Premium vs. Regular Gas

[Ksyrup]

I've got a 2005 Acura TL, and the manufacturer recommendation is to use premium (91 or higher) gas. That's what I've done for the 2 years I've had the car. Even had the original dealership tel me the horrors of using regular, about how sludge can build up in the engine, requiring $1K flush, and jkust generally about performance suffering with less than premium gas.

So fast-forward 2 years, I'm getting the 30K mile service and get a call from the dealership recommending a few additional services (of course). First thing the guy asks me: "What level of gas do you use?" I tell him I have always used the recommended 93. He tells me that's a problem and suggests I switch to regular, since it won't cause me any performance problems, but that the premium is leaving all sorts of deposits in the tank/engine, causeing the automotive equivalent to artery-clogging. He tells me that Acura is making this recommendation to servicers now, despite what I may have been told when I bought the car. And of course, they want to charge me $300 to flush the system. I politely decline.

So...WTF? Who do I trust here? Do I just stick with the manufacturer's recommendation and maybe buy a can of that fuel injector stuff and do it myself, or do I buy into the argument and try the regular or mid-grade for awhile? What a crock of crap this is. Anyone with any thoughts on this? I'm thinking about calling Acura directly to find out what's the truth here. With my luck, I'll have an issue with the car before the warranty is up, and they'll find out I haven't been using the "recommended" gas, causing me to void the warranty.

[albionmoonlight]

http://www.operationsports.com/fofc/showthread.php?t=4753

For what it is worth.

[Ksyrup]

That's been my default - do what the manufacturer recommends. But now, I'm being told by the manufacturer's representative (a franchisee, I know, but still has the Acura name on the door) to do the opposite. I guess I'll try calling Acura directly to see what they say. I have no problem throwing these people under the bus if I get a "they told you WHAT?" type of response.

I guess I'm basically screwed either way - use premium, pay more for gas, and need an expensive system flush, or use regular, pay less for gas, but get poor performance and need an even more expensive system flush.

[KevinNU7]

Why not contact Acura yourself

[Maple Leafs]

I have a 98 Acura and I've never put anything but Regular in it. The dealer told me when I bought it that you shouldn't put Premium in an Acura.

[DanGarion]

It all depends on if it's a high compression engine...

[CU Tiger]

This whole regular vs. premium article is actually dated.

As engines have moved away from gravitational carburetor mixers, to computer controlled direct port injection they have also added sensors at every step of the process. Now microprocessors can advance or retard the timing many times/second as well as physically alter the air fuel ratio. All that said 99% of the time your engine's computer will compensate for whatever grade of gas you use.

Compression does play a role as stated, but with the aforementioned sensor active adaptation, every car has ping or knock sensors and if pre-spark detonation (or spark knock, which is caused by high compression/low grade combination. Essentially the compression is so high that heat and pressure cause the combustion charge to be ignited without a spark, just liek aa diesel engine) is occuring the spark signal is just advanced enough to prevent damage. This can lead to slight power and economy losses, but should not damage your engine.

Any yahoo that says higher octane gasoline is causing increasing quantities of deposits to be left is a liar or just plain ignorant.

The only possible danger of higher octane gas, is dumping .20/gallon out the tailpipe.