1989 Corvette Gas Type?
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
What brand of gasoline do you buy & use in your 87 Bob ?
I have been told that all gasoline comes from the same vendor or wholesaler in the past.
Beginning to question Shell & B.P gasoline myself.
Here in Illinois there are Casey General stores all over outside of Chicago area.
At times I have filled my 87 up with Casey store 89 octane gasoline(highest octane they carry & sell) & it seems to run A-OK with no pinging at WOT.
Next day I fill up with Shell 93 Gas & it seems to run sluggish sometimes.
Slight pinging present too for 1 or 2 seconds & there disappears,
ESC knock sensor kicked in & retarded ignition timing.
Next time I buy Shell gasoline elsewhere,
A- OK again.
I have been told that all gasoline comes from the same vendor or wholesaler in the past.
Beginning to question Shell & B.P gasoline myself.
Here in Illinois there are Casey General stores all over outside of Chicago area.
At times I have filled my 87 up with Casey store 89 octane gasoline(highest octane they carry & sell) & it seems to run A-OK with no pinging at WOT.
Next day I fill up with Shell 93 Gas & it seems to run sluggish sometimes.
Slight pinging present too for 1 or 2 seconds & there disappears,
ESC knock sensor kicked in & retarded ignition timing.
Next time I buy Shell gasoline elsewhere,
A- OK again.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
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EFI cars have knock sensors as part of their design. When your motor even THINKS about pinging, it will pull timing to prevent it. (The KS can "hear" knocking before you can.) Occasionally, you'll get knocking if you install platinum plugs. (They run hotter and can be a source of detonation). Some shops now recommend AGAISNT platinum plugs in C4's.
That said, you can run lower octane (aka cheap) gasoline. By doing so, I'll guarantee your knock sensor will be more active and you'll be missing some power. If power isn't that important, run the cheap gas. As long as your ESC is in working order, you won't blow up the engine. It can pull anywhere from 5 to 20-degrees of timing depending on what RPM range you're in.
If you run cheap (lower octane) gasoline, I bet you could be missing up to 10% of peak power levels.
That said, you can run lower octane (aka cheap) gasoline. By doing so, I'll guarantee your knock sensor will be more active and you'll be missing some power. If power isn't that important, run the cheap gas. As long as your ESC is in working order, you won't blow up the engine. It can pull anywhere from 5 to 20-degrees of timing depending on what RPM range you're in.
If you run cheap (lower octane) gasoline, I bet you could be missing up to 10% of peak power levels.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
My guess is there's one for each of the major oil companies. And, that the smaller guys (including convience stores) buy from the big boys. Of course, they'd get the mega-gallon quantity discount which probably enables them to undercut the brand-name stations.
OTOH, I've never noticed the top-tier 92-93 octanes at the cheaper places. Shell, BP and Philips 66 are the only ones around here that carry it.
BTW: The reason why you'll rarely hear cheaper gas ping was addressed in my post above.
Le Mans Master
Joined: Aug 2010
Posts: 9,272
Likes: 17
I actually buy the cheapest, usually arco, thrifty, etc. The bad old days of them watering the tanks are pretty much over and if you have ever looked at the tank farm loading racks, you will see trucks from 76, arco, shell,etc, but you will also see unmarked trucks. Those are delivering the same fuel to the independents. years and years ago, when I would put on a load of fuel for an independent, the rule was that you left it 500 gallons light, pull around to the water rack and top it off with water, that way it could shake and mix in prior to dumping it at the station. I've pulled up to stations and the owner would be standing at the fill with a garden hose . Thats all gone, thankfully, there's alot of oversight now days that we didnt have back then, and theres are water sensors at the bottom of most of the station tanks that set off alarms with moisture. In smaller markets its still possible to get a load of bad gas, and if you think you've been given some, there's a number on each pump that you can call , and they will come out and test the tanks, if you've saved your reciept, refunds are available. sorry , a bit to wordy.
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Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
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By "cheap", I mean lower octane than premium. The manual states premium as a requirement (91 octane I believe). And, their timing tables are coded accordingly.
Safety Car
Joined: Sep 2001
Posts: 4,155
Likes: 553
From: Glenbeulah Wi
EFI cars have knock sensors as part of their design. When your motor even THINKS about pinging, it will pull timing to prevent it. (The KS can "hear" knocking before you can.) Occasionally, you'll get knocking if you install platinum plugs. (They run hotter and can be a source of detonation). Some shops now recommend AGAISNT platinum plugs in C4's.
That said, you can run lower octane (aka cheap) gasoline. By doing so, I'll guarantee your knock sensor will be more active and you'll be missing some power. If power isn't that important, run the cheap gas. As long as your ESC is in working order, you won't blow up the engine. It can pull anywhere from 5 to 20-degrees of timing depending on what RPM range you're in.
If you run cheap (lower octane) gasoline, I bet you could be missing up to 10% of peak power levels.
That said, you can run lower octane (aka cheap) gasoline. By doing so, I'll guarantee your knock sensor will be more active and you'll be missing some power. If power isn't that important, run the cheap gas. As long as your ESC is in working order, you won't blow up the engine. It can pull anywhere from 5 to 20-degrees of timing depending on what RPM range you're in.
If you run cheap (lower octane) gasoline, I bet you could be missing up to 10% of peak power levels.
For max power with these cars you want high octane.
Le Mans Master
Joined: May 1999
Posts: 6,515
Likes: 1,302
From: Windermere FL
Covered a gazzillions times. All gas comes in at the same terminal pipeline. Different vendors will add additives at the depot unque to their brand. Chevron adds Techroline (sp?). Others do similiar. That is what makes a brand.
You can run it with cheap gas, but you won't be getting max performance. The knock sensor will limit you.
BTW - you call can thank the Gooberment for adding Ethanol which will decrease your milage significantly. You can also thank the EPA for boutique blends that raise the cost of gasoline since the refiners have to produce hundreds of different formulas.
Le Mans Master
Joined: Aug 2010
Posts: 9,272
Likes: 17
amen, with the upgrades learned on this site for vettes, many thanks to all of you, I get 25-27mpg and never stick my foot in it......anymore....well not all the way...ok, ok, not as much...peak hp not an issue.
Last edited by oldalaskaman; Aug 30, 2011 at 10:00 AM.
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From: One day you're a Comet...the next day you're dust... Arkansas
Team Owner
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Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
I actually buy the cheapest, usually arco, thrifty, etc. The bad old days of them watering the tanks are pretty much over and if you have ever looked at the tank farm loading racks, you will see trucks from 76, arco, shell,etc, but you will also see unmarked trucks. Those are delivering the same fuel to the independents. years and years ago, when I would put on a load of fuel for an independent, the rule was that you left it 500 gallons light, pull around to the water rack and top it off with water, that way it could shake and mix in prior to dumping it at the station. I've pulled up to stations and the owner would be standing at the fill with a garden hose . Thats all gone, thankfully, there's alot of oversight now days that we didnt have back then, and theres are water sensors at the bottom of most of the station tanks that set off alarms with moisture. In smaller markets its still possible to get a load of bad gas, and if you think you've been given some, there's a number on each pump that you can call , and they will come out and test the tanks, if you've saved your reciept, refunds are available. sorry , a bit to wordy.
You have confirmed 20 years of my own suspicion Bob.
Here in Illinois 100 miles south of Chicago>>>>>>>>>
There is not a single Non- white turbine hat wearing gas station owner.
Just in hickville.
My late buddie threatened to kill all of them when alive several times.
Had to pick him up out of jail a few times.
LOL.
64 years old too.
They allways smile ear to ear when I drive off.
My Red 87 C4 included.
mother f****@#s.
Last edited by 87 vette 81 big girl; Aug 30, 2011 at 11:32 PM.
Intermediate
Joined: Apr 2011
Posts: 36
Likes: 0
From: KC
I made the mistake of using 89 since it was the same price as 87. It just didnt have the same feel so i have been using bp 93 ever since but its hard to find... i found a place called www.octanelocator.com that has a few stations listed around the country but not enough near me for a road trip....
