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Discussion Starter #1
https://youtu.be/hpVHLTRrxCw i just watched this video. i assumed everyone uses premium gas in their Vette. i also just looked at my owners manual and it states for best performance to use 91 octane. It also says you can use 87 octane but no lower if your engine knocks. just curious if anybody uses regular or midgrade gas regularly.
 

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Are you sure it doesn't say to use 91 octane or higher? Obviously, the main thing to avoid is pre-detonation, which higher octane will prevent.
 

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I have used 87 octane in my 1987 Corvette.
I does fine as long as your cruising and not much WOT action.
Such as extended highway driving for 1-2 hours non stop.
It defiantly likes 91-93 octane better.

If outside temps are 50 F & Lower I have found often 87 octane can be used with almost no detonation.

If its 85-100F or more I would use only 91-93 octane.
 

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Been using regular gas in my 03 Coupe about 75% of the fill ups. No problems but a cruise about pretty near daily ride here. Average about a tank of gas every two weeks with a fill up of about 13 to 15 gallons.
 

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I sure miss the days when mid grade was 10¢ more than regular and premium was 20¢ more. Around here it's 30¢ for each grade difference.
 

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I don't know about the C4's but starting with the C5's the programming is such that if the knock sensor observes "ping" then it assumes that it is because of a lower grade octane like 87 and then it changes the spark timing tables and performance levels. After a certain number (not sure how many) of start cycles without ping it reverts back to the original table again assuming that it is being fed 91 octane or higher
 

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Just read my owners manual and the LT1 calls for 91 and the LT4 can use 87 or 89 with the statement of possible decreased performance. The ethanol-free gas I use is rated at 90 octane and I've never noticed a knock.
 

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I don't know about the C4's but starting with the C5's the programming is such that if the knock sensor observes "ping" then it assumes that it is because of a lower grade octane like 87 and then it changes the spark timing tables and performance levels. After a certain number (not sure how many) of start cycles without ping it reverts back to the original table again assuming that it is being fed 91 octane or higher
It's about the same on the LT1/LT4 ECM's also except that it retards timing constantly when knock is present. I don't think it ever reverts to another table for an extended period of time.

Just read my owners manual and the LT1 calls for 91 and the LT4 can use 87 or 89 with the statement of possible decreased performance. The ethanol-free gas I use is rated at 90 octane and I've never noticed a knock.
You've just ruined my whole nights sleep. The LT1 had 10.4 compression ratio and the LT4 has 10.8 but you can use a lower octane with the higher compression. I know the knock modules were different between the LT1's and the LT4's. That was because of the extra noise made by the LT4 roller rockers. Maybe the cam opened a bit later ABDC and lowered the dynamic compression ratio. Just not sure but the compression thing is making me take a sleeping pill.

My C4 is stockish but the twol Impala SS's are both LT4 cars. One is a 383 with 11.8 compression and the six speed Impala is a LT4 with the 845 cam, SLP headers and a nifty ram air setup. It has the 10.8 compression and has only ever seen premium.
 

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To be clear , there is a world of difference between recommending 91 or higher fuel and saying one can use regular to get by if one can't find the recommended fuel. The owners manual is clear about the recommended fuel for my ls1. 91 or higher. I am in the c5 section, correct?

I am certain my knock sensors can't tell the future, they only work after the knock. I plan on going the distance, and the condition of my car is important to me. Plus, in my area, traffic is such that reliability can be a real safety concern.

I think some guys here need to buy an economy car if they only care about getting by with lower grade fuel. However, it is a free country , and they are the guys who will pay after finding that inferior fuel will have the same results as any other attempt to ignore the design limits . Some guys also run dyno oil, using the same logic, nothing has broken so far.

every machine has operating instructions, for good reason. As a matter of fact, I have spent time with highly trained chief marine engineers on super tankers who run the systems they control only by the book, because of possible legal exposure if a system fails and they decided to "wing it" instead of following the book. These are guys that could rewrite the book if needed, and have all the system manuals all along the walls, so they can look stuff up quickly.

If you want to cheap out on fuel, fine with me. Some guys even ignore the quality of food they eat, and then cry about their health when they get my age. Because the system can compensate for some abuse, but is not designed to run on cheeseburgers and fries for any extended length of time.

At least with a car, you can sell before the abuse surfaces , something every corvette owner seeks to avoid when buying used. Some of the answers here illustrate to me why skilled corvette buyers are so careful. An abused corvette can be an expensive hole to fall into . Myself, I knew nothing about corvettes so my buying decision rested on how I felt about the owner and what I could gather about his stewardship of the car.
 

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^^^^^^^^^^^^^ I like this guy.........even if he is a Californian.:laughing: I agree with the above post and I eat too many cheeseburgers and fries. Wow, I've never heard logic like that from the left coast. Welcome to DC. Are you sure you're not a Kentuckian?
 

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Discussion Starter #15
i was just curios about the fuel everyone used, in my first post i just assumed everyone used premium. in post # 5 the manual says for best performance use 91 or higher. it states you may use lower octane but may have reduced performance. if you use lower than 87 and it knocks use 87 or higher as soon as possible.
 

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Discussion Starter #16
i think everyone like me assumed we had to use higher octane fuels which i have always done .
 

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i think everyone like me assumed we had to use higher octane fuels which i have always done .
YEs, common sense would suggest that, but there are always guys who will try to out think common sense.

I don't think the guy posting non LS1 fuel information was trying real hard to help.
 

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^^^^^^^^^^^^^ I like this guy.........even if he is a Californian.:laughing: I agree with the above post and I eat too many cheeseburgers and fries. Wow, I've never heard logic like that from the left coast. Welcome to DC. Are you sure you're not a Kentuckian?


But......bu.....but....:laughing:

Nice to know that not all of us left coaster's aren't all Squizzied up. :cheers:
 
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