Just a quick question. When i was reading about the specs on the new C6 it says it recommends 93 octane gasoline. But here in California the highest you can get is 91. Is that gonna be a problem. Or are they gonna fix it so it still can produce the same amount of power with 91 octane?

 

Man....I feel for you Cali folks. Your gas prices are the highest, yet you get the worst gas. I'd assume you all will just have to deal with less timing due to using the low octane tables in the PCM.

 

I've always heard premium gas was atleast 91 octane. So either an engine called for premium or id called for regular, (87 octane). We had 94 octane available in Mich. Good for summer heat! But I think the LS2 like the LS1 will run just fine an premium 91-94 octane.

 

Or, for that matter, 87.

 

Yeah, but you *MAY* lose HP on warmer days with only 87 octane.

As stated above, there are 2 timing tables in the PCM for octane.

My low octane table is now identical to my high octane table, so if false knock puts me into the low table, I'll still have the nice aggressive timing curve.

 

No doubt. But out of 305 HP, I don't think I'll really miss 10 or 15 HP . And of course it only makes a difference at wide-open-throttle.

 

Only two timing tables? Does that mean that if I can't get 92 or 93 octane (I can't) that I should only get 87?

I've noticed that on hot days, the engine pings quite a bit. It's not a constant ping like in an old car, presumably because the timing is adjusted pretty quickly. Even when I could get 92 octane, there would be a bit of ping. 91 doesn't help matters. I figured that if I ever got 87, that the pinging would be non-stop.

 

i don't know how you make that conclusion just form the octane rating. our gas is the most expensive because the refinement process is more complex, but it's the cleanest burning in the world. depending on how you look at it, you could say we have the best gasoline.

BTW, our gas is oxygenated (especially for the summer), which means it's less likely to cause detonation despite it's lower octane rating.

 

I wasn't aware that California had it's own refineries. I guess I was just ignorant the subject. I do know that my car gets up to 5* of KR (Autotap recorded) with 91 octane.

I also find it interesting that CA has taken all these steps to curb pollution, yet their cities continually rank the worst in the United States for smog, etc. Is it actually helping?

 

Yes. In spite of millions more people and cars and industry, the skies in Los Angeles are quite a bit clearer than they were 30 years ago.

What is "autotap recorded"?

 

Oxygenated gasoline is essentially useless on closed-loop FI cars. The O2 sensors simply read the additional oxygen in the exhaust stream and call for more fuel. Their only benefit is on older carbureted cars.

 

Autotap is a diagnostic tool that runs on a PC and connects to the ALDL port under the driver's side dash. You can monitor many operating perameters of the vehicle and log runs to review later.

 

Just to add to what Teal98 posted, Los Angeles will probally always be one of the worst cities in the US as far as pollution, even as all cities (including LA) become cleaner. This is because LA is surrounded on all sides (save a thin area by the southern coast) by mountains, and the fact that LA is rarely windy.

In the summer, with low winds and high temps (occasionally over 100) the air just simply sits there, exhaust, smog & all.

So while LA is far cleaner than even when I 1st lived there 10 years ago, it's still going to rank low.

What confuses me is why is Houston Texas, with all it's open space, now ranking worse than LA?

 

Lotta rednecks with pick up trucks??

 

Actually not just at WOT. There is difference in power even at 3/4, especially on a hot day.