toyotatom93

Been researching this topic and basically comes down to no money savings, as in 91 costs more obviously but you get better performance and mileage. 87 = worse performance and worse mileage.
I heard the truck can distinguish between the two and adjust itself accordingly.
I also heard its better to stick to one or the other, not to switch between the two frequently. Is mid grade a happy medium?

Just want to know what people actually do when they go to the pump.

I only ask because we are on the verge of picking up a sweet 07 sport.

runn4me

Using 87...i never considered using any other grade...just what is recommended but it definitely makes sense to use a better grade of gas.

nothingbetter

I've never heard of a vehicle adjusting itself for octane. I've looked into this as well seeing as my boost numbers are about double what they are from factory. Now please correct me if I'm wrong....Just from my understanding, higher octane means it has a higher tolerance to pre ignition ie, detonation. This is only useful if your driving with high hp, rpm or boost situations where detonation can kill your engine in seconds. Since your not high hp, rpm or boost I think you should be ok to stick with 87.

Over here in Alberta our 91 has no ethanol in it, 89 has up to 5% ethanol, and 87 has up to 10%. The ethanol is probally where your seeing the "performance and mileage" difference, not the octane.

When sledding in BC we found some purple 97 oct that we ran in the sleds because it was cheap. Didn't notice a difference in how they ran.

Team420

The only real difference I notice between 91-87 octane, is with 87, I notice quite a bit of pinging, 91, not so much. so.... when I run 87, and the motor pings, timing will be backed down a bit by the ecu to compensate, and try to eliminate the pinging, so in that regard, yes, mpg's and performance may be slightly better with the higher octane, but... if your rig dont ping with 87 octane, you prolly wont notice any difference at all.

turbocoupe

There are few vehicles that will auto-adjust for sensing octane. The new Coyote Mustangs for example will automatically advance spark for better performance but gas mileage WILL suffer. And also e85 (103+ oct.) friendly F150 trucks will also advance spark.

I hear from so many people how they throw their money away thinking they get better performance or fuel mileage from higher octane. This is completely WRONG. Higher octane fuel has a higher flashpoint and is actually harder to ignite than a lower grade, I.E. the lower the grade the easier and better the fuel will burn. You cannot get better mileage from more octane. When most people test this theory, just like with worthless throttle body spacers, Tornadoes and the like, they either consciously or subconsciouly drive extremely easier than they normally would to see how good they can get. There is a reason why the factory puts "Use 87 octane fuel" in the manuel.

If you are experiencing better performance from more octane, then something is wrong with the callibration of your ECU where it is comanding to much spark advance. But most of the time people experience pinging, it's because they are buying gas at no-name stations to save a few cents a gallon. There is a reason their fuel is cheaper as every tuner on planet will tell you to only buy fuel at a WELL known and BRAND name station.

toyotatom93

Thanks guys. I figured it was probably fine to run 87 but always good to get tho opinions of actual people who live their Toyota trucks.

aa1911

iTrader: (1)

I fully support running 87 octane but I do notice better fuel economy with 92; I run 92 in all my rigs and from calculating the mpg's, the extra cost is more than paid for with the extra mileage I'm getting. and no I'm not driving like grandma, I drive pretty aggressively on the skinny pedal all the time.

when gas was $1/gal, 20 cents was a huge difference between octane ratings, not worth it; now that gas is pushing $5, 20-25 cents difference is NOTHING. One drawback is that there is the possibility of the 92 octane being much older gas because it is not used near as much, but it is just fine IMO and experience.

I agree that you should stick with brand name gas stations, for whatever reason, Shell stations give me better mpg's about 9/10 times compared to ARCO or whatever. You get what you pay for.... if you're lucky.

anyway, that's my $.02 ...... or maybe .05.....

hooray for 92 octane.... boo for ethanol....

rustyf99

iTrader: (1)

I am a moderately conservative driver and experience very little difference between grades, but HUGE differences in quality of the gas. Definitely stick with name brands!!

Higher octanes are typically for higher COMPRESSION engines, whether from combustion chamber or boost. Otherwise, 87 should do OK except for the ethanol blends. You will see less mileage with ethanol, and if you think about it an 87 octane ethanol blend actually has much lower octane gas, blended with the higher-octane ethanol, so that may be a double-whammy for mileage and HP in a performance engine.

And most ECM engines do adjust for octane (indirectly) by adjusting timing based upon the knock sensor, O2 readings, temperature, etc.

Lycanistic

Ok, a little confused here, higher octane yields less performance/mileage, is that what the consensus is? I must be missing something here... I thought race fuels like CAM2 were in the 110-130 octane area, which has been said to be harder to burn??? Dont know about dyno or mileage numbers, but 87 alone vs 93+CAM2 mixture is a big difference in throttle response and how it pulls... Can you shed some light on what you mean please? My blend when I run it is 3gal of CAM2 + 13gal of 93.

rustyf99

iTrader: (1)

I don't think that's the consensus, most everyone agreed that lower octane is probably less performance and slightly less mileage. However, I don't think you'll see much of a difference until you have a higher-performance engine with high compression or a lot of boost. Pre-detonation is definitely an issue with lower octane gas, especially with higher compression ratios.

The low octane fuel burns easier at a lower temperature, so it starts to burn from the heat of compression before the engine flashes the spark plug (think of how a high-compression diesel engine works without spark plugs). This creates pinging which is corrected by the ECU by retarding the timing and richening the mixture (I believe - more gas offsets the pinging?), which results in poor performance and lower mileage.

This is offset with higher octanes which have a higher flashpoint (burning point) so they don't start burning until after the compression is complete, then the spark plug flashes and burns the gas. This is ideal for performance and fuel mileage at the ideal timing, compression and fuel mix.

eli_lilly

10.5ish:1 isn't a low compression engine, the only reason it can run 87 octane is the variable valve timing and spark knock sensors retarding the timing when running 87 octane.

anndel

I get worse gas mileage and knowing with regular gas. In Hawaii, it contains up to `10% ethanol. I get better gas mileage and a smother running engine with premium (92) gas.