91oct versus 100oct with no tuning, big gains!
10-13-2005, 10:18 AM
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91oct versus 100oct with no tuning, big gains!
Chart says it all. This is from my buddy's Miata. He has intake and exhaust mods. He then switched from 91 to a 100 octane mix, let the ECU adjust for about 3 weeks. Then returned and dyno'd again. Too big a difference to blame weather conditions or any other factors. And it is 'corrected'.
He's getting a better tuner ECU now so he can tune and switch on the fly for 91 and 100. He does have an Emanage but his timing was locked for 91 both runs.
All he did was fill up with 100 octane. I guess it makes sense when you know that 87 can make yer car ping and retard timings. Giving it more octane could allow it to advance timings and give you more go-go juice.
He's getting a better tuner ECU now so he can tune and switch on the fly for 91 and 100. He does have an Emanage but his timing was locked for 91 both runs.
All he did was fill up with 100 octane. I guess it makes sense when you know that 87 can make yer car ping and retard timings. Giving it more octane could allow it to advance timings and give you more go-go juice.
10-13-2005, 10:49 AM
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9oct. doesn't give anywhere near 11whp
Just can't...hell I wish. lol
We can get 103oct fuel from the pump from certain Sunocos
Hell, we can even get C16 from the local track. I WISH it would give even 5whp...
Now talking about BOOSTED cars is a WHOLE other story.
Just can't...hell I wish. lol
We can get 103oct fuel from the pump from certain Sunocos
Hell, we can even get C16 from the local track. I WISH it would give even 5whp...
Now talking about BOOSTED cars is a WHOLE other story.
10-13-2005, 11:53 AM
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Originally Posted by Tattude
9oct. doesn't give anywhere near 11whp
Just can't...hell I wish. lol
We can get 103oct fuel from the pump from certain Sunocos
Hell, we can even get C16 from the local track. I WISH it would give even 5whp...
Now talking about BOOSTED cars is a WHOLE other story.
Just can't...hell I wish. lol
We can get 103oct fuel from the pump from certain Sunocos
Hell, we can even get C16 from the local track. I WISH it would give even 5whp...
Now talking about BOOSTED cars is a WHOLE other story.
10-13-2005, 12:39 PM
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I think your logic is flawed though....Yes going from 87-91 Octane will increase hp because the engine will not be knocking, but the car was designed to run 91 Octane. With 91 Octane the car shouldn't be knocking, therefore going to 100+ Octane should have no effect.
All I can think of is that if your car is out-of-tune and is knocking for some reason with 91 Octane, then upping the Octane would improve performance. But this would be a result of the engine being out-of-tune or some extreme conditions like heat etc.
All I can think of is that if your car is out-of-tune and is knocking for some reason with 91 Octane, then upping the Octane would improve performance. But this would be a result of the engine being out-of-tune or some extreme conditions like heat etc.
Originally Posted by FairLady32
i can believe it ... if going from 87 to 91 causes my car to not ping and perform alot better..then going from 91 to 100 or more will deff increase power !!
10-13-2005, 12:58 PM
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No way. It's not the octane. There are tons of articles on the web that will explain why increasing the octane above the normally recommended value will have no effect on performance, and in some extreme cases, may actually make it worse.
Last edited by undrgnd; 10-13-2005 at 01:03 PM.
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10-13-2005, 01:14 PM
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Originally Posted by undrgnd
No way. It's not the octane. There are tons of articles on the web that will explain why increasing the octane above the normally recommended value will have no effect on performance, and in some extreme cases, may actually make it worse.
Nice chart, but hard to believe.......
10-13-2005, 01:20 PM
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Funny. You show them the proof yet they do not believe. Now I know how Mulder felt having to deal with Scully.
As for going over in suggested octane rtaing...if your ECU can advance timing based on incoming fuel quality, it will. That is true. This will give you more power. It's why cars in certain parts of the country actually post stronger dyno numbers across the board, all models. Because of the different fuel mixtures.
As for going over in suggested octane rtaing...if your ECU can advance timing based on incoming fuel quality, it will. That is true. This will give you more power. It's why cars in certain parts of the country actually post stronger dyno numbers across the board, all models. Because of the different fuel mixtures.
Last edited by Mr_Q; 10-13-2005 at 01:22 PM.
10-13-2005, 01:26 PM
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Originally Posted by Mr_Q
Funny. You show them the proof yet they do not believe. Now I know how Mulder felt having to deal with Scully.
10-13-2005, 01:57 PM
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well there is one way to find out ... a buddy of mine owns a dyno shop !! ill find 100 octane and run it for a week or two ..then dyno it ..and dyno it as well before !! ill post the results
10-13-2005, 02:09 PM
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Originally Posted by FairLady32
well there is one way to find out ... a buddy of mine owns a dyno shop !! ill find 100 octane and run it for a week or two ..then dyno it ..and dyno it as well before !! ill post the results
10-13-2005, 03:50 PM
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Originally Posted by Mr_Q
Funny. You show them the proof yet they do not believe. Now I know how Mulder felt having to deal with Scully.
As for going over in suggested octane rtaing...if your ECU can advance timing based on incoming fuel quality, it will. That is true. This will give you more power. It's why cars in certain parts of the country actually post stronger dyno numbers across the board, all models. Because of the different fuel mixtures.
As for going over in suggested octane rtaing...if your ECU can advance timing based on incoming fuel quality, it will. That is true. This will give you more power. It's why cars in certain parts of the country actually post stronger dyno numbers across the board, all models. Because of the different fuel mixtures.
This is NOT proof???
The ECU will not re-tune the engine when you put higher oct. fuel in it.
It will only de-tune the engine when detecting knock/ping.
haha
According to your proof, running C16 would gain about a .5 at the 1320.
100, 103, 105, 115 oct. fuel DOES NOT improve performance on regular N/A cars.
Go to the track with less then a 1/4 tank of whatever gas your car RECOMMENDS and do 3-4 runs. Then put race gas/C16 in it. Do 3-4 runs... Then come in here and tell us the results. lol
You'll be VERY disappointed.
Now I know how the Smoking Man felt like...
10-13-2005, 03:55 PM
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Originally Posted by Mr_Q
Chart says it all. This is from my buddy's Miata. He has intake and exhaust mods. He then switched from 91 to a 100 octane mix, let the ECU adjust for about 3 weeks. Then returned and dyno'd again.
10-13-2005, 04:01 PM
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Yup, and it doesn't really matter. It isn't the same day around the same time. WAY too many factors come into play when dynoing cars. Mine have varied more then 15whp with the SAME mods. It is nothing new.
Again, before ya'll go waste money buying into this crap do just a little research first.
Again, before ya'll go waste money buying into this crap do just a little research first.
10-13-2005, 04:46 PM
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Chart says it all. This is from my buddy's Miata. He has intake and exhaust mods. He then switched from 91 to a 100 octane mix, let the ECU adjust for about 3 weeks. Then returned and dyno'd again. Too big a difference to blame weather conditions or any other factors. And it is 'corrected'.
He's getting a better tuner ECU now so he can tune and switch on the fly for 91 and 100. He does have an Emanage but his timing was locked for 91 both runs.
All he did was fill up with 100 octane. I guess it makes sense when you know that 87 can make yer car ping and retard timings. Giving it more octane could allow it to advance timings and give you more go-go juice.
True and not true.......
From a pure cause/effect standpoint, retarding the timing is basically equivalent to lowering the compression ever so slightly. This is why a timing retard yields lower power, all other thing being equal. Similarly, the ECU can only advance the timing to the point that the spark is allowing the maximum rated compression ratio of the engine to actually be reached. Octane is highly resistant to spontaneous combustion secondary to compression, whereas heptane will much more easily ignite with compression (as opposed to the spark from your spark plug). The point here is that raising the octane content of the gasoline will only increase the power to the point that the ECU progamming for octane and timing max out. To know this, one has to know with what octane the ECU is programmed to allow greatest timing advance. If the ECU allows maximal timing advance with 93 octane, for example, going to 100 octane won't make a difference.
Does anyone know for sure with what octane fuel the engine hp ratings are calculated? Does anyone know for sure to what octane levels is timing advance mapped to in the ECU?
By the way....the ECU can "figure out" the octane rating of the gasoline being burned by the EGT and oxygen sensor readings. Other than the knock sensor, it is really these values, based in part on the ocatne of the fuel being burned that actually determine timing advance and retard. Of course once one throws any breathing mods into the mix, the whole system's inputs change. There now becomes too many variables to really figure out exactly what is doing what!!!!
Bottom line......for stock US Z's I *believe* performance is maxed out with 93 octane. This may not be true for the Miata, whose ECU may be mapped up to EGT's and A/F's based on the burning of 100 octane.
Disclaimer: some of what I have said is an oversimplification, but this reply was getting way too long! sorry if it raises more confusion and questions than it answers!
He's getting a better tuner ECU now so he can tune and switch on the fly for 91 and 100. He does have an Emanage but his timing was locked for 91 both runs.
All he did was fill up with 100 octane. I guess it makes sense when you know that 87 can make yer car ping and retard timings. Giving it more octane could allow it to advance timings and give you more go-go juice.
True and not true.......
From a pure cause/effect standpoint, retarding the timing is basically equivalent to lowering the compression ever so slightly. This is why a timing retard yields lower power, all other thing being equal. Similarly, the ECU can only advance the timing to the point that the spark is allowing the maximum rated compression ratio of the engine to actually be reached. Octane is highly resistant to spontaneous combustion secondary to compression, whereas heptane will much more easily ignite with compression (as opposed to the spark from your spark plug). The point here is that raising the octane content of the gasoline will only increase the power to the point that the ECU progamming for octane and timing max out. To know this, one has to know with what octane the ECU is programmed to allow greatest timing advance. If the ECU allows maximal timing advance with 93 octane, for example, going to 100 octane won't make a difference.
Does anyone know for sure with what octane fuel the engine hp ratings are calculated? Does anyone know for sure to what octane levels is timing advance mapped to in the ECU?
By the way....the ECU can "figure out" the octane rating of the gasoline being burned by the EGT and oxygen sensor readings. Other than the knock sensor, it is really these values, based in part on the ocatne of the fuel being burned that actually determine timing advance and retard. Of course once one throws any breathing mods into the mix, the whole system's inputs change. There now becomes too many variables to really figure out exactly what is doing what!!!!
Bottom line......for stock US Z's I *believe* performance is maxed out with 93 octane. This may not be true for the Miata, whose ECU may be mapped up to EGT's and A/F's based on the burning of 100 octane.
Disclaimer: some of what I have said is an oversimplification, but this reply was getting way too long! sorry if it raises more confusion and questions than it answers!
Last edited by Speedracer; 10-13-2005 at 04:52 PM.
10-13-2005, 04:55 PM
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Originally Posted by Jason@Performance
did you re-flash between dyno's too? looks like the revlimiter is higher post...
10-13-2005, 05:02 PM
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Originally Posted by Speedracer
Bottom line......for stock US Z's I *believe* performance is maxed out with 93 octane. This may not be true for the Miata, whose ECU may be mapped up to EGT's and A/F's based on the burning of 100 octane.