Premium fuel

[Draken187]

I. Put premium in my tank..bwas down to 6 miles to go and wasnt sure how far til the mext gas station and they were out of regular.. So i filled it with premium. Not thinking about it i drove home.. 30 min backroads and 20 min highway.. The car "felt" "stronger" similar situation with my accord i did not feel any difference.. Once i got home i looked at my fuel economy.. 44.7mpg on a 22 degrees Fahrenheit day.. Wow.. Normally i get about 35mpg on that drive...

Thoughts? Experience? Gonna measure and do the math on next fill up.. But wow.... Seriously...

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[wilbur_the_goose]

Placebo on how it felt. Higher octane prevents knocking. It doesn't make your car faster/stronger.

The highly qualified engineers at Honda designed it to run on 87 Octane.

Don't waste your money on anything other than 87.

 

[Quicksipper]

Placebo on how it felt. Higher octane prevents knocking. It doesn't make your car faster/stronger.

The highly qualified engineers at Honda designed it to run on 87 Octane.

Don't waste your money on anything other than 87.

there is multiple threads on this and the myth that it's placebo has been put to rest by Hondata and Vit. the car has knock control so it can take advantage of higher octane, the sport has the same motor and takes advantage of high octane. the manual that comes with your vehicle actually states 87 OR higher. they don't advertise it makes more power, why? because it effects cost of ownership and that would turn people away from the everyday drivers non sport civic.

 

[Draken187]

Placebo on how it felt. Higher octane prevents knocking. It doesn't make your car faster/stronger.

The highly qualified engineers at Honda designed it to run on 87 Octane.

Don't waste your money on anything other than 87.

The manual clearly states 87 octane or higher as the recommended fuel.. So honda engineer's do not recommend only 87 octane.. But recommend using anything from 87 89 91 93 94.. This isnt 1990 to 2000.. And im sure car computers dont just take a 93 octane and make adjustments so it behaves just like 87 octane.. In the last 20 years im sure an engineer somewere said. Hey isntead of wasting the 93 that someone puts in the tank.. Why dont we use it to our advantage since we know its gonna ignite slightly later..


I will also add that the first person to feel the difference was not me, however as it was my wife in the passenger seat.. Her words were to the tune of.." Jesus (my real name) did you start messing with this car like your type r in spain? " she then said something like without using the word pull.. Its pulling/pushing me into the seat more than usual.. At no point did i add any bolt ons or such and never told her a filled it with premium..

I told her myself its in your head and the cars the same... Only decided to post this after i got home and saw the much better fuel economy than i would normally get for that drive.. Just short of 10mpg better is pretty amazing... Although not a controlled test.. The fact that my wife thought i was driving more spirited'ly than usual.. And the lower temp than usual 100% leads me to believe it was the fuel..

10 years ago you told me it was placebo/all in my head.. I would agree with you... Fortunately times change... So people just dont think that other things change with time... A manufacturer can decide to make a car run better with better fuel... And still say 87 is all you need... Especially when they sell a ton of cars based on.. You guessed it.. 87 is all you need (at the bare minimum)

 

[NorthernEX-T]

Placebo on how it felt. Higher octane prevents knocking. It doesn't make your car faster/stronger.

The highly qualified engineers at Honda designed it to run on 87 Octane.

Don't waste your money on anything other than 87.

That's actually a false statement, but I was wrong too. Do some more research please.

 

[Newflyer3]

Or you know, the engineers wrote in the manual to use 87 on models that don't say premium recommended and that 91 is recommended on labels for premium gasoline. I mean, do whatever you want since it's your car and I'm sure the engineers did have in mind the resolve of people who will put 87 in it anyway.

 

[josby]

the myth that it's placebo has been put to rest by Hondata and Vit. the car has knock control so it can take advantage of higher octane, the sport has the same motor and takes advantage of high octane.

Did either of them ever publish dyno results for regular and high octane on the stock tune? I only saw results for high octane on custom tune. I'd be curious to see how different their numbers are from Honda's regular/sport numbers.

From Honda's numbers, it doesn't seem like the Civic ECU takes as much advantage of higher octane as it could. 174 HP on regular versus 180 on high octane is only a 3% gain. Compare that to the K24 2.4L that's in the current-gen Accord and TLX - 189 HP on regular gas in the Accord (dual exhaust models) versus 206 HP on high octane in the TLX. 9% gain. Same block, same compression ratio, same head, same fuel injectors, etc, so that gain is just from being tuned for higher octane.

 

[dblshock]

Sunday I ran 115mi. 65-75 and 130 mi. 75-85 zero wind. 41mpg on E091 mixed with 640:1 TCW-3 oil.

 

[Design]

I wouldn't be surprised if the ECU parameters were the same on the Civic Hatch Sport and the other 1.5T trims. If a +5-7 HP increase and higher detergent ratio seems worth it to you, get 91/92.

IMHO, we're splitting hairs until we start modifying for performance.

 

[VarmintCong]

I wouldn't be surprised if the ECU parameters were the same on the Civic Hatch Sport and the other 1.5T trims. If a +5-7 HP increase and higher detergent ratio seems worth it to you, get 91/92.

IMHO, we're splitting hairs until we start modifying for performance.

Definitely worth it to me, my Sport comes alive with 93 in it.

 

[Quicksipper]

I wouldn't be surprised if the ECU parameters were the same on the Civic Hatch Sport and the other 1.5T trims. If a +5-7 HP increase and higher detergent ratio seems worth it to you, get 91/92.

IMHO, we're splitting hairs until we start modifying for performance.

1. Hondata
   No you cannot expect to gain 12 HP. Maybe 7-8. That is a best guess. A rigorous test would involve;
   • Test with 87, and noting the knock control.
   • Draining the tank and filling with 93, would take two tankfuls as the tank does not completely empty.
   • Test with 93, which is not easily available in California.
   There were no mods on the car. It was stock. Octane helps, but the best performance mod for the dollar is the FlashPro.
   
   
   

 

[Quicksipper]

I wouldn't be surprised if the ECU parameters were the same on the Civic Hatch Sport and the other 1.5T trims. If a +5-7 HP increase and higher detergent ratio seems worth it to you, get 91/92.

IMHO, we're splitting hairs until we start modifying for performance.

Hondata
The ECU code and data relating to performance is the same as in the lower horsepower turbo

 

[dblshock]

Hondata
The ECU code and data relating to performance is the same as in the lower horsepower turbo

So do you know where they found the extra 5hp?

 

[Quicksipper]

So do you know where they found the extra 5hp?

assuming "they" is Honda and "extra horsepower *for the sport model*" as Hondata was implying, it is fuel grade, since the coding was the same for the ecu, if coding is the same, and internals are the same I assume it's a combination of opening up the exhaust a bit more and stamping the premium recommended label on it.

 

[Quicksipper]

Did either of them ever publish dyno results for regular and high octane on the stock tune? I only saw results for high octane on custom tune. I'd be curious to see how different their numbers are from Honda's regular/sport numbers.

From Honda's numbers, it doesn't seem like the Civic ECU takes as much advantage of higher octane as it could. 174 HP on regular versus 180 on high octane is only a 3% gain. Compare that to the K24 2.4L that's in the current-gen Accord and TLX - 189 HP on regular gas in the Accord (dual exhaust models) versus 206 HP on high octane in the TLX. 9% gain. Same block, same compression ratio, same head, same fuel injectors, etc, so that gain is just from being tuned for higher octane.

I don't think they showed a dyno chart between premium and regular but I don't know what they would have to benefit over such a claim.

...I can speculate why the sport isn't "tuned" for high octane don't want to get into SI territory do we?

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