Premium Gas In '05 Corollas... - Corolland: the Toyota Corolla Forums

Chad_G_77

Just wanted to throw a question out there. There is a gas station near my home that offers Premium gas (93 octane) at the price of Regular gas (87 Octane) on Mondays. With my previous car, I always filled up with the Premium fuel on Mondays just for kicks.

So, my question is this... I've read where the '05 Corolla engine is not designed to work as well with 93 octane. Is this true? Would it hurt the car's engine and/or its performace if you were to use 93 octane?

Just curious if there was anyone out there that had filled up with 93 octane in your '05 Corolla and if you saw an increase/decrease in MPG or any other performance related changes.

Thanks!

My car is an '05 Corolla Sport, Automatic trans. if that makes a difference in your response. Don't know if the standard -vs- automatic would make any difference.

Max

You can search the (many, many) threads on octane here. Popular opinion is: Use 87 octane, as there is no benefit from going any higher. Jury is out as to whether it could actually do any harm to use higher octane.

Dai_Shan

As far as I have heard here and else where if you use a higher octane that is recommended/nessescary it reduces your gas mileage. The technical reason behind it escapes me at the moment...

I notice a slight benefit when accelarating especially at higher speeds. I can tell when my wife has filled up with regular versus premium. (I actually guess and ask her).

Only use the gas that is recommended for your car. IF you put Supreme in your corolla, were it ask's for regular, it won't give you more peformance or gas mileage. It will make things more worse, the higher octane is for engines with higher compression ratios. Like the LS1 and Northstar engines and engines that use Superchargers and turbos. The engine will have a harder time in combusting the higher octane gas, then you will start pinging, have low performance and bad gas mileage. Vice-versa with high compression motors that use regular instead of Supreme. So just stick with the regular.

friendly_jacek

High octane in regular car can burn slower and conrtribute to carbon deposits. Whether it is a problem in Corolla, have no idea.

On the other hand, check if the higher octane gas has alcohol in it. Alcohol is bad for cars:

Higher MPG

more rust in gas lines

more deposits in engine

more engine wear

the manual reccomends at least 87 octane. it does not advise against higher octane but also does not suggest that it will lead to greater performance. I have considered shooting an e-mail to toyota on this matter as I have had older 1.8 VW's that say similar things but suggest using higher octane under "high load conditions." The toyota manual does, however, mention that premium fuel will give greater performance for the motor in the XRS. Who knows... I'm interested to know more on this also.

friendly_jacek

High octane in regular car can burn slower and conrtribute to carbon deposits. Whether it is a problem in Corolla, have no idea.On the other hand, check if the higher octane gas has alcohol in it. Alcohol is bad for cars:

Higher MPG
more rust in gas lines
more deposits in engine
more engine wear

Ooops!

I meant lower MPG (as alcohol generates less energy from combustion).

I stand on the other points.

As engines start to get older or conditions that could cause excessive engine pinging / preignition (heavy loads, higher than normal ambient air temps, zero humidity. etc.) could benefit from higher octane numbers.

Other than those specific circumstances - most of the info floating around is that you will not see any performance gain or loss from using higher octane. I agree that you have to check how the octane is improved, friendly_jacek makes a good note about alcohol, it can improve octane - but not safe for some engine components when concentrations start to go 10% or more (eats plastics, seals, rubber o-rings, corroded metal, etc.)

But most agree it more of a cost isse - the extra cost in premium and the minimal gains that it might give you. But if you can get it at the same price as regular (at is not doped with alcohol) then knock yourself out. Fill up with the "good" stuff and then let us know what you think.

I switched from low to midgrade in my Dodge Dakota after about 110,000 miles to cut back on pinging during load/acceleration.

I read on BITOG forums that the 1.8L engine will sludge if abused, and one of the factors was using high octane gas while driving conservatively. Terry Dyson posted it, but I can't find the post at the moment.

Everyone else says that the 1.8 1ZZ isn't paticularly prone to sluding. So, if you want to run premium once a week for the added detergents and whatnot, fire away I say default_smile