Grand Sport at Costco....
10-09-2012, 04:02 PM
#41
Melting Slicks
If I am remembering correctly, Ethanol does increase the Octane Rating. I was reading recently that the Flexfuel vehicles that can burn E85, that octane is somwhere around 105 ...But with Ethanol, you get much less mpg.
10-09-2012, 04:02 PM
#42
Racer
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The deposits are probably from hardened valve guide seals causing oil leaks down the valve guide , a very common problem with todays engines,not the fuel
10-09-2012, 04:09 PM
#43
Nothing wrong with Costco gas and nothing wrong with 87 in a GS.
All gas comes from the same refineries. At the actual gas station, is when they will add any specialized detergents or boosters as the truck fills up the in-ground station tanks. The GS runs just fine on 87, it even says so right in the manual. Yes you will lose from 3-5% horsepower by running lower octane 87.. but Im pretty sure 410hp is still more that adequate to accomplish anything you will ever need to do on a public street with a posted speed limit. If you are putting the car on the track, then I can understand why premium would be "necessary".
But the scary part isnt the GS owner at Costco. Whats scary is all the garage queen owners freaking out, over something that really is common sense and public information.
All gas comes from the same refineries. At the actual gas station, is when they will add any specialized detergents or boosters as the truck fills up the in-ground station tanks. The GS runs just fine on 87, it even says so right in the manual. Yes you will lose from 3-5% horsepower by running lower octane 87.. but Im pretty sure 410hp is still more that adequate to accomplish anything you will ever need to do on a public street with a posted speed limit. If you are putting the car on the track, then I can understand why premium would be "necessary".
But the scary part isnt the GS owner at Costco. Whats scary is all the garage queen owners freaking out, over something that really is common sense and public information.
The manual says that 87 is fine. I dont see what the big deal is unless they are tracking the car with 87. Now, if the manual states 93 ONLY, then it would be an issue.
Naysayers, what is it to you if owners wanna run 87? It's their car. If something happens (which I doubt because the manual even says that 87 can be used), who will pay for it? Them.
Just calling it like I see it.........
10-09-2012, 04:13 PM
#44
10-09-2012, 04:15 PM
#45
Le Mans Master
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St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16-'17-'18-'19-'20-'21
10-09-2012, 05:51 PM
#48
Burning Brakes
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I have not tried with the Corvette, but that has been my experience with previous cars that called for premium gas. I always lost enough MPG that I wasn't saving anything, so why bother.
10-09-2012, 06:21 PM
#49
SUBVETTE
Who wants timing pulled?
With most gas in CA maxed out at 91 octane I regularly run Lucas octane booster to prevent power loss from timing pull. My tuner and dyno confirm the benefit.
With most gas in CA maxed out at 91 octane I regularly run Lucas octane booster to prevent power loss from timing pull. My tuner and dyno confirm the benefit.
10-09-2012, 06:38 PM
#50
Burning Brakes
All 4 my cars recommend premium; MDX, TL, S2000, & GS.
Been running costco premium for last 3 years now and still have yet to get a bad tank or any problems.
Wife's s2k redlines at 9k I believe, it would sound like a can of marbles with bad gas.
Talking to the attendant and he said all sorts cars come through from aston martin to bently's.
My old mustang with a 70mm turbo probably would have puked the head gaskets with bad gas if I had gotten bad gas from there.
Been running costco premium for last 3 years now and still have yet to get a bad tank or any problems.
Wife's s2k redlines at 9k I believe, it would sound like a can of marbles with bad gas.
Talking to the attendant and he said all sorts cars come through from aston martin to bently's.
My old mustang with a 70mm turbo probably would have puked the head gaskets with bad gas if I had gotten bad gas from there.
10-10-2012, 12:16 AM
#53
Drifting
If the manual says 87 is fine for the LS3, and GM warrants it for 100,000 miles when you do, then who am I to disagree? For over 36,000 miles in 15 months I've never wasted money on 89, 91, or 93 and never will. No problems so far, and if there are, the warranty covers them.
The statements along the lines of "why buy an expensive car and then put cheap gas in it" are pure emotion without any facts or logic behind them. Claims of higher mileage are interesting but I don't remember the same thing happening with any of my previous cars when I switched between grades. I get at least 23mpg most days and on last month's trip from southeast NC to Cleveland to Bowling Green and back, the DIC said 31mpg.
The statements along the lines of "why buy an expensive car and then put cheap gas in it" are pure emotion without any facts or logic behind them. Claims of higher mileage are interesting but I don't remember the same thing happening with any of my previous cars when I switched between grades. I get at least 23mpg most days and on last month's trip from southeast NC to Cleveland to Bowling Green and back, the DIC said 31mpg.
10-10-2012, 12:20 AM
#54
Pro
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Premium fuel for my GS only!! Nothing less!! Just like synthetic oil only for my Vette!! Will not settle anything below that!! If there was anything higher than 91 octane readily available around the Bay Area..that would be my choice also. Although I don't see anything wrong with putting Costco gas as long as it is premium. My commute Honda Civic I fuel it with 87 octane only.
10-10-2012, 12:52 AM
#55
Lower octane (i.e., less knock resistant) gasoline can be used in a Corvette, but maximum power and BSFC (fuel economy) will be compromised a bit. I'd be astonished if carbon deposits or durability are significantly affected.
Like most all recent gasoline-fueled vehicles with EFI and TWCs, I'm fairly certain that all current Corvette engines have knock sensors that approximately compensate for fuel octane characteristics (by advancing or retarding ignition timing, and I think nothing else) and O2 sensors to compensate for fuel C/H ratio (by adjusting A/F ratio).
I suspect that the main effect of using lower octane gasoline is that the ECM gets a signal from the knock sensor and retards the timing a bit, which slightly decreases WOT power and increases BSFC.
Obscure factoid: You can probably increase maximum power bit by adding some evil-doer aromatic like Toluene (a natural component of gasoline in years past) to your gasoline. It has a relatively high stoichiometric F/A x LHV product and also a high octane rating.
I'm open to being corrected on any of these slightly educated guesses.
Like most all recent gasoline-fueled vehicles with EFI and TWCs, I'm fairly certain that all current Corvette engines have knock sensors that approximately compensate for fuel octane characteristics (by advancing or retarding ignition timing, and I think nothing else) and O2 sensors to compensate for fuel C/H ratio (by adjusting A/F ratio).
I suspect that the main effect of using lower octane gasoline is that the ECM gets a signal from the knock sensor and retards the timing a bit, which slightly decreases WOT power and increases BSFC.
Obscure factoid: You can probably increase maximum power bit by adding some evil-doer aromatic like Toluene (a natural component of gasoline in years past) to your gasoline. It has a relatively high stoichiometric F/A x LHV product and also a high octane rating.
I'm open to being corrected on any of these slightly educated guesses.
10-10-2012, 02:15 AM
#56
I've seen in logs my computer pull 12 degrees of timing even on 93 octane...this was almost a 20hp loss from the timing pull alone and that's on 93.
You are correct in saying that running 87 octane is fine because the computer will detect knock, pull timing and slowly ramp it back in until it knocks again, but it will cost you mileage, throttle response, and who wants to rely on a knock sensor to save your motor anyway?
You are correct in saying that running 87 octane is fine because the computer will detect knock, pull timing and slowly ramp it back in until it knocks again, but it will cost you mileage, throttle response, and who wants to rely on a knock sensor to save your motor anyway?
10-10-2012, 02:26 AM
#57
Racer
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I did not have time to read all posts in this thread, so forgive me if this has already been posted...... Gas in grades below 93/94 octane have ethanol in them. The ethanol in the fuel, engine and exhaust systems after the vehicle has been shut down, evaporates into water as the vehicle cools.... this water sits in the systems and areas noted above and rusts, corrodes and damages the car from the inside out. This is what causes the knocking, hesitations, bucking and surging in the car and over time can cause damage, especially in those that city drive a lot and are turning there cars on and off frequently..... To what degree this process damages the car in the long run I am not sure...... I spring for the 94 that contains no ethanol and have always noticed a HUGE difference in any sports car I have owned.
10-10-2012, 03:37 AM
#58
Team Owner
Premium fuel for my GS only!! Nothing less!! Just like synthetic oil only for my Vette!! Will not settle anything below that!! If there was anything higher than 91 octane readily available around the Bay Area..that would be my choice also. Although I don't see anything wrong with putting Costco gas as long as it is premium. My commute Honda Civic I fuel it with 87 octane only.
10-10-2012, 04:43 AM
#59
Tolero Apto Victum
10-10-2012, 05:53 AM
#60
Drifting
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Good for the Grand Sport owner....it's his car to do with as he pleases. Personally, I wouldn't run regular gas in my Corvette. I feel high fuel prices like everyone but I didn't buy a high performance Corvette to worry about fuel economy or to 'cut corners' using lower octane, regular fuel. I understand a little savings here and there all adds-up but if fuel economy was that much of a priority I'd drive something else. 
...well stated.