I was wondering because here in Vancouver, I've been used to going to Shell and sometimes Chevron. Shell's max octane level is 91 and I've filled up with that a few times. Is this okay? I forget but I think the manual suggested 93+ or something like that. Hope I haven't done anything wrong!

 

If that's all you can find near you that will work. I like to run 93 but you'll be fine with 91. If I didn't have somewhere close that had 93 available I'd have no problem running 91.

 

you can run any "octane level" you want.

the ecu will take care of the engine if there is any engine knock going on.

the car does not know what octane level is being used ,

it just constantly make adjustments based on numerous parameters.

 

i was a bit hesitant to run 91 on my way back from st louis this past summer. usually run 93 or 94 when i can find it on my 04 evo. no problems what so ever

 

What about running on E10 (10% ethanol) + 90 octane, will there be any problem.
The car definately feels sluggish.

 

In California 91 is the highest octance we have and I'm doing fine.

 

yea the manual says use 93 I just put some good booster in it everytime I fill up. So i running about a 97 right now.

 

Is it necessary to reflash the ecu when using ethanol blend fuel or at least change injectors, sensors...

 

What is good booster? please dont tell me that youre running autozone octane booster. if you are i highly doubt that its getting you up to 97 octane. those octane boosters are just a waste of money. the only sure fire way to gain octane points is to mix a higher octane fuel such as adding a few gallons of 105 to your full tank.

 

No you don't need to reflash the ECU. According to the manual the Ralliart can handle E10 (10% ethanol) fuel.

 

When you say Ralliart, are you referring to the stock ecu or the ralliart ecu.

 

Your car from stock can handle E10 fuel (Stock Lancer Ralliart) (Stock ECU/No tune)

 

I doubt it too but thats what the bottle says of course it some NOS brand though.

 

Oh an I am in the west we only have 91 I have to drive to hollywood where they drive lambos to find a anything higher.

 

In BC, Chevron and Husky/Mohawk have 94 octane and some Shells also do but not many of them. I use the Chevron myself and like it. In the manual it suggest 93+ octane but says 91 is fine if that is all that is available. I've read that the RA ecu has 2 maps on it, one for lower octane and one for higher octane so u should be fine.