Hi Octane Gas - Benefits?

[vesnyder]

Found a local source for high octane gas - 104 or 105 - sold primarily to race car drivers. Is there benefit to this high octane gas? What are they? Any potential problems?

[beepbeep]

Yes, if your car can take advantage of it (knock-sensor or raised boost), otherwise no benefits!

[stlrj]

It mostly benefits your gas retailer and OPEC.

Cheers,

Joe

[Vipergrün]

Benefits ONLY if you need it, ie; high compression, detonation, etc.

I am running at 35 degrees of advance and mix in some 100 octane if I'll be driving at elevation, or on hot days. Otherwise no real need for it. Now, if I had those 9.8:1 Mahles.......

[speeder]

I am constantly reading on this board of SC owners, (stock, U.S. spec), who use 92 or 93 octane gas. These cars specify 87 octane, (91 RON), I use 87 octane w/ 35deg. total advance and no pinging. People come back with, "gas isn't what it used to be," etc. Octane is octane. You can put 120 octane gas in an 87 octane car, there would still be no benefit. The only difference is that higher octane fuel is less combustible. It explodes at a higher temperature to prevent pre-ignition, (knocking), if you do not have knocking/pinging, there is no benefit to using premium. (Except to oil companies who make higher profits by people using premium in regular gas cars).

Even some very intelligent people are using more octane than needed, the only problem is that not one of them has ever been able to provide me with proof that there is a benefit besides anti-knocking. If anyone has such proof, in the words of Ross Perot, "I am all ears".

[Jim Richards]

Too many people believe in the "octane fairy". I only use what's spec'd for my p-cars w/o any problems. The Honda CRV gets one grade higher as I've always experienced pinging with the spec'd grade of gas in Hondas.

[widebody911]

Originally posted by stlrj
It mostly benefits your gas retailer and OPEC.

Actually, it's only the stateside refinery and retailer that see the difference.

[1980SC]

I'm with Speeder. I only use 87 octane in my SC. 35 degrees of timing. No knock. It's silly to pay for "premium" fuel when it's not needed.

Rob
1980SC

[sweater914]

only big difference is the type/amount of additives the suppliers put in the fuel

[widebody911]

You need to use the octane that matches your ignition and compression requirements.

Any lower octane, you'll get pinging/knocking. Any more, you're getting fleeced.


Modern fuel injected cars with knock sensors can take advantage of higher octane, but how much is dependent on how aggressive the FI computer is. Basically, the computer will advance the timing to see how much it can get away with; when it gets a knock (via the knock sensor) it backs off a tad. Sounds like me on a date.

I fill my 911 with Unocal 76 when I'm at the track ($5/gallon!) but it runs much better than with street gas. Around town, I'll detect a little knocking on occasion; I'm pretty sure my chip was developed for 93. I don't get any knocking on the track. Also, by the end of the day, all of the soot in my tailpipes is gone! It takes just a couple of days for it to come back on the street.
I can also reduce the knocking by adding 2 gallons of toluene per tankful, but that's not practical on a week-to-week basis.

[RoninLB]

I think that using a higher octane than needed reduces gas mileage because more additives means less"base" fuel

[bell]

great thread
i just got back from one of our turbo dodge tech meetings and were discussing fuel with an additive mfg.
they had some interesting things to say, their website http://www.bndautomotive.com/
there is some VERY good information on their site on their "anti-wear" and fuel additives sections, speaking with these guys left an impression.

[Langers]

Cars to tend to need a higher octane fuel as the engines become older, due to carbon buildup raising the compression ratio. Other than that, and the fact that you can feel secure that your car will never "ping", there is no benefit in using a higher octane fuel than the manufacturer specifies.

[RoninLB]

Originally posted by Langers
Cars to tend to need a higher octane fuel as the engines become older, due to carbon buildup raising the compression ratio.
", there is no benefit in using a higher octane fuel than the manufacturer specifies.

1) I agree
2) somewhat agree.. if you know your car's consistant drive, you can taylor the octane..
and.. the mfg. may not account for commuting from Aspen to Boulder, Co.. or a summer cruse thru Death Valley at 90mph
- anyway, my concern is for the different flavors of coloring they use.. colorless gas = clean spark plugs, IMO

[Vipergrün]

Originally posted by bell
great thread
i just got back from one of our turbo dodge tech meetings and were discussing fuel with an additive mfg.
they had some interesting things to say, their website http://www.bndautomotive.com/
there is some VERY good information on their site on their "anti-wear" and fuel additives sections, speaking with these guys left an impression.

The Internet is pretty amazing. Here is a tidbit about the TK-7 product I found;

Sabawi Ibrahim al-Tikriti, a half brother of Saddam Hussein, attended a meeting in London in the fall of 1987 during which a fuel additive company in Oklahoma City, Oklahoma was targeted for acquisition. Sabawi, at that time, played a key role in Iraq’s overseas procurement program. The London meeting also included Dr. Ihsan Barbouti, an Iraqi. Barbouti was later identified in official German government reports and by the United States as being a key procurement agent for both Libya and Iraq’s weapons of mass destruction programs. The Oklahoma City company that was targeted, TK-7 Fuel Additives, was desired by Iraq because Iraq believed that the fuel additive would extend the range of its scud missiles and because the U.S. company would provide an unwitting front for the acquisition of chemicals and materials useful in chemical weapons development and in the preparation of explosives.

[turbo6bar]

Is it as easy to hear pinging from the 911 as with other cars (front-engined)? My exhaust roars when I hit the go pedal. I really doubt I could make out pinging, and if so, it'd have to be pretty bad. I was told to run 93 octane with my '78 SC (has rebuilt '83 SC engine). At the worst, I am running no greater than 9.3:1. Go ahead and run the lower octane fuel?

Jurgen

[Vipergrün]

Jurgen,

I asked Bruce Anderson a question about timing advance, detonation and octane a while back. He even put it in his Excellence column

Anyway, he indicated that it is VERY difficult to actually hear detonation in our cars and the only real way to tell is to get the car on a dyno equipped with knock sensing devices. He also indicated that higher octane fuel would address the detonation problem. With 9.3:1 compression, 87 *should* be fine. I always run 91, though. Perhaps I'll try 87 again myself....

[dd74]

I agree with Jurgen on this one: 91 octane (LA premium) provides peace of mind. If there was pinging, I think I would hear it on load while going uphill. But to date, I've heard no pinging, which is fortunate.

Prevention, not performance is why I use it. In the long run, higher octane (hopefully) pays for itself two or three times in what pinging can do to your engine when using lower octane gasoline.

[bell]

Originally posted by bb80sc
The Internet is pretty amazing. Here is a tidbit about the TK-7 product I found..........

wow.........he did touch on how it is used at the exhaust outlets/valves of us military rockets due to it not burning off at 4000 degrees ...........
man........the internet is an amazing thing

[RoninLB]

Originally posted by dd74
I I think I would hear it on load while going uphill.

that's been my experience at low rpm/up hill. I can hear the pinging. I do want a knock sensor for the future 2.7 upgrade..
and I always run 91/93 on 8.5 pistons, on a low heat engine. not lugging, but on low rpm mild acceleration, below 3k.. this doesn't happen in a LA type areas............... Ron