Anyone using Shell 89 octane?
With the V Power (93 octane) over $4.25 here some of us old retired guys are thinking of down-grading to it.

 

it isn't great but you guys still have it better than Canada. Same 93 is well over $5.00 for 3.78 liters...a US gallon.
Just stop idling at a drive through for a coffee or a burger instead.:-)

 

This is a wating to happen.

This topic is “debated” often and always ends the same way.

http://forums.corvetteforum.com/c5-g...st-report.html

 

Sloatsburg ??????????? One heck of a place to retire to . If you can afford the NYS taxes you can buy the $4 gas.

(I used to live in Rockland Co. back when it was almost rural.)

 

Sure, I use Shell 89 octane. In my Ford Ranger pickup. For the 'Vette, it gets only Chevron 91 octane (at $4.59/gal) here in CA. And I'm financially challenged, but there are some things that I refuse to scrimp on.

 

This is an age old question that has come up a many times.

Yesterday - we had occasion to dyno tune an '08 C6 (LS3) with an Edelbrock supercharger that had been installed and tuned in Indiana. The car was tuned for 93 octane....we have only 91 octane here in Arizona.

The car detonated with anything more than about 8-9 degrees of timing. We tried everything to figure out why. We pulled out a boroscope and took a look at the tops of the pistons. They were all cratered and looked very similar to the surface of the moon. The owner admitted that he had been running 87 octane from time to time. Also the installing shop had de-sensitized the knock sensors to the point of them not working at all.

This car should have been able to run 12-14 degrees of advance with no issue, and would not without a lot of detonation. Bottom line is we de-tuned the car, the owner is going to try a couple of cans of Sea-Foam to break up the carbon on top of the pistons. We'll re-check the car after he does the Sea-Foam, and runs a couple of tankfuls of 91 Chevron through it. I have my doubts, it looked like damage to me.....

So to answer the question - can the car run lower than recommended octane? Yes - if the timing is retarded. The knock sensors should be able to handle it - but the long term affect is not desireable. You will get less performance due to the retarded timing, and less fuel mileage as well. All in the interest of saving about twenty cents per gallon times maybe 15 gallons. That's three dollars for a 15 gallon tank. To me - not worth it.

I try to run the fuel that is recommended, and that is at least 91 octane. Your car - your choice.

 

Thanks for the input, will stick with the V Power 93

 

Better to spend an extra 3 dollars at the pump than be a retard destroying an expensive engine nullifying the price by getting worse fuel economy. If you can't afford 3 more dollars at the pump why do you have a 20-60K car? This subject just irks me.

 

No need to be irked or call the OP a retard......he didn't know and that was why he asked. He responded that he is sticking with the 93. Take a chill pill my friend - it's all good.

 

Sorry, I was out of line. I need to stay away from these topics lol.

 

Great input Randy

 

Good idea.

 

Geez put in premium or sell the car.

 

This is something you can appreciate. I bought a Pontiac last summer, August 1, it was a 39 month lease turn-in and it ran great. I filled it with 93 octane as recommended in the owners manual, something not read by the original leasers. The car perfect till the summer was over and the first night were temps were down to 70 degrees. I went out and the would crank but not catch. I tired and gave up and called AAA. They towed it to my Chevrolet dealership. Once there the car started perfectly and they looked the car over but found no problems.

I got a ride up to the dealership and drove it home. two days later it was quite chilly over night. Went out the next morning and the car would not start again, I tried again but it just wasn't going to start. Once again AA towed in on a flatbed back to the Chevy dealership and they let it sit over night but it started OK. Once again it ran fine. but they kept it for a few days and on the last day of the week it was down right cold. The Corvette technician came out at 8:30 and tried to start it and sure enough it wouldn't start. They tried all sorts of thing and called me to come get it. I did and drove it home and sure as S*&^T it would not start in the morning. Yes it went back to the dealership where the shop foreman and the senior Corvette technician after the other techs went home pulled in in and just went through the software and no codes were set so they just did old fashion and started with Compression/fuel/ and spark.

The car had excellent compression, it had perfect spark and it had perfect fuel pressure. They rechecked everything right to the cylinder. The only thing that was off in any way was the fuel. For some reason the fuel wasn't getting to the intake valve. but upon closer inspection the cause was clear. On page 338 of the Owners Manual it states the engine, being supercharged needed 91 octane minimum and cannot be run on any fuel containing anymore than 10% of ethanol.

The problem was that the previous owners had never bother to read the owners manual ( They leased it so who cares) but they fed it a diet of 87 octane for those leased years and by using cheap, crud fueled gasoline, it had built up deposits on the inside of the intake valves that in the start cycle the fuel mixture which was fine, but it could not move fast enough to get past the huge build up of carbon and general low cheap fuel in a enough quantity that by the time the valve closed it had enough gasoline to ignite to have combustion. They used a GM product twice to break up the crap that coated the intake valves. I suppose it is akin to sea-foam and it was sucked in by the brake booster hose, once done twice they shut it off and put everything back together and backed it outside and ran it for an hour as it was smoking like all hell. Once they brought it back in they changed the oil and filter.

They called to come get it. Once there the foreman told me the trouble and said to run it on 91 octane, I said I have read the owners manual and I only have run 93 octane in it and he said along with the 93 octane to buy a five or six big bottles of Chevron/Techron and for the next six month to run a bottle thorough it with every other tankful, which I have. But that is the effect of 87 octane being run in an engine designed for 91 octane fuel. So if you own a Corvette and resent having to put high octane fuel instead of cheap regular. . . do everyone a favor, go trade in the Corvette for a Cobalt or a Chevy Sonic or whatever. If your going to own it, then you need to take care of it.

 

Your $4.25 will be a bargain before long. Premium comes with the territory. Whatever you do...do NOT run the car on fumes. Fuel pumps need to stay cool at all times. Gasoline keeps em cooled down.

Your alternative is to make it a garage queen. W/o the proper additives you will pay more in repairs down the road.

JMOP

 

10 or so years ago we were told not to use Shell brand because it contained too much Sulfur. We were having problems with fuel tank sending units. I think at one time there was a class action law suit involving Shell Oil. Use Chevron with Tecron.

 

+ Texaco w/Techron

 

Don't run the E10 either if you can help it. That stuff is poison for aluminum, rubber and filters over time plus you MPG will drop 10-15%

 

My experience in other cars that are built to run on 89 or 91 is that you get better mileage out of 91 so it offsets the price and then some. Plus, you get a power loss at the same time and risk detonation until computer adjusts for it. You can use 89 but, it is recommended that you only put 5 gals in when you are in an emergency and need to get somewhere. It's is suggested to use 89 as a emergency measure only. No full thottle takeoffs and you should fill up with Premium as soon as you can to bring the octane rating back to a higher level.

Now if you have a newer C6 the standard model is built for use with regular. That might give some of you a reason to upgrade. However, the cost of the car outweight the gas prices savings of course. ;-)

I run Chevron 90% of the time .... and if I get cheap I run top tier gas and I use Techiron additive every other tankful. It works out to about the same per gallon. However, sometimes it's just more convenient when I'm traveling etc...

Wish I could get 93 here in Cali.

 

I agree with the comments already mentioned here - go ahead and spend the extra few bucks per tankful and put premium gas in the car. It will pay off in the long run.