Are you losing cash on premium gasoline in case your automotive does not want it? | Articles

I had a Nissan Maxima, the final of the entrance engine-rear drive fashions, and it at all times ran stronger on premium.  It did not knock on common both.

I owned an auto restore store in NW Indiana from 1981 via 2006.  Trying again it was the worst time to begin an automotive restore enterprise with ALL the adjustments occurring with automobiles on the time. 

Complicated emission management techniques, Computer systems, ABS brakes, Digital dashes, RWD  to FWD, distributors shedding out to coil packs, a number of carburetor modifications then gasoline injection in a number of totally different varieties, the listing goes on. Extra adjustments within the decade of the 80’s than the prior 50 years!

We “fastened” numerous drivability issues simply by having our buyer “swap” to Premium Grade Gas (largely Amoco again then).  Most issues we noticed had been carbon buildup over time affecting gasoline injectors & some valve sealing points.  Normally round 60-80,000 miles. Like smoking cigarettes, you aren’t getting lung issues till a in a while. The Premium Grade fuels, just like the article states, are a “higher” grade (NOT simply greater Octane) with a  higher detergent bundle and being extra steady.

We had been capable of observe this very precisely over time as our buyer base was very stable with some being 2 or 3 generations of drivers.  We might have simply made more cash doing repairs but when the “swap” solved the issue (arduous beginning, tough idle, hesitation, and so on) The shopper was glad & advised their associates about us which made us each glad in the long term…

In reply to Carman944 :

Is it nonetheless true immediately that greater octane fuels get higher detergents? Have you ever seen a distinction over say… the final 20 years in comparison with the earlier 20?

Honda recommends premium for the G1 Ridgeline when towing over 3500 kilos. 

A publish on the Ridgeline boards by Gary Flint, an engineer on the Ridgeline, states that peak HP goes from 247 to 258 when switching from common to premium. Peak torque goes from 32.4 kg-m to 34 kg-m with the identical swap. He additionally states that a rise in gasoline financial system is usually however not at all times seen on account of how the transmission responded to the additional torque. The gasoline financial system is extra noticeable in high-load conditions, decrease temps, and climbing grades. 

I run common 99% of the time with the occasional tank of premium. 

MrFancypants mentioned:

In reply to Carman944 :

Is it nonetheless true immediately that greater octane fuels get higher detergents? Have you ever seen a distinction over say… the final 20 years in comparison with the earlier 20?

It isn’t what it used to be- as gasoline now has to have particular detergent packages in them for all fuels.  A part of having SULEV30 automobiles final for 150k miles.  If corporations have greater in premium, it is loads much less of a distinction in contrast once I was interning with Chevron again in ’89.

jerel77494 mentioned:

I had a Nissan Maxima, the final of the entrance engine-rear drive fashions, and it at all times ran stronger on premium.  It did not knock on common both.

Am I lacking one thing?

When did Maxima’s change into rear drive?

z31maniac mentioned:

jerel77494 mentioned:

I had a Nissan Maxima, the final of the entrance engine-rear drive fashions, and it at all times ran stronger on premium.  It did not knock on common both.

Am I lacking one thing?

When did Maximas STOP BEING rear drive?

Fastened that for you. (And fairly positive the reply is 1985, the 12 months after we began the journal.)


I can say even at 18mpg and a tune, 91-93 premium I really feel has made my Avalanche much less failure inclined. Knock on wooden, troublefree for the 170k miles I’ve used premium…




11/23/21 2:57 p.m.

In Canada, a lot of the stuff that is not premium has 10% ethanol in it and we have discovered that the gasoline goes stale a lot sooner with ethanol.

In reply to ShawnG :

Even the premium down right here has 5-10% E. Hate it. The Rio is the primary automotive I’ve had that beneath the correct circumstances Premium gasoline helps. I will run about each third tank of premium. Holds 10 gal, normally fill with about 6-ish so it is probabl nearer to 89 octane common than 87.

In reply to bobzilla :

???  E10 has been the nominal gasoline right here for a really very long time.  And one thing automotive corporations have been constructing round for at the least 20 years.  I am usually extra stunned that folks can discover E0 in regular pumps lately.

(and as my anecdote- I’ve not pushed my Alfa over the previous decade- perhaps one tank of gasoline.  Which the final tank was E10- it has had zero issues.  My Miata solely has had issues as a result of the pump was out of the gasoline for five years)

In reply to MrFancypants :

Can’t say for positive as I bought my “primarily” day by day driver restore operation again in 2006 to focus simply on 60’s-70’s Restorations, which is what I do now.   

I DO understand it did make a noticeable distinction at the moment. We proved it time and time once more & received over a whole lot of dis-believers.   Plus the value unfold was solely .20-.30 cents between the grades so Premium was not that rather more once you did the maths, which we did for MANY prospects.  

I nonetheless use Premium “largely” to at the present time based mostly on the outcomes we noticed even thought it IS now dearer…

There was an engine masters about this and it was attention-grabbing that on each gasoline the engine made the identical energy and wished the identical timing to make it; besides e85.

In reply to z31maniac :

Really, they had been entrance engine/rear drive first (1st gen), then entrance drive (2nd gen and up).

Excellent news, everybody: Talked with Zach and Sunoco a bit yesterday about premium fuels, so search for a follow-up on this subject very quickly. 

I take advantage of 91 premium for higher fuel mileage. The decrease octane fuel in my automobiles produces much less miles per gallon. Additionally I buy non ethanol fuel (91 octane) that actually improves the mileage. Again within the day once I decided the mileage distinction it appeared that the associated fee distinction evened out. For those who purchased the common cheep fuel (decrease octane not premium) you bought decrease mileage so you’d be on the fuel station sooner spending extra.  However when you spent the additional for the upper octane my mileage went up sufficient to justify the upper price. This was in 4 cylinder automobiles not V8’s.          In case your automobiles a knockin there’s greater than doubtless another downside.



New Reader

2/20/22 11:11 p.m.

I believe premium does not make extra energy, it restores energy that your ECM might take away in excessive load conditions on common gasoline.  Bear in mind the upper the octane the slower and cooler the burn at detonation (spark).  So in case your automotive usually runs on 87 or 89 with out pre-ignition, after which on a scorching day, pulling a load or on a hill, the engine will get barely hotter, it can begin pre-ignition (knocking), though as famous beforehand you do not hear it in fashionable automobiles (i.e. pc managed ignition, final 20 years or so). Why? as a result of earlier than the knocking will get unhealthy or audible, the ECM ought to robotically retard the timing to maintain your engine out of pre-ignition.  When your ignition is retarded, your automotive makes decreased energy. Through the use of premium beneath these excessive warmth or excessive load circumstances, the upper octane gasoline will detonate cooler, eliminating the necessity for the ECM or ECU to scale back timing, subsequently sustaining your regular degree of (horse) energy.   Bear in mind the previous muscle automobiles – the trick to achieve horsepower was to advance timing, shave the pinnacle or run a skinny head gasket to bump up compression – however when you did not additionally run greater octane, all the additional warmth generated would create large audible knocking and burn a gap in your piston. 

In reply to Carman944 : Shell V-Energy® NiTRO+ has seven occasions the cleansing brokers required to satisfy federal requirements and removes a mean of 70% of baked-in deposits left by lower-quality premium gasoline, beginning with the very first tank.✱✱ Shell V-Energy® NiTRO+ supplies unsurpassed safety in opposition to gunk to assist enhance engine efficiency.


I run a half a tank or extra of Shell V-Energy in my automobiles as soon as a month for its enhanced cleansing brokers.

BP gasoline with Invigorate was launched to the US in 2016, on the time describing it as its “finest gasoline ever,” providing 10 occasions higher safety in opposition to deposits vs. abnormal gasoline. Its premium grade—branded Amoco Final With Invigorate—has the very best ranges of BP’s Invigorate additive, which allows it to offer 20 occasions higher safety in opposition to engine-deposit formation in comparison with minimum-detergent fuels, in accordance with BP. All of BP’s grades of gasoline are High Tier licensed, which means they’ve detergent ranges that exceed the federal minimal commonplace.

I take advantage of BP mid-grade 89 octane in my Mustang GT, and both BP Premium or Shell Premium as soon as a month for the additional detergent.

I am working a turbocharged rotary up round 20 psi.  Premium gasoline appears like a smart thought to me.

I had a knock managed VW get higher sufficient gasoline financial system that it greater than offset the additional expense.  This was 2008ish when 93 octane was $4.50 in 2008ish {dollars}.

The automotive that changed it was an older, pre knock management mannequin with primarily the identical combustion chambers however a lot decrease compression.  87 vs 93 made no measurable distinction in financial system.  So I went the opposite method, including cetane enhancer to 87 to extend combustibility and scale back octane (these don’t at all times correlate!)  Gas financial system went up, however precisely as a lot as would offset utilizing half a $9 bottle of magic stuff in each tank, so I went again to utilizing 87…

Mazda says my ND can run on 87 with decreased efficiency, however recommends a minimal of 91. I can’t fathom feeding 87 to an engine with a compression ratio of 13:1. It would get 93 so long as I personal it.

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