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Author Topic: Placebo or Real? 87 or 92 octane  (Read 1165 times)

Offline MrF

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Re: Placebo or Real? 87 or 92 octane
« Reply #25 on: August 28, 2017, 08:25:53 PM »
Nothing gets folks worked up on a car or motorcycle forum quite like an octane rating thread.  Well, maybe a "what oil should I use?" thread comes close.

This is in reply to a slew of impassioned responses, I'm not picking on any one person.

The focus was on octane rating because that was the original question in the thread.  Not additives, winter vs summer, density altitude, etc.  Now that we've eliminated the octane rating as being a factor (I think... I hope...), lets figure out what's going on!

You're absolutely right that science involves questioning, but when a data point lies in opposition to over a century's worth of knowledge you can't get too upset when it's not give the same weight right off the bat.

DD, I'm still intrigued about your MPG increase.  Not because I think the octane rating did it (I don't), but I would like to figure out what's causing your results.  It's the only piece of empirical evidence in this thread so far.  I have a few theories, but I don't want to poison everyone's interpretation of your data with them.

I'll finish with this article by some guys who have more money to spend on test motors and gas that I do:
http://www.hotrod.com/articles/0901phr-difference-between-pump-race-gas/

It's not quite what we're talking about since they're using 91/100/118 for their test, but it's related to the discussion.  Essentially, 100 and 118 in a motor tuned for 91 resulted zero gain, and a power loss respectively.  When they tuned the motor specifically for 110 with a secondary jet change they were able to get 7 ft-lbs and 7 horsepower more.  In the 355 small block they were testing in, that's not a huge difference and they had to change the jetting to get it.  They were unable to get an increase out of 118 at all.  If the motor isn't designed for it (and tuned for it), increasing the octane rating alone buys you nothing.
1997 Nighthawk 750 (Sold) |  2016 V-Strom 650

Offline DesertDragon

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Re: Placebo or Real? 87 or 92 octane
« Reply #26 on: August 29, 2017, 10:41:37 AM »
MrF,
First of all, a very nice and reasoned reply.
I am in agreement that a difference in the octane rating in and of itself is very unlikely to be causing any observed changes, real or imagined.
Although the original thread post mentioned octane, myself and others, were commenting on OBSERVED changes in behavior in our machines, based on a fuel change.  In my case, I never attributed any of these to "octane" or an "octane rating". 
Maybe regular vs super would be a better way to couch it.
While the argument was focused on octane, those ranting about that (IMHO) completely missed the point.

Your test result for octane differences and horsepower were again solely octane based, and jetting changes were required...
It could be that my bike's setup is taking advantage of the new fuel, and the regular it always used wasn't ideal.
I don't know either way about that.

For me, it was a question of the results of using regular unleaded vs. super unleaded, in my case, the Mobil Corp product suite, and observing any differences, either positive or negative, between them to address the controversy initiated by the original poster (Rubo?). 
I had no expectations either way, but I anticipated there would be no difference, largely, because as you stated, the consensus opinion that I was aware of is that using a super grade isn't necessary and/or provides no value, if there is no pre-ignition (knock) using regular fuel.  I know that's "common" knowledge.

But - Gasoline is not "octane" - It is a complex chemical formulation consisting of a large and varied number of initial components, variations in process, and very different additive packages.  To argue, as some have, that there can't be a difference in fuels because more octane won't help, is in a word - stupid, because it ignores a vast number of differences.
Observed results cannot be ignored and dismissed while claiming to have a "scientific" orientation.

My feathers got ruffled when I laid out a reasonable outline of the experiment I conducted, and those results were summarily dismissed, in no small part (IMHO) to an emotional connection to a theory that would not allow for any disagreement. 
This is a classic example of corruption in the scientific method.

There IS more than just my mileage difference as empirical evidence, but speaking of that, if you read back through my posts, I did not expect to discover ANY difference other than the extra money I spent.
But I did.
I did not drive differently. 
I drove the same route under the same conditions in order to do an apple to apple comparison, with less variation than most could accomplish, due to my somewhat unique circumstances.
There was a significant difference in mileage. 
I've NEVER in 11 years got over 50 mpg and I measure mpg on every tank.
If it was you making the comment on data points, I agree with you, or whomever made that comment, that more is better and necessary to confirm.
The point for me was that it was worth exploring, because there were unexpected results, rather than trying to explain it away because it didn't fit a  theory.
There are other cases of evidence:
To wit - After the switch to super, idle speed increase was observed by at least 3 people, myself included.
Conversely, I think it was Captain Kirk, who noted he had to turn up his idle to prevent stalling after switching back to regular. 
Regardless of anyone's position on octane, the fact remains that an observed, quantifiable and measurable difference occurred. 
You cannot make an argument (if you wish to be taken seriously) that this is a result of bias on the part of the observer.

Again, I think it was the Captain who noted, as I did, that his bike was able to run without a choke much sooner than when using regular.
This is an easily observed phenomena, just like the idle. 
My bike didn't stop stumbling because I wanted it to because I wanted super to be better, and for someone to summarily dismiss that observation as bias is to me, offensive. 
I happen to be a retired, certified Six Sigma Master Black Belt, and I've saved millions of dollars via implementation of process improvements.
I think I can manage a simple comparison mpg test without screwing it up.

As far as subjective factors, e.g. more power - I didn't notice that, nor is it something I care about. 
My bike has plenty of power for me, but the other item mentioned, "runs better", although subjective does have a basis for me, as I mentioned that my bike's consistent stumble at the top end of my tach went away... "probably" not because I wanted it to because I tried a new fuel.

The bottom line for me is, there appear to be several benefits to the use of Mobil premium fuel in my bike vs their regular.
I intend to continue (as I always have) to monitor and calculate my mpg and I would encourage others to experiment on their own and report their results, and while doing so, I would suggest that folks be aware of the potential for bias, which can impact results, but not typically tachometers.
 haphap

That being said, I stand by my comment - While I am not a chemical engineer, nor claim to be, and have no specific theory as to what factor or factors are at work between the two fuel grades I've tried which caused the observed improvements, IMPROVEMENTS WERE OBSERVED, and to dismiss those noted as a placebo effect or observer bias has no basis in fact.

Keep the Rubber on the Bottom!

DD

Offline Captainkirk

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Re: Placebo or Real? 87 or 92 octane
« Reply #27 on: August 29, 2017, 01:15:19 PM »
To carry this a step further, for the remainder of the season I will begin burning 97 octane premium in my NH to see if there are any changes. FWIW I ave not tried running that fuel in my 700S as of yet, only the avgas.
Unfortunately, mileage won't be on my agenda because I don't always ride the same road, and sometimes can't control my exuberant wrist which would throw the mileage thing out the window anyway. But I will pay close attention to warm-up and idle speed, anyway...
Measure twice, cut once

Offline MrF

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Re: Placebo or Real? 87 or 92 octane
« Reply #28 on: August 29, 2017, 09:15:07 PM »
DD, thanks for the well-thought-out reply. 

I think regular vs super is the right way to go about this.  The thoughts I have that could make a difference are additives, detergents, and vapor pressure, and those even could be intertwined.  All base stock in a geographic area is the same for a given octane level.  Some detergent gets mixed in at the terminal.  Individual brands mix their proprietary additives  and detergents in at the truck.  What brand gas you bought could be a useful data point.  Even if you're not buying a brand that pitches their additives (Chevron with Techron!), top tier gas will meet a certain minimum level of detergency (http://www.toptiergas.com/licensedbrands/) over top of non top tier brands.

Kirk, I'd still track the milage.  Even if your route varies, over time the average will settle out and might be useful.  I have a gas milage spreadsheet for my car that goes back eight years.  Even though the milage on individual tanks varies a lot, the average of any six month period falls within 2-3 MPG. 
1997 Nighthawk 750 (Sold) |  2016 V-Strom 650

Offline Captainkirk

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Re: Placebo or Real? 87 or 92 octane
« Reply #29 on: August 29, 2017, 09:39:10 PM »
Point taken. I will track the mileage, then.
Measure twice, cut once

Offline Rubo

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Re: Placebo or Real? 87 or 92 octane
« Reply #30 on: August 30, 2017, 08:12:51 AM »
I can confirm my mileage is up by about 7-8 mpg.I have been writing down numbers and using same gas station 93 premium gas.
Its true my mileage is up and my bike does run smoother and yes choke time far less.
Is it all due to additives in the gas?Maybe I am not sure but results are so positive that I will continue using premium gas from same station.
FYI I live in Medford MA metro Boston so East cost mix.

Offline sgarnett

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Offline DesertDragon

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Re: Placebo or Real? 87 or 92 octane
« Reply #32 on: August 30, 2017, 11:00:46 AM »
MrF - Good post.
I have spreadsheets for everything else ;-) but I never created one for my bike's mileage.
To this point I've had so little variation that it didn't seem necessary, but you gave me an idea.
I'm thinking if other folks want to participate, perhaps some data in a common format would provide grist for the analysis mill...
I was thinking:
Bike make / model / beginning mileage
Combustion intake type (carb or injected)
Run log - miles driven that day / time of day (multiple runs per day)
Environmental Factors - temp/humidity
Ride type (commute/canyon race)
Ride "Quality" Open road / Heavy traffic / etc
Unusual activity - e.g. major throttle application to avoid brain dead cager / outrunning a train (I'm joking)  whoohoo1
... and a summary of:
Total Miles on Tank
Total Gallons added
Brand of Gas and grade
Fuel additive  MTBE / Ethanol
MPG (calculated)
If you can think of any other pertinent factors, great.
I wonder if the moderators might be interested, and if there might be a way to capture the info on the forum.
Would an oil company want to get involved... but (as usual) I'm thinking ahead...

Like you, I am intrigued how an adequate (in terms of octane rating) fuel could be outperformed by a different formulation that theoretically shouldn't be making any difference... From feedback on the forum, the surprise results I had seem to be more prevalent than just a fluke.
With enough data, a design of experiment could be conducted to statistically determine significant factors, but shy of that it is possible that a pattern could emerge... Maybe some brands are better than others.. Maybe fuel injected bikes show no difference.. Maybe the mpg increase "evaporates" over time... Who knows.  At this point it's all conjecture.

In any case, I think the results could be interesting, and it could make for an entertaining forum "class" project.... 

Have a good one!

Keep the Rubber on the Bottom!

DD

Offline Captainkirk

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Re: Placebo or Real? 87 or 92 octane
« Reply #33 on: August 30, 2017, 11:13:27 AM »
Interesting, far more interesting and valuable than one or two random members tracking partial data. Mods?
Measure twice, cut once

Offline DesertDragon

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Re: Placebo or Real? 87 or 92 octane
« Reply #34 on: August 30, 2017, 11:20:29 AM »
https://www.afpm.org/State-Motor-Fuels-Specifications/
SG - Wow - Exponential expansion of fuel factors... It looks like most of what they address in statutes (based on a cursory read) are the vapor pressure and required additive(s) and limitation on what a particular state considers a "naughty" ingredient rather than specific input formulation requirements...
But still... Even in the same state at the same time there could be multiple local variants.... 
This could skew results on a ride where the bike gets different formulations even if they are from the same retail name and grade....
Keep the Rubber on the Bottom!

DD

Offline DesertDragon

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Re: Placebo or Real? 87 or 92 octane
« Reply #35 on: August 30, 2017, 11:29:43 AM »
Interesting, far more interesting and valuable than one or two random members tracking partial data. Mods?
Aye Captain!
By Mods, I'm thinking you meant bike modifications?  Like a 4 into one / velocity stacks / cams ...
I'm thinking logistically, a home on the forum would be good if there is serious interest in pursuing this..
Does anyone know the forum moderators and perhaps have a conversation with him/her/them ?

Keep the Rubber on the Bottom!

DD

Online mollusc

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Re: Placebo or Real? 87 or 92 octane
« Reply #36 on: August 30, 2017, 12:00:49 PM »
On fuelly.com, you can easily match your vehicles against the same model, same year, etc.  I use the site for all of my vehicles.  Personal consumption data can be easily downloaded.
You can put notes about any modifications in your own comments but that info probably doesn't appear in any download files.
If someone sets up a public Google sheet or some such, I'd be happy to contribute my several years worth of bike data.
made of meat

Offline sgarnett

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Re: Placebo or Real? 87 or 92 octane
« Reply #37 on: August 30, 2017, 12:29:27 PM »
But still... Even in the same state at the same time there could be multiple local variants.... 
This could skew results on a ride where the bike gets different formulations even if they are from the same retail name and grade....
Yes, absolutely! Large urban areas can have different formulation standards than surrounding counties due to pollution levels. In my state, Kentucky, the standards are different for the Louisville and Covington areas.

Offline Larry Fine

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Re: Placebo or Real? 87 or 92 octane
« Reply #38 on: August 30, 2017, 04:00:10 PM »
I'm too cool (i.e., lazy) to keep records, but I am willing to try a tank or few of BP/Amoco regular grade and report any noticeable changes. I figure changing grade and nothing else should point to octane reduction only, presuming otherwise-equal formulation.

Offline DesertDragon

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Re: Placebo or Real? 87 or 92 octane
« Reply #39 on: August 30, 2017, 05:23:45 PM »
I'm too cool (i.e., lazy) to keep records, but I am willing to try a tank or few of BP/Amoco regular grade and report any noticeable changes. I figure changing grade and nothing else should point to octane reduction only, presuming otherwise-equal formulation.
Thanks for the offer to step up, and yes - See what happens. 
So, you already use super in your bike.... If so a single tank won't hurt and maybe save you a $1..
Please try to be aware that there is a possibility of bias..
Based on what you've read here, you may "expect" (or not) to see differences in performance.  But yes, please do and post!

The facts of octane rating of a particular grade of fuel may or may not be a relevant factor in this equation..
The consensus opinion (okay -the world being flat was also a consensus opinion at one point) for which there is a good deal of testing on and for, is that primarily, a higher octane rating in a fuel provides a benefit to reduce knock (pre-ignition) in typically high compression engines.
The official evidence says that an octane increase alone won't make a difference to an engine that doesn't knock, so it's a waste.
(If your engine STARTS knocking - Go back to super because you NEED it!)

I would point out that most of the testing evidence I've seen addresses power performance.. Tested on a dyno - BUT..
Has anyone seen test results pointed towards comparisons between fuel grades based on fuel economy, or engine performance at the opposite ends of the performance curve (i.e. startup / warmup / redline performance) ?  These are the areas where I noticed a difference.  Not in power output.

At this point, can anyone can say with authority (impassioned opinions aside) exactly what is happening, and what is causing any performance change?
My contention is that I did notice unexpected changes, and think it worthy of further investigation.
Maybe that investigation has already been done.
Maybe any potential benefit may be isolated to specific cases.
Maybe not.
If so, maybe we need to do the testing ourselves...
Keep the Rubber on the Bottom!

DD

Offline hppants

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Re: Placebo or Real? 87 or 92 octane
« Reply #40 on: August 30, 2017, 06:17:12 PM »
FWIW, I'm subscribed.

A spreadsheet of data that DD is proposing would be worth reading.  Furthermore, I'm not too stubborn to learn something new.  I'm leaving tomorrow for a 5 day, 1500 mile trip.  I'll try at least one tank of premium and see if any difference are observed/felt, including mileage.  Remember, I ride an FJR, so any input to your project would be worthless.  None the less, I'm curious...

I still stand by my comments, but am not at all proud of my tone.  That is not who I am.  Granted, I am sensitive to the issue, but all here (and everywhere) are entitled to their opinion.  My apologies to anyone (especially DD) for any offense offered.

Offline DesertDragon

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Re: Placebo or Real? 87 or 92 octane
« Reply #41 on: August 30, 2017, 07:25:27 PM »
Sorry for my continued verbosity, and for any prior offense - especially to you Pants Man - I shouldn't be so passionate.. But I am..
 haphap
There is a lot more chaff than seed out there, but here are a few factors with some consensus I've been able to sift out so far...

Factors which increase engine fuel octane requirements:

* Compression: Higher engine compression ratios increase the engine's octane requirement (91-03 'hawks are 9.3 to 1)
* Temperature: Hotter air increases the engine's octane requirements
* Humidity: Drier air increases the engine's octane requirements
* As engine spark timing is increased, the octane requirement increases
* Driving method: Rapid acceleration and heavy loading increase the engine's octane requirement

Factors which decrease octane requirements:
* Altitude: Higher altitudes decrease your engine's octane requirements (and reduces effective compression)
* Modern Engine Control systems: Automatically compensate for nearly every factor

Looking at some very complex interactions, it appears that there is data to support the case why MY CB750 Nighthawk runs better on high octane fuel:

* Bike designed with (relatively) high compression engine
* My observed (adjusted) compression (see post in Engine Tab - Your bike's compression is better than you think) is close to factory spec ~ 185 +/- 5
* I ride in a very warm, dry environment (during testing period) > 90 F 10% RH
* Higher octane fuel performs better in full advance / high RPM situations - High speed full throttle performance improvement was noted
* My bike is carburated without engine control systems

I do live at altitude ~ 5000' which is a mitigation factor for octane need. 
My hypothesis is the other factors overcome this, to some extent.  (note: I'm NOT driving down into the heat to test this)

Based on these in totality, an effective octane rating for maximum performance for my bike in my environment is estimated between 91 and 93 - NOT 87.
Super (higher octane generally) fuel actually burns slower, but more effectively in the right cylinder, which may be a factor improving low rpm performance.
More effective burn will improve mileage through less fuel needed for a given rpm and cylinder charge.

I'm pretty sure another mystery - for me - Has been solved.

If you are driving a 'Hawk with good compression, in a warm environment "robustly", and especially if you are at relatively low altitude and humidity,
your ride may well benefit from an increase in octane that will be "noticed"....

If no factors apply, probably not (especially bikes with engine control systems).

There may well be other factors involved in fuel formulation components (or lack therof) / additive packages / alternative components (ethenol / MTBE) Etc... Etc... Etc....

This would be a candidate for a lot more input if there is an interest in experimentation.
In the meantime, it's summer, the weather is nice so go for a ride, check it out for yourself and see if you notice a difference...
It will cost you nearly a whole dollar for a tank.... Or don't.

Regards to All
Keep the Rubber on the Bottom!

DD

 

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