Octane confusion...anyone with facts?
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Octane confusion...anyone with facts?
For quite some time there has been some discussion of Octane and its effect on performance. Then there is the thread from FVD saying the programming can't be adjusted in the ECU for higher Octane, because the ECU will re-adjust automatically based on the systems sensors (sorry for the short explanation...see hereFVD Programming
So which is it...seems GIAC, UMW, et.al. have higher octane programming and FVD does not. Any expert care to provide some facts...instead of theory.
I'm sure many would like to know this! TIA!
So which is it...seems GIAC, UMW, et.al. have higher octane programming and FVD does not. Any expert care to provide some facts...instead of theory.
I'm sure many would like to know this! TIA!
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I am no expert on the issue, so take my comments with a large grain of salt.
I am informed that the ECU’s ability to adjust to different octane levels is limited, meaning it can only pull so much timing to correct for lesser octane levels. Moreover, while the ECU can pull timing if the octane is below the particular program requirements, I do not know if the ECU can add timing beyond the particular program requirements if one uses higher octane than required by the program. Furthermore, I am confident that the ECU adds little or no boost if higher octane is used. I know this because, when I ran higher octane fuel using an ECU tuned for pump gas, I did not see more boost (I obviously cannot speak to timing).
For example, if you are running the OEM program, which is optimized for European gas (approximately 93 octane), the ECU will pull timing if you run California 91 octane. However, I do not know if the ECU has sufficient flexibility to pull enough timing if you ran 87 octane. More importantly, if you filled your talk with 110 octane using the OEM program, the ECU would not add any boost (certainly no more than .1 bar), nor enough timing to take advantage of the far superior fuel. Thus, if your program is optimized for lesser octane, your car will not take full advantage of higher octane fuels – little or no additional boost and whatever additional timing the ECU adds will likely fall short of what higher octane fuel would permit the car to run if properly tuned for the higher octane fuel. Kevin, am I close?
If one tunes a car specifically for higher octane fuel, I am confident that they would be able to run more timing and boost, and generate more power, than a FVD ECU that is not specifically tuned for the higher octane but simply adapts within parameters of the ECU’s inherent adaptability. In fact, I am so confident of this that I will bet money on it. Have FVD send an ECU to Kevin, so he can compare his high octane file against FVD’s generic octane file. If they make the same power, I will pay FVD $1,000. If not, FVD pays $1,000 to me, $1,000 to Kevin, and pays all of Kevin’s costs. Deal?
One other anecdote to mull over. I previously had FVD tuning in my car (many years ago). The folks at FVD repeatedly supplied me with inconsistent information regarding the program(s) that I had, the different programs offered by FVD, and related issues, including whether my program was optimized for California 91 octane fuel. Consequently, I personally have little confidence for information supplied by FVD and I personally would never use FVD programming again.
That’s my uninformed, uneducated 2 cents . . . to be taken with a large grain of salt.
Craig
I am informed that the ECU’s ability to adjust to different octane levels is limited, meaning it can only pull so much timing to correct for lesser octane levels. Moreover, while the ECU can pull timing if the octane is below the particular program requirements, I do not know if the ECU can add timing beyond the particular program requirements if one uses higher octane than required by the program. Furthermore, I am confident that the ECU adds little or no boost if higher octane is used. I know this because, when I ran higher octane fuel using an ECU tuned for pump gas, I did not see more boost (I obviously cannot speak to timing).
For example, if you are running the OEM program, which is optimized for European gas (approximately 93 octane), the ECU will pull timing if you run California 91 octane. However, I do not know if the ECU has sufficient flexibility to pull enough timing if you ran 87 octane. More importantly, if you filled your talk with 110 octane using the OEM program, the ECU would not add any boost (certainly no more than .1 bar), nor enough timing to take advantage of the far superior fuel. Thus, if your program is optimized for lesser octane, your car will not take full advantage of higher octane fuels – little or no additional boost and whatever additional timing the ECU adds will likely fall short of what higher octane fuel would permit the car to run if properly tuned for the higher octane fuel. Kevin, am I close?
If one tunes a car specifically for higher octane fuel, I am confident that they would be able to run more timing and boost, and generate more power, than a FVD ECU that is not specifically tuned for the higher octane but simply adapts within parameters of the ECU’s inherent adaptability. In fact, I am so confident of this that I will bet money on it. Have FVD send an ECU to Kevin, so he can compare his high octane file against FVD’s generic octane file. If they make the same power, I will pay FVD $1,000. If not, FVD pays $1,000 to me, $1,000 to Kevin, and pays all of Kevin’s costs. Deal?
One other anecdote to mull over. I previously had FVD tuning in my car (many years ago). The folks at FVD repeatedly supplied me with inconsistent information regarding the program(s) that I had, the different programs offered by FVD, and related issues, including whether my program was optimized for California 91 octane fuel. Consequently, I personally have little confidence for information supplied by FVD and I personally would never use FVD programming again.
That’s my uninformed, uneducated 2 cents . . . to be taken with a large grain of salt.
Craig
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Mark (FVD) modified his statements in the FVD thread, and now appears to be acknowledging the benefits of an ECU tuned specifically for higher octane fuel, at least with respect to "cars with more than just a program and an air filter," as well as highly tuned cars and “996TTs with serious mods.†Now, instead of claiming that no performance benefits are achieved from an ECU tuned specifically for higher octane fuel (Mark/FVD’s original claim), Mark (FVD) states that it "isn't exactly realistic†for FVD to write custom programs optimized for higher octane fuels in cars that can benefit from higher octane fuels. That maybe so, but the fact remains that such a car can benefit from customized tuning for higher octane fuel, even if it is not realistic for FVD to offer the programming. Thats why custom tuners exist.
Its fine to state, as Mark/FVD now does, that FVD does not supply higher octane files because there are too many variables and FVD does not want to service that end of the business. However, IMHO, it was wholly disingenuous and improper for Mark/FVD to initially claim that there is no benefit to custom tuning for higher octane fuel . . . a claim Mark/FVD has now retreated from.
Now you see why I personally question information supplied by FVD.
Its fine to state, as Mark/FVD now does, that FVD does not supply higher octane files because there are too many variables and FVD does not want to service that end of the business. However, IMHO, it was wholly disingenuous and improper for Mark/FVD to initially claim that there is no benefit to custom tuning for higher octane fuel . . . a claim Mark/FVD has now retreated from.
Now you see why I personally question information supplied by FVD.
Originally Posted by FVD-USA
Well said, however, I am not knocking the performance ability of higher octane fuels used with heavly modified vehicles running lots of cylinder pressure. Full blown race, dragsters or seriously modified streetcars, cars with more than just a program and an air filter fall into this catagory. Most 996TT with serious mods would benefit from running a higher octane. This becomes necessary due to the the increased cylinder demands as the race fuel has less chance preigniting. But, to write a program for one specific octane due to the increadible amount of other variables encountered on a street car, isn't exactly realistic. Once again, the knock sensor is not the only sensor used in determing ign timing as it was to sound in your above statement, and it isn't so simple as to mearly increase tolerances on other sensors or bumping up setpoints elsewhere in the ECU. Marketing in the ECU tunner world is a big thing, and it makes it real easy to sell a program to someone when you say it is optimized for a specific fuel rating, even if the truth is those 2,3 ,10 or even 100 different tuner programmed maps, only come into the ECU's fuel map scenario for a split second during a drive cycle before being overwritten. I would tell you exactly how we program, but then you wouldnt need to buy a program from us . However, if I knew that all you wanted was a program for 108 octane, to run on a 1/4 mile drag strip in Denver during the month of June, and you were to run nothing but 108 octane from there on out in the car, it would be possible. But to sell programming based on optimal tuning for 100 octane fuel, which is only slightly higher than pump grade gas and what Porsche recomends you run all the time, depending on what part of the world you are in, is silly. Germany does not use a MON # to calculate octane rating. Their 98 octane is only calculated using a research octane, and is equivelant to our 93. Also so everyones on the same page, a little math is required to interpet Porsches above statement: 98RON /88 MON as (R+M)/2 is the equation= 93 octane fuel. I am avail for further questions @ 1800-274-2220. Thanks!
Mark @ FVD
. However, if I knew that all you wanted was a program for 108 octane, to run on a 1/4 mile drag strip in Denver during the month of June, and you were to run nothing but 108 octane from there on out in the car, it would be possible. But to sell programming based on optimal tuning for 100 octane fuel, which is only slightly higher than pump grade gas and what Porsche recomends you run all the time, depending on what part of the world you are in, is silly. Germany does not use a MON # to calculate octane rating. Their 98 octane is only calculated using a research octane, and is equivelant to our 93. Also so everyones on the same page, a little math is required to interpet Porsches above statement: 98RON /88 MON as (R+M)/2 is the equation= 93 octane fuel. I am avail for further questions @ 1800-274-2220. Thanks!Mark @ FVD
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Thanks for the replies so far...I am still a little confused...what does octane have to do with boost? I thought that higher octane (less volatile) allowed for greater combustion (as a result of improved detonation/timing) and that's where the power is made. I did not think boost had much to do with this...for example...I run 1.2 boost with 93 octane and 1.2 with 100 octane...my boost did not change, but power was greater.
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Originally Posted by wross996TT
Thanks for the replies so far...I am still a little confused...what does octane have to do with boost? I thought that higher octane (less volatile) allowed for greater combustion (as a result of improved detonation/timing) and that's where the power is made. I did not think boost had much to do with this...for example...I run 1.2 boost with 93 octane and 1.2 with 100 octane...my boost did not change, but power was greater.
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Originally Posted by KPG
Bill...Timing is increased. After Kevin finished his 660/640 on 92 octane at 1.3 bar he tried race gas. He turned boost down to 1 bar and cranked up the timing and saw much more hp and tq than on pump gas at a LOWER boost level and peak tq went from 3500 rpms to 3100 rpms...Timing, timing, timing....
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Originally Posted by wross996TT
Thanks for the replies so far...I am still a little confused...what does octane have to do with boost? I thought that higher octane (less volatile) allowed for greater combustion (as a result of improved detonation/timing) and that's where the power is made. I did not think boost had much to do with this...for example...I run 1.2 boost with 93 octane and 1.2 with 100 octane...my boost did not change, but power was greater.
I run 1.2 bars on pump, 1.4 on race gas. Kevin, based upon you mixing advice, I should be able to run 1.3 on a 50/50 blend, yes?
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Originally Posted by wross996TT
..upgrading the fuel system is next I suppose.
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Kevin,
I definately will be safe at 1.2....until my recent fuel system upgrade and retune by Todd K, I ran 1.2 on pump, although that was a touch high, I know.
What you are saying is that to be completely safe, I should stick to 1.2 for a mixture and go higher only if I have a preponderance of race fuel in my tank. However, most of my racing is done w/ a mixture.
The way it usually works in my part of the world is, the boys will all hang out on a Sat night. We usually see how we feel after 10;30 at night (when our "Mexican" roads clear up ) and only then will we run the cars. In anticipation, I will bring a 5 gallon container of race gas and dump it in my tank and go.
I would like to run 1.3 on the mixture, but understand that I will be taking a risk if I do so. Better to lose than to blow the motor, I suppose.
If I want to really get serious I will have to empty the tank out completely and use C-12.
By the way, I am really impressed by your new packages.
I definately will be safe at 1.2....until my recent fuel system upgrade and retune by Todd K, I ran 1.2 on pump, although that was a touch high, I know.
What you are saying is that to be completely safe, I should stick to 1.2 for a mixture and go higher only if I have a preponderance of race fuel in my tank. However, most of my racing is done w/ a mixture.
The way it usually works in my part of the world is, the boys will all hang out on a Sat night. We usually see how we feel after 10;30 at night (when our "Mexican" roads clear up ) and only then will we run the cars. In anticipation, I will bring a 5 gallon container of race gas and dump it in my tank and go.
I would like to run 1.3 on the mixture, but understand that I will be taking a risk if I do so. Better to lose than to blow the motor, I suppose.
If I want to really get serious I will have to empty the tank out completely and use C-12.
By the way, I am really impressed by your new packages.
Last edited by Dr_jitsu; Aug 14, 2007 at 02:44 PM.
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Originally Posted by wross996TT
For quite some time there has been some discussion of Octane and its effect on performance. Then there is the thread from FVD saying the programming can't be adjusted in the ECU for higher Octane, because the ECU will re-adjust automatically based on the systems sensors (sorry for the short explanation...see hereFVD Programming
So which is it...seems GIAC, UMW, et.al. have higher octane programming and FVD does not. Any expert care to provide some facts...instead of theory.
I'm sure many would like to know this! TIA!
So which is it...seems GIAC, UMW, et.al. have higher octane programming and FVD does not. Any expert care to provide some facts...instead of theory.
I'm sure many would like to know this! TIA!
The ecu has the ablity to retard timing up to 14 degrees. Once an ecu pulls timing it can be very slow to recover. If a file is optimized for 93 and 91 octane is run, timing will be significatnly retarded and often times wont be able to recover quick enough to add timng back before then end of a 1/4 pass or multi gear pull at the track.
Total timing on many cars can be as many as 5 degrees different at peak tourque from a 91 octane program to a 93 octane program. This can result in the ecu having to over compensate if the program was tuned on higher octane then the car is running or could leave alot of power on the table if the car is running higher octane then the car is tuned on.
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Then what about the stategy of running and ECU tuned for 100 and running pump gas most of the time except when you go to the track or otherwise occasionally run 100. This seems to be the strategy that Softronic (the supplier of FVD's software) is touting...arguing that the ecu will dial back and select/create the best timing maps based on KS readings and existence of knock or not.
http://www.softronic.us/index.php
http://www.softronic.us/index.php
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it's all rather easy - run the gas meant for your current program.
higher octane burns slower; if you run 110 in a stock file, you wil *lose* performance. if you run 91 in a 110 file, knock will probably get you.
as you increase octane, you can increase boost b/c the fuel burns slower and, thus, is less prone to detonation. when you increase boost, you are increasing the air inside the combustion chamber - if octane too low (and thus burns faster), the combustion more resembles a wildfire than a controlled explosion - detonation.
- chuck
higher octane burns slower; if you run 110 in a stock file, you wil *lose* performance. if you run 91 in a 110 file, knock will probably get you.
as you increase octane, you can increase boost b/c the fuel burns slower and, thus, is less prone to detonation. when you increase boost, you are increasing the air inside the combustion chamber - if octane too low (and thus burns faster), the combustion more resembles a wildfire than a controlled explosion - detonation.
- chuck
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thanks, chuck. I wasn't really asking what gas to run. I was following the tread and raising the question as to the soundness of the theoratical basis of the tuning method which relies on the knock sensor so heavily.
dw
dw