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Old 04-13-2016, 02:06 PM
  #21  
Black 02
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Originally Posted by phoneman91
That was a design mistake. New car's OLM will tell you when not only when the mileage has been exceeded-but when the time limit has been exceeded. GM shouldn't have extended the oil change mileage limit to 15k miles-if there wasn't a timer in the OLM. Most of these cars are not driven more than 15k miles per year.
The newest C5 can almost be legally driven by someone born the same year it was made. Give the designers a break lol.
Old 04-13-2016, 02:45 PM
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Originally Posted by Black 02
I have a gasoline question. Why is premium 40-50 cents more than regular now?
Well...as a guy who tuned various gasolines over the years, I've dedicate a lot of time and effort to my knowledge of fuels. The question you ask is a pretty loaded one. It has to do with your particular area, where your fuel distribution actually comes from, your state tax, the "blend" (as was spoken of earlier), etc. There is no one culprit involved, it just comes down to many factors.

In areas where premium is typically vastly more expensive, it usually has to do with the local demographics and consumption of premium. If you have a lot of blue collar, trucks, econoboxes, etc and it's not exactly a densely populated or mixed demo, the premium prices skyrocket. This generally is due to the fact that your local stations don't sell enough to get it at a cost that is more competitive.

Beyond that, summer gasoline is more expensive to produce, due to EPA mandates on emissions, anti-vapor additives, etc.
Old 04-13-2016, 03:03 PM
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Originally Posted by RC000E
Why do people post these questions about gasoline? If you bought a Corvette, how in the HELL can you not afford the extra 2.50/fillup for premium octane? Will the car "run" on regular...sure, at part throttle and some quit hard throttles, yea it will. If it detonates/pre-ignites, the knock sensors will detect it and retard the timing as a result. In that situation, an engine can tolerate some pre-ignition and detonation short term. Fact is though, you're pounding the ring lands and piston crown with frequency and heat that is potentially catastrophic.

Only a fool runs 87 octane in an engine designed around 91+
Where are you finding 91 octane for 10 cents a gallon? It's $1 a gallon over 87 octane here. That's closer to $25.00 a tank. It hasn't been 10 cents a gallon here for like 25 years

Jim
Old 04-13-2016, 03:10 PM
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Originally Posted by RC000E
Well...as a guy who tuned various gasolines over the years, I've dedicate a lot of time and effort to my knowledge of fuels. The question you ask is a pretty loaded one. It has to do with your particular area, where your fuel distribution actually comes from, your state tax, the "blend" (as was spoken of earlier), etc. There is no one culprit involved, it just comes down to many factors.

In areas where premium is typically vastly more expensive, it usually has to do with the local demographics and consumption of premium. If you have a lot of blue collar, trucks, econoboxes, etc and it's not exactly a densely populated or mixed demo, the premium prices skyrocket. This generally is due to the fact that your local stations don't sell enough to get it at a cost that is more competitive.

Beyond that, summer gasoline is more expensive to produce, due to EPA mandates on emissions, anti-vapor additives, etc.
Every 16 year old girl here has a 3er or a c class. Houston is nothing but luxury cars so I don't think premium is in low demand. I think we're just getting screwed

That or they're just all running regular because premium "isn't worth it" and that's money that can go to Starbucks.

While we're on the subject. With the one hose system on new pumps, am I paying premium prices for a small amount of regular? If so, that is also annoying to me.



Ok, I'm done
Old 04-13-2016, 03:28 PM
  #25  
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Only my thought,befoe that BS resesson there was only a 10 cent diff, between mid grade and a 10 cent diff.between mid. And prem.its the same gas as always.so the answer is were getting screwed
Old 04-13-2016, 03:29 PM
  #26  
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Your car WILL operate on low octane fuel... Especially in colder weather where the air is colder and denser. Will it operate at its OPTIMUM PERFORMANCE LEVEL??? NO!

If you live in an area where it is very hot and humid,, High Octane fuel is a LOT more important to prevent pre-ignition (KNOCK) and to keep the PCM from pulling timing and then going to the LOW OCTANE timing tables.

I agree. Run some Chevron TEHCRON Fuel System Cleaner in a couple tank fulls of fuel and ENJOY YOUR NEW C5!
Old 04-13-2016, 03:43 PM
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Originally Posted by danny99
Dear all,

Is regular gas Ok in a 2002 base coupe? The original owner told me they've always used regular gas, car has 20k miles on it.

No harm to continue using regular? or should i switch to mid, or premium?
Danny - here's what your owner's manual says:

"Use premium unleaded gasoline with a posted octane of 91 or higher for best performance. You may also use middle grade or regular unleaded gasoline rated at 87 octane or higher, but your vehicle’s acceleration may be slightly reduced. If the octane is less than 87, you may get a heavy knocking noise when you drive. If it is bad enough, it can damage your engine."

Should you use premium - yes. Is the engine harmed by the PO using regular - probably not at all. Am I an expert - No. Do a search on the subject and you'll find good websites - CarTalk & Edmunds to name a couple, that agree with the owner's manual. No harm done.

Congratulations & Enjoy your ride!
Old 04-13-2016, 03:48 PM
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^ In response to Bill, when air is colder/denser, and volumetric efficiency increases, which increases your dynamic compression ratio, then you say 87 is even BETTER. You're dead wrong.

By reducing intake temps you may see a small net increase in combustion stability, but when offset by increase charge density, it'd take a pure data analysis to prove that argument either way.

In increased temps, you increase stress risers, as well as pre-ignition possibility but you also increase fuel atomization which aids combustion chamber mixture homogeny. Again, it's an offset balance of extremes.

If you ping/ring/detonate/pre-ignite a motor, it is putting wear on your ringlands, piston crowns, bearings, wrist pins, etc. Yes, the knock sensors will detect and subsequently retard timing, but knock sensors aren't psychics...they need to physically HEAR damage before they can further prevent it. Period...

Last edited by RC000E; 04-13-2016 at 03:48 PM.
Old 04-13-2016, 03:59 PM
  #29  
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The fuel mapping table compensates for 87. All it does is reduce performance.

The car is fine. That said, fill it up with premium, use a top-tier gas, throw in some techron. And blow out the built up carbon deposits that probably accumulated over 20k miles of not seeing more than 3-4k rpms.
ever.

Premium Gasoline here runs 60-70 cents more per gallon (if you can do math, that equates to 60-70% more than regular, not 10%). And fuel prices are about to skyrocket if the oil prices stay up and with summer coming, that's a double whammy. (oil has increased by 61% per barrel in the last couple of days and while fuel stations won't be paying that price for another month, I guarantee you it will be more expensive this weekend to fill up. Price gouging FTW).

I always use premium. But that's my choice. My car will compensate for 87 octane, same as yours. It retards timing if it detects spark knock. because my job is 3 miles away and I sit in a lot of a traffic, about once a month I give it a good run to blow out any carbon build up that accumulates. This lady probably never gave it a good WOT run the entire time she owned it.

The fact that the husband said it was the wife's car, means he made sure it was taken care of for her. Sounds like you got a gem.

All the doom sayers need to quit freaking the new vette owner out. I swear some people thrive on being jackasses.

As far as why there is such a disparity between the higher octane fuels, while our federal government subsidizes fuel to lower the cost, many states use that as an excuse to tax it. South Carolina charges a road tax and I swear to god the only roads they keep in shape are on the coast where the tourists all visit. When fuel prices got really low, they immediately tried to pass a gas tax to pay for road repairs, which we are already taxed on and they are already supposed to be repairing. In short, the answer is greed.

We're lucky we're not paying 4-5 pounds (7-8 dollars) for a liter of fuel, or we'd all be spending 100-140 dollars just to fill up every week.

Last edited by CriticalmassGT; 04-13-2016 at 04:30 PM.
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Old 04-13-2016, 04:14 PM
  #30  
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Originally Posted by Black 02
The newest C5 can almost be legally driven by someone born the same year it was made. Give the designers a break lol.
No--no break for designers that increase the recommended oil change mileage from 10k to 15k in 2001 when the OLM can't track time . The OLM is known to most owners--but it wasn't clear that the OLM doesn't measure the time frame and some owners probably left the oil in the crankcase until the 10k or 15k mile limit was reached--after several years.

Marketing apparently overrode common engineering sense.

And this is even more so an issue when these C5s are operated now with new owners-- when other newer cars do have OLMs that keeps track of time since last reset of the OLM.

Last edited by phoneman91; 04-13-2016 at 04:22 PM.
Old 04-13-2016, 04:23 PM
  #31  
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Originally Posted by Black 02
I have a gasoline question. Why is premium 40-50 cents more than regular now?
My first guess is there is a lot less demand for premium than the old days. Maybe the taxes are higher for the gas hogs.
Old 04-13-2016, 04:23 PM
  #32  
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Congrats and good luck with your new old baby! First, use only premium fuel. Second, if you didn't get an owners manual with the car, get one. Third, find a good, honest, recommended corvette shop, book it in for a thorough one end to the other check, have your fluids and filters all changed out so that you have a good baseline to work from. The value of being armed with good information cannot be overestimated. Best wishes to you!
Old 04-13-2016, 04:25 PM
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Daaaaaaaaaaaaaamn Daniel!
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Old 04-13-2016, 04:29 PM
  #34  
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Originally Posted by Evil-Twin
2002 with 20 K its 14 year5s old... IM willing to bet it has 14 year old tires on it, its never been serviced... and just a low mileage abused car... low mileage cars like this can be a disaster.. Owner nerve did the most basic maintenance and using regular is the big hint. The ownere who took delivery og the car was never told to use regular, but chose too. the owners manual says you can use regular when nothing else is available, to get you to a station with premium fuel,
This car will need new tires, ( 14 years old .. and at least 5 years over any DOT safety recommendation ), new tire sensor monitors, all fluids changed, belts and hoses. There is no way the owner changed the oil every year, and the oil in the motors has turned acidic, causing pitting of all the internal engine bearings both connecting rod, and mains. I'm giving a very bad scenario, and without any maintenance history... A low mileage pretty car owned by a nice old coup0le without a clue about automotive care, can be bad news, lets hope I am wrong....
You should focus very heavily on these points... Good luck, I hope I'm wrong and welcome to the forum... No IM not a boo bird, or someone willing to sugar coat a potential disaster... while it would be nice to say all the warm and fuzzy stuff... This car could need a lot of attention and quickly, if you want this one to last.
Bill aka ET
just ride the brakes they will wear out real fast, sounds like someone who drives a vette not a vette lover ??? (cheap also) !!!!
Old 04-13-2016, 04:54 PM
  #35  
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Originally Posted by thisMSGgood4me
So not only are you getting screwed on the price, you're also getting screwed on the quantity. Feel better now?
They could at least offer to buy me dinner beforehand!
Old 04-13-2016, 04:55 PM
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Originally Posted by akapounder
just ride the brakes they will wear out real fast, sounds like someone who drives a vette not a vette lover ??? (cheap also) !!!!
Lots of burnouts sounds more fun for the rears. Who needs a line lock?
Old 04-13-2016, 05:13 PM
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Originally Posted by danny99
This does paint a worst case scenerio, but I hope it's not the case. I drove the car home about 250 miles. The car seems like it was babied. I pulled an autocheck for free via ebay and a carfax and all the service records did come up. tires were new, brakes and rotors also new. Battery was replaced last year and passed inspection in Aug I think. I hope it will give me no headaches..it was a major purchase for me
It does paint a pretty grim scenario and it's certainly possible that this car was poorly maintained thru every second of its life and it's only a couple miles away from starting to fall apart HARD.

OTOH?

When I hear:
1. Bought from a couple
2. Car is in good condition to the "eye" and only has the one fob issue
3. Rotors and pads being swapped when they still (likely) have a ton life left

Seems it could just as easily be owned by someone that was car clueless. Sure, just like everyone over the age of 18 they know to replace oil/etc. Age related replacement of tires and proper octane usage is most certainly NOT common knowledge outside the car enthusiast community though, IMO. It would also explain how they could be talked into prematurely replacing braking components by a less than scrupulous mechanic. Entirely possible that they're basing the gas they use off of (bad) advice they were given by someone else. Lord knows it wouldn't be the first time someone at a shop gave out bad advice.

Don't get me wrong, all the things mentioned should have a look taken at them but man. Sure seems like we're jumping to the arguing the benefits of chemotherapy vs surgery on a cancerous brain tumor when the only symptom so far is a headache.

Last edited by Down; 04-13-2016 at 05:15 PM.

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Old 04-13-2016, 05:36 PM
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Originally Posted by Bill Curlee
Your car WILL operate on low octane fuel... Especially in colder weather where the air is colder and denser. Will it operate at its OPTIMUM PERFORMANCE LEVEL??? NO!

If you live in an area where it is very hot and humid,, High Octane fuel is a LOT more important to prevent pre-ignition (KNOCK) and to keep the PCM from pulling timing and then going to the LOW OCTANE timing tables.

I agree. Run some Chevron TEHCRON Fuel System Cleaner in a couple tank fulls of fuel and ENJOY YOUR NEW C5!
Thank you all for the replies!

Bill, do I first put the chevron techron cleaner in a empty tank first and then fill it up with premium? or premium first and then the techron? : )
Old 04-13-2016, 05:38 PM
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Originally Posted by danny99
Thank you all for the replies!

Bill, do I first put the chevron techron cleaner in a empty tank first and then fill it up with premium? or premium first and then the techron? : )
techron cleaner in a empty tank first //// yes !!!
Old 04-13-2016, 05:57 PM
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We tried to make this car idiot proof.. but as time has shown, there is a much higher order of idiot out there..
BTW the OLM algorithm string was changed in 2000.
The base line was increased from 10,000 miles to 15000 miles. The OLM was that good...

How smart do you have to be to read, Change the OIL when the OLM says too, or at one year, which ever comes first. Seems to me even an 8 year old could figure that one out.

Just for the idiots among us... when I said GM changed the OLM algorithms base line in 2000 to 15000 miles from 10,000 miles, that doesn't mean you can drive your car 15,000 miles between oil changes.... this car was so designed and the OLM updated to be idiot proof to insure a 200,000 mile motor. BTW the DOT compliance sticker on the door for tire pressure was put there because, these very same idiots were putting 65 psi in their tires because that's what it said on the sidewall. Max pressure 65 psi. They figure more must be better.

Premium fuel ( 93 Octane ), in Pennsylvania, where I live is 5 cents more than mid-range fuel . regular fuel is 15 cents cheaper than Mid range. Anyone who drives a Corvette, and is concerned about 4 dollars a fill, is driving the wrong car. Premium fuel is not always necessary but when your car need the extra octane at sea level or under load or in a lug load condition, its good to have it there...... every time the knock sensors are activated, that pre ignition explosion before top dead center is destroying your engine one molecule at a time. plus you are loosing any added performance value, and for what? 4 dollars? Seems pretty stupid to me.. but then stupidity breads those idiots we so lovingly talk about. Those are the guys you would not want to be the second owner of their car.


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