Costco 91 gas vs shell 91

[jonathanyu]

Do they actually have different?
Got all kinds of different information from people
 

[dante]

91 is pretty low, we have 93 here.  Shell is supposed to have additives that for the most part you may not notice unless you have a direct injected engine.  They help postpone carbon build up but you still need the "italian" tune up to do the trick once and again.

I don't know if Costco offers any additives.

[nugglets]

The only difference between different gas "brands" in the US is going to be the additives. Shells additives are pretty good, Chevron as well (though at one time there was some anecdotal evidence of "Techron" buildup in some turbocharged engines).

But all the actual gasoline goes into the pipelines and gets mixed with all of the other gasoline. The companies get a quota based on how much they pump in, which allows them to pump out equal amounts.

And the EPA now requires all gasoline to contain certain amounts of some additives, anyways, so the differences by and large are minimal anymore.

[tp4tissue]

Way way back..  I could drive further on exxon and shell gas vs the off-brands, like raceway..

on BP gas I've gotten the least mileage when they first started the ethanol.


For Costco gas, the price as member is much lower than the surroundings, so just on price it wins.


As long as you have a newer car, it shouldn't matter, because the computer knows what's going on, and will adjust the engine timings accordingly

[jerue]

I don't know much about gas...but I will only buy gas from Costco or Shell. I think Shell is a bit better but most times the savings from Costco add up and the gas is fine. The few times I've cheaped out and used stations like Murphy Express I've regretted it, my car won't perform as well.

[kenmai9]

My anecdotal experience with shell is that i get less mileage than chevron.

Also I use 87 only

[jonathanyu]

91 is pretty low, we have 93 here.  Shell is supposed to have additives that for the most part you may not notice unless you have a direct injected engine.  They help postpone carbon build up but you still need the "italian" tune up to do the trick once and again.

I don't know if Costco offers any additives.

Haven't seen 93 in my life...

If it is just addictive, then I will just stick with costco 87 then
I drive ****ty car anyways

[Leslieann]

The only difference between different gas "brands" in the US is going to be the additives. Shells additives are pretty good, Chevron as well (though at one time there was some anecdotal evidence of "Techron" buildup in some turbocharged engines).

But all the actual gasoline goes into the pipelines and gets mixed with all of the other gasoline. The companies get a quota based on how much they pump in, which allows them to pump out equal amounts.

And the EPA now requires all gasoline to contain certain amounts of some additives, anyways, so the differences by and large are minimal anymore.

Well said!
I will add that most of the difference you find is a matter of how old the station's tanks are and how dirty they are, not necessarily the gas itself. Also, ANY new car should run for 100k miles without the need for any fuel additives such as Techron and such. If your car needed it, the manufacturer would have specified it.



As for 87, 89, 91 vs 93...
Before people get too deep in this, understand much of the world rates gas different, using the R.O.N. scale rather than octane. If I remember right, 93 R.O.N. is the same as 91 octane. Our gas isn't garbage, it's rated different (not that the rating means what many think it does).

Use what the manufacturer states. Higher octane actually burns slower (yes slower!) and requires the ignition timing adjusted to compensate, the slower burn  means less explosion under high compression and heat. Some modern injection systems can compensate, but most are tuned for only one or two grades, usually what is stated and e85*.

There are cases where you may be better to run something higher and that is an older high mileage car or a carburetor vehicle. If your engine is pinging on hills (detonation, which is BAD!), while you should get a tuneup (o2 sensor is probably failing), higher octane can sometimes help, but if it's not pinging, run what the manufacturer says because you are wasting money, but also...


So what happens if you run higher octane when you shouldn't?
On older cars you simply waste gas, on newer cars, the emissions controls are so insanely tight that you can actually burn up the catalytic converter. It can clog and drastically reduce performance and even blow out the EGR valve. Contrary to popular belief, removing this stuff will not make your engine run better (not without a computer re-tune). In other words, DON'T! Older carb'd cars had looser emissions and the cats could tolerate some abuse, newer cars absolutely cannot, so unless you want to spend a few hundred on new catalytic converters, run what you are supposed to.


*E85...  It may be cheaper, but you also go a lot shorter distance as it contains less energy. If you do the math, it needs to be about 2/3rds the price to break even with normal gas,which is now also being diluted with ethanol. Ethanol is grossly over-rated.

[jonathanyu]

The only difference between different gas "brands" in the US is going to be the additives. Shells additives are pretty good, Chevron as well (though at one time there was some anecdotal evidence of "Techron" buildup in some turbocharged engines).

But all the actual gasoline goes into the pipelines and gets mixed with all of the other gasoline. The companies get a quota based on how much they pump in, which allows them to pump out equal amounts.

And the EPA now requires all gasoline to contain certain amounts of some additives, anyways, so the differences by and large are minimal anymore.

Well said!
I will add that most of the difference you find is a matter of how old the station's tanks are and how dirty they are, not necessarily the gas itself. Also, ANY new car should run for 100k miles without the need for any fuel additives such as Techron and such. If your car needed it, the manufacturer would have specified it.



As for 87, 89, 91 vs 93...
Before people get too deep in this, understand much of the world rates gas different, using the R.O.N. scale rather than octane. If I remember right, 93 R.O.N. is the same as 91 octane. Our gas isn't garbage, it's rated different (not that the rating means what many think it does).

Use what the manufacturer states. Higher octane actually burns slower (yes slower!) and requires the ignition timing adjusted to compensate, the slower burn  means less explosion under high compression and heat. Some modern injection systems can compensate, but most are tuned for only one or two grades, usually what is stated and e85*.

There are cases where you may be better to run something higher and that is an older high mileage car or a carburetor vehicle. If your engine is pinging on hills (detonation, which is BAD!), while you should get a tuneup (o2 sensor is probably failing), higher octane can sometimes help, but if it's not pinging, run what the manufacturer says because you are wasting money, but also...


So what happens if you run higher octane when you shouldn't?
On older cars you simply waste gas, on newer cars, the emissions controls are so insanely tight that you can actually burn up the catalytic converter. It can clog and drastically reduce performance and even blow out the EGR valve. Contrary to popular belief, removing this stuff will not make your engine run better (not without a computer re-tune). In other words, DON'T! Older carb'd cars had looser emissions and the cats could tolerate some abuse, newer cars absolutely cannot, so unless you want to spend a few hundred on new catalytic converters, run what you are supposed to.


*E85...  It may be cheaper, but you also go a lot shorter distance as it contains less energy. If you do the math, it needs to be about 2/3rds the price to break even with normal gas,which is now also being diluted with ethanol. Ethanol is grossly over-rated.

If that is true, why high performance car usually suggests 91 or even higher?
I'm just curious btw

[tp4tissue]

If that is true, why high performance car usually suggests 91 or even higher?
I'm just curious btw

bigger octane = m0ar power


supposidly it also has to do with the engine designed for the gas,  but because of the computer,  there's absolutely no reason why it can't run on p00r people gas,.

<but you won't get the power>



But the POWER is stupid anyways,  because WHY ? you want to get to work quicker ?  yea you realllly love work do ya ?..  gotta save the boss some time..

hahahahahhahahahah....

[nugglets]

If that is true, why high performance car usually suggests 91 or even higher?
I'm just curious btw

bigger octane = m0ar power


supposidly it also has to do with the engine designed for the gas,  but because of the computer,  there's absolutely no reason why it can't run on p00r people gas,.

<but you won't get the power>



But the POWER is stupid anyways,  because WHY ? you want to get to work quicker ?  yea you realllly love work do ya ?..  gotta save the boss some time..

hahahahahhahahahah....

Because driving is fun, and more power = more fun =)

[Leslieann]

If that is true, why high performance car usually suggests 91 or even higher?
I'm just curious btw

I thought someone was putting me on the first time I heard it as well.  )

The more fuel and air you can put into an engine and compress it, the more power you can get out. However, the more you compress it, the more unstable the fuel becomes, at some point it detonates. Under the right conditions, this can literally blow the head off the engine.

The slower burning fuel makes it resistant to exploding under high pressure or temperatures allowing you to have higher compression without it going boom. While it sounds counter intuitive to burn slower, it's easy to compensate for by adjusting the timing to ignite it a little sooner, which is exactly what they do.

It's the ability to run higher compression or forced induction that makes more power, not anything the fuel itself is doing.

supposidly it also has to do with the engine designed for the gas,  but because of the computer,  there's absolutely no reason why it can't run on p00r people gas,.

You are sort of right.

Not every engine, computer controlled or not, can completely compensate for cheap gas, even if it can, that doesn't mean it will get the most from it.

Many that do compensate do it in a crude manner by simply listening for pinging/detonation and retarding the timing until it stops (this was common on older Camaros). The engine isn't re-tuned or anything, it's simply just cut off at the knees. You need to do more than just adjusting the timing to completely compensate. If it can adjust, and some newer cars can, it's still a compromise and can take most of a tank (or more) before it really learns the new fuel curve (switching back and forth is a BAD idea). Again, it's still a compromise because the compression ratio of the engine is the biggest determining factor  for what octane it requires and you cannot change without altering the heads or pistons. Your asking the system to compensate and make do, not run how it was designed.

Now, here is where it gets dangerous...
In a new car, odds are this won't be an issue, but as it ages, the detonation sensors can falsely trip leading to a loss of power (older Camaros) or fail to register it entirely. You start running lower octane and the engine may not pick up that it's detonating and slowly but surely just destroy your engine (or not so slowly!).  As the engine ages and carbon builds up, it becomes even more susceptible to detonation (old Camaros). Some Nissan Xterras and Forntiers are known for this and many owners switch to mid-grade gas to compensate for it, is it the right way of dealing with it? No, but it works. And no, you don't get more performance since you didn't  up the compression ratio, it's simply a bandaid to keep the engine from eating itself.


Many people think fuel injected engines are complex, and the truth is, they often are actually quite crude and low on computing power. Other than Tesla, most car makers really have not embraced technology willingly, this is probably why Cadillac was so scared of Tesla, they simply do not understand the technology and they only use it because they have to.

[jonathanyu]

LOL nope

[nugglets]

(Attachment Link)

LOL nope

WTF? I live in CA, too, and I haven't seen over ~$3.25 in awhile.

[JaccoW]

(Attachment Link)

LOL nope

WTF? I live in CA, too, and I haven't seen over ~$3.25 in awhile.

Meh, still cheap compared to Europe.

I was in Texas a few weeks ago and people apologized for the expensive gas @ $2.25/gallon.
We pay €1.65/Liter around here. (that's somewhere around $6.85/gallon)

The guy did a double take and mentioned that getting groceries would be really expensive at those prices. )

[Leslieann]

While liters in the UK and the US are the same, the gallons are not.
3.7854 liters to make a US gallon.
4.546 liters to make a UK gallon.

€1.65/Liter is actually:
€6.25 per US Gallon (about $7 USD)
€7.50 per UK gallon (about $8.41 USD)

As for our gas being cheaper, we buy more because our economy currently depends on it and it being cheap. The average mileage in the U.K. is 9700 miles per year, while we drive 13.7k (almost 50% more), with some age groups pushing 20k miles on average per year. I don't think the US average annual mileage has been under 10k since the late 80's early 90's.

[JaccoW]

While liters in the UK and the US are the same, the gallons are not.
3.7854 liters to make a US gallon.
4.546 liters to make a UK gallon.

Fun fact: They are both currently a secondary unit of measurement and based on the primary measurement of one liter.

You don't necessarily buy more because you economy depends on it but because you are an oil-producing country. Gas is cheap in Russia and Saudi Arabia as well fot example but those too are producers.
I live in the Netherlands where it has to be imported. Besides that we also tax it heavily because we have a high population density, which leads to risk of air pollution and there are plenty of alternatives in the form of public transport.

[Leslieann]

You don't necessarily buy more because you economy depends on it but because you are an oil-producing country. Gas is cheap in Russia and Saudi Arabia as well fot example but those too are producers.
I live in the Netherlands where it has to be imported. Besides that we also tax it heavily because we have a high population density, which leads to risk of air pollution and there are plenty of alternatives in the form of public transport.

This last year was the first time in history we exported more than we imported because we use so much, in fact when oil goes up, our economy struggles. Despite Chinese manufacturing, the US is still a huge producer of goods, particularly items using oil.  Also, Scotland is an oil producer, it's fueled the last economic boom you had. Based on your theory, your  fuel should also be cheap.

If you think we pay very little, we pay actually pay a truckload compared to the other countries you mentioned. Russia is paying 70 cents per gallon and Saudi pays only 24 cents per gallon.

[jonathanyu]

(Attachment Link)

LOL nope

WTF? I live in CA, too, and I haven't seen over ~$3.25 in awhile.

Meh, still cheap compared to Europe.

I was in Texas a few weeks ago and people apologized for the expensive gas @ $2.25/gallon.
We pay €1.65/Liter around here. (that's somewhere around $6.85/gallon)

The guy did a double take and mentioned that getting groceries would be really expensive at those prices. )

usually costco 91 is like 2.55-2.75 in where i have been in ca...
chervon usually like 3.35-3.55...
this 3.999 is just pure bull****

While liters in the UK and the US are the same, the gallons are not.
3.7854 liters to make a US gallon.
4.546 liters to make a UK gallon.

€1.65/Liter is actually:
€6.25 per US Gallon (about $7 USD)
€7.50 per UK gallon (about $8.41 USD)

As for our gas being cheaper, we buy more because our economy currently depends on it and it being cheap. The average mileage in the U.K. is 9700 miles per year, while we drive 13.7k (almost 50% more), with some age groups pushing 20k miles on average per year. I don't think the US average annual mileage has been under 10k since the late 80's early 90's.

dafuq
i never notice that uk use gallon..... and even a different gallon

[chyros]

The way these numbers work is that the plants take high grade petrol and put as much crap on them as they're allowed within the confines of the law and as much low grade petrols to get that number.

[katushkin]

You guys talking about 91 vs 87 octane... Our Shell V-Power in the UK is 99 RON...

[Leslieann]

UK uses RON, the US uses AKI (average knock index, a mix of MON and RON)

99 RON = 93 AKI*, which you can find in the US at various stations.
We also have E85 which is 102-105RON or 94-95 AKI, though it's getting harder to find.

*Had it wrong earlier.

[nugglets]

You guys talking about 91 vs 87 octane... Our Shell V-Power in the UK is 99 RON...

I bought 100 octane (pre-E85) for years in my old custom tuned car, what's your point? 

[tp4tissue]

You guys talking about 91 vs 87 octane... Our Shell V-Power in the UK is 99 RON...

I bought 100 octane (pre-E85) for years in my old custom tuned car, what's your point? 

did you get ur engine timings and bore adjusted for 100 octane ??

[chyros]

You guys talking about 91 vs 87 octane... Our Shell V-Power in the UK is 99 RON...

Knowing what the number means, I'd rather have cheap petrol than high octane fuel. The Americans have it right in this matter.

[digi]

And here I thought all you gals would be driving electric cars by now

[JaccoW]

You don't necessarily buy more because you economy depends on it but because you are an oil-producing country. Gas is cheap in Russia and Saudi Arabia as well fot example but those too are producers.
I live in the Netherlands where it has to be imported. Besides that we also tax it heavily because we have a high population density, which leads to risk of air pollution and there are plenty of alternatives in the form of public transport.

This last year was the first time in history we exported more than we imported because we use so much, in fact when oil goes up, our economy struggles. Despite Chinese manufacturing, the US is still a huge producer of goods, particularly items using oil.  Also, Scotland is an oil producer, it's fueled the last economic boom you had. Based on your theory, your  fuel should also be cheap.

I don't really get your highlighted comment. Could you explain what you mean?
One reason for our high prices is that it has some of the highest taxes on fuel that I know of.

As for fuel prices;

Gasoline prices, 15-May-2017: The average price of gasoline around the world is 3.89 U.S. Dollar per us gallon. (1.03 U.S. Dollar per liter)However, there is substantial difference in these prices among countries. As a general rule, richer countries have higher prices while poorer countries and the countries that produce and export oil have significantly lower prices. One notable exception is the U.S. which is an economically advanced country but has low gas prices. The differences in prices across countries are due to the various taxes and subsidies for gasoline.

All countries have access to the same petroleum prices of international markets but then decide to impose different taxes. As a result, the retail price of gasoline is different.

Globalpetrolprices.com

If you think we pay very little, we pay actually pay a truckload compared to the other countries you mentioned. Russia is paying 70 cents per gallon and Saudi pays only 24 cents per gallon.

Depends on how you compare. In absolute sense, sure. But if you compare to how much that takes out of your income each year it is a different story:
USA: $2.57/gal.The average driver uses 421.56 gallons a year, which eats up 1.82% of the typical salary.
Saudi Arabia: $0.91/gal. The average driver uses 258.34 gallons a year, which eats up 1.11% of the typical salary.
Russia: $2.58/gal. The average driver uses 89.55 gallons a year, which eats up 2.07% of the typical salary.
The Netherlands: $6.30/gal. The average driver uses 80.75 gallons a year, which eats up 1.13% of the typical salary.
Hong Kong: $7.23/gal. The average driver uses 29.03 gallons a year, which eats up 0.48% of the typical salary.
Source: Gasoline Prices Around the World: The Real Cost of Filling Up - Bloomberg

So even though that guy from Russia only uses 20% of what the American uses each year, he is still spending more of his total income on gas.
In that regard, it sucks to be Mexican, they spend 3.86% of the typical salary on gas.

[nugglets]

You guys talking about 91 vs 87 octane... Our Shell V-Power in the UK is 99 RON...

I bought 100 octane (pre-E85) for years in my old custom tuned car, what's your point? 

did you get ur engine timings and bore adjusted for 100 octane ??

You don't need to bore the motor for an increase in octane.

But yes, the car was dyno tuned for both 100 octane and 97 octane (because a full tank of 100 is $$$, so I had the road course tune set for 97 which was achieved by mixing 91 and 100 at a 1:2 ratio). I also had a 91 tune for road trips that focused on MPG, because I never wanted to buy a truck and a trailer just to haul my toys around when I could drive them instead. Changing the tune took less than 90 seconds with a laptop, most of that time spent fidgeting with cables.

[tp4tissue]

You don't need to bore the motor for an increase in octane.

But yes, the car was dyno tuned for both 100 octane and 97 octane (because a full tank of 100 is $$$, so I had the road course tune set for 97 which was achieved by mixing 91 and 100 at a 1:2 ratio). I also had a 91 tune for road trips that focused on MPG, because I never wanted to buy a truck and a trailer just to haul my toys around when I could drive them instead. Changing the tune took less than 90 seconds with a laptop, most of that time spent fidgeting with cables.

How do you know if the tuning is working efficiently from day to day.


For example, even the same gas station could be supplied with different sources of gas

So maybe it's all 91 octane, but the additives could be different than the gas you had when you went to the tuner..   or a radically different ethanol mix..  these things could greatly alter tuning curves.


Is there some sort of monitoring tool such that you KNOW for a fact that it's working, or is it the belief behind this ordeal that you're really after.

[nugglets]

You don't need to bore the motor for an increase in octane.

But yes, the car was dyno tuned for both 100 octane and 97 octane (because a full tank of 100 is $$$, so I had the road course tune set for 97 which was achieved by mixing 91 and 100 at a 1:2 ratio). I also had a 91 tune for road trips that focused on MPG, because I never wanted to buy a truck and a trailer just to haul my toys around when I could drive them instead. Changing the tune took less than 90 seconds with a laptop, most of that time spent fidgeting with cables.

How do you know if the tuning is working efficiently from day to day.


For example, even the same gas station could be supplied with different sources of gas

So maybe it's all 91 octane, but the additives could be different than the gas you had when you went to the tuner..   or a radically different ethanol mix..  these things could greatly alter tuning curves.


Is there some sort of monitoring tool such that you KNOW for a fact that it's working, or is it the belief behind this ordeal that you're really after.

Does tp4 actually know about engine tuning, or is this just another judgmental assumption about the motives of other peoples spending?

The quality discrepancy between different fuels is very unlikely to have a significant impact, honestly. "Bad" gasoline just isn't common at all in my experience.

But since you seem so genuinely worried about my engine, let me assure you that between the wideband O2 and having direct access to every factory sensor on my laptop, one can "KNOW for a fact." And the ECU would make timing, fuel, boost and other adjustments automatically depending on several factors within specific margins. I was also capable of making minor software adjustments on my own or, for more complex adjustments, sending the data logs to the tuner and getting a new tune to flash.

The stock management system on that car was particularly robust compared to most, especially for it's time. Once the community cracked it open, a whole new world of custom tuning became available to anyone with the time and patience to learn it.

[digi]

Once the community cracked it open, a whole new world of custom tuning became available to anyone with the time and patience to learn it.

[tp4tissue]

Once the community cracked it open, a whole new world of custom tuning became available to anyone with the time and patience to learn it.

Show Image

also.. it explodes into blue flames.. /super cool.

[digi]

Once the community cracked it open, a whole new world of custom tuning became available to anyone with the time and patience to learn it.

Show Image

also.. it explodes into blue flames.. /super cool.

Yea, just like my outdoor wok when I throw the chicken into the oil!

[nugglets]

Once the community cracked it open, a whole new world of custom tuning became available to anyone with the time and patience to learn it.

Show Image

But in all seriousness, I've never owned a car with nitrous or alcohol injection, ITBs or any of that super fancy stuff.

[tp4tissue]

Does tp4 actually know about engine tuning, or is this just another judgmental assumption about the motives of other peoples spending?

The quality discrepancy between different fuels is very unlikely to have a significant impact, honestly. "Bad" gasoline just isn't common at all in my experience.

But since you seem so genuinely worried about my engine, let me assure you that between the wideband O2 and having direct access to every factory sensor on my laptop, one can "KNOW for a fact." And the ECU would make timing, fuel, boost and other adjustments automatically depending on several factors within specific margins. I was also capable of making minor software adjustments on my own or, for more complex adjustments, sending the data logs to the tuner and getting a new tune to flash.

The stock management system on that car was particularly robust compared to most, especially for it's time. Once the community cracked it open, a whole new world of custom tuning became available to anyone with the time and patience to learn it.

I'm am not your enemy.

Your own oversight however MIGHT BE..



The oversight here is,  you've invested in a claim, but you've not conclusively / aggressively tested that claim for yourself.


Your statement includes information that --YOU COULD--..  but the description of your methodology indicates that it would be impractical as the procedure is time-intensive.


AND so, the entire investment is ineffective at capturing the peak efficiency you've championed the practice upon.


It's the same as buying holtites and hotswappable keyboards..  NO BODY goes through the trouble of doing swaps more than once because the benefits are seldom tangible..



For your car,  Yea, you seem to have the capacity to retune,  but the process is so troubling, that you probably wouldn't bother doing it too often..



So ,  for all of the potential mixtures out there which could impact the efficiency curve,  you're not always optimized without an automatic way of persistent monitoring..



In the end,  the bulk of this purchase is you feeling better about your car,  while you actually have no idea if it's actually happening.. 

You've Not truly accomplished the your original claim to efficiency improvement due to the limitation of monitoring.

[nugglets]

Does tp4 actually know about engine tuning, or is this just another judgmental assumption about the motives of other peoples spending?

The quality discrepancy between different fuels is very unlikely to have a significant impact, honestly. "Bad" gasoline just isn't common at all in my experience.

But since you seem so genuinely worried about my engine, let me assure you that between the wideband O2 and having direct access to every factory sensor on my laptop, one can "KNOW for a fact." And the ECU would make timing, fuel, boost and other adjustments automatically depending on several factors within specific margins. I was also capable of making minor software adjustments on my own or, for more complex adjustments, sending the data logs to the tuner and getting a new tune to flash.

The stock management system on that car was particularly robust compared to most, especially for it's time. Once the community cracked it open, a whole new world of custom tuning became available to anyone with the time and patience to learn it.

I'm am not your enemy.

Your own oversight however MIGHT BE..



The oversight here is,  you've invested in a claim, but you've not conclusively / aggressively tested that claim for yourself.


Your statement includes information that --YOU COULD--..  but the description of your methodology indicates that it would be impractical as the procedure is time-intensive.


AND so, the entire investment is ineffective at capturing the peak efficiency you've championed the practice upon.


It's the same as buying holtites and hotswappable keyboards..  NO BODY goes through the trouble of doing swaps more than once because the benefits are seldom tangible..



For your car,  Yea, you seem to have the capacity to retune,  but the process is so troubling, that you probably wouldn't bother doing it too often..



So ,  for all of the potential mixtures out there which could impact the efficiency curve,  you're not always optimized without an automatic way of persistent monitoring..



In the end,  it seems you may feel better about your car..  but you've Not truly accomplished the your original claim to efficiency improvement due to the limitation of monitoring.

Wat.jpg

It took 10 minutes to make minor adjustments, I did it all the time. On top of that, engine tuning isn't as black and white as you're making it out to be. As I said, the system was setup such that it made it's own adjustments in milliseconds based on real time sensor data which was checked against several tables for optimal performance over a wide range of conditions.

No mechanical engine will ever run at 100% efficiency, that's unattainable. To claim that anything short of that has accomplished nothing shows how far out of your own depth this topic is.

I also never claimed anything, other than the car had been tuned for higher octane fuel. It's petty easy to see if the tune is providing greater efficiency over a stock tune, or lesser grade fuel, or anything, really,  when you have acceleration data readily available in real time.

You never answered my question, though. Does tp4 actually know anything about engine tuning that he didn't look up on the internet in the last several hours?

[digi]

Does tp4 actually know anything about engine tuning that he didn't look up on the internet in the last several hours?

TP IS the Internet, it's impossible for him to "look it up"