100 Octane Gas????
09-19-2006, 04:27 PM
#1
Racer
Thread Starter
100 Octane Gas????
I have a 2006 6speed Z51 convertible. Besides killing my pocket book what would a full tank of 100 octane gas do? Would it hurt anything? Should I mix it with 91 octane?
09-19-2006, 05:16 PM
#2
Melting Slicks
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Originally Posted by robwah
I have a 2006 6speed Z51 convertible. Besides killing my pocket book what would a full tank of 100 octane gas do? Would it hurt anything? Should I mix it with 91 octane?
It will likely do close to nothing since the car is tuned for 91-93. And why would you want to mix 100 octane with anything?!
09-19-2006, 05:29 PM
#6
Burning Brakes
100 octane? Can't find that anywhere in my parts. That 100 octane may be obtained by using MMT, which the owners manual suggests staying away from.
It would be a waste of money.
It would be a waste of money.
09-19-2006, 05:32 PM
#7
Le Mans Master
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Originally Posted by robwah
I have a 2006 6speed Z51 convertible. Besides killing my pocket book what would a full tank of 100 octane gas do? Should I mix it with 91 octane?
what would a full tank of 100 octane gas do?
Nothing more than 93 (R+M)/2
Would it hurt anything?
No
Should I mix it with 91 octane?
Whats the point? Just buy 91 to 93 Octane.
09-19-2006, 05:37 PM
#8
Team Owner
According to the GM website use 93 octane for max performance. For some theoretical reasons using higher octane may actually lessen output.
I mix 4 gallons of 100 octane no-lead + 12 gallons of 91 octane to yield my typical fill up of 16 gallons of 93 octane.
I mix 4 gallons of 100 octane no-lead + 12 gallons of 91 octane to yield my typical fill up of 16 gallons of 93 octane.
09-19-2006, 05:41 PM
#9
Melting Slicks
HMMM Let's see hear.
A fuels "Octane" is a fuels ability to withstand heat & pressure BEFORE detonation.
Therefore putting a fuel with a higher octane than what is called for would probably inhibit a complete burning during combustion.
This would cause "sooting" at the tailpipes, and possibly fouled sparkplugs.
DON'T DO IT!
A fuels "Octane" is a fuels ability to withstand heat & pressure BEFORE detonation.
Therefore putting a fuel with a higher octane than what is called for would probably inhibit a complete burning during combustion.
This would cause "sooting" at the tailpipes, and possibly fouled sparkplugs.
DON'T DO IT!
09-19-2006, 05:45 PM
#10
Drifting
Another possible thing you may be seeing is a place that misleads you by selling "100 octane" that is 100 by the "R" method. Normal premium gasoline that is posted 93 octane is by the (R+M)/2 method. The sleazier the operator, the greater the difference between R and M. Spread can go as high as 14, with R always higher. So the guy might be selling you 93 octane posted gasoline from a sleazy refinery, that is 100R and 86M, to get to it's 93 posting. Reputable refiners seldom go over a 10 spread, so posted 93 is usually around 97-98R and 88-89M.
If the stuff you are talking about is actually 100 by the (R+M)/2 method, then I'd echo the other comments. You won't do any harm, but you also won't do any good, beyond deflating your wallet. Once octane is high enough to allow your engine to achieve design spark advance without knocking (and that happens at 91 (R+M)/2, then further octane increase has zero impact.
If the stuff you are talking about is actually 100 by the (R+M)/2 method, then I'd echo the other comments. You won't do any harm, but you also won't do any good, beyond deflating your wallet. Once octane is high enough to allow your engine to achieve design spark advance without knocking (and that happens at 91 (R+M)/2, then further octane increase has zero impact.
09-19-2006, 07:29 PM
#11
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Sunoco makes a product called "gt100 unleaded" it comes in a 5 gallon pail.
I used it when we were hit by a hurricance last year.
As long as it says UNLEADED,it will not harm the pistons or the catalist.
I used it when we were hit by a hurricance last year.
As long as it says UNLEADED,it will not harm the pistons or the catalist.
09-19-2006, 08:22 PM
#13
Safety Car
Originally Posted by nuvetteowner
Sunoco makes a product called "gt100 unleaded" it comes in a 5 gallon pail.
I used it when we were hit by a hurricance last year.
As long as it says UNLEADED,it will not harm the pistons or the catalist.
I used it when we were hit by a hurricance last year.
As long as it says UNLEADED,it will not harm the pistons or the catalist.
09-19-2006, 08:23 PM
#14
Le Mans Master
I've used 100 Octane unleaded in My 68 GTO many times over the years. It is hard to find and very expensive when you do find it. Around here, it's sold under the CAM 2 brand name.
The car runs great on it but not enough of a difference over 93 Octane to justify feeding the GOAT a steady diet of the stuff.
I don't think I would put in in a new Corvette though.
The car runs great on it but not enough of a difference over 93 Octane to justify feeding the GOAT a steady diet of the stuff.
I don't think I would put in in a new Corvette though.
09-19-2006, 08:58 PM
#15
Melting Slicks
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Won't make a difference. The car has knock sensors to retard timing if it starts to detonate due to low octane fuel but it does not have octane sensors that will advance timing to higher level because you are using a higher octane fuel. The car won't know the difference between 93 octane and 100 octane. The only benefit that I can see with the 100 octane fuel is you were running forced induction with a lot of boost. In that case, the added octane may make a difference in terms of detonation.
09-19-2006, 09:47 PM
#16
Racer
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Originally Posted by 70454
Sunoco still sells "race fuel" locally here in the Philly burbs. I put it in my 70 454 on occasion. Big bucks but I treat it every now and then.
09-19-2006, 10:31 PM
#17
Safety Car
Originally Posted by John Bravo
Racing gasoline is made for high compression motors and at 10.9 to 1 we are perfect with 93. I have a 70 big block Chevelle with higher compression and I mix 93 and 100 octane for the best tested results. That car made less power on the 100 octane than the 93 but I had a slight pinging so a little testing and I got the best formula.
09-19-2006, 10:39 PM
#18
Get Some!
Octane discussion.
--------------------------------------------------------------------------------
http://forums.corvetteforum.com/sho...cts&forum_id=74
by LDB
Lots of gasoline comments lately. I’m an engineer for a major oil company, familiar with engine testing for performance, economy, and emissions. I think my company’s gasoline is slightly better than other majors, but I’m not going to use the forum for advertising. Instead, I’ll make a few points about what you should look for in a gasoline. If you do that, my company will get more than an average share of your business.
Octane is generally misunderstood. High octane gasoline isn’t more powerful, it simply offers better resistance to engine knock. Lower than needed octane is a big penalty from knocking and/or spark retard, but higher than needed octane gives no benefits. Sounds odd, but it’s true as described below. Premium gasoline does have some benefits even to a car designed for regular, but those benefits aren’t from octane. They are from some other characteristics which are described at the very end, DI and additives. Let’s talk octane first.
Two main factors set octane requirement: compression ratio and spark advance. Compression ratio is a design feature of the engine, with higher ratios giving better performance, but also requiring higher octane rating. Corvettes need premium gasoline because they are high compression ratio, which requires high octane. Best performance in any given engine is at a particular spark advance, and going in either direction makes poorer performance. But while it costs performance, less than optimum spark advance does have the advantage of lowering octane requirement. So your knock sensor can compensate for low octane fuel by retarding the spark, at a cost in performance. But the reverse is not true. Once octane is high enough to allow optimum spark advance, more octane doesn’t help, because greater than optimum spark advance does not increase performance.
The Corvette gasoline spec is 91. There is some variability in engine response depending on a myriad of other characteristics including engine age, but it’s safe to say that benefits of 93 versus 91 are small, and 94 versus 93 are nil. You can make similar comments about the benefits of greater than 87 octane in a normal car. Its compression ratio is lower, so it can get to optimum spark advance on 87 octane. Running 93 octane will not help turn it into a Corvette, because it doesn’t have the compression ratio to utilize the higher octane.
Bottom line on octane is that benefit of being over manufacturers recommendation is slim to none. The only three things that can cause you to get significant benefit from going higher are: 1) a 100,000 mile engine probably needs a couple of numbers more than new due to various irregularities in an old engine, 2) if you live at high altitude, a couple of numbers over normal spec are usually needed, or 3) if you do major engine modifications to raise compression ratio.
Other issues are a detergent additive package for valve and injector cleanliness, a reliable quality control system, and good DI, drivability index, a measure of how well the fuel evaporates. All majors are roughly equivalent in those areas, and most premium gasolines have more detergent and better DI than most regulars. There are shades of gray differences in additives, but once you are with a major oil company, you need careful tests to see them. All majors (including my own) have had quality control lapses, usually with sulfur (causes odor, emissions, and gas gauge problems), particulates (plugs filters prematurely), and/or water (the worst of all, and can devastate an engine, but this one is almost unheard of with the majors). But when the rare lapse does occur, we quickly correct the problem, including any damage it may have caused. When you buy from the grocery store, or Wal-Mart, or a convenience store, you are much more exposed. Some of the time, those places buy from the majors, and their gas is perfectly OK. But all too often, they buy on the spot market, the cheapest stuff that happens to be floating by on a barge. This gives you higher probability of a serious quality control incident, and also exposes you to poor additives and DI. In the short term, you’d never notice lack of detergent additives, but over time, you engine will foul. DI symptoms are subtle, mostly a rough warm up period, but poor DI also tends to foul the engine, especially if it is short on detergent. So you have to ask yourself, do you want to fuel a $50,000 car from the lowest bidder.
Anyway, at the very end of this tome, I’d advise you to set you minimum standard as being at least recommended octane, from one of the majors. Once you are at that point, differences become small. Does 93 versus 91 or 94 versus 93 make much difference? Probably not, unless you live in the mountains or have an aging engine. Is premium worth it in your regular car for the slightly higher additive concentration and slightly better DI if you don’t need the octane? You have to make that decision. There are benefits, but you are into small stuff. It’s kind of like Mobil 1 versus normal oil. Sure, Mobil 1 is very slightly better. It’s also $4 versus $1 per quart. But that’s another long post, and I’m out of energy for now.
Quote:
Originally Posted by......
Too much octane rating when not needed, can infact decrease performance, as the burn rate of the fuel is slowed with higher octane fuel, and can act like timing retard.
Duke is a retired GM engineer.
That's a myth! Normal combustion flame propagation speed is not effected by octane. What octane does is prevent all or some portion of the unburned mixture from reacting virtually instantly, rather than being consumed by the flame front at normal flame propagation speed.
Higher octane than necessary doesn't do any good, but neither does it do any harm other than cost you more for no benefit.
Preignition and detonation are not the same phenomena, but one can lead to the other, which can rapidly damage an engine.
Duke
--------------------------------------------------------------------------------
http://forums.corvetteforum.com/sho...cts&forum_id=74
by LDB
Lots of gasoline comments lately. I’m an engineer for a major oil company, familiar with engine testing for performance, economy, and emissions. I think my company’s gasoline is slightly better than other majors, but I’m not going to use the forum for advertising. Instead, I’ll make a few points about what you should look for in a gasoline. If you do that, my company will get more than an average share of your business.
Octane is generally misunderstood. High octane gasoline isn’t more powerful, it simply offers better resistance to engine knock. Lower than needed octane is a big penalty from knocking and/or spark retard, but higher than needed octane gives no benefits. Sounds odd, but it’s true as described below. Premium gasoline does have some benefits even to a car designed for regular, but those benefits aren’t from octane. They are from some other characteristics which are described at the very end, DI and additives. Let’s talk octane first.
Two main factors set octane requirement: compression ratio and spark advance. Compression ratio is a design feature of the engine, with higher ratios giving better performance, but also requiring higher octane rating. Corvettes need premium gasoline because they are high compression ratio, which requires high octane. Best performance in any given engine is at a particular spark advance, and going in either direction makes poorer performance. But while it costs performance, less than optimum spark advance does have the advantage of lowering octane requirement. So your knock sensor can compensate for low octane fuel by retarding the spark, at a cost in performance. But the reverse is not true. Once octane is high enough to allow optimum spark advance, more octane doesn’t help, because greater than optimum spark advance does not increase performance.
The Corvette gasoline spec is 91. There is some variability in engine response depending on a myriad of other characteristics including engine age, but it’s safe to say that benefits of 93 versus 91 are small, and 94 versus 93 are nil. You can make similar comments about the benefits of greater than 87 octane in a normal car. Its compression ratio is lower, so it can get to optimum spark advance on 87 octane. Running 93 octane will not help turn it into a Corvette, because it doesn’t have the compression ratio to utilize the higher octane.
Bottom line on octane is that benefit of being over manufacturers recommendation is slim to none. The only three things that can cause you to get significant benefit from going higher are: 1) a 100,000 mile engine probably needs a couple of numbers more than new due to various irregularities in an old engine, 2) if you live at high altitude, a couple of numbers over normal spec are usually needed, or 3) if you do major engine modifications to raise compression ratio.
Other issues are a detergent additive package for valve and injector cleanliness, a reliable quality control system, and good DI, drivability index, a measure of how well the fuel evaporates. All majors are roughly equivalent in those areas, and most premium gasolines have more detergent and better DI than most regulars. There are shades of gray differences in additives, but once you are with a major oil company, you need careful tests to see them. All majors (including my own) have had quality control lapses, usually with sulfur (causes odor, emissions, and gas gauge problems), particulates (plugs filters prematurely), and/or water (the worst of all, and can devastate an engine, but this one is almost unheard of with the majors). But when the rare lapse does occur, we quickly correct the problem, including any damage it may have caused. When you buy from the grocery store, or Wal-Mart, or a convenience store, you are much more exposed. Some of the time, those places buy from the majors, and their gas is perfectly OK. But all too often, they buy on the spot market, the cheapest stuff that happens to be floating by on a barge. This gives you higher probability of a serious quality control incident, and also exposes you to poor additives and DI. In the short term, you’d never notice lack of detergent additives, but over time, you engine will foul. DI symptoms are subtle, mostly a rough warm up period, but poor DI also tends to foul the engine, especially if it is short on detergent. So you have to ask yourself, do you want to fuel a $50,000 car from the lowest bidder.
Anyway, at the very end of this tome, I’d advise you to set you minimum standard as being at least recommended octane, from one of the majors. Once you are at that point, differences become small. Does 93 versus 91 or 94 versus 93 make much difference? Probably not, unless you live in the mountains or have an aging engine. Is premium worth it in your regular car for the slightly higher additive concentration and slightly better DI if you don’t need the octane? You have to make that decision. There are benefits, but you are into small stuff. It’s kind of like Mobil 1 versus normal oil. Sure, Mobil 1 is very slightly better. It’s also $4 versus $1 per quart. But that’s another long post, and I’m out of energy for now.
Quote:
Originally Posted by......
Too much octane rating when not needed, can infact decrease performance, as the burn rate of the fuel is slowed with higher octane fuel, and can act like timing retard.
Duke is a retired GM engineer.
That's a myth! Normal combustion flame propagation speed is not effected by octane. What octane does is prevent all or some portion of the unburned mixture from reacting virtually instantly, rather than being consumed by the flame front at normal flame propagation speed.
Higher octane than necessary doesn't do any good, but neither does it do any harm other than cost you more for no benefit.
Preignition and detonation are not the same phenomena, but one can lead to the other, which can rapidly damage an engine.
Duke
09-19-2006, 11:44 PM
#20
Pro
Member Since: Mar 2006
Location: Antelope CA
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Originally Posted by bajapointe
HMMM Let's see hear.
A fuels "Octane" is a fuels ability to withstand heat & pressure BEFORE detonation.
Therefore putting a fuel with a higher octane than what is called for would probably inhibit a complete burning during combustion.
This would cause "sooting" at the tailpipes, and possibly fouled sparkplugs.
DON'T DO IT!
A fuels "Octane" is a fuels ability to withstand heat & pressure BEFORE detonation.
Therefore putting a fuel with a higher octane than what is called for would probably inhibit a complete burning during combustion.
This would cause "sooting" at the tailpipes, and possibly fouled sparkplugs.
DON'T DO IT!
after cleaning.I don't think I'll catch it, so if any one does, please let me know.
If you use the correct octane in a high performance engine, why would it build up more carbon ? Maybe it's all the horsepower makes it too scary to wind up the engine and blow it out in a street driving situation. Curious if a race car on a track would have less carbon build up, same engine, milage, and gas ?
Greg