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If the owner’s manual calls for 87- or 89-octane gasoline, are you wasting your money by filling up the tank with 93? As with most things in life, it depends.
Sponsored Content Presented by Sunoco.
If the owner’s manual calls for 87- or 89-octane gasoline, are you wasting your money by filling up the tank with 93? As with most things in life, it depends.
I had a Nissan Maxima, the last of the front engine-rear drive models, and it always ran stronger on premium. It didn't knock on regular either.
I owned an auto repair shop in NW Indiana from 1981 thru 2006. Looking back it was the worst time to start an automotive repair business with ALL the changes going on with cars at the time.
Complex emission control systems, Computers, ABS brakes, Digital dashes, RWD to FWD, distributors losing out to coil packs, several carburetor modifications then fuel injection in several different forms, the list goes on. More changes in the decade of the 80's than the prior 50 years!
We "fixed" quite a lot of drivability problems just by having our customer "switch" to Premium Grade Fuel (mostly Amoco back then). Most problems we saw were carbon buildup over time affecting fuel injectors & some valve sealing issues. Usually around 60-80,000 miles. Like smoking cigarettes, you don't get lung problems until a later on. The Premium Grade fuels, like the article states, are a "better" grade (NOT just higher Octane) with a better detergent package and being more stable.
We were able to track this very accurately over time as our customer base was very solid with some being 2 or 3 generations of drivers. We could have easily made more money doing repairs but if the "switch" solved the problem (hard starting, rough idle, hesitation, etc) The customer was happy & told their friends about us which made us both happy in the long run...
In reply to Carman944 :
Is it still true today that higher octane fuels get better detergents? Have you noticed a difference over say... the last 20 years compared to the previous 20?
Honda recommends premium for the G1 Ridgeline when towing over 3500 pounds.
A post on the Ridgeline forums by Gary Flint, an engineer on the Ridgeline, states that peak HP goes from 247 to 258 when switching from regular to premium. Peak torque goes from 32.4 kg-m to 34 kg-m with the same switch. He also states that an increase in fuel economy is often but not always noticed due to how the transmission responded to the extra torque. The fuel economy is more noticeable in high-load situations, lower temps, and climbing grades.
I run regular 99% of the time with the occasional tank of premium.
MrFancypants said:In reply to Carman944 :
Is it still true today that higher octane fuels get better detergents? Have you noticed a difference over say... the last 20 years compared to the previous 20?
It's not what it used to be- as fuel now has to have specific detergent packages in them for all fuels. Part of having SULEV30 cars last for 150k miles. If companies have higher in premium, it's a lot less of a difference compared when I was interning with Chevron back in '89.
jerel77494 said:I had a Nissan Maxima, the last of the front engine-rear drive models, and it always ran stronger on premium. It didn't knock on regular either.
Am I missing something?
When did Maxima's become rear drive?
z31maniac said:jerel77494 said:I had a Nissan Maxima, the last of the front engine-rear drive models, and it always ran stronger on premium. It didn't knock on regular either.
Am I missing something?
When did Maximas STOP BEING rear drive?
Fixed that for you. (And pretty sure the answer is 1985, the year after we started the magazine.)
Margie
I can say even at 18mpg and a tune, 91-93 premium I feel has made my Avalanche less failure prone. Knock on wood, troublefree for the 170k miles I've used premium...
In Canada, most of the stuff that isn't premium has 10% ethanol in it and we've found that the fuel goes stale much faster with ethanol.
In reply to ShawnG :
Even the premium down here has 5-10% E. Hate it. The Rio is the first car I've had that under the right conditions Premium fuel helps. I'll run about every 3rd tank of premium. Holds 10 gal, usually fill with about 6-ish so it's probabl closer to 89 octane average than 87.
In reply to bobzilla :
??? E10 has been the nominal fuel here for a very long time. And something car companies have been building around for at least 20 years. I'm normally more surprised that people can find E0 in normal pumps these days.
(and as my anecdote- I've not driven my Alfa over the past decade- maybe one tank of fuel. Which the last tank was E10- it has had zero problems. My Miata only has had problems because the pump was out of the fuel for 5 years)
In reply to MrFancypants :
Cannot say for sure as I sold my "mainly" daily driver repair operation back in 2006 to focus just on 60's-70's Restorations, which is what I do now.
I DO know it did make a noticeable difference at that time. We proved it time and time again & won over a lot of dis-believers. Plus the price spread was only .20-.30 cents between the grades so Premium was not that much more when you did the math, which we did for MANY customers.
I still use Premium "mostly" to this day based on the results we saw even thought it IS now more expensive...
There was an engine masters about this and it was interesting that on every fuel the engine made the same power and wanted the same timing to make it; except e85.
In reply to z31maniac :
Actually, they were front engine/rear drive first (1st gen), then front drive (2nd gen and up).
Good news, everyone: Talked with Zach and Sunoco a bit yesterday about premium fuels, so look for a follow-up on this topic very soon.
I use 91 premium for better gas mileage. The lower octane gas in my cars produces less miles per gallon. Also I purchase non ethanol gas (91 octane) that really improves the mileage. Back in the day when I determined the mileage difference it appeared that the cost difference evened out. If you bought the regular cheep gas (lower octane not premium) you got lower mileage so you would be at the gas station sooner spending more. But if you spent the extra for the higher octane my mileage went up enough to justify the higher cost. This was in four cylinder cars not V8's. If your cars a knockin there is more than likely some other problem.
I think premium doesn't make more power, it restores power that your ECM may take away in high load situations on regular fuel. Remember the higher the octane the slower and cooler the burn at detonation (spark). So if your car normally runs on 87 or 89 without pre-ignition, and then on a hot day, pulling a load or on a hill, the engine gets slightly hotter, it can start pre-ignition (knocking), although as noted previously you don't hear it in modern cars (i.e. computer controlled ignition, last 20 years or so). Why? because before the knocking gets bad or audible, the ECM should automatically retard the timing to keep your engine out of pre-ignition. When your ignition is retarded, your car makes reduced power. By using premium under these high heat or high load conditions, the higher octane fuel will detonate cooler, eliminating the need for the ECM or ECU to reduce timing, therefore maintaining your normal level of (horse) power. Remember the old muscle cars - the trick to gain horsepower was to advance timing, shave the head or run a thin head gasket to bump up compression - but if you didn't also run higher octane, all the extra heat generated would create tremendous audible knocking and burn a hole in your piston.
In reply to Carman944 : Shell V-Power® NiTRO+ has seven times the cleaning agents required to meet federal standards and removes an average of 70% of baked-in deposits left by lower-quality premium gasoline, starting with the very first tank.✱✱ Shell V-Power® NiTRO+ provides unsurpassed protection against gunk to help improve engine performance.
I run a half a tank or more of Shell V-Power in my vehicles once a month for its enhanced cleaning agents.
BP gasoline with Invigorate was introduced to the United States in 2016, at the time describing it as its “best fuel ever,” offering 10 times better protection against deposits vs. ordinary fuel. Its premium grade—branded Amoco Ultimate With Invigorate—has the highest levels of BP’s Invigorate additive, which enables it to provide 20 times better protection against engine-deposit formation compared to minimum-detergent fuels, according to BP. All of BP’s grades of gasoline are Top Tier certified, meaning they have detergent levels that exceed the federal minimum standard.
I use BP mid-grade 89 octane in my Mustang GT, and either BP Premium or Shell Premium once a month for the extra detergent.
SeniorPBA2B said:In reply to Carman944 : Shell V-Power® NiTRO+ has seven times the cleaning agents required to meet federal standards and removes an average of 70% of baked-in deposits left by lower-quality premium gasoline, starting with the very first tank.✱✱ Shell V-Power® NiTRO+ provides unsurpassed protection against gunk to help improve engine performance.
While the cleaning action will help keep the injectors clean for all vehicles, it won't help cleaning the back side of intake valves in direct injection engines more common in newer cars today, where fuel is injected directly into the cylinders, not in the intake manifold or just before the back side of the intake valves where the fuel can actually clean the deposit there.
I'm running a turbocharged rotary up around 20 psi. Premium gasoline sounds like a sensible idea to me.
I had a knock controlled VW get better enough fuel economy that it more than offset the extra expense. This was 2008ish when 93 octane was $4.50 in 2008ish dollars.
The car that replaced it was an older, pre knock control model with essentially the same combustion chambers but much lower compression. 87 vs 93 made no measurable difference in economy. So I went the other way, adding cetane enhancer to 87 to increase combustibility and reduce octane (these do not always correlate!) Fuel economy went up, but exactly as much as would offset using half a $9 bottle of magic stuff in every tank, so I went back to using 87...
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