Must I use 93 Octane? Gas is $4.06 (93 Octane) a gallon here in Dallas TX.
A friend of mine told me he has been using unleaded for 2 years and everything is normal on his Ralliart. What do you guys think? It is very tempting!

 

If you must save a dollar, just use 91 octane, dont bother with 87 crap
It really isnt MUCH of a difference, and the extra insurance from good gas for your car is well worth it

 

all gas sold at stations is unleaded (87, 89, 91, 93) so you might be a little confused. Your friend "thinks" nothing is wrong but his motor is probably knocking like crazy under boost and he just doesnt know it. I would suggest sticking with 93. the price difference is nothing compared to an engine rebuild.

 

uhm... 93 Octane IS unleaded...

I only use the highest Octane unleaded gas available to me, which is 91 in most of California and it's about $0.20 more expensive per gallon than your 93...

The stock RA comes with a "low octane" AFR map. Though, personally, while I wouldn't ever run the lower octane fuels in my RA, I think I would have a reputable shop check it out before switching to the low octane stuff for daily use... low octane fuels are more prone to pre-ignition and detonation (if either of these occur badly enough you'll hear an audible "knock") than high octane fuels. Pre-ignition and detonation are the enemy and can destroy an engine so fast it'll make your head spin...

 

If you want your car to knock constantly then sure use the lowest grade gas you can find. Seriously though, I'm fairly sure the owner's manual (and supplemental material) as well as the inside of the fuel door all say "Premium Unleaded Only" or something to that affect so running 87 or 89 octane is essentially throwing your warranty out the window.

On the other hand, if you were serious about running pee water, you could get tuned for it, but since your not wanting to spend the extra 20 cents per gallon I doubt you will want to pay for a custom tune that will allow you to safely run on low octane gas.

 

No matter what the price of gas is, premium is usually only $.10 more than mid grade. On the RA that's only about a $1.50 per tank which really isnt worth running mid grade.

 

Good point! $1.50 or have a knocking motor... I think I'll go couch diving and find the extra two bucks

 

Mitsubishi only recommends running regular or plus in emergency situations only, like when you can't find 91 or 93. It isn't worth the extra $100 per year to risk damaging your engine.

 

If $2/tank is really that big of a deal to you sell the RA and get a regular Lancer.

 

I understand some people wanting to get better gas mileage just to be more efficient and use less gas. If you HAVE save $2 per tank, it probably means you bought more car than you can afford. However, if you just want to save $2 if you could, then, no, you shouldn't.

 

AHH very well said that is a way to look at it! thnks

 

I WISH 93 octane was only $4.00/gal up here in Canada. Usually the cheapest 91 octane is $1.35/L ($5.40/gal if you do a direct conversion excluding any variables). If you're even thinking of running anything below 91, you have the wrong car. Better to pay the extra few bucks and have peace of mind that your engine will be fine.

 

Hehe... hard to pimp on a budget. That's why I drive a 1.6L Corolla daily. :}

 

Buy a beater and save your evos engine

 

All automotive gasolines are unleaded due to health concerns. Only avgas is still leaded.

You must use 91 octane or higher. That is what the car is tuned for. The engines ecu can adjust timing and stuff a little to make moderate driving save, in case you're low on fuel and can't find premium gasoline, but if your going wot it can and probably will damage your engine.

Tell your friend to follow the guidelines laid out in the owners manual as to what octane gasoline to use.