Let's Talk About Gasoline....

neilcrichton · Jan 24, 2008

tumprgt said:
When you are off roading or towing, you tend to put the engine under a greater load. This is where the higher octane would help. You can run at the same timing and not get knocking.

Remember back in the day when you timed the cars yourself and you set it to a spot let's say 12 BTC. It ran fine under normal conditions but under heavy acceleration it would knock once in awhile. You then had to bring it back to 9 or 10 BTC to make it go away completely but the pickup was never the same. If you were running a higher octane gas, you probably would not have had the knock as the higher octane fuel resists preignition. The same holds true when off roading, your tend to put the engine under "abnormal" stress, so the ECU would adjust the timing to compensate if it sense the knocking. Thus reducing the torque/power then engine can deliver. The higher octane would reduce the chance of knocking thus allow the engine to give you its max.

Also with the possiblity of more detergents in the costlier grades, it doesn't hurt when you engine goes from hard pounding getting up the trail, to idling at the top, to running on a dirt track, to fording a stream, to...

Several years ago, my local branch of the Studebaker Drivers Club had a guest speaker, who was a petroleum engineer for Shell. The octane question came up, and his answer was clear and unequivocal... There is zero advantage in using a higher than recommended octane. High octane gas is for high compression engines, to avoid pre-ignition (pinging). A low compression engine that "pings" is in need of a tune-up. The engineer also said that people mistakenly believe that high octane gas will give a performance boost. It doesn't. However, since it is recommended for high performance (high compression) engines, people think that simply switching to 93 or 97 will give them a performance kick. Not so.

I think maybe tumprgt has a point about high stress situations like off-roading and towing. However, we have members who have indulged in both, and I don't recall any complaints about pinging.

RHill · Jan 25, 2008

quasimodem51 said:
Thanks so much, indianrefining, tumprgt and RHill.

Mitigating the "vacant space" in my wallet overrides the perceived performance gains from using 89 octane. For some reason I just felt better; but I guess it is like washing your Patriot. For some reason it just feels like it runs better when it knows you babied and cared for it a bit. [wry smile]

Actually, washing it does help. It makes the surface smoother and reduces drag, thereby increasing performance and fuel economy.

indianrefining · Jan 25, 2008

RHill said:
Actually, washing it does help. It makes the surface smoother and reduces drag, thereby increasing performance and fuel economy.

FWIW and YMMV

True. Then, again, the "aero" properties of most Jeeps probably won't be impacted very much by a little dirt!

Terasec · Jan 25, 2008

Aero properties?

indianrefining said:
True. Then, again, the "aero" properties of most Jeeps probably won't be impacted very much by a little dirt!

like the aero properties of a brick

JoeBecker · Jan 25, 2008

Terasec said:
like the aero properties of a brick

Now come on, it is not that bad. Maybe a tumbled brick because it does have slightly rounded corners.

You probably would be able to get pretty good gas mileage if you drove in reverse. It is a little more aerodynamic that way!

Let's Talk About Gasoline....

neilcrichton

RHill

indianrefining

Terasec

JoeBecker

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