From what I understand they want to be able to increase compression and increase efficiency. It would lead to better mileage for sure.
Using a lower octane fuel than recommended
- Thread starter The Critic
- Start date
From what I understand they want to be able to increase compression and increase efficiency. It would lead to better mileage for sure.
- Joined
- Aug 14, 2021
- Messages
- 845
I remember in the mid 1990s a Sunoco station near me used to have 86 octane. It was slightly less expensive than 87 and I would fill my old carbureted Hyundai Excel with it and it ran fine, like always. But with cars today, no I wouldn’t use anything lower than what the manufacturer requires.
True. Not because of the octane rating in and of itself however.
No, but I have not owned anything yet that requires high octane. If I did buy something, I would probably run 3+ tanks of each so as to gauge performance and cost per mile impact.
On a summer toy that won’t get many miles per year I would just go high test, but on a daily driver I would want to run the numbers. Pre pandemic I bought a tank of fuel once a week. Sometimes more often than that.
Like I said, it depends on whether the damage will present a durability issue during the term of your ownership. If it will not and the driver is not concerned about optimal drivability, then a financial case for running 87 should be considered.
2 min road test with customer cars and I can tell if they are running regular or not. Often scan the car just to double check, and almost always right.
I run 87 in my wife's 2018 Equinox 1.5 turbo- no issues. I had a coworker buy a 2019 Equinox with the 2.0 turbo which I think recommends 89 or higher but he never had any issues with it (had about 30k if I remember).
Nope. Other than the Cobalt, which recommends premium, all of the fleet uses 87 octane. I don't drive the Cobalt as much as the rest of the fleet, and it is supposed to be a performance car so why cheap out on the gas?
I have done the opposite and gone up to mid-grade. My old S-15 Jimmy's 4.3L engine would ping on regular gas in really cold weather so I'd alternate fill-ups in the winter, using regular one time and mid-grade the next. Seemed to keep the engine happy doing that.
I have done the opposite and gone up to mid-grade. My old S-15 Jimmy's 4.3L engine would ping on regular gas in really cold weather so I'd alternate fill-ups in the winter, using regular one time and mid-grade the next. Seemed to keep the engine happy doing that.
What do you notice?
Pre-ignition is a sliding scale from light pinging to full-on detonation. To prevent engine damage, the knock detector must kick in early before detonation.
Mike Busch has a great video on this. It's about aviation but the basic concepts carry over to car engines.
Yeah the way we leaned it in college was that you wanted incipient detonation but since that was impossible to determine you had to always run slightly retarded.
I'm fine with it as long as it costs the 10cents extra it takes to make it and not the 60cents to 1.10 extra it costs currently.
Lower than recommended or lower than required? or both.
I'd guess way more than half of the Hemi RAMs, and V6 Mitsubishi Outlanders here are run only on regular gas. Mid grade is often 20% more than regular and 91 can be 30-35% more... Both aren't really vehicles where the slight increase in hp they get with designing an engine for higher octane gas really matters to sales at all IMO. For towing both these vehicles really benefit from higher octanes but just for getting around, its more cost effective to run regular with a slight mpg hit.
Stellantis definitely makes it clear that 87 might result in some light pinging, but durability is probably not compromised enough to be a concern (in their eyes). Mine does feel a bit weak (off-the-line) when running 87, but I have not been able to verify any difference in fuel economy.
I can't speak to the newer cars, but the 2002 Maxima with a 3.5l V6 calls for premium and I switched to 87 several months back. So far no noticeable effects one way or another. Been listening for any knock but so far none. One caveat is I am dosing it with Lucas fuel treatment every tank. FWIW it does mention on the label it eliminates the need for higher octane fuel? Probably just marketing hype, but it does help keep the injectors clean.
Yeah, I'm pretty sure my Dad only runs regular in his 2019 Ram Classic 5.7 6spd, I'm always surprised how "cammy" it feels with hard acceleration. Or like like the older honda vtec motors, when you could really feel the switch over. I guess once the rpms climb a bit it can switch to running more advance with the regular gas? He probably runs regular in it when towing too, but he still likes it over the 5.4 2V F150 he had before.
My G35 only needs 87 octane (from the owners manual) but the fuel filler door says "Premium unleaded fuel only". Anyway, if I put 87 in it, it doesn't run "nice" (definitely can feel it during medium to hard acceleration and can hear pinging). If I put 89 in it, it's fine but with 91-93, I can absolutely feel an improvement. In my wife's Fusion (1.5L Ecoboost), I can't feel any difference between 87 to 93 octane but it does get better fuel economy with the higher octane fuel.
Probably some reference to a supposed cleaning of the combustion chamber. Whatever it does or doesn't do, one thing it does not do is increase the octane rating.
And just interested, how do you know it keeps the injectors clean? Do you remove them for inspection?
I get similar results with the CX5. I run premium due to the 13:1 compression ratio even though Mazda says 87 is okay.
Similar threads
- Locked