U. N. O.

just for the heck of it and curiosity also remembering all that talk in the past about using lower octanage gas, i decided to use 87 in this last tank.

In any other car i ALWAYS notice a difference in response and mialage when using 87 or 93, but in this car, i am getting the exact same miles (+- 220 miles) and have driven it hard and responds just as well!!
so why to pay the extra $.20 more for the same result?

M-ster

Over here where I come from, most of the higher octane gas have some sort of cleaning agent/additive in them. Usually they burning clearner, thus leaving lesser carbon or non, thus giving the engine a longer live spent. I've posted a thread in the FarEast Sec asking what most 8 owner put into their tank, but not much responded. Anyway I'll try a couple diff oct gas and see what works best.

mikeb

someone has already gone a huge log and it showed no difference also

asparapani

You guys are telling me that there's NO DIFFERENCE IN POWER?

Any credited published artciles on this? I would like to check this out.....

U. N. O.

i am sure there is but it is "un-noticible" to the driver now if you go from 87 to 100+ is different.
for now it is only personal use experience

energie

only thing I am concerned about is whether or not it will affect the life of the engine.

come 8 me

that is right engine life is most important.
lets take it to extreme:
"would want to win one race only or race 1000 races." the rice men said.

Zio

I've heard people have had pinging with 87 octane and 91 octane...

Rick

If the engine does not knock and the timing does not change, there would be no noticeable power difference between 87 or 91.

Squidward

Enlighten yourself...

http://www.caranddriver.com/article....&page_number=2
http://www.motortrend.com/features/n...41/index3.html
http://www.hotrod.com/techarticles/72498/index.html
http://www.sportcompactcarweb.com/ed...ble/index.html
http://chemistry.about.com/gi/dynami...1gasoline.html
http://chemistry.about.com/library/w...abyb100401.htm
http://www.techweasel.com/articles/octane.htm
http://www.mydailydriver.com/mdd_content.cfm?ID=27
http://ca.autos.yahoo.com/030731/11/u47t.html
http://www.indianaobserver.com/2002/09/octane.html
http://www.autospeed.com/A_0145/cms/article.html

asparapani

Squidward great references!

Ummm....Basically all the publications run on the same theory. Normal car (civic,neon,camry,protege,sunfire,etc...) should run on regular and hig performance engines should run on premium.

Do we all agree or disagree?

Wing

Well I've been running 89 or 87 since I had the car for 2 weeks, the car seems just as fast and there is no knocking or pinging. The mileage is the same and I don't feel as bad burning the fuel. It also starts better and idles less rough.

O.R.A.

It depends on what the car does with the higher octane.

Some cars will keep advancing timing and optimizing the mapping, up to a point, until it reaches the max level of adjustment or the car shows knocking. If it detects knocking, it backs timing, etc. a notch. In those cars, you'll make more power with higher octane.

Some other cars don't take that into account. In those, you don't get any benefit from a higher octane. As long as there is no knocking, the higher octane is wasted.

From reading on this board, it is my understanding that the RX-8 does benefit significantly from higher octane in terms of increased performance. As to how this correlates to fuel consumption, I don't know.

mikeb

since day 1
91 or higher for me

8_wannabe

Obviously, Car & Driver disagrees with you. As does Mazda. This is a direct quote from squiddie's Car & Driver link:

"Our tests confirm that for most cars there is no compelling reason to buy more expensive fuel than the factory recommends, as any performance gain realized will surely be far less than the percentage hike in price. Cheapskates burning regular in cars designed to run on premium fuel can expect to trim performance by about the same percent they save at the pump. If the car is sufficiently new and sophisticated, it may not suffer any ill effects, but all such skinflints should be ready to switch back to premium at the first sign of knock or other drivability woes."

I understand I am giving up a little power using lower octane, but I've gone back and forth several times and it is completely imperceptible to me. As Car and Driver recommends, at the first sign of knock I will shift back. 4300 miles and no knock yet. Furthermore, on another thread I posted an email from MNAO where they affirmed that neither damage nor degraded mileage will occur with 87. You will only have a slight loss of power. And I don't care. You, too, have a slight loss of power as we all do, so what's the big deal?

8_wannabe

From the Motor Trend link: "Nissan says premium is "recommended" for that engine -- automaker code for regular is OK, but you'll only get the advertised power on premium."

Is anyone reading these articles besides me? They all seem to back up the argument that it's no big deal. I utterly don't care about power loss that I can't feel; I'm not so elitist that I gotta squeeze in a few more octane just so I can say I'm doing it. There are no, zero, nada, ill effects other than unnoticeable decrease in power.

8_wannabe

From the hotrod link: "We filled our 2-gallon fuel cell with a dose of 87 octane and set the total ignition timing at 31 degrees BTDC. Despite the sleazy gas and heavy dyno loading, the smooth power curves indicated no sign of detonation. Then we tried 34 degrees and still no sign of detonation. Yet another counter-clockwise twist of the Accel Billetproof electronic distributor gave the Mopar 36 degrees total; despite the lousy gas, the motor liked the additional timing." Not until they got up to 38 did they detect detonation. And this was in a 10.4:1-compression-ratio 360 Mopar.

I thank squiddy for posting all the links that confirm the reduced octane is no big deal.

8_wannabe

The sportcompactcarweb is useless drivel; just some kid saying anything below 92 in any car is bad all the time and will hurt your engine (he really says this; read it.)

From the chemistry link: "Many people believe that using a high octane level fuel may cause their cars to perform better, get better mileage, go faster or run cleaner. All of these notions are false, according to the FTC...

According to the FTC, car owners may also know if they're using the right level of octane simply by listening to their engine. If there are no pinging or knocking noises, the correct octane level is being used.

Although a higher octane fuel may prevent engine knocking, it does not prevent engine deposits from forming. It also fails to remove previous engine deposits or clean the engine, according to the FTC. Every octane grade of fuel for all brands of gasoline, however, is required by the U.S. Environmental Protection Agency to contain an engine cleaning detergent to protect the engine against harmful deposits."

I'm using 87. My engine doesn't knock. Mazda tells me this is fine. I'm a happy camper.

U. N. O.

just pushed my car to the limit last night, i got 220 miles in 87 oct. gas. i replanish the tank again with 87 oct to do another test ( i put in 14.2 gallons, yes i dried the sucker)

so far no knocking no nothing. it is smoth and performs well as before. if i was running 1/4 miles or so, i might see some difference but in the regular day driving .. nope. I will post as miles go by..

mikeb

I got 205 miles with 13 gallons
but I filled with 91 and right when orange warning came on
thats 15.76 mpg

energie

just curious, is 15.76 acceptable to you?

U. N. O.

yeah thats bad mikeb ...

mikeb

honestly yes
I was hitting 17 and 18
so 15 isnt my best

energie

fair enough. 18 would be tolerable for me.

my best so far is 16.1, that's never going over 3750k

U. N. O.

exactly how many gallons do we have as soon as the light goes on? i think 2 gallons am i correct?