all ranges of octanes. I can't say that I noticed much difference. The wind affects me more than anything so I just buy the cheapest stuff from my local station. They have an 87 or 89 at the same price so I buy the 89 with 10% ethanal. When I tried the 91 or 93 they had I did get about a mile or two better milage if I remember but that didn't justify the higher price. I have no engine knock even when towing my popup camper (~2200# I am guessing) and that included towing about 70 mph for 4 hours straight.
 

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I have been using 87 octane due to the ridiculous gas prices. The only difference in gas mileage for me switching to regular was about two miles to the gallon. The problem I did notice is the rotten egg smell in my cabin when I use the "cheap" gas. I usually get the smell when i hit 60mph. When I was using "Super" I did not have that problem.
 

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I only use premium. I tried mid-grade and noticed a loss of performance and milage. Being a mile high, we're supposed to be able to get away with a lower octane, yet I notice a difference, so I continue to stick with premium.
 

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Originally posted by mittech@Jul 11 2005, 07:56 PM
It can also damage your fuel injectors!!!!
[snapback]21955[/snapback]​

I guess High Fuel prices are forcing me to ruin my injectors,.... I guess we are spending the money either way we go,.....

Oh,...never had the egg smell........thats some funny stuff though!! hHAHAHAHHAA
 

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I don't know how Mittech thinks low octane fuel will ruin injectors.... Read the manual. It says you can use low octane but expect less power. The computer and knock sensors will adjust to it. Curse the gas companies and the government for not enforcing better mileage cars.
I rented a diesel BMW in England last month and got 55 miles per gallon. Full size car with four people in it all week. It can be done but politics have us screwed.
 

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I've been looking at the fuel qaulity for quite a awhile now, through this forum and goverment research papers. The problem is not just with the low octane but with other impurities in the fuel like sulfur (rotton egg smell). In NZ we have a base higher octane 91 but I cannot even run my 3.5 litre Pajero on that because of the high sulfur so I have to use the premium petrol at 96. If you use the lower octane high sulfur stuff it will leave alot of carbon build-up and eventully plug the injectors. Good idea to run some cleaner through it and run the engine a bit harder to blow it clean. Using Etanol blends may help as well but be carefull of any rubber components. I wouldn't use it in the winter either as you may have starting problems and any water in your tank will get absorbed by the alcohol.

It might be an idea to survey what station fuel you run and if know what refinery it comes from as this will make a differnce to. You might find that you can run the lower octane (pee water) if the impurities are lower.

Jim
NZ
 

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I don't know how Mittech thinks
If you worked on cars daily you would know using lower octane can clog injectors and/or ruin fuel pumps. It can also cause rough idle, stumbling, hesitation, stalling, pinging, and not to mention turn your check engine on with misfire codes. I understand gas is expensive now but use a calculator to figure out how much you save by using low octane versus premium on a fill-up it's less than $5. And if that is still too much as least buy an octane booster to dump in the tank .
 

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Being in the industry too I would have to agree totaly with mittech on this subject in the long run I think you will find that using a low octane fuel is a false economy! :thumbsup:
 

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Mittech & comscan what are you saying is low octane? And are you saying with or without ethanal? 87 octane is the normal low here and then 10% ethanal has 89 and then the premium running from 91-93 typically.
 

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I used to run 87 as well but have now changed...lets look at the science behind this. The compression ratio of the endeavor is 10:1. Typical cars are 8:1. A higher compression ratio calls for higher octane gas. Reason behind this is because when it say 87 octane, it basically saying that the gas is 87% octane, and 13% heptane. Heptane has a lower compression ratio, meaning it will spontaneously combust (without a spark) at lower compression.

87 octane gas is good for compression ratio's of 8:1. 91+ octane is good for engines with compression ratio's above 8:1. If you operate the Endeavor with 87 octane, you basically are subjecting the Piston, connecting rod, rod bearing (etc)in the engine to premature combustion due to the heptane content of the fuel. So as the cyclinder is in its compression cycle, the heptane will spontaneously combust which prematurely applies force in the opposite direction on the piston which can eventually cause damage to the engine.

Gas mileage doesn't really mean crap. It is about the combustion characteristics of the engine, and the compression ratio should dictate octane. Running lower octane in the Endeavor will lead to lower horsepower, lower performance, and could eventually damage the engine. Running intermittant 87 (if 91-93) is not available should be okay.
 

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I've been using 87 octane since I purchased the Endaevor. I have 2WD, not AWD. One of Mitsubishi's mechanics told me the 2WD can get away with 87 octane, but the AWD needs the higher octane.

But yeah, I've always 87 and never had a problem.
 

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I have been driving my XLS now for 2 years. Never filled it up with hi-octane. No problem so far, nor any pinging or low-octane related problem on the engine. I understand that the fuel sensor will adjust to the octane rating. The engine is equipped too with an oxygen sensor on the exhaust manifold for any unburned gas. I don't think that the injector will plugged up due to regular (87) octane gas.
Perhaps when u do a lot of towing that u need a higher octane. burt for day-to -day driving I think 87 is just fine. Hi- octane is recommended to achieve the optimum performance of the engine. but at city/-hiway driving the engine is literally running at half of its maximum hp or even less.
Did u know that some vehicles now like hemi, oddessey can run on 4 cyliner????
 
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