· Premium Member
Has anyone experienced any knocking from running regular unleaded in their 5.7?
What owner manual are you looking at? The manual specificaly says 87 or better. Last time I checked, 87 is not considered mid grade. Nobody on this forum so far has benefited from putting anything higher than 87 in the truck = no knocks, pings, added MPG or anything else.Midgrade or premium is suggested in the owners manual! I have 1600 miles on my Crewmax and only run midgrade. Truck runs great!
I don't know if everyone read this post, but a few that posted after should read it.87 octane is recommended in the owners manual. This link may work, may not. Octane rating - Wikipedia, the free encyclopedia. Check out the information here and it should clear up the octane mystery. Octane rating has nothing to do with combustability of fuel for spark ignition internal combustion engines but rather is a rating system designed to identify the fuel's ability to resist predetonation (pinging, knocking, running on). That said, 87 octane has the same energy release per detonation as 93 octane.
Thats top tiear gasThe one thing that I have read about different types of gas is always try to stick to "teir 1" gas. It can be 87 as long as it is "teir 1", which I believe is just a standard to ensure quality gas, correct me if I am wrong please.
Your engine shouldn't knock with 87 as the knock sensor will pull timing as necessary to prevent knock. However, if the computer is pulling timing you are giving up ultimate power and economy. The computer will retard timing instantly as knock is detected. It could take much longer to advance it back to optimum. It may be as little as a start cycle or as much as a couple tankfulls- Only a factory engineer could tell you the exact learning period. I drive in 90 degree weather at sea level and I drive hard. I want ALL the power my engine will give. I'll use 93. At 10 cents per gal difference(here) that's only $2.50 per tank. Some people pay hundreds of dollars for a "chip" (almost $1000 for unichip) to get advanced timing when it may already be built into the truck.
BTW- the same light petroleum distillates (toulene, xylene, benzene, heptane etc) that boost octane in gasoline blends are also the ones that are solvents that keep your fuel system(esp injectors) clean.
If you use 87 and are satisfied-great.
87 octane is cheaper and adequate
93 octane is costlier and better
run what you want.
See red text above...Timing just controls when the spark goes off, if you gas is igniting before the spark goes off the engine can't control that...right, and lower octane fuels tend to combust from compression.
The only thing you are successfully doing by using 93 octane is making it harder for the spark plug to ignite your gas...no, the spark will ignite the fuels the same, the 93 octane will allow for full compression, may advance the timing, may increase power, and may increase fuel mileage.
So I disagree 93 is not better...
How old is that information? Still shows Celicas, Corolla XRS, MR2 Spyder....According to Toyota, for improved vehicle performance use premium unleaded, 91 or greater. but 87 in minimum
FAQ: What is the minimum octane rating gasoline that I should use in my vehicle?