Octane booster Info/Questions
11-27-2003, 10:40 PM
#101
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You're right, I lost this arguement badly. I just don't see any reason to run toluene in a stock (or mostly stock) rx8 engine.
p.s. let's go to the track and see who loses badly. My 10 year old car still has no problem spanking rx8's. and before that arguement starts, you guys will NEVER, ever be able to spool a huge turbo like a peripheral exhaust port engine.
p.s. let's go to the track and see who loses badly. My 10 year old car still has no problem spanking rx8's. and before that arguement starts, you guys will NEVER, ever be able to spool a huge turbo like a peripheral exhaust port engine.
11-27-2003, 10:54 PM
#102
You would probably be excused if you left it at the first sentence. No one in this place ever said that Toluene was a magical "turbo killing" remedy for an RX8. We are under no illusions, and now you lost the argument, you seem to think that all is resolved on the race track. My car previous to the '8 was putting over 300HP down at the wheels. But I am still smiling.
Here we are interested in seeing what improvements can be made to the RX-8.
Cheers,
Hymee.
Here we are interested in seeing what improvements can be made to the RX-8.
Cheers,
Hymee.
11-27-2003, 10:59 PM
#103
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Hey, I think you guys are all pretty smart guys and this was a great discussion to read.
Congrats to everyone, win or lose, I learned something therefore, the real winner is "me" ..
alex
Congrats to everyone, win or lose, I learned something therefore, the real winner is "me" ..
alex
12-01-2003, 01:39 PM
#104
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Quick question. I have been using Toluene for about the 5 tankfulls. I now have access to Xylene. Can I switch to Xylene, while still having remanents of Toulene in my tank? Is it okay to mix the 2 ? Most importantly is it safe?
12-03-2003, 10:40 PM
#106
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I have been having a discussion on the 7 forum, regarding the use of Toluene as a anti det device. Can someone shed some light on this one?
Stoich is short for "stoichiometric", which means the chemically-correct air/fuel ratio by weight. Different types of fuels have different chemical compositions. Each composition has a chemically-correct mixing ratio with air. Here are some common ratios (some brands of fuel will vary slightly, especially with complex fuel like pump gas):
14.7:1 Regular Unleaded Pump Gas
14.4:1 Premium Unleaded Pump Gas
11.5:1 Toluene
6.5:1 Methanol Racing Fuel
Reducing air (or increasing fuel) to this ratio will result in what is called a "rich" air/fuel ratio. The extra fuel doesn't have enough air to react with chemically, so it is wasted, which means that gas mileage suffers. However, the extra fuel cools the combustion process, creating more power and reducing the chance of detonation. Therefore, the "best power air/fuel ratio" is more rich than the stoichiometric ratio. Here are the approximate best power air/fuel ratios of the before-mentioned fuels:
12.5:1 Regular Unleaded Pump Gas
12.0:1 Premium Unleaded Pump Gas
9.8:1 Toluene
4.5:1 Methanol Racing Fuel
Of course, each engine system is different, so the best power air-fuel ratio needs to be determined by an experienced engine tuner. Also, richer ratios than those listed above may be desirable to combat detonation if the tuner determines this to be more advantageous than the more power-efficient "best power" ratio.
Adding air (or subtracting fuel) to the stoichiometric ratio will result in what is called a "lean" air/fuel ratio. Usually a lean air/fuel ratio will yield better gas mileage than the stoichiometric ratio because the fuel consumption rate is reduced. However, since there is less fuel to cool the combustion process, heat is increased, which increases the chance of detonation.
Now, if you look at the numbers posted, you will see that 11.5:1 would correspond to a slightly rich air/fuel ratio for best power when using premium unleaded pump gas (11.5:1 is more rich than 12.0:1). However, when it comes to toluene, 11.5:1 is its stoichiometric ratio, which would be similar to running premium unleaded pump gas at a 14.4:1 ratio. This is usually too lean to run an engine under boost in a safe manner.
I thought that Toluene was supposed to help with detonation but it looks like, becasue of its stoichiometric make up, it can create a potentially dangerous lean condition? Can someone explain how this works, and why it is still considered a good anti detonation fuel?
Stoich is short for "stoichiometric", which means the chemically-correct air/fuel ratio by weight. Different types of fuels have different chemical compositions. Each composition has a chemically-correct mixing ratio with air. Here are some common ratios (some brands of fuel will vary slightly, especially with complex fuel like pump gas):
14.7:1 Regular Unleaded Pump Gas
14.4:1 Premium Unleaded Pump Gas
11.5:1 Toluene
6.5:1 Methanol Racing Fuel
Reducing air (or increasing fuel) to this ratio will result in what is called a "rich" air/fuel ratio. The extra fuel doesn't have enough air to react with chemically, so it is wasted, which means that gas mileage suffers. However, the extra fuel cools the combustion process, creating more power and reducing the chance of detonation. Therefore, the "best power air/fuel ratio" is more rich than the stoichiometric ratio. Here are the approximate best power air/fuel ratios of the before-mentioned fuels:
12.5:1 Regular Unleaded Pump Gas
12.0:1 Premium Unleaded Pump Gas
9.8:1 Toluene
4.5:1 Methanol Racing Fuel
Of course, each engine system is different, so the best power air-fuel ratio needs to be determined by an experienced engine tuner. Also, richer ratios than those listed above may be desirable to combat detonation if the tuner determines this to be more advantageous than the more power-efficient "best power" ratio.
Adding air (or subtracting fuel) to the stoichiometric ratio will result in what is called a "lean" air/fuel ratio. Usually a lean air/fuel ratio will yield better gas mileage than the stoichiometric ratio because the fuel consumption rate is reduced. However, since there is less fuel to cool the combustion process, heat is increased, which increases the chance of detonation.
Now, if you look at the numbers posted, you will see that 11.5:1 would correspond to a slightly rich air/fuel ratio for best power when using premium unleaded pump gas (11.5:1 is more rich than 12.0:1). However, when it comes to toluene, 11.5:1 is its stoichiometric ratio, which would be similar to running premium unleaded pump gas at a 14.4:1 ratio. This is usually too lean to run an engine under boost in a safe manner.
I thought that Toluene was supposed to help with detonation but it looks like, becasue of its stoichiometric make up, it can create a potentially dangerous lean condition? Can someone explain how this works, and why it is still considered a good anti detonation fuel?
12-04-2003, 11:06 PM
#107
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>>Can I switch to Xylene, while still having remanents of Toulene in my tank?<<
xylene (actually four compounds, ortho-, meta-, para-xylene and ethylbenzene), and toluene are very similar chemically. They are both aromatics (benzene with methane stuck on them, nasty carcinogens). Xylene has a higher molecular weight and less volatility than toluene. Because of their similarities, you could blend them in any proportion and expect a linearly proportional change in the blended properties (octane, volatility, heat of combustion, air stoich ratio). There is no reactivity between them. No chance of phase separation.
Go for it.
xylene (actually four compounds, ortho-, meta-, para-xylene and ethylbenzene), and toluene are very similar chemically. They are both aromatics (benzene with methane stuck on them, nasty carcinogens). Xylene has a higher molecular weight and less volatility than toluene. Because of their similarities, you could blend them in any proportion and expect a linearly proportional change in the blended properties (octane, volatility, heat of combustion, air stoich ratio). There is no reactivity between them. No chance of phase separation.
Go for it.
12-08-2003, 12:49 AM
#109
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Doc, and everyone else-
You guys dont seem to understand that there are huge differences between knock and pre-ignition. And that the word "pre-det" is made up from ignorance.
First off, i will explain pre-ignition
Pre-ignition is extreamly rare. When it occurs, the engine is generally is generally destroyed in seconds, piston or wankle. It is caused by glowing carbon deposits generally, and occasionally hot places caused by repeated knock(this is extreamly rare). Pre-ignition puts less pressure on cumbustion area then normal healthy cumbustion cycle. It is also nearly silent and not deceted by knock sensors. The greater pressure a gas comes under, the more difficult it becomes to ignite. This is why high compression engines and forced induction cars generally need to upgrade there ignition systems to have more powerful sparks. Pre-ignition does not happen when the piston is moving up at all, that would make it much more difficult to light, its most likely to occur right as fresh mixture contacts the hot area(usually glowing carbon). If pre-ignition makes lower pressure levels then normal ignition, why is it so damageing? Simple, when the mixture burns right after entering the chamber, it compresses this mix and huge amounts of heat are absorbed in to the chamber, this means death to the materials that have a melting point much below these tempatures because of the time it takes for heat to be able to dissapate into the water jacket and be converted into warming air.
Ones octane level does not effect pre-ignition, infact it can do the opposite, N-heptane is very easy to pre-ingite if you have something glowing in the chamber, but has a great anti-knock ability.
Now for knock.
Long after the spark plug has fired is the only time possible for knock to occur. I dont think anybody here gets that, but i cant stress it enough.
After the spark plug fires, it starts a flame wave burning. This flame front starts to sweep the chamber. The gas on the ends is called "end gas". When the flame front reaches too high of pressure before spreading clear accross to the "end gas". It can spontaniously cumbust this small bit of gas in the corners. This causes it to explode and makes a pressure spike in the chamber that if continued for extened periods of time can heat an area hot enough to cause pre-ignition.
This is why retarding timing is effective at reducing knock. If knock had anything to do with blowing-up before the spark, then making the spark happen later wouldnt have much purpose would it? It would still blow up before. I dont know how you guys can claim you know how an engine works and miss that little detail.
Anyways, when you retard the spark, it lowerd knock because its not under as much mechanically caused compression while burning. This means that "end gas" is less likely to POP under rapidly increasing temperature and tremendous pressure.
Once again:
KNOCK HAPPENS AFTER THE SPARK FIRES!!!!
It seems amazing that you can have 90some replies to something and nobody knows whats going on.
Wakeesh- if you dont understand something at all, please dont just write BS, some people might think you know what you are talking about and get all mixed up. Pretty much everything you said in this post was just stright BS or clearly wrong. Dont make extra work for people who have to re-teach things.
And lastly, for gods sake i need to say it. Karosen is one of the highest energy fuels, and its used to power jet fighters. We would use it in cars except is has low anti-knock, not high.
The guy the poured RC fuel in his car would not hurt anything at all, and i have done it myself. I slighty raises octane with one of the safest fuels on earth nitro-methane. It also smokes a bit, from the quality synthitic oil added to lubricate the 2cycles it normally powers. Nitro-methane is so safe, go buy some RC car fuel and pour a bit on the ground and try to light it, its very very difficult, its extreamly stable, thiats how cars with 150lbs of boost and 10:1 compression run it.
I am not trying to personally attack anybody, i am trying to set you guys straight. Sorry if it seems a bit drastic, I am just shocked a thread can go so long with nobody understanding the meaning of the words "knock" and "pre-ingition", yet they are used in nearly every post.
-Luke
You guys dont seem to understand that there are huge differences between knock and pre-ignition. And that the word "pre-det" is made up from ignorance.
First off, i will explain pre-ignition
Pre-ignition is extreamly rare. When it occurs, the engine is generally is generally destroyed in seconds, piston or wankle. It is caused by glowing carbon deposits generally, and occasionally hot places caused by repeated knock(this is extreamly rare). Pre-ignition puts less pressure on cumbustion area then normal healthy cumbustion cycle. It is also nearly silent and not deceted by knock sensors. The greater pressure a gas comes under, the more difficult it becomes to ignite. This is why high compression engines and forced induction cars generally need to upgrade there ignition systems to have more powerful sparks. Pre-ignition does not happen when the piston is moving up at all, that would make it much more difficult to light, its most likely to occur right as fresh mixture contacts the hot area(usually glowing carbon). If pre-ignition makes lower pressure levels then normal ignition, why is it so damageing? Simple, when the mixture burns right after entering the chamber, it compresses this mix and huge amounts of heat are absorbed in to the chamber, this means death to the materials that have a melting point much below these tempatures because of the time it takes for heat to be able to dissapate into the water jacket and be converted into warming air.
Ones octane level does not effect pre-ignition, infact it can do the opposite, N-heptane is very easy to pre-ingite if you have something glowing in the chamber, but has a great anti-knock ability.
Now for knock.
Long after the spark plug has fired is the only time possible for knock to occur. I dont think anybody here gets that, but i cant stress it enough.
After the spark plug fires, it starts a flame wave burning. This flame front starts to sweep the chamber. The gas on the ends is called "end gas". When the flame front reaches too high of pressure before spreading clear accross to the "end gas". It can spontaniously cumbust this small bit of gas in the corners. This causes it to explode and makes a pressure spike in the chamber that if continued for extened periods of time can heat an area hot enough to cause pre-ignition.
This is why retarding timing is effective at reducing knock. If knock had anything to do with blowing-up before the spark, then making the spark happen later wouldnt have much purpose would it? It would still blow up before. I dont know how you guys can claim you know how an engine works and miss that little detail.
Anyways, when you retard the spark, it lowerd knock because its not under as much mechanically caused compression while burning. This means that "end gas" is less likely to POP under rapidly increasing temperature and tremendous pressure.
Once again:
KNOCK HAPPENS AFTER THE SPARK FIRES!!!!
It seems amazing that you can have 90some replies to something and nobody knows whats going on.
Wakeesh- if you dont understand something at all, please dont just write BS, some people might think you know what you are talking about and get all mixed up. Pretty much everything you said in this post was just stright BS or clearly wrong. Dont make extra work for people who have to re-teach things.
And lastly, for gods sake i need to say it. Karosen is one of the highest energy fuels, and its used to power jet fighters. We would use it in cars except is has low anti-knock, not high.
The guy the poured RC fuel in his car would not hurt anything at all, and i have done it myself. I slighty raises octane with one of the safest fuels on earth nitro-methane. It also smokes a bit, from the quality synthitic oil added to lubricate the 2cycles it normally powers. Nitro-methane is so safe, go buy some RC car fuel and pour a bit on the ground and try to light it, its very very difficult, its extreamly stable, thiats how cars with 150lbs of boost and 10:1 compression run it.
I am not trying to personally attack anybody, i am trying to set you guys straight. Sorry if it seems a bit drastic, I am just shocked a thread can go so long with nobody understanding the meaning of the words "knock" and "pre-ingition", yet they are used in nearly every post.
-Luke
12-08-2003, 02:28 AM
#110
Ricer is Nicer.....
AND your point is...?
Wow, I been EDUMACATED!
So your point is that Toluene or Xylene are not a good fuels?
They DON'T offer 110+ anti-knock index?
Or that they are not the MOST powerful gasoline components in existence?
(O.K., diesel fuel has more power, but with an octane rating of 32, I think we can discount it from the discussion....)
Yes, obviously detonation happens after ignition....that's why retarding the spark WORKS.
And pre-ignition IS rare, but not in der WANKELMASCHINEN.
Wankels suffer from having no cool down during the 'intake' cycle, and no rest during the 'exhaust' phase.
Every pass is a firing/power phase, and the poor trailing plugs never cool down. Soon we have a 1900*F glowplug. You don't need any 'carbon deposits', even brand new clean plugs can destroy the engine.
I think that when you see the ultimate tuning of the N.A. Renesis, it will actually have the trailing plugs dormant.
"Hear me now, and believe me later....." - Hans & Frans.
.
.
.
doc
So your point is that Toluene or Xylene are not a good fuels?
They DON'T offer 110+ anti-knock index?
Or that they are not the MOST powerful gasoline components in existence?
(O.K., diesel fuel has more power, but with an octane rating of 32, I think we can discount it from the discussion....)
Yes, obviously detonation happens after ignition....that's why retarding the spark WORKS.
And pre-ignition IS rare, but not in der WANKELMASCHINEN.
Wankels suffer from having no cool down during the 'intake' cycle, and no rest during the 'exhaust' phase.
Every pass is a firing/power phase, and the poor trailing plugs never cool down. Soon we have a 1900*F glowplug. You don't need any 'carbon deposits', even brand new clean plugs can destroy the engine.
I think that when you see the ultimate tuning of the N.A. Renesis, it will actually have the trailing plugs dormant.
"Hear me now, and believe me later....." - Hans & Frans.
.
.
.
doc
12-08-2003, 02:45 AM
#111
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The trailing plugs reduce knock buy starting a flame front near the end to help burn "end gas" before pressure/heat blow it up. This is why higher compression ***** like the r26b have 3 spark plugs, to get that mix started burning in more areas and heance compleating the burn faster.
Knock makes spark plugs get abnormally hot. If normal cumbustion made plugs get abnormally hot, you would install a colder plug. The faster the burn happens, the less likey knock is to occur.
If disableing the trailing plug reduces pre-ignition, i would love to here the physics behind that. Because a side effect is a larger amount of pressure that builds on the "end gas" before it gets to have flame reach it, disableing its ability to knock.
educate me Doc.
P.S. are you are chem E?
Knock makes spark plugs get abnormally hot. If normal cumbustion made plugs get abnormally hot, you would install a colder plug. The faster the burn happens, the less likey knock is to occur.
If disableing the trailing plug reduces pre-ignition, i would love to here the physics behind that. Because a side effect is a larger amount of pressure that builds on the "end gas" before it gets to have flame reach it, disableing its ability to knock.
educate me Doc.
P.S. are you are chem E?
12-09-2003, 07:46 PM
#112
New Member
Really ok?
Really
I saw in the Mazda Welcome brochure that fuel additives are not advised.
I asked and reconfirm and also ask a question of octane booster. This is their response
I saw in the Mazda Welcome brochure that fuel additives are not advised.
I asked and reconfirm and also ask a question of octane booster. This is their response
Dear Takahashi san
> Mazda Australia does not recommend nor condone the use of any aftermarket
> fuel additives other than those approved by the Distributor. Subsequent
> Mazda support may therefore be compromised should usage be affected.
>
> Yours sincerely,
>
> Michael Minenna
> Customer Service Manager - Technical
> Mazda Australia Pty. Limited
> Toll free: 1800 034411
> email: mminenna@mazda.com.au
>
> WEBSITE ENQUIRY - 2003/12/05 Service
>
>
> How can we help you:
>
> In the Mazda welcome package. There is a brochure of how to run in a
> car. In that, there is a paragraph about fuel additives in rotary
engines.
> I wonder if Mazda are talking about fuel injector cleaner or octane
> boosters. They are slightly different composite and I wonder I can
use
> either of them in the RX8.
>
> Mazda Australia does not recommend nor condone the use of any aftermarket
> fuel additives other than those approved by the Distributor. Subsequent
> Mazda support may therefore be compromised should usage be affected.
>
> Yours sincerely,
>
> Michael Minenna
> Customer Service Manager - Technical
> Mazda Australia Pty. Limited
> Toll free: 1800 034411
> email: mminenna@mazda.com.au
>
> WEBSITE ENQUIRY - 2003/12/05 Service
>
>
> How can we help you:
>
> In the Mazda welcome package. There is a brochure of how to run in a
> car. In that, there is a paragraph about fuel additives in rotary
engines.
> I wonder if Mazda are talking about fuel injector cleaner or octane
> boosters. They are slightly different composite and I wonder I can
use
> either of them in the RX8.
>
12-09-2003, 09:40 PM
#113
Ricer is Nicer.....
Additives, Lies and Video Tape....
Oh, I was afraid this would come up-
I am pretty sure no one wants to hear a re-hash of the Octane Booster threads, you all know what is in them, and how much you would have to use to get any real effect!
The 'cleaner' additives are different however - there are two basic categories (and, of course, no way to tell which is in the jug!)
The first is the hi-tech approach, they buy drums of a 'detergent/dispersant' formula from a company like Octel, and dilute it quite a bit. You don't need much to double the amount already present in the gas. Some packages even have deposit modifiers included, that raise the 'glow point' of any deposits that remain, to prevent pre-ignition.
The other type is definitely low-tech, but also seems to work!
They contain a fraction of the crude called 'mineral spirits', heavier, almost diesel, paraffins. Possibly a carry over from the truck driver practice of adding ATF to gasoline, but does seem to free up deposits....go figure. A downside of these fractions is their octane rating is actually negative - put enough in and you will start to 'ping'.
I didn't want to go there, because I must admit to a bit of an 'additive problem' myself.....
Hi, my name is Doc.....and I'm an additiveholic.
The minute I saw the Wankel engine, with its huge swept surfaces, its crappy 'crankcase oil' injectors, and its reliance on an oil seal for compression, I thought I knew what was lacking - some serious lubricity in the housing.
I have yet to fuel my car without adding two stroke oil.
I use the best that money can buy, a synthetic rated 'ISO-GD'.
GD tested oil surpasses the tough Japanese 'JASO-FC' rating for deposits, emissions and is absolutely smoke free.
250ml per fill of 50 litres = 200:1 or 0.5%, and a jug treats four fills.
Humor me, it's a long term experiment, check back with me in the year 2024, and I'll let you know how it went!
.
.
.
doc
I am pretty sure no one wants to hear a re-hash of the Octane Booster threads, you all know what is in them, and how much you would have to use to get any real effect!
The 'cleaner' additives are different however - there are two basic categories (and, of course, no way to tell which is in the jug!)
The first is the hi-tech approach, they buy drums of a 'detergent/dispersant' formula from a company like Octel, and dilute it quite a bit. You don't need much to double the amount already present in the gas. Some packages even have deposit modifiers included, that raise the 'glow point' of any deposits that remain, to prevent pre-ignition.
The other type is definitely low-tech, but also seems to work!
They contain a fraction of the crude called 'mineral spirits', heavier, almost diesel, paraffins. Possibly a carry over from the truck driver practice of adding ATF to gasoline, but does seem to free up deposits....go figure. A downside of these fractions is their octane rating is actually negative - put enough in and you will start to 'ping'.
I didn't want to go there, because I must admit to a bit of an 'additive problem' myself.....
Hi, my name is Doc.....and I'm an additiveholic.
The minute I saw the Wankel engine, with its huge swept surfaces, its crappy 'crankcase oil' injectors, and its reliance on an oil seal for compression, I thought I knew what was lacking - some serious lubricity in the housing.
I have yet to fuel my car without adding two stroke oil.
I use the best that money can buy, a synthetic rated 'ISO-GD'.
GD tested oil surpasses the tough Japanese 'JASO-FC' rating for deposits, emissions and is absolutely smoke free.
250ml per fill of 50 litres = 200:1 or 0.5%, and a jug treats four fills.
Humor me, it's a long term experiment, check back with me in the year 2024, and I'll let you know how it went!
.
.
.
doc
12-10-2003, 12:11 AM
#114
mostly harmless
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nah, 2 stroke oil in the gas has been a long-time rotary trick. longer than long time. some people wanna use the stock metering system and have a separate resevoir draw (RG and CS and some other guy who wants to claim it's "his" idea), but this in my eyes is needless complexity.
anyways, in race engines where you just wanna run pure synth the whole way, and you're modifying the block (or even further building your own out of all aluminum-cast blanks that haven't had the oil bungs bored) so that you don't want to use the oil metering system anymore, just add oil to the gas (at a 100:1 or a 70:1 or a 50:1 or a 2:1 :o ratio, whatever you personally deem necessary for the application) and presto, you're set.
so yes, good thread.
anyways, in race engines where you just wanna run pure synth the whole way, and you're modifying the block (or even further building your own out of all aluminum-cast blanks that haven't had the oil bungs bored) so that you don't want to use the oil metering system anymore, just add oil to the gas (at a 100:1 or a 70:1 or a 50:1 or a 2:1 :o ratio, whatever you personally deem necessary for the application) and presto, you're set.
so yes, good thread.
12-12-2003, 04:28 PM
#116
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Too bad none of us have a dyno and a wide band in our garage, and access to all the wonderful organic chemicals talked about here.
Even after reading all these posts, I am not sure what exactly the net effect of these additives would be.
Regardless, I don't think any of these fuels will prove to be worth the extra cost on a daily basis. Drag strip slightly, and I hope that's why people are interested.
You can only create as much power as you have oxygen to burn which is limited by your effective displacement.
Of course, if a given fuel has more energy content per liter, it will create more heat during combustion and increase power output.
Also, if the fuel requires less oxygen, you can dump more fuel per cycle with the proper fuel management. More fuel equals more power. The lower s.r. for x and t, would mean they need less air, but unless your computer knows how to compensate, it won't put any more in there leaning the mixture.
Since the RX-8 appears to be running rich, this may be beneficial, but I wouldn't do it without the proper equipment.
Leaning the mixture will raise combustion temps. Unburned gas has a much higher specific heat than air, and can absorb the heat.
I really don't like it when people say it will "lower combustion temperatures thus increasing power" that is a very ambiguous statement.
The efficiency of the internal combustion energy is a simple formula, the difference in coldest temp (BDC) vs hottest temp (TDC) over the hottest temp. Look up Carnot cycle for more info.
By advancing the timing, you are trying to create the greatest difference in the two combustion temperatures (which is proportional to pressure acting on the piston due to the nature of gas PV=nRT).
The colder the temps, or the more stable the fuel, the closer combustion can be moved to TDC without knocking. But typically, more stable fuels have lower energy content. The octane rating is a stability rating from my understanding.
I am by no means an expert, I wrote this mainly to convince myself.
After reading books on the subject, I still don't totally understand detonation or knocking. And the thing that bothers me most is that the catalytic converter needs heat to work properly. If the RX-8 wasn't passing emissions, why did they apparantly remap the car to run rich?
Even after reading all these posts, I am not sure what exactly the net effect of these additives would be.
Regardless, I don't think any of these fuels will prove to be worth the extra cost on a daily basis. Drag strip slightly, and I hope that's why people are interested.
You can only create as much power as you have oxygen to burn which is limited by your effective displacement.
Of course, if a given fuel has more energy content per liter, it will create more heat during combustion and increase power output.
Also, if the fuel requires less oxygen, you can dump more fuel per cycle with the proper fuel management. More fuel equals more power. The lower s.r. for x and t, would mean they need less air, but unless your computer knows how to compensate, it won't put any more in there leaning the mixture.
Since the RX-8 appears to be running rich, this may be beneficial, but I wouldn't do it without the proper equipment.
Leaning the mixture will raise combustion temps. Unburned gas has a much higher specific heat than air, and can absorb the heat.
I really don't like it when people say it will "lower combustion temperatures thus increasing power" that is a very ambiguous statement.
The efficiency of the internal combustion energy is a simple formula, the difference in coldest temp (BDC) vs hottest temp (TDC) over the hottest temp. Look up Carnot cycle for more info.
By advancing the timing, you are trying to create the greatest difference in the two combustion temperatures (which is proportional to pressure acting on the piston due to the nature of gas PV=nRT).
The colder the temps, or the more stable the fuel, the closer combustion can be moved to TDC without knocking. But typically, more stable fuels have lower energy content. The octane rating is a stability rating from my understanding.
I am by no means an expert, I wrote this mainly to convince myself.
After reading books on the subject, I still don't totally understand detonation or knocking. And the thing that bothers me most is that the catalytic converter needs heat to work properly. If the RX-8 wasn't passing emissions, why did they apparantly remap the car to run rich?
12-13-2003, 01:45 PM
#117
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Originally posted by jdwk
If the RX-8 wasn't passing emissions, why did they apparantly remap the car to run rich?
If the RX-8 wasn't passing emissions, why did they apparantly remap the car to run rich?
02-25-2004, 09:10 AM
#120
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[QUOTE]Originally posted by Lock & Load
Kas
Fuel used in japan is 100 octane level so the rx8 is made to run on higher fuel not the supposed 98 ron we get here , i have been told that some cars dont make it to oz because of our low quality fuels. [/QUOTE
You know... people drop this left and right... but guess what. Japan has 2 grades of fuel... regular and super. I have never checked the RON, but I am betting super = 100 and regular is like the low 90's RON.
Kas
Fuel used in japan is 100 octane level so the rx8 is made to run on higher fuel not the supposed 98 ron we get here , i have been told that some cars dont make it to oz because of our low quality fuels. [/QUOTE
You know... people drop this left and right... but guess what. Japan has 2 grades of fuel... regular and super. I have never checked the RON, but I am betting super = 100 and regular is like the low 90's RON.
02-25-2004, 09:20 AM
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Originally posted by XeRo
Turborex is correct in that aspect...of tuning...US is much stricker on emission standards...also go figure...why do you think they pay ~$3.98 a gallon for fuel over there (in J-Pan)? Our fuel standards here ..regardless of what Shell, Amoco, Chevron claim SUX compared to other countries...i mean even Iraq has better fuel...or had
BUT....in light of Kas' response...there is no point...until all this BS talk of turbo and intake becomes reality and force higher end fuel management..
Turborex is correct in that aspect...of tuning...US is much stricker on emission standards...also go figure...why do you think they pay ~$3.98 a gallon for fuel over there (in J-Pan)? Our fuel standards here ..regardless of what Shell, Amoco, Chevron claim SUX compared to other countries...i mean even Iraq has better fuel...or had
BUT....in light of Kas' response...there is no point...until all this BS talk of turbo and intake becomes reality and force higher end fuel management..
My bad.. this thread is mad old... sorry all!
Last edited by Japan8; 02-25-2004 at 10:03 AM.
04-05-2004, 07:47 PM
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Originally posted by TerenceT
it's a tax free paint thinner
it has the same carbon based as gasoline
about $4/gallon
it's a tax free paint thinner
it has the same carbon based as gasoline
about $4/gallon
I am very happy so far except a flat spot out side the power curve.
I have bought 2 gallons of xylene and mixed it at approx. 1 gallon for 12 gallons of sunoco 94 octane(I live in NY and our gas has 10% alcohol)
I have no way to test this but I do feel a seat of the pants improvement. the car pulls harder and the shifts are very solid now.
my question is where are you paying 5 bucks a gallon?????
sherwin willians sells it for 8.95 per gallon .....if you buy the 5 gallon can it drops a little over a buck a gallon.
walmart does not carry it.put in a call to Home depot but they have not gotten back to me yet.
the man at the Sherwin store said 5 bucks no way!!!
so help me out..any ideas where to go to get it cheaper???
thanks in advance
Robert
04-10-2004, 12:23 AM
#123
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Originally posted by Kas
I'm no mathamatitian (or however its spelt) nor a genius like some, but i've had some great reading here and alot of work has gone into this post....but still cant figure out the outcome of it all ?
more power safely? or not?
I'm no mathamatitian (or however its spelt) nor a genius like some, but i've had some great reading here and alot of work has gone into this post....but still cant figure out the outcome of it all ?
more power safely? or not?
It did run although did not have as much power but seemed to have more torque. Ran about 2 tanks full with about 18 miles per gallon and then rebuilt it and switched back to pump gas since it didn't significantly increase the power or mileage. It had no apparant permanent damage when we tore it down and it was still running just fine 4 years later when I sold it.
04-19-2004, 05:44 PM
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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.
