$34.99...

Apr 23, 2008 53 Replies

The main thrust of the 3 articles your provided links for is to convince people that if your engine is designed for regular gas, there is no benefit of using premium and you should stick to regular. That sounds OK. But at no point did any of the articles address the situation found in most Toyota V6 engines, which are specifically designed to run on regular OR premium, and according to the Toyota owners manual, the engine will deliver more horsepower with premium. The articles only focused on engines that were designed to run only on regular, concluding (rightly so) that it would be a waste to use premium in these vehicles.

In fact, one article actually says that one could use regular even if the engine is designed for premium, so that pretty much throws into doubt everything else in the article. Here is the exact quote:

"Even if you have a super-performance sportster with a big "91 ONLY" sticker on the gas cap, no harm will likely come if 87 is added by mistake."

Now this "may be" true for some engines spec'ed to use premium, but certainly not all engines, and it is very poor advice. If your engine is designed to use premium only, that is what should be used.

Regarding my original point about an engine running cooler on premium (or "not cooler" in your opinion), you seem to playing games with the facts. Look at this way--if a Toyota V6 engine delivers more horsepower with premium as Toyota claims (my dealer actually made me sign an acknowledgement of this fact when I took delivery of my V6 Camry), then for a given vehicle speed, less fuel will be used because the premium delivers more horsepower for the same amount of fuel. And since (as you said above) premium and regular have the same BTU content, then less heat will be generated with premium assuming that the vehicle is traveling the same speed as it would be with regular fuel.

This is what the magic of higher octane does. It makes the fuel burn slower to deliver more power and better mileage (assuming that the engine is designed to take advantage of the higher octane). Since premium gas burns slower than regular at the same vehicle speed, there is less heat generated as a byproduct of combustion using premium fuel.

BTW. Most of us who had cars (especially cars that were not so new) in the "old days" before electronic ignitions and fuel injection knew that engine knock is much more likely to occur on a very hot day, compared to a cold day. And we also know that engine knock can be reduced or eliminated by using higher octane fuel.

Very true.

Engines that can produce more horsepower when using premium but can still run on regular do so because the ECM is programmed to advance the ignition timing more aggressively. Advancing timing more aggressively can lead to knocking. Modern vehicles have knock sensors, and if the sensor detects pinging or knocking, the ECM retards the ignition timing until the knocking stops. Since premium fuel resists knocking better than regular, the ignition timing can be advanced more before it has to start retarding the timing.

In other words, the higher horsepower comes from the advanced timing, not cooler combustion.

Yes, the LIEberal Deomcrats crossed over to help McCain win, now they get mad at the Republican'ts when they return the favor to help Hillary win.

So can we legally get someone to change his name to None of the Above, so we can write him in?

Charles the Curmudgeon

"Ray O" ...

OK, now I'm confused again. Sounds like premium or mid-grade would still be better, even in my little car?

Natalie

"Jeff Strickland" ...

Ah, thanks.

:-D

Natalie

At no time did I ever say, nor did I ever imply, that additional horsepower comes from cooler combustion.

Besides sidestepping your post that I refuted, you are now trying to completely make up quotes, and then refute them, in order to make your own wrong answers look less conspicuous.

I suspect that the Echo calls for 87 (regular) octane, but many Toyota V6 engines are specifically designed to run on regular or premium, with better horsepower with premium (and therefore better fuel economy).

So the correct answer is to look at the users manual, and see if calls for:

  1. Regular
  2. Premium
  3. Regular or Premium

Possibly, but very unlikely, especially if you don't floor the gas pedal when the light turns green.

Echos and Scions are going to programmed with a bias towards fuel economy instead of performance, so regular will do just fine.

"Ray O"

Danke

:-)

Natalie

I don't get offended when you post information contrary to mine. I do get offended when you misquote me, then refute my misquoted statement, and meanwhile ignore the part of my post that proves you are wrong.

If you say so...

:-)

Natalie

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