Difference with premium gas!

I think its all in your head higher octane reduces engine knock, thats it Did your engine knock when using regular gas? Does your owners manual require premium or just regular? If it only requires regular, your throwing your money away with premium

I've got a 96 Integra SE and have always used regular gas. My daughter likes to put Shell super in it and I told her she was wasting her money. However I drove it afterward and it seems smoother, peppier and even quieter on the super!

It's got 135k on it maybe its carboned up and has higher compression now. What do you think?

-- Ron Ron did it run fine before on regular 87 octane with-out any pinging or knocking? a vehicle designed for regular 87 octane should not need premuim fuel if premuim fuel makes a knock or pinging go away then its due to increased compression due to carbon buildup in the combustion chamber get the carbon cleaned out and you can go back to regular fuel.

Well of course it is, that's where perception takes place!

You are just quoting the dogma but believe me it runs better. It is obvious to everyone who drives the car. Could it be the better additive package in super shell compared to the Meijer's gas I usually run? rj

Personally I think Premium is better for the vehicle and gives you better mpg but when it comes to cost it's pretty much even.

"Ron Jones" wrote in news:jAdpg.7998$ snipped-for-privacy@tornado.ohiordc.rr.com:

Psychosomatic.

In engines with knock detectors - I'm sure the 96 Integra has one - low octane or advanced ignition don't produce audible detonation. When the Volvo dealer (of all people!) set the ignition 25 degrees advanced on my Volvo it didn't audibly ping at all, but had a faint surging feeling under acceleration. I presume that was from the knock detector retarding the spark. The retarding is done rather heavy-handedly in order to protect the engine. I wouldn't be surprised if the amount was ten degrees or more.

Under those conditions using regular instead of premium actually amounts to retarding the timing a lot during acceleration, with all the loss of efficiency that implies.

My understanding of "octane rating" is that it does not involve burn rate or energy content... directly, anyway. The steps taken to improve octane may have either or both those effects. Anyway, the "octane rating" historically was measured in a test apparatus that approximated an engine cylinder to determine the point at which the fuel/air mixture transitioned from ignition being spread by the flame front to being spread by the pressure front - detonation. More recently spectrometer measurements have become common.

It's also important to understand that detonation is different from pre-ignition (where the mixture is fired by hot spots like carbon). Pre-ignition can't be controlled by knock detectors because the spark isn't causing ignition, and for the same reason premium fuel is not very effective in dealing with pre-ignition. If there is carbon in the combustion chambers and it is causing pre-ignition it must be cleaned out.

Mike

Come on TeGGeR what are you really saying? Are you a regular or premium fan?

What you say is often true, but not always. Honda's project manager on the 2003 Accord redesign claims that it's V-6 makes higher than specified horsepower when fueled with premium gas: "Baker says ... if you run premium fuel in your Accord you'll get more horsepower..." {

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With knock sensor equipped engine management systems it is possible that a more aggressive advance map be used with better fuel. It really all depends on the software embedded in the car and variables with the vehicle itself.

The OP theory that combustion chamber deposits might have raised the compression ratio is plausible. The car might be dialing back it's timing map on regular fuel and then providing more advance with premium.

Only a dyno, dragstrip or one of those nifty g-tech in-car accelerometers will tell for sure.

John

Modern knock sensors should never allow audible knock or pinging, so your test doesn't apply to most modern vehicles. 1980s and earlier technology, sure, but not the newer stuff.

John

"jamo" wrote in news:4bxpg.4045$ snipped-for-privacy@nasal.pacific.net.au:

I'm not a "fan" of anything. Gas is gas.

I've done some testing with my own '91 Integra on 87 and 91 octane. I cannot tell any difference at all in engine behavior and performance with either octane rating. My car was designed to use 87 octane.

There appears to be some evidence that 91 octane gives me about 2% less mileage, but my testing periods are necessarily long (several months), so weather may play more of a role in that than octane.

"Michael Pardee" wrote in news:hsidnZc2DvF77jvZnZ2dnUVZ snipped-for-privacy@sedona.net:

There is lots of misinformation about octane and burn speed. Automotive gasoline burns at exactly the same rate regardless of octane.

The energy content of gasoline tends to decrease as octane rises, but higher compression ratios and chamber pressures can then be used to improve power output.

Detonation is when the fuel/air mixture explodes all at once. It is this which higher octane is supposed to prevent.

Preignition can also be caused by spark plugs of the wrong heat range.

Does the 96 Integra have knock detector with capability to adjust the timing?

Ron

Regardless of what you say, I know what my Honda Euro does and does not do on different octane fuel. In Australia there are two primary premium fuels, the lower premium is 95 octane and the higher is 98. I find my 2.4 litre 140Kw engine gives far better results on 98.

95 octane is 6 cents per litre dearer than standard inleaded (27c per gallon), while 98 is 10c per litre extra (+45c per gal). The mpg figures vary by approximately 3mpg. You might think that's not much but to me it's huge. In America your gas costs are miniscule compared to the rest of the world so think yourself lucky. Today (July 6) the common price in my area is $AUD 1.43 per litre, that's $6.50 a gallon. Gas stations here tend to discount over the weekend with fuel reaching a low point around Tuesdays. Tuesday just gone the price was $AUD 1.29 per litre, or $5.86 a gallon. In Europe the prices are much higher, so, as I said, consider yourself lucky in North America, you're being artificially protected from reality. As long as the Iraq, Palestine and North Korea problems keep happening it ain't going to get better. By the way, who is responsible for all this world instability?

Uh, wait a minute, your fuel costs are high because of extraordinarily high taxes on fuel in your country. How does the fact that the US has lower fuel taxes than the outrageously high ones imposed in many other countries mean that US drivers are being "protected from reality". I guess you consider taxes on fuels higher than the cost of the fuels themselves to somehow be "reality" ?????

John

Bottom line is use what your vehicles octane rating calls for you to use. its listed in your "owners manual" i have read a few articles a while back some time by some top technitions in the automotive field that suggest not using

a "high octane in a low octane engine" not just because of the added expense of buying it. but more on how it effected a catalytic converter by running it hotter there by overworking it and damaging it over time. if i recall it had to do with the higher octane not completly burning off well enough in the combustion chamber. if i find those articles i will post them up. this fella agrees as well scroll down his site on. #5

"Ron Jones" wrote in news:kx_qg.11434$ snipped-for-privacy@tornado.ohiordc.rr.com:

I don't know for sure if that model has a knock sensor. Considering it's OBD-II, it very likely does.

"jamo" wrote in news:fs7rg.4239$ snipped-for-privacy@nasal.pacific.net.au:

Those are RON numbers. Equates to North American 89 and 91 "pump octane" (an average of RON and MON).

As our legal disclaimers say, "Your mileage may vary"...

I cannot, after extensive and repeated testing that consists of detailed fillup and mileage recording, detect any difference except slightly lower gas mileage with the higher octane, and even that is suspect. If there was any change in power, it was too small for the seat of my trousers to notice.

No, YOU'RE being banged up the arse by your government. Remove TAXES from the equation, and gas (sorry, petrol) is about the same cost everywhere.

You'll like this link. It's from a server on your continent:

Mostly George Bush the Second, unfortunately. He did not listen to his father, George Bush the First, and we suffer for the child's sins.

Dont worry TeggeR Americans have it too good now with cheaper gas prices compared to Europe but there too will come a time when they too will feel the crunch when it starts effecting there pocket and yes those little

1.4Liter cars over in Europe will start to look so attractive to them =D