2001_STL_c5

I always put premium 93 in when I fill up and in the owners manual it recommends 91+ and I would assume most everyone would follow this to make sure you don't get any pinging...wrong. I work at a gas station overnight to fill up my hours of insomnia and in the last week I have had 4 different corvette owners come in and fill up with 87. I talked to one of the guys and his response was I don't want to pay the extra 30 cents per gallon! Maybe I'm crazy but if I'm gonna spend my money on nice things, I'm gonna do what is recommended to keep them in good shape and if you can't afford the gas in it you probably bought the wrong car. Am I missing something here? I know that cars make the most power with the lowest safe octane level for the setup (correct me if I'm wrong) but isn't 87 pushing it?

DeeGee

At least you tried to educate them

The LS1/2 is a high compression engine (10.5 :1) and it needs high octane gas. The knock sensors detect any pre ignition and retard the timing. This should protect the engine in the short term but its not good for regular use

In my view the engine is compensating after the event. Pinging causes damage and by using 87 octane you're deliberately introducing the problem. Add to that with the timing adjustment youre getting lower power and affecting the mpg. Just not worth the .30c to me. All that said, there are plenty here who are prepared to take the risk

Luckily, here in UK even regular gas (95 RON) is equivalent to 91 octane in the US.

I suspect E-T will offer his wisdom on this one.

98tadriver

Yeah, I never got why people are like that. 93 all the time here. if you reallly wanted to, you could have someone tune ur car to run on 87

tak06

Not necessarily, many automotive engineers claim that if you don't notice any power loss pinging/detonation then you're just wasting money on 93 octane, mine '02 Z06 runs perfectly fine on 91.

2001_STL_c5

I understand that, but 91 is still in the recommended range. Just seems like 87 is a bit of a stretch.

DeeGee

The owners manual suggests 91 octane and I agree that too much octane is a waste. Temperature and altitude affect the equation too. The point is the driver may not notice the loss as the knock sensor is compensating. The damage is still occurring. If you blow a ring or damage a piston it'll be way more $$$ than the .30 cent saving can ever cover.

tak06

Agreed, not suggesting in lower than 91 octane just to abide by owner's manual, but 93 maybe overkill, but couldn't do any harm other than monetary.

2001_STL_c5

Gotcha, in my area most stations have 87, 89 and 93 so it's not that I search it out, its just pretty much my only option.

jrose7004

Around here you can only get 91 so thats what I use. My car will ping on 87.

Evil-Twin

After 8,768 post from me on this topic in the last ten years, this is the last. Anyone who chooses 91 0ctane over 93 when available is a complete idiot. The difference between the two grades is 3 to 5 cents. Those using 87 are just plain stupid.. anyone who thinks their car runs good with 87 octane does so because they are just uneducated on engine damage cause by ping, ping is not knock, ping is rarely heard, but still causes big [problems over time. And the ones who say you can retune your car to run 87, just ghettoizes this car.. because of this problem I would never recommend anyone buying a C5 from someone that they do not know. Too many cheap people like the bling of a corvette C5 but do not deserve to own one or drive one.

One other point, 93 octane may only be necessary for 10 % of your actual driving: when its very hot, or your engine is under load or in the wrong gear. Trying to pass up hill in the wrong gear etc. with 93 octane this 10 % underload condition could otherwise be dangerous to the longevity of your engine. With 93 octane you wont have any issue when this 10 % load condition occurs. The cheap people will say well Ill use the lower grade because the other 90 % doesnt require it. The people who put 87 octane in their C5 also use the cheapest oil, and change it when it gets to 15,000 miles no matter how many years it takes. Because some oils say extended life oil good for 15,000 miles.
The End

Jet-Jock

Evil, some of your post do humor me.

However, you are a voice from the engineering team and that carries more weight than many here.

Let me further recommend choosing Chevron Supreme or Texaco Supreme as both have the Techron additive.

PostShawn

In Cali we only have 91 octane as our highest. I never use anything less though. If I'm going to be frugal about my gas I just go to a cheaper gas station. But lower grade gas, I think not.

itzza427

93 is my regular fill as well. Lately there have been a few stations around here that have been switching to 91 swill and still charging the same price as the stations that pump 93!! Now over the course of the years I've owned it there has been a couple of times that out of laziness/convenience that I topped off at a near by station that only sold 87 & 89. It was winter and I wasn't doing any "spirited" driving,mostly highway,and it was mixing with a substantial amount of 93,,so I figured 89 and 93 still came in around 91. That and cold temps I'd get buy for a one time deal!! Wouldn't dream of it in any kind of warmer temps and or hard driving!!Would only use 87 in an extreme emergency,,and then only enough to get to some 93!! I also believe,,if you can't afford the gas,,don't buy the car!! At 30cents a gallon difference,,and a 14 gallon fill up,,you are only talking $4.50!! Figuring that these cheapo's are occasional drivers and a fill up will last 3-4 weeks,,,that is REALLY cheaping out at about a $1.12 a week!!Premium fuel,,and changing your SYNTHETIC oil by the OLM,,,cheap insurance for LOTS of fun!!!

killain

Quote:
Originally Posted by Evil-Twin
After 8,768 post from me on this topic in the last ten years, this is the last. Anyone who chooses 91 0ctane over 93 when available is a complete idiot. The difference between the two grades is 3 to 5 cents. Those using 87 are just plain stupid.. anyone who thinks their car runs good with 87 octane does so because they are just uneducated on engine damage cause by ping, ping is not knock, ping is rarely heard, but still causes big [problems over time. And the ones who say you can retune your car to run 87, just ghettoizes this car.. because of this problem I would never recommend anyone buying a C5 from someone that they do not know. Too many cheap people like the bling of a corvette C5 but do not deserve to own one or drive one.

One other point, 93 octane may only be necessary for 10 % of your actual driving: when its very hot, or your engine is under load or in the wrong gear. Trying to pass up hill in the wrong gear etc. with 93 octane this 10 % underload condition could otherwise be dangerous to the longevity of your engine. With 93 octane you wont have any issue when this 10 % load condition occurs. The cheap people will say well Ill use the lower grade because the other 90 % doesnt require it. The people who put 87 octane in their C5 also use the cheapest oil, and change it when it gets to 15,000 miles no matter how many years it takes. Because some oils say extended life oil good for 15,000 miles.
The End

Here in PA you can buy 91 octane or 93 octane. IF I fill up with 93 Octane over 91 octane the cost difference to fill the tank is $0.54 cents. Really that much ! And I have been chastised here for changing my oil with 75% life still on the DIC, Yet I have only driven 4K miles in the past year and personally, if $0.54 cents is a cash flow burden, then you really should be driving a Colbalt NOT a Corvette. MY DD, a 2002 Chevy Cavalier spent it whole life on Long Island, NY drinking 87 and it's very happy with it's current Best motor oil and regular 87 octane diet.

For me, I spent $48K for a brand new 2003 50th. Anniversary coupe which I keep in like-new condition. I'll die before I cut corners on how the car is to be taken care of. But so many people look at a Corvette and see only another appliance ! No better than a Chinese made refrigerator. To those folks, they usually trade it in after three years of lease and abuse. And hay, if it makes their boat float great, but I'm cut from much older and different cloth. With these cars you'll find people who'll spend more on car wax/polish than Motor oil much less gasoline ? I'll stick with the advice Evil-Twin kindly doles out to us. His opinion isn't one of some stranger to the C5, but one of the thinkers back when the C5 wasn't even a C5 on a file stuck in some folder hidden away on a shelf at the GM building. I stick with the maintenance schedule thought out and written by he and his fellow engineers.

Yello95

Recommend Chevron or Texaco Supreme all you want...Anyone living in
Delaware, Indiana, Kentucky, North Carolina, New Jersey, Maryland, Ohio, Pennsylvania, South Carolina, Virginia, West Virginia, Washington, and parts of Tennessee can no longer buy Chevron or Texaco ...period

P.S......I use the highest octane gas no matter what it costs...also...I started stocking up on bottles of Techron concentrate...

m6 c5

I always fill up with 92 and it rarely takes me more than 35$ and never more than 40$ to fill up which is right at the same amount it cost to fill up my camaro(v6) with 87 and it only has a 16 gallon tank if Im not mistaken.

Aerovette

30 cents x 16 gallons = $4.80 per tankful

$4.80 is a great price for insurance if you ask me.

herZ06

93 all day long... that's what the car is tuned for and that's what I buy.

Except the time we were on a road trip and almost ran out of gas in the middle of no where and the only gas station had 87. Then, we got a few gallons, went easy on it, and found a place with 110 to even out the mix shortly thereafter. Boy do I love that smell...

98tadriver

that 110 wasnt leaded was it? lol thatll mess with or mess up the 02 sensors. once upon a time, in my newbieness, i put a gal of 110 in my t/a at the track when i almost ran out of gas. they didnt have any 103 unleaded left, and at the time, i thought 110 was unleaded as well lol. the car kept throwing 02 sensor codes until all of the 110 was burned off. sure did smell good tho!

m6 c5

And if I am not mistaken it will mess up your cats too.
I know around here you can only get up to 104 without it being leaded unless you are just looking at the RON number which you can get 109 RON but that is not the standard rating system in the US. The standard in the US is R+M/2 in case anyone wants to know.