Repecat

I think he was pulling your leg.

Xpditor

This dealer is unbelievable - literally.

Whether the octane is 87 or 93 has nothing to do with clogging of injectors. Impurities and detergent additives have something to do with that.

Our TL, like most modern cars, has a knock sensor that will detect pre-ignition which is what happens when the car "diesels" or spontaneously combusts due to the compression of the air/fuel mixture before the spark plug fires (too early). When this happens, forces are exerted on the piston, rod, and crank and, if not checked, could damage your engine. The engine computer, if knock is detected, will alter the timing of the spark to prevent it. What causes our car to need 91 octane fuel, mainly, is the 11:1 compression ratio.

Octane is increased with additives that delay combustion. This delay allows a spark timing that maximizes performance and complete burning. The engine will operate at its best and most efficient with the recommended fuel octane.

If you use a lower octane, the car will adjust itself so no damage is done at the cost of efficiency and power -but it is not the way the engine was designed to run.

If my dealer told me they put anything less than the recommended fuel in my new car, I would have him remove it and make sure Acura heard about it. I'm not sure but it's possible the onboard computer stores historical information on the timing. It has the capability.

In any case, the car's computer adjusts the timing on the fly- advance or retard - to get the best performance without knocking. It goes both ways. It doesn't ratchet as your dealer suggests. That would be foolish, IMO.

frainc

I just got the Fall J.D.Power Car Guide in the mail and they have a some information on just this topic;

"Yes, you could use a lower-octand gasoline but the electronics in the engine instantly sense a knocking sound as soon as the noise begins. Immediatley, the electronics adjust the spark timeing to a retard stting at which the knock disapperars. In the retard setting, the engine will run, but it loses power and efficiency."

So spend the extra $1 or $2 per fillup and enjoy the power.

Krypton Ken

This implies that you would get better efficiency too, hence, increased gas mileage. So, you are getting (most or all of) what you pay for in premium, power AND mileage. That works for me.

Krypton Ken

Yes, there is a Car and Driver article on gasoline.
Regular or Premium?
Is premium fuel worth the premium price? Can you hurt a high-octane car by running it on the cheaper stuff?
http://www.caranddriver.com/article....&page_number=1

Very good article, imo. A few points from the article...

"High altitude reduces the demand for octane."

"Knock sensors are used in virtually all new GM, Ford, European, and Japanese cars, and most DaimlerChrysler vehicles built today. According to Gottfried Schiller, director of powertrain engineering at Bosch, these block-mounted sensors—one or two of them on most engines and about the size of a quarter—work like tiny seismometers that measure vibration patterns throughout the block to identify knock in any cylinder. Relying on these sensors, the engine controller can keep each cylinder's spark timing advanced right to the hairy edge of knock, providing peak efficiency on any fuel and preventing the damage that knock can do to an engine.

"The results were more dramatic with the test cars that require premium fuel. The turbocharged Saab's sophisticated Trionic engine-control system dialed the power back 9.8 percent on regular gas, and performance dropped 10.1 percent at the track. Burning regular in our BMW M3 diminished track performance by 6.6 percent, but neither the BMW nor the Saab suffered any drivability problems while burning regular unleaded fuel. Unfortunately, the M3's sophisticated electronics made it impossible to test the car on the dyno."

And last......
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 (Ken adds: TLs certainly are), 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.

d1sturb3d119

iTrader: (1)

Well the fact is that a dealer would love to keep your car running as long as you're paying him to do it. I've been running on 91 and it keeps the engine clean, keeps the performance up, reducing your need to get on the gas more than you need to thus increasing mileage. The cost difference is minuscule. The fact is you would probably spend that money getting a couple cans of coke every month...