Being shunned by my friend for using 87 octane

[BHopkins]

Over the years I have read many a report on this subject. They all say the same thing. Even Chevron, which has a financial interest in selling us high octane gas, says the same thing.

Using an octane higher than recommended in the Owner's Manual is doing nothing but burning money. It will not make your car perform any better. It will not result in better MPG. It will, however, make your wallet lighter.

 

[silverrat]

My Civic, a 2003 model, recommends a minimum octane of 86. From the manual

"Your Honda is designed to operate
on unleaded gasoline with a pump
octane number of 86 or higher. Use
of a lower octane gasoline can cause
a persistent, heavy metallic rapping
noise in the engine that can lead to
mechanical damage."

From 2001 Sentra manual

"Your vehicle is designed to operate on
unleaded gasoline with an octane rating
of at least 87 AKI (Anti-Knock Index)
(Research octane number 91)."

For comparison here is a 2003 350z

"Use unleaded premium gasoline with an octane
rating of at least 91 AKI (Anti-Knock Index)
number (Research octane number 96).

If premium gasoline is not available, unleaded
regular gasoline with an octane rating of 87 AKI
number (Research octane number 91) may be
temporarily used, but only under the following
precautions:

I Have the fuel tank filled only partially with
unleaded regular gasoline, and fill up with
unleaded premium gasoline as soon as possible.

I Avoid full throttle driving and abrupt acceleration.
However, for maximum vehicle performance,
the use of unleaded premium gasoline
is recommended."

 

[silverrat]

Here is the recommendation for a 2013 Subaru BRZ. In the "Additional Information" insert section they have

Quote:
Fuel
Use premium unleaded gasoline with an octane rating of 91 AKI or higher.


And then later in the manual

Quote:
Fuel types
Unleaded gasoline (93 AKI [Research Octane Number 98] or higher)
If unleaded gasoline with an octane rating of 93 AKI (98 RON) is not available,
unleaded gasoline with an octane rating of 91 AKI (95 RON) may be
used with no detriment to engine durability or driveability.


And the 2012 Corvette

Quote:
Recommended Fuel
If the vehicle has the 6.2L V8 engine
(VIN Code W), use premium
unleaded gasoline with a posted
octane rating of 91 or higher.

You can also use regular unleaded
gasoline rated at 87 octane or
higher, but the vehicle's acceleration
could be slightly reduced, and a
slight audible knocking noise,
commonly referred to as spark
knock, might be heard.

If the octane
is less than 87, a heavy knocking
noise might be heard when driving.
If this occurs, use a gasoline rated
at 87 octane or higher as soon as
possible. Otherwise, you could
damage the engine.

If heavy
knocking is heard when using
gasoline rated at 87 octane or
higher, the engine needs service.

If the vehicle has the 6.2L V8 engine
(VIN Code T) or the 7.0L V8 engine
(VIN Code E), use premium
unleaded gasoline with a posted
octane rating of 91 or higher.

For best performance, use premium
unleaded gasoline with a posted
octane rating of 93.

In an
emergency, you can use regular
unleaded gasoline with an octane
rating of 87 or higher.

If 87 octane
fuel is used, do not perform any
aggressive driving maneuvers such
as wide open throttle applications.
You might also hear audible spark
knock during acceleration. Refill the
tank with premium fuel as soon as
possible to avoid damaging the
engine. If heavy knocking is heard
when using gasoline rated at
91 octane or higher, the engine
needs service.



Just thought it was interesting how they are all worded.

 

[Trav]

Being shunned over gasoline? what kind of friend is that?
Tell him to fill the tank if he feels the need or else go scratch his behind with a broken bottle.

 

[Kestas]

He says, "he would never use less than 93 oct because he thinks using 87 would have damaged the motor," despite overwhelming evidence to the contrary.

He's probably the same type of person who also says:
- once you use synthetic oil, you can't go back to dino.
- tires can never be cross rotated.
- and probably a few other myths I can't think of at the moment

He needs to talk less and read more.

 

[Artem]

My 1998 Toyota Camry V6's manual stated something along these lines... "the engine is designed to run on 87 or high, but the use of premium fuel will result in better engine performance".

I use mid grade 90% of the time for "improved" engine performance over the regular 87 juice.

If a 98 Camry, which is designed as a grocery getter, can benefit from premium fuel, I'm sure any car will. How much of an improvement depends on the engine design. This is why they all state "the recommended fuel is 87 or HIGHER."

 

[Bamaro]

Your friend is grossly misinformed.

 

[exranger06]

This thread reminds me of this

:

 

[exranger06]

Originally Posted By: Artem

If a 98 Camry, which is designed as a grocery getter, can benefit from premium fuel, I'm sure any car will. How much of an improvement depends on the engine design. This is why they all state "the recommended fuel is 87 or HIGHER."

No. Your car probably has knock sensors and has a computer that can adjust timing to take advantage of higher octane. Many cars don't have this and will not benefit in any way using higher octane. The reason manufacturers state 87 octane OR HIGHER is because using a higher octane will not damage the engine and is acceptable to use. What the manufacturers fail to mention however, is that it's a total waste of money.

 

[badtlc]

Hard to say. YOu won't know for sure without measuring timing and knock. Even basic Ford Fiestas are pulling timing on 87 octane now days. IMO, manufacturers are designing a lot of engines that should be running on 91+ now days but then patch them to allow use of 87 octane.

 

[mclasser]

Big oil loves people like your friend. Ignore him and use 87. A simple Sentra has no need for premium.

 

[sciphi]

Originally Posted By: badtlc
... IMO, manufacturers are designing a lot of engines that should be running on 91+ now days but then patch them to allow use of 87 octane.


+1. It's well-documented by many folks and some big car mags that some modern DI and/or turbo engines do in fact get better fuel mileage on premium rather on regular. Those engines do have the ability to advance timing/lean out the engine when less fuel is needed to combat knock.

My Cruze and your MZ3 are good examples of engines that were originally designed for higher octane fuels, then run aggressive knock retard maps to keep themselves alive on 87 octane.

 

[Mach1Owner]

I find it funny that the Escort coupes from 97-2003 if Ford retuned to 91+oct can go from 130hp to 150, and in 2002 Ford made the SVT focus that was higher compression, different head, different cam, adjustable cam, dual stage intake... and only made 20hp over 10k Escort with a single tune change.

Despite all those upgrades the tune changed Escort would go dead even with the 8k more expensive Focus in autoX and 1/4mile tracks while getting much better MPG.

While running 91 or 03 in a stock car that asks for 87 is useless, I think that having your car tuned to use 91 or 93 can be one of the best modifications to a car.

 

[SteveSRT8]

^^^But you simply cannot make generalizations across all cars because of your excellent results with one platform.

 

[steve20]

I've tried 93 in my 05 Accord 2.4 & the 2004 Tahoe 5.3 on straight trips to FL, where there are less variables as it is all steady speed highway driving. Both vehicles returned consistently worse MPG when premium was used on a 1250 mile test

 

[Mach1Owner]

Not at all. Its just an example of how much power/MPG could be left on the table due to makers tuning for 87 and not 91 or 93.

Every car that I've had the ECU retuned on got better MPG that offset the cost of 91+ oct.

 

[Tdbo]

Originally Posted By: Astro14
I'm sorry...did I miss something?

Who owns the car now?

That's the person who chooses what goes in it...

And yeah, 87 is all it needs...but your friend sold the car, so he no longer has any say in what the car gets...


Agreed.