[99VTECCoupe]

Took my Accord on the same exact dyno with the same exact dynapack setting and nearly the exact same ambient conditions (see numbers on right side.)

The run today was done with the following differences: Seafoam, TB cleaned, new spark plugs (OEM NGK) and 8 months of using BP 93 octane.

The light line is the 87 octane run in 2007...the bold line is the 93 octane run in 2008.

Extremely disappointing. I guess I won't be buying 93 octane anymore.

 

[05AV6]

I have seen differences of as much as 10 WHP from one dyno run to the next, and there are several other factors that can contribute to lower numbers especially over 8 monthes..

 

[99VTECCoupe]

I have seen differences of as much as 10 WHP from one dyno run to the next, and there are several other factors that can contribute to lower numbers especially over 8 monthes..

Great. I have 4 dyno runs from today and 4 from last year, all were within 1 peak WHP.

edit: I knew you sounded familiar: http://www.v6performance.net/forums/showthread.php?t=148839

This is a serious thread, no talking out of the ass please. We've all been under the impression that using higher octane fuel advanced the ignition timing and led to a peak increase of about 10HP , but I seriously doubt that's true now.

 

[stupidaznmunkey]

for the 6th gen accord, there were obvious reasons why 93 would make no difference against 87 such as lack of a knock sensor, extremely conservative timing etc

but i dont know what about the 7th gen - i guess its the same?

 

[MorePower4me]

Hmm. I have always been using 87 but I guess I was hoping that there would be at least some difference!

Did you check the normal dyno things - similar air pressure in the front tires (that really does make a difference) - car completely cooled before the dyno?

Either way there could be a thousand things that changed that you would have no idea of including recent ECU Fuel mapping. I guess the real thing is whether you feel a difference when using 93?

No one races dyno's, so if you car only dyno'd 190whp but your the quickest guy in town... who cares!

 

[99VTECCoupe]

Apparently. The theory was that because the J30A4 has the knock sensor, it can advance timing with higher octane fuel. I have a scangauge and the timing is actually more advanced vs. 87...on full throttle the timing ATDC was 10-12 and on 93 its 4-8.

On the J30A1 it's been proven that using 93 decreases power, but when the '03 Accord first came out a Honda engineer was quoted in a magazine (car and driver?) that using 93 in the car advanced timing and added 10 horsepower. I guess he was talking out of his ass...

 

[CRV_33]

i dont see why this come to a suprise, honestly this has been covered in the past on this forum.

Regardless, thanks for taking the time to posting your results! I can't really think of any other forum where members contribute their findings :up2:

 

[99VTECCoupe]

Hmm. I have always been using 87 but I guess I was hoping that there would be at least some difference!

Did you check the normal dyno things - similar air pressure in the front tires (that really does make a difference) - car completely cooled before the dyno?

Either way there could be a thousand things that changed that you would have no idea of including recent ECU Fuel mapping. I guess the real thing is whether you feel a difference when using 93?

No one races dyno's, so if you car only dyno'd 190whp but your the quickest guy in town... who cares!

It's a dynapack so the wheels are unbolted and the dyno is bolted straight onto the hubs. Like I said I've been using 93 for well over 10,000 miles and did my most recent tune up stuff 3,000 or so miles ago. I'm more than happy with 220hp at the wheels, the run today was just to see what the 93 octane did. The only difference I've noticed on 93 is slightly better gas mileage around town and no combustion knocking below 1500RPM in high gears.

 

[05AV6]

Great. I have 4 dyno runs from today and 4 from last year, all were within 1 peak WHP.

edit: I knew you sounded familiar: http://www.v6performance.net/forums/showthread.php?t=148839

This is a serious thread, no talking out of the ass please. We've all been under the impression that using higher octane fuel advanced the ignition timing and led to a peak increase of about 10HP , but I seriously doubt that's true now.

I was talking from my experience as well, not out of my ass, all I said is that there were a number of reasons why it could have changed...thanks for the personal attack though :rolleye2:

 

[nighthawk04v6]

temperature, humidity, engine temp, maintenance, wear and tear on the engine all play a role. =| also calibration of the dyno. Dynapacks require alot of maintenance and calibration.

 

[Synthetic599]

I can't seem to find another dyno comparing the two octanes then again I can't find my wallet even if its in my back pocket. Was there any other dyno comparison that proved otherwise?

 

[1iLlaV6]

ok.....so are there really any REAL benefits for using 93?if not im gonna friggin start using 87 no doubt!

 

[99VTECCoupe]

I was talking from my experience as well, not out of my ass, all I said is that there were a number of reasons why it could have changed...thanks for the personal attack though :rolleye2:

No personal attack intended, but in July you were convinced that you gained 25hp between dyno runs and wouldn't listen to anybody.

temperature, humidity, engine temp, maintenance, wear and tear on the engine all play a role. =| also calibration of the dyno. Dynapacks require alot of maintenance and calibration.

As I said, temp, humity, engine temp and calibration were the exact same (incredibly, the temp was 6 degrees lower and the rel hum was likw .5% lower...taking into account the SAE CF, there should be no difference). They had saved my cal file from the previous year. Granted my engine had an extra 20k miles or so, but I did seafoam/plugs/cleaned my intake filter a month ago. Also dida compression test, perfect score all around. The first dyno was with about 90k miles, this one is around 110k. The two possible explanations for the nearly identical power curves are:

1) 93 octane has no effect
2) My engine lost exactly the amount of power that 93 octane had increased it by across the entire curve.

What's more reasonable? 4 dyno runs were within 1 peak WHP of 4 dyno runs taken a year ago...I put 93 octane in my car for 8 months because I believed/hoped that it increased power (and theoretically it should), but I can't possibly believe it right now.

I can't seem to find another dyno comparing the two octanes then again I can't find my wallet even if its in my back pocket. Was there any other dyno comparison that proved otherwise?

Negative, just that statement from the Honda engineer. In order to really prove the effects, the dynos would have to be taken thousands of vehicle miles apart to ensure that the ECU had fully adjusted to the changes.

ok.....so are there really any REAL benefits for using 93?if not im gonna friggin start using 87 no doubt!

Better driveability at low RPM/high throttle (no pinging) when it's hot and humid out. I'll be using 87 this winter but might go back to 93 in the summer.

 

[05AV6]

Actually i had my Dyno redone, they didn't hookup the wideband sensor correctly on my first runs. after Tuning with the Apexi AFC Neo I netted a peak of 219 whp, which is where i thought my car should have been...sorry for any misunderstanding

 

[99VTECCoupe]

Actually i had my Dyno redone, they didn't hookup the wideband sensor correctly on my first runs. after Tuning with the Apexi AFC Neo I netted a peak of 219 whp, which is where i thought my car should have been...sorry for any misunderstanding

Glad to hear you got it straightened out. Remember that most shops are all too happy to take your money as long as you seem happy.

 

[Skeezer]

Found the USA Today article where the engineer says 10hp gain. It is in the third paragraph of the Powertrain section, also is repeated in the side bar that compares our sweet ass car to that POS Camry.

http://www.usatoday.com/money/autos/reviews/2002-08-01-accord_x.htm

 

[Swift]

what spark plugs did you use?
Did you gap them properly?
Did you change type of oil you are using?
change out fuel filter?

things change, some things just never do. Such as ignorance, and ignorance is bliss.

 

[AccordWhite00]

My service guy told me if I ran 93 octane my car will just retard the timing or something, so running 87 and 93 will give you the same effect.


I was told high a compression motor needs higher octane to burn efficiently; the higher the octane the higher the combustion rate.
And low compression motors can use any 87 or 93, but will not have any gain or lose.

I dunno, but I know 93 burns longer then 87 octane.

 

[99VTECCoupe]

My service guy told me if I ran 93 octane my car will just retard the timing or something, so running 87 and 93 will give you the same effect.


I was told high a compression motor needs higher octane to burn efficiently; the higher the octane the higher the combustion rate.
And low compression motors can use any 87 or 93, but will not have any gain or lose.

I dunno, but I know 93 burns longer then 87 octane.

High compression motors need high octane to avoid pre-detonation. Octane is a measure of the resistance of the fuel to compression detonation...basically they have more long carbon chain molecules that are tougher to break apart.

what spark plugs did you use?
Did you gap them properly?
Did you change type of oil you are using?
change out fuel filter?

things change, some things just never do. Such as ignorance, and ignorance is bliss.

OEM NGK Iridium.
You're not supposed to re-gap iridiums (iridium is a very brittle metal, if the gap is out of spec they tell you to send them back. obviously I checked the gap with my gage.)
I've been using Mobil 1 5W-20 since I bought the car. Either way it wouldn't make any noticeable difference...there are several SAE papers that go into the subject, it's really splitting hairs unless you're going from 10W-60 to 0W-20 in an engine with tiny tolerances.
AV6's have permanent fuel filters.

 

[TonyWare]

I think I read here in this forum a while back that a Honda engineer did point out that higher octane will give +10hp. So, whoever wrote that obviously made it up because the dyno results are for everyone here to see.

Usually compression 11.0:1 means premium gas. I think that all the J engines in all v6 Acuras are 11.0:1. What is really interesting is that the Lexus GS430 has a compression ratio of 10.5:1 and still requires premium gasoline while the 09 Accord has the same ratio and they recommend regular gas. Go figure.