Does octane rating make a difference

[twosixthree]

Will a higher octane gas make a difference in a stock engine in eather proformance or mpg? Also is there any use in useing octane boosers?

Thanks,
Tony

[Vmix06]

not really you should just stick to the regular gas the only time that i know of that u can change to a higher octane is when you are boosting at higher levels other than that i would do it because you will just be paying more than you should for gas

[beyond305]

When I pump 93 into my tank I can feel the car become a little more agressive, not a whole lot but enough that I can feel it. I think it would take away milelage seeing as it burns faster.

[TBITB]

i dont think it's worth using higher octane since 1. there isn't a substansial increase in performance and 2. gas prices are ridiculously high.

i wouldnt waster my money on octane boosters either unless i had proven dyno numbers for the tC. i dont know how much a new car like ours would benefit from that

[twosixthree]

Just filled it up with 92 yesterday from nearly empty. It's 20 cents higher per gallon here so thats 2.80 more for 14 gallons. I havn't seen or felt one bit of diference except for my mpg droping noticibly..Maybe 2-3 mpg.

My conclusion: Stay with the 87, save money, don't drive like a race car driver unless you make money like one too. Save the high octane for those boosting.

Thanks to all that replied!
-Tony

[navylife59]

2-3MPG is nothing to write off. I would love to get that in my 13MPG 2007 Tundra. For the tC, though, I think it gets fairly good mileage so the cost is a big factor.

Everyone is right and here is why. Gas is gas. In the same Octane Class, the only difference is additives. From El Cheapo Gasolina to Shell, it pretty much is the same gas delivered by the same pipeline. I would dare say that 95% of 87 Octane gas is chemically exact. If you are worried about deposits, spend $2.99 once or twice per month (depending on your driving/environment) on a good grade injector cleaner.

Most Octane boosters on the market are nothing but snake oil like most oil additives and the Turbonator. There is a slight of words being used here. There is Octane Number (Rating) and then there is Octane Points. It takes 10 Points to equal one Number. What the majority are telling you is that they are boosting the Points, not Numbers. I use only Lucas Octance Booster as an added safety margin against detonation when I know that I am going to push my car hard. There products are race proven in just about every motorsport. It is impossible for a chemical additive in a 12OZ bottle (that isn't super toxic) to take 87 Octane and make it 104+ Octane race gas. Pump gas and race gas are not the same. That is why you see guys with tuned turbo setups with pump and race gas maps.

Now for the ECM. Knowing that our ECM's are learning computers (most OBDII and all CAN modules are), will changing from 87 to 93 Octane increase my STOCK engine performance? There answer is yes and no. Mostly no, though. The reason is simply this, CARB. Emissions drives how our engines behave. Our computers are programmed to keep the engine at 14.7 stoichiometric. Performance increases by higher Octane is going to be subdued by the ECM to keep the emissions in check. Now, if you were a heavy vehicle (too much ICE) or pulling a load (a tC w/ a trailer hitch; I shutter at the thought), then the extra Octane would allow the engine to advance the timing to increase power further because of less detected knock. There is a limit, though imposed by the programming, to keep power levels from over stressing the internals and to keep those emissions still in check. For a stock N/A motor, stay with 87Octane. With out a piggy back or stand alone engine management, your not going to get the bang for the buck. For boosted apps, it is a different story because of the higher cylinder pressures. When my tC was running 9PSI on just the TRD tuned map, my car actually ran better on 89Octane as compared to 93. It was very noticible. Now that I have the Greddy Ultimate that is tuned, running either one now has no noticble difference.

[TBITB]

WE'RE NOT WORTHY!!! WE'RE NOT WORTHY!!!

but yea so basically, stock engines - stick with regular. the gains are negliglibe. right?

and navy, i was gonna start a thread asking what gas people use since i just spent $45 to fill mine this morning... but u say gas is gas pretty much? so shell "v-power" is no different than sunoco, which is no diiferent than luk-oil, etc, etc? cuz i was thinkin about switching from WAWA (northeast - you know what WAWA is!) to shell. would this move be pointless? they are typically a few cents more expensive daily.

i get an injector cleaner regularly since i habitually keep less than half a tank of gas in my car.

[twosixthree]

Wowza..Thanks alot!

Back to the 'ol 87 for me!