Quote:
Originally Posted by OlePhu
There are a lot of ways to spin this discussion but you can't dispute the laws of physics or mechanics. Just from a personal observation, for the 1st 2000 miles of ownership, I used 87 octane and was averaging 19.2 mpg. For the next 3200 miles, I used 93 octane and jumped up to 19.6 mpg and that was after installing a CAI and going with aluminum wheels so in that respect, it doesn't appear to be advantages to go with premium. However, it does feel a little more peppier and I'm noticing less "soot" buildup on the tail pipes. Unfortunately, most of my driving is 40/60% city/highway so, hopefully, YMMV. I would like to say the 93 burns cleaner and is more responsive but I really can't say ... maybe when gas prices go back up I'll drop down to 87 but for now, I'll stick with the 93 just because of the perceived performance increase.
It's a sports car dammit!  |
Quote:
Originally Posted by VTSummit
compression ratio alone doesn't determine the octane requirement of the engine. .4MPG change, yet you put on a less restrictive intake and lighter wheels and attribute all changes to the wrong fuel?
I retired from GM, but I have somewhere in my boxes of crap I've got the air/fuel/timing map for the stock ECU. It can adapt from 86 to 93, but it's not going to result in more power with higher octane without the tune to go with it. The ECU has a very mild "aggression" when it comes to timing.
Use higher octane if you want, but in all likelihood you're causing carbon to build up faster in the combustion chambers. I've seen 100K mile LFX engines from Equinox owners who ran high octane because they believed marketing- it's not pretty in there. The LFX is known to have issues from carbon deposits already- so why add to the problem?
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If OlePhu installed RS aluminum wheels and tires he saved 6.8 lbs. on the wheels but added 16 lbs. with the tires. For a net increase of 9.2 pounds. And the increase in weight, being in the tires, means it is as far away from the center of rotation as you can get. That is certainly a detriment.
As for a CAI, I haven't experimented on my Camaro, but from what I see there may be a gain in WOT (where everyone dyno tests) but I am willing to bet there is no gain at all, and perhaps even a loss in efficiency, when driving like a citizen.
By deleting the resonator in the stock intake you are introducing a high pressure area in your intake tube that limits airflow.
As for your Equinox owners.
Just how often do you think they take the machine out and blow the carbon out? If they are the typical drivers I see on the streets the answer is never.
I see idiots who slow because the vehicle in front of them is going to make a turn, and when the road is clear again, there is not one chance in hell that they will press the accelerator enough to make the vehicle downshift to regain their speed. They think they are going to blow up if they cause a downshift, "Oh My God! What is all that noise?"
While you and I say "Whoo Hoo!"
My ex used to putz back and forth to work and every other week I would take her car to refuel it and blow the carbon out. I could actually see in the rearview the crap spewing out the exhaust. Two or three WOTs and it was good to go for another couple of weeks.
When I get the chance at home I spark up the old stereo and burn the dust off. Crank it up and you can actually smell it.
It is firmly in my mind that, just like people, machines need exercise or they will wither. My LS3 cries at me if I don't go WOT often enough.