Kestas
Staff member
They recommend premium. They all have knock sensors, so I'm not worried about ruining the engine.But do your cars spec premium or 87?
They recommend premium. They all have knock sensors, so I'm not worried about ruining the engine.But do your cars spec premium or 87?
You're right. I checked a few stations in the Bay Area and the price spread is under 10%. Where I fill up (Costco), it fell down to a 17% spread. A quick check on other stations in my area shows a similar spread. It appears the differences are regional.Where are you seeing that much of a spread?
It's always been interesting where over the years I've typically seen a 10 cent difference between 87/89/91(or 92 when it was a thing around here). I was in Arizona years a couple of decades ago and it was .799/.899/.999 per gallon. That was the most common price spread (10 cents) for decades, although a lot of places vary these days, although it's still typically less than a 10% difference.
Knock sensors report to the ECU which most all OEM ECU programs are very limited to adjusting all that is needed to protect the engine and for the knocking condition medium and severe engine knock all your doing is pounding the engine .They recommend premium. They all have knock sensors, so I'm not worried about ruining the engine.
You're right. I checked a few stations in the Bay Area and the price spread is under 10%. Where I fill up (Costco), it fell down to a 17% spread. A quick check on other stations in my area shows a similar spread. It appears the differences are regional.
The spread is significant enough for me the continue using regular. My goal is to keep my cost of going from point A to point B at a minimum.
Not true. it requires the same minimum level of performance requirements over the federal requirements. Top Tier doesn't stop gasoline providers from making their 91/93 AKI premium over 87/89, as a long as all of the levels meet the Top Tier performance requiremnentNot true anymore with the advent of top tier, which requires the same detergents in all grades of gasoline
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They recommend premium. They all have knock sensors, so I'm not worried about ruining the engine.
Yup, knocking is not good for the engine and can lead to damage if left unchecked, even light knocking. Knock sensors only prevent catastrophic damage (like a broken ringland etc) from severe uncontrolled knock.Knock sensors report to the ECU which most all OEM ECU programs are very limited to adjusting all that is needed to protect the engine and for the knocking condition medium and severe engine knock all your doing is pounding the engine .
You can get cheap low quality OBD-II access monitoring and find knock sensor values. Then go see what happens between 87 and 91-93 or higher values. Return as say the use of higher then 87 octane fuel is not perhaps a wiser choice overal and especially with engines in the 75-100k miles category.
Yes this is somewhat accurate. Unfortunately when you cause a constant input information to the ECU it’s called adaptive. Once you do this it can take several complete engine cycles to change them back to best or base line programming operation. Unless you clear the adaptive sin the ECU. The proper way is to either flash the ECU or access and reset the ECU via the OBD-II connector.Not true. it requires the same minimum level of performance requirements over the federal requirements. Top Tier doesn't stop gasoline providers from making their 91/93 AKI premium over 87/89, as a long as all of the levels meet the Top Tier performance requiremnent
Yes, knock sensors will pull back on timing, etc... but the ECU will always try to revert back to its specified tuning until it gets knock again, then the vicious circle repeats over and over again, until you put enough of the AKI back in and it doesn't need to pull back on timing, etc.
Total BSI was at my tire shop this morning fine-tuning my recent wheel balancing. While waiting, I thumbed through an auto racing magazine and came across this article. Forgive the poor quality of the pic. It was taken with the magazine balanced on my lap in poor light.
View attachment 72063
Recommended and required are very different… my truck recommends 89 but I can’t tell a difference when running 87. A 6.4 SRT or Hellcat requiring 91 minimum is going to have a very bad time on 87.They recommend premium. They all have knock sensors, so I'm not worried about ruining the engine.
You could possibly need it if your vehicle isn't getting refueled enough. I think after three weeks and maybe sooner in high humidity conditions that ethanol blended fuel would start to break down and loss their octane. My mother is semi disabled so if I borrow the new CRV with the 1.5T then after I am done I top it off with premium non ethanol to help out. I thought some of the big name companies like Chevron use a more stout additive for their higher octane fuels. In sure that there is some faux marketing in the Shell promotion, but at one time or another many people fell for the same BS with Seafoam or Lucas Oil Stabilizer.
Octane is an element that helps resist compresion related per-detonation. Octane does not increase or improve the energy density in the fuel. It is helpful in higher compression-ratio gas engines which can benefit from advancing the spark timing, as long as the octane level can sustain the proper flame propogation and not pre-ignite. Higher octane fuels do not improve combustion past the level needed for the engine requirement. "Required" is not the same a "recommended". As discussed in posts above, the anti-knock sensors will retard spark timing to prevent engine damage. It is beneficial to pick a fuel grade and run that same level all the time, versus trying to jump up/down the choices, because the ECUs are trying to keep a constant level of performance and benefit from steady inputs. In short, if your car does not require or recommend high octane, it won't benefit from it. Much older engines may actually have experienced a CR increase due to carbon build-up on the piston and head surfaces, and while they may have been rated for 87 when new, they may benefit from 89 two or three decades later. But a really good dose (or doses) of high-quality detergent fuel additives can help remove some of that build up (some of the top Gumout products and Techron have huge amounts of PEA and can clean the chamber well). But that's octane related ... there are other fuel characteristics to discuss as well.
It has been a while since I ran that test but the range has always been higher than 100, that's just the number that is assigned to isooctane. IIRC it goes up to 120 or something for other fuels or mixtures (isooctane and TEL for example).I'm not quite sure how it works for fuels that have an octane rating higher than 100.
It has been a while since I ran that test but the range has always been higher than 100, that's just the number that is assigned to isooctane. IIRC it goes up to 120 or something for other fuels or mixtures (isooctane and TEL for example).
Your Accent doesn't knock like a Jehovah's Witness on 87?Instead of paying for higher octane gas, for my vehicles that only require 87 octane, I would rather spend that extra money to buy ethanol free gas.