Octane booster Info/Questions
04-19-2004, 11:22 PM
#126
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Originally posted by pcldletter
went with a half a gallon fo toluene in about 5 or 6 gallons of mobil 93 octane. I seemed to get an even more unstable idle than I had before, no niticable power gains.
went with a half a gallon fo toluene in about 5 or 6 gallons of mobil 93 octane. I seemed to get an even more unstable idle than I had before, no niticable power gains.
Now the octane rating is still lower then racing fuel suitable for street cars. For about $5 a gallon of 100 octane unleaded, it's just a little more expensive then going with the toluene method.
I wish I had the time (or money) to go experiment and see if there really is a difference. Again Internet wisdom says there probably will not be a gain for naturally aspirated cars.
05-08-2004, 05:59 PM
#127
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I finally tried Xylene in my 4 banger. 1 gallon Xylene + full tank of 91 (until I find 93). Now that about 1-2 gallons of fuel have been used from this tank I can feel a real difference. Engine runs smoother, and is more willing to rev. It's totally smooth up to redline. It feels more responsive to throttle inputs and has given more torque from 2000-4000 rpms where there is usually none. Its much smoother when starting from a stop and has drastically reduced the stuttering that I sometimes feel when not engaging the clutch perfectly. Im a believer and this is an NA 4 cyl engine were talkin about here. Now I need to convince my friend that its ok for his FD and find a cheap supply.
Last edited by KC_Prelude; 05-08-2004 at 06:03 PM.
05-09-2004, 12:49 AM
#128
Originally posted by Jsuzuki
Again Internet wisdom says there probably will not be a gain for naturally aspirated cars.
Again Internet wisdom says there probably will not be a gain for naturally aspirated cars.
And remember Octane and Power are not directly related. You can have a higher octane fuel that makes less specific power.
Cheers,
Hymee.
05-09-2004, 05:46 PM
#129
New Member
Originally posted by Hymee
The "wisdom" I gleened from reading others posts in this place is that Toluene and Xylene will give more power as they have more energy available.
And remember Octane and Power are not directly related. You can have a higher octane fuel that makes less specific power.
Cheers,
Hymee.
The "wisdom" I gleened from reading others posts in this place is that Toluene and Xylene will give more power as they have more energy available.
And remember Octane and Power are not directly related. You can have a higher octane fuel that makes less specific power.
Cheers,
Hymee.
05-09-2004, 06:03 PM
#130
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Easy... read the thread. Your average pump gasoline uses as little toluene and xylene as possible (these are normal components of gasoline), and instead uses cheap additives and other chemicals for octane and mandated emissions. These cheaper alternatives have less engery content (joules) than xlyene and toluene. Thus... a gasoline mixture that contains a higher percentage of xylene and/or toluene will have a higher energy content than a gasoline of the same octane rating, but uses cheap alternatives. More energy content = more power. Simple.
05-09-2004, 06:27 PM
#131
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I was asking Hymee this question:
"And remember Octane and Power are not directly related. You can have a higher octane fuel that makes less specific power." How??
"And remember Octane and Power are not directly related. You can have a higher octane fuel that makes less specific power." How??
05-09-2004, 06:50 PM
#132
Taka - you need to read more threads than you post 
The Octane Rating of a fuel is NOT a measure of it's ENERGY. It is a measure of the ability of the fuel to resist detonationion (knock). It is best though of as the "anti-knock" rating.
Think of it this way - put heaps of water in your fuel - it will have a very high "resistance to knock", but it wont give you much power.
Or like this - LPG has roughly the same equivalent "anti-knock" rating as AVGAS. But LPG makes less power than gasoline.
The "Octane" molecules are probably more potent than other hydrocarbons - hence the notion that more octane is more power. But the Octane Rating is not a measure of the actual octane in the fuel. It is more of a rating that equates to the anti-knock rating offered by octane molecules. They used to use lead to increase the Octane Rating. Lead isn't going to make more power. I don't even think it burns that much!
Toluene and Xylene are hydrocarbons that increase the "Octane Rating" (because the have octane molecules in them) but they also provide more energy in the combustion because of those actual octane molecules (a bigger "bang").
Octane Rating and specific power are not directly related.
Did this help to clarify?
Cheers,
Hymee.
PS - I am not a chemical engineer, but I know just enough to be dangerous. I have personally discussed this with a chemical engineer.
The Octane Rating of a fuel is NOT a measure of it's ENERGY. It is a measure of the ability of the fuel to resist detonationion (knock). It is best though of as the "anti-knock" rating.
Think of it this way - put heaps of water in your fuel - it will have a very high "resistance to knock", but it wont give you much power.
Or like this - LPG has roughly the same equivalent "anti-knock" rating as AVGAS. But LPG makes less power than gasoline.
The "Octane" molecules are probably more potent than other hydrocarbons - hence the notion that more octane is more power. But the Octane Rating is not a measure of the actual octane in the fuel. It is more of a rating that equates to the anti-knock rating offered by octane molecules. They used to use lead to increase the Octane Rating. Lead isn't going to make more power. I don't even think it burns that much!
Toluene and Xylene are hydrocarbons that increase the "Octane Rating" (because the have octane molecules in them) but they also provide more energy in the combustion because of those actual octane molecules (a bigger "bang").
Octane Rating and specific power are not directly related.
Did this help to clarify?
Cheers,
Hymee.
PS - I am not a chemical engineer, but I know just enough to be dangerous. I have personally discussed this with a chemical engineer.
05-09-2004, 06:54 PM
#134
An other thing - cars that require a higher octane fuel generally make more power because the run at a higher compresssion ratio. A higher compression ratio give a higher volumetric efficency - hence more power for the same displacement.
This is another contributing factor to the myth that a higher octane fuel has more energy in it.
Cheers,
Hymee
This is another contributing factor to the myth that a higher octane fuel has more energy in it.
Cheers,
Hymee
05-09-2004, 07:54 PM
#135
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No offense Hymee, but I just don't understand the way you are trying to explain it. Octane molecules? I am not new to chemicals and hydrocarbons in general and understand much of the jargon used, but Octane molecules. Maybe it would be more correct for you to replace the word "Octane" when combining it with the word "molecules" with the word "energy" or "power producing".
I think I agree with what you are trying to say. I guess I really would like to hear from a chemical engineer working at a gasoline refinery and I would like to hear the explanation in the actual chemical engineering jargon. Then it is up to me to learn or remember enough to translate it into something I can understand or pass on.
Thanks
I think I agree with what you are trying to say. I guess I really would like to hear from a chemical engineer working at a gasoline refinery and I would like to hear the explanation in the actual chemical engineering jargon. Then it is up to me to learn or remember enough to translate it into something I can understand or pass on.
Thanks
Originally posted by Hymee
Taka - you need to read more threads than you post
The Octane Rating of a fuel is NOT a measure of it's ENERGY. It is a measure of the ability of the fuel to resist detonationion (knock). It is best though of as the "anti-knock" rating.
Think of it this way - put heaps of water in your fuel - it will have a very high "resistance to knock", but it wont give you much power.
Or like this - LPG has roughly the same equivalent "anti-knock" rating as AVGAS. But LPG makes less power than gasoline.
The "Octane" molecules are probably more potent than other hydrocarbons - hence the notion that more octane is more power. But the Octane Rating is not a measure of the actual octane in the fuel. It is more of a rating that equates to the anti-knock rating offered by octane molecules. They used to use lead to increase the Octane Rating. Lead isn't going to make more power. I don't even think it burns that much!
Toluene and Xylene are hydrocarbons that increase the "Octane Rating" (because the have octane molecules in them) but they also provide more energy in the combustion because of those actual octane molecules (a bigger "bang").
Octane Rating and specific power are not directly related.
Did this help to clarify?
Cheers,
Hymee.
PS - I am not a chemical engineer, but I know just enough to be dangerous. I have personally discussed this with a chemical engineer.
Taka - you need to read more threads than you post
The Octane Rating of a fuel is NOT a measure of it's ENERGY. It is a measure of the ability of the fuel to resist detonationion (knock). It is best though of as the "anti-knock" rating.
Think of it this way - put heaps of water in your fuel - it will have a very high "resistance to knock", but it wont give you much power.
Or like this - LPG has roughly the same equivalent "anti-knock" rating as AVGAS. But LPG makes less power than gasoline.
The "Octane" molecules are probably more potent than other hydrocarbons - hence the notion that more octane is more power. But the Octane Rating is not a measure of the actual octane in the fuel. It is more of a rating that equates to the anti-knock rating offered by octane molecules. They used to use lead to increase the Octane Rating. Lead isn't going to make more power. I don't even think it burns that much!
Toluene and Xylene are hydrocarbons that increase the "Octane Rating" (because the have octane molecules in them) but they also provide more energy in the combustion because of those actual octane molecules (a bigger "bang").
Octane Rating and specific power are not directly related.
Did this help to clarify?
Cheers,
Hymee.
PS - I am not a chemical engineer, but I know just enough to be dangerous. I have personally discussed this with a chemical engineer.
05-09-2004, 08:25 PM
#136
Methane, Ethane, Propane, Butane, Pentane, Hexane, Heptane, Octane....
8 Carbon atoms and 18 Hydrogen atoms = a molecule of Octane.
Also - Have a read of http://chemistry.about.com/cs/howthi.../aa070401a.htm
Cheers,
Hymee
8 Carbon atoms and 18 Hydrogen atoms = a molecule of Octane.
Also - Have a read of http://chemistry.about.com/cs/howthi.../aa070401a.htm
Cheers,
Hymee
05-10-2004, 09:13 AM
#137
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Originally posted by Hymee
Methane, Ethane, Propane, Butane, Pentane, Hexane, Heptane, Octane....
8 Carbon atoms and 18 Hydrogen atoms = a molecule of Octane.
Also - Have a read of http://chemistry.about.com/cs/howthi.../aa070401a.htm
Cheers,
Hymee
Methane, Ethane, Propane, Butane, Pentane, Hexane, Heptane, Octane....
8 Carbon atoms and 18 Hydrogen atoms = a molecule of Octane.
Also - Have a read of http://chemistry.about.com/cs/howthi.../aa070401a.htm
Cheers,
Hymee
Octane is the main part of gas and Octane rating or level is the antiknock rating based on the percentage of Octane to Heptane in the gas. Octane by itself would be rated at 100 on the antiknock scale and Heptane would be rated at 0. There are two different methods of measuring it, RON with an engine running at 600 rpm and MON with an engine running at 900 rpm. We use the average of the two to get our Octane ratings. So this makes 93 octane gas 93% Octane and 7% Heptane and different additives alter this ratio.
Also according to the article, Aviation gas still is allowed to have lead in it as an additive to boost octane ratings up to 115. Guess I'll have to read up on how they measure that one. That information also removes all thoughts of ever putting any avgas in my 8.
05-10-2004, 09:07 PM
#139
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Did anyone find this interesting? sleepyhead posted the link:
http://members.ij.net/mrmazda/cfaqtext.html#ROCTANE
Below is a quote from that page:
What do y'all think about that? Why does Mazda tell us to use the highest octane, if a lower ocatane is just fine, and will save us money, and will improve mileage?
Where I live, gas is currently about 2.40 per gallon. I spend over 30 bucks at every fill up. I wouldn't mind saving a little on that...
http://members.ij.net/mrmazda/cfaqtext.html#ROCTANE
Below is a quote from that page:
What's the best fuel for my rotary car?
It depends. If your rotary Mazda is equipped with a turbocharger, all the normal rules about octane apply. Use the highest available octane premium fuel for best power and best protection against the ravages of detonation. You may find slighly better fuel mileage using lower octane, but you need to be very careful about using the available power on lower octane. If you are good at exercising restraint, you can save a little money on a long trip using regular, but it's probably best to stick with premium for normal use.
WIth the NA rotary, the highest octane you should use is US pump (AKI) 87, typically RON 91 outside the US, no matter how heavily your engine is modified. Octane in excess of any engine's actual requirement is always wasted. The issues of purity and additives in more expensive fuels are entirely separate issues. There's no reason not to want either in a NA rotary.
The rotary engine's high turbulence combustion chamber provides a very high resistance to detonation. Its duration of combustion is also longer, remembering that the rotors turn at 1/3 of the tachometer reading, and the slow burn* of high octane is undesirable in it. Pump 80 octane is more than sufficient for most of them. Best power and mileage is usually produced with the lowest available octane.
Many serious rotary racers bring their own low octane gasoline to tracks that supply only racing gasoline. From "How to Modify Your Mazda RX-7", by Dave Emanuel and Jim Downing, HP Books, 1987, ISBN 0-89586-383-9, p 47-8:
". . . the best results are obtained with conservative spark-lead calibrations provided the engine is fed a diet of low-octane fuel. The fact that both 1985 and 1986 IMSA Camel Lights championships were won with low-octane fuel is a rather definitive statement . . . ."
So if you want best performance from your NA rotary, you want lowest octane. The lower cost of it is a nice bonus.
* Note - the time allowed for combustion at high RPM is measured in ten-thousandths of a second. Some literature ascribes lower volatility rather than a slower burn as the characteristic of a higher octane value. In contrast, consider the following: From "14-to-1 compression", By David Green, NASCAR Winston Cup Scene:
It depends. If your rotary Mazda is equipped with a turbocharger, all the normal rules about octane apply. Use the highest available octane premium fuel for best power and best protection against the ravages of detonation. You may find slighly better fuel mileage using lower octane, but you need to be very careful about using the available power on lower octane. If you are good at exercising restraint, you can save a little money on a long trip using regular, but it's probably best to stick with premium for normal use.
WIth the NA rotary, the highest octane you should use is US pump (AKI) 87, typically RON 91 outside the US, no matter how heavily your engine is modified. Octane in excess of any engine's actual requirement is always wasted. The issues of purity and additives in more expensive fuels are entirely separate issues. There's no reason not to want either in a NA rotary.
The rotary engine's high turbulence combustion chamber provides a very high resistance to detonation. Its duration of combustion is also longer, remembering that the rotors turn at 1/3 of the tachometer reading, and the slow burn* of high octane is undesirable in it. Pump 80 octane is more than sufficient for most of them. Best power and mileage is usually produced with the lowest available octane.
Many serious rotary racers bring their own low octane gasoline to tracks that supply only racing gasoline. From "How to Modify Your Mazda RX-7", by Dave Emanuel and Jim Downing, HP Books, 1987, ISBN 0-89586-383-9, p 47-8:
". . . the best results are obtained with conservative spark-lead calibrations provided the engine is fed a diet of low-octane fuel. The fact that both 1985 and 1986 IMSA Camel Lights championships were won with low-octane fuel is a rather definitive statement . . . ."
So if you want best performance from your NA rotary, you want lowest octane. The lower cost of it is a nice bonus.
* Note - the time allowed for combustion at high RPM is measured in ten-thousandths of a second. Some literature ascribes lower volatility rather than a slower burn as the characteristic of a higher octane value. In contrast, consider the following: From "14-to-1 compression", By David Green, NASCAR Winston Cup Scene:
Where I live, gas is currently about 2.40 per gallon. I spend over 30 bucks at every fill up. I wouldn't mind saving a little on that...
05-10-2004, 09:31 PM
#141
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Honestly? I have no f-ing clue. But I do always find it intersting, and confusing when I read two totally different points of view. So I guess I would be interested in to know why the above paragraph does not apply.
I mean it does say that NA rotary are fine with lower octane, isn't the Renisis a NA rotary?
I mean it does say that NA rotary are fine with lower octane, isn't the Renisis a NA rotary?
05-10-2004, 10:56 PM
#143
I look at it this way - the handbook says I need to use a certain minimum grade fuel. If I don't and I have problems - who's fault is that?
The difference to me in filling with ULP compared to PULP is about $3. I spent $60k on the car, so I try not to worry about $3 once a week.
Cheers,
Hymee.
The difference to me in filling with ULP compared to PULP is about $3. I spent $60k on the car, so I try not to worry about $3 once a week.
Cheers,
Hymee.
05-11-2004, 06:56 AM
#144
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Originally posted by Hymee
I look at it this way - the handbook says I need to use a certain minimum grade fuel. If I don't and I have problems - who's fault is that?
The difference to me in filling with ULP compared to PULP is about $3. I spent $60k on the car, so I try not to worry about $3 once a week.
Cheers,
Hymee.
I look at it this way - the handbook says I need to use a certain minimum grade fuel. If I don't and I have problems - who's fault is that?
The difference to me in filling with ULP compared to PULP is about $3. I spent $60k on the car, so I try not to worry about $3 once a week.
Cheers,
Hymee.
Here's what it says in the US manual:
Your Mazda will perform best with Premium unleaded fuel "91 [ (R+M)/2 method] or above (96 RON or above)". You may use a regular unleaded fuel with Octane Rating from 87 to 90 (91 to 95 RON) but this will slightly reduce performance.
So as I read it, maximum performance aside, the minimum grade fuel from the US manual is 87 (R+M/2) or 91 RON.
Cheers,
rx8cited
05-11-2004, 07:34 AM
#145
Thanks mate,
This is what our one says:
p 4-2
Fuel requirements
Vehicles with catalytic converters..... <snip>
Fuel with lower rating could cause the emission control system to lose effectiveness. It could also cause engine knocking and serious engine damage.
Your Mazda will perform best with the fuel listed in the table:
Fuel
Premium Unleaded Fuel
Research Octane Number
95 or above
There is also this big honk'n decal inside the fuel filler lid saying PULP (95 RON or above) ONLY
I don't doubt any of the data people have collected over the last 30 years with rotars and low octane fuels. Just repeating what our manual says.
Cheers,
Hymee.
This is what our one says:
p 4-2
Fuel requirements
Vehicles with catalytic converters..... <snip>
Fuel with lower rating could cause the emission control system to lose effectiveness. It could also cause engine knocking and serious engine damage.
Your Mazda will perform best with the fuel listed in the table:
Fuel
Premium Unleaded Fuel
Research Octane Number
95 or above
There is also this big honk'n decal inside the fuel filler lid saying PULP (95 RON or above) ONLY
I don't doubt any of the data people have collected over the last 30 years with rotars and low octane fuels. Just repeating what our manual says.
Cheers,
Hymee.
05-11-2004, 10:08 AM
#146
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Yes, well, I will continue do do what the manual said as well. I was just curious about that what that page had to say about octane, low, vs. high, and if anyone had an opinion on that.
No reason to turn this thread into something like the one about which oil to use.
No reason to turn this thread into something like the one about which oil to use.
06-04-2004, 09:58 PM
#147
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Has anybody experimented with regular fuel and supplementary octane booster products to make up the difference? Or how about adding a cat cleaner product in small increments?
06-04-2004, 11:18 PM
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I go to Sunoco gas station and I get 94 octane gas for $2.31, I have been using it since I bought my car. Xylene is dangerous and could burn the cat, if not properly mixed (exhaust temp goes sky rocketing). I burned my BMWs cat buy getting it up to 104 using octane booster, and it didn’t pass inspection emissions even when i put 87 octane. So don't try putting in anything higher then 95 like the book says, because you will have big problems like me.
06-04-2004, 11:31 PM
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O and I forgot to mention, Mazda had to redo the emissions system for the RX-8 to be legal in the U.S. and I saw that a lot of people sued Mazda for misprinting their HP. The 8 would produce less HP with premium pump gas. That’s why I use 94 from Sunoco.
06-05-2004, 12:22 AM
#150
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Originally posted by SLK_VIK
O and I forgot to mention, Mazda had to redo the emissions system for the RX-8 to be legal in the U.S. and I saw that a lot of people sued Mazda for misprinting their HP. The 8 would produce less HP with premium pump gas. That’s why I use 94 from Sunoco.
O and I forgot to mention, Mazda had to redo the emissions system for the RX-8 to be legal in the U.S. and I saw that a lot of people sued Mazda for misprinting their HP. The 8 would produce less HP with premium pump gas. That’s why I use 94 from Sunoco.
You have read the threads on NA rotaries and premium gas, right?
Even reading this thread, you do realize that the anti-knock index, octane rating, has nothing to do directly with making power. So just adding 94 octane to an NA car, does NOT make your car any faster. It can actually make it SLOWER!