I wish we had chevron here. I live in Indy, and the closest chevron is a few hours away...

 

running high octane on 87 recomended car will not do anything but make your wallet thinner. It will not ignite earlier...octane just measures knock resistance. Hence running high octane in high compression or high boost or performance engines.

Notice the manual says 87 "Minimum" nothing wrong with running higher octane. Higher octane usually has detergents which help clean your engine, but unless your engine is knocking and causing the timing to retard and lose power. youre really not putting your money to good use other than maybe cleaning the engine a bit but I think good quality gas has detergents on all octanes...not positive on that though

The ECU is tuned to run on 87 but you will see people advancing their timing for more power requiring the use of higher octane. Just running higher octane will not make power. its set at 87 with conservative timing...good for our wallet. I dont think we gotta worry about knock and higher octane unless we start tuning or have racked up huge mileage and have crazy deposits on our pistons lol

 

I have noticed the same thing this little power less car is now getting some life. I am at 4800km I have changed the oil to Mobil One . The car is a lot more peppier. I use 91 Octane.

 

I have been keeping good track of my mileage - I am averaging about 8.7L/100km - that's about 27 mpg for you south of the 49th...I have a manual though, and tend to coast up to red lights in neutral whenever i can.

PS - Like everyone else has been saying, stick with the recommended octane. Higher octane does NOT mean more power, it means more energy is required for combustion. That is why cars with larger compression ratios need higher octane fuel, or else their timing could be off. But on that same note, better quality gas = better mileage, which could explain the Techron difference 08lancer was describing.

 

city sucks for me ... but highway is awesome. about 20 for city / 30 + for highway

 

23 city, 30 highway going steady 80 mph

 

23-24 city
30-31 highway
Manual

 

Only got 400 miles on car but, city 23-24, highway with A/C on about 30 no A/C 34-35mpg at 75mph

 

i recommend you drive it on the highway for a couple of km at a steady rpm it should help...your fuel consuption break-in. that is if you are in the break in stage intially i was getting 12.0-13.0 l / 100 km....on the second tank now im gettin like 9.6 to 10.1 after i drove on the highway about 40 km and even after driving in city as usual... whereas before it was 12 to 13.. it wa a dramatic change.. one of my friends recommend driving at steady rpm and not too high revs he worked for race company he was there mechanic... so drive in the highway oh yeah keep it in auto if you have auto... i kept my rpms at 2 ish.. for a long time helped alot n now i can go up to 3,000 rpm n it doesnt change much at varying speeds

 

27 city dont know hwy ... dont drive it enough

 

there is an issue with trying to compare mileage with brand new car .. it's not totally 'broken in' .. and they are learning cars now.. so allll of our mileage will vary some as the car learns to the specific person

on teh whole octane thing... okay I have to stop some 'myths' here.. the typical thing heard that higher octane will effect your engine running/mileage etc diversly is wrong.. this stems from the days of leaded/unleaded cross over.. and people running HUGE octane racing fuels

todays cars on 87-94 oct if your car will run optimally on 87 oct, you will notice bascially no difference except thinner wallet on 94 .. although in the long run your combustion chamber and cat converter will be cleaner.

now if a 10:1 comp engine is running optimally on 87.. it's running some slack *** timing.. or very impressive head design

personally I run 90 oct from mohawk.. my F100 seems to like it alot (but I run ALOT of timing) and I'll run the same in the GTS (same price as 87 ) but I'm also picking up a peramiter monitering dealy to see all the fuel trims. timing, knock, o2 etc etc etc so I can make some tuning choices and such from that.

 

I've got a confession to make - I was preaching earlier about how you should use the recommended fuel - Well Mitsu says 87 octane minimum. I was averaging about 8.7 L/100km (27mpg) with 87 octane. I tried a tank of 89 octane and the fuel economy improved to 8.3 L / 100 km (28.5 mpg). I measure based on my odometer change and the amount of fuel I refill with, not using the onboard computer. I am trying out 91 octane (V-power from Shell). Will post if I see any improvement.

Also, the car seemed to run a bit better on 89 octane. Probably becuase of the 10:1 compression ratio.

All my gas comes from Shell. This is from about 80% city driving too.

 

are you guys using your computers to tell you the average?

my computer keeps on resetting.

Also I am getting about 7 being nice and 9.5 going mixed

 

I average about 8.5 to 9.2. The trick is with the CVT transmission is to acheive your cruising as early as possible. Now just short of gunning the peddle to the ground, its important to get to your cruising speed early and coast the rest of the way. even in the city under moderate distances between lights. now stop and go traffic well, you have not choice but to do the slow accel.

But i find the gradual / slow accell route just doesnt work with the CVT very well. you burn to much fuel in the accel stages that your economy goes out the window. even on the highway i find.

it goes against common logic with regular cars but its true. try it

 

not to knock anyone directly when it comes to octane claims but the fuel numbers you got would most likly be from your driving vs. an actual gain in fuel economy based on combustion. Unless you have an advanced engine with dynamic timings and higher compression ratio the fuel would burn no different. and the car, if it has the capability to sense octane changes thru timing advance and retarding would take a while to learn based on the new octane level.
2nd or 3rd tank your looking at.

Octane mixes so if you add 89 to 87 to the same level equally then you get a 50 50 blending producing 88 octane fuel.

On the flip side, it is recommend you use higher octane if you can afford it due to its lower sulfer content, it will burn cleaner in your engine. but that benefit doesnt equal the price tag.

Al Bundy if you wish to test your octane consumption levels. you should fill your tank first with 87 and ensure that its only 87 from the same company and do a road trip on the highway somewhere. somewhere where you know you will get a consistant reading. Fuel your tank up to full, drive to your desired destination and then refuel right away, write down how many liters / Galons it took to refill the tank. do it over again going home, refuel and record. then for about 2 weeks use 89 octane and do the same thing.

I am pretty certain with 2 pooling results for each fuel you will find almost no difference.

Fuel economy in my oppinion depends 60 on how you drive 40 how well you maintain your car.

if you want to boost your fuel economy, increase the effiency of the engine, Intake, header and exhaust will give your car a 15 to 20% boost in economy so long as you do not speed past what the manufacturer recommends as its peak effiency point. i know for my mazda its 95km/h but i was reading in the manual andi think i saw it say something like 80, i will have to check again.

Anything above that peak point you will be using more fuel do to certain ratios adjusted for the increase in air flow.

Cheers