What Octane should I use in my 5.0?
4/10/12, 02:44 PM
#21
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Ok here goes...you have to keep in mind its all about the maps the ECU will look up. The car is rated at 412hp with 91 octane, 420 now for the 2013s. The issue is the timing map the car will run depending on the conditions. So to say that 93 octane will give better performance is probably a pretty sure thing providing all the other variables are there for the ECU to take advantage of this. I know this is kind of a half answer but it is what it is.
Even with 93 octane though the car may not see maximum timing tables, it may require even higher octane. The question is where is the diminishing return at. For the S65 powerplant in the M3 its 95 octane, anything above this and you are wasting your money. I think its safe to bet that the ECU in the Coyote powerplant is somewhat similar. If you are at sea level with cool ambient air and temps and you are running 93 octane,the other variables are in place, you will get to a higher timing table for the ECU as the chance of detonation with these positive variables will allow the higher timing table. The engine tries to adjust to the best timing table before knock occurs.
Keep in mind in hot weather you won't be able to use the high end timing table as the ambient air temp, along with other variables just won't support this table as detonation will be detected and the knock sensors will make the ECU pull back timing. Running higher octane in this condition can alleviate this somewhat.
Also, where in the country are you located. Are you usinig a Cali blend of fuel? Here in Cali our 91 is not the same as other 91s around the country. We can't even get 93 octane here. I have to blend 4 gallons of Sunoco GT 100+ to get me just over 93 octane, and yes there is a difference. It was worth 10rwhp for my M3 to go to 93 octane vs. 91.
Dave
Even with 93 octane though the car may not see maximum timing tables, it may require even higher octane. The question is where is the diminishing return at. For the S65 powerplant in the M3 its 95 octane, anything above this and you are wasting your money. I think its safe to bet that the ECU in the Coyote powerplant is somewhat similar. If you are at sea level with cool ambient air and temps and you are running 93 octane,the other variables are in place, you will get to a higher timing table for the ECU as the chance of detonation with these positive variables will allow the higher timing table. The engine tries to adjust to the best timing table before knock occurs.
Keep in mind in hot weather you won't be able to use the high end timing table as the ambient air temp, along with other variables just won't support this table as detonation will be detected and the knock sensors will make the ECU pull back timing. Running higher octane in this condition can alleviate this somewhat.
Also, where in the country are you located. Are you usinig a Cali blend of fuel? Here in Cali our 91 is not the same as other 91s around the country. We can't even get 93 octane here. I have to blend 4 gallons of Sunoco GT 100+ to get me just over 93 octane, and yes there is a difference. It was worth 10rwhp for my M3 to go to 93 octane vs. 91.
Dave
Last edited by Dave07997S; 4/10/12 at 02:45 PM.
4/10/12, 02:44 PM
#22
Shelby GT500 Member
If you can't tell the difference in horsepower between the two fuels, why spend the extra $ on the 93/94? You're not driving a NASCAR circuit, you're driving to work.
4/10/12, 02:45 PM
#23
Originally Posted by kcoTiger
If you can't tell the difference in horsepower between the two fuels, why spend the extra $ on the 93/94? You're not driving a NASCAR circuit, you're driving to work.
4/10/12, 06:56 PM
#26
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Ok here goes...you have to keep in mind its all about the maps the ECU will look up. The car is rated at 412hp with 91 octane, 420 now for the 2013s. The issue is the timing map the car will run depending on the conditions. So to say that 93 octane will give better performance is probably a pretty sure thing providing all the other variables are there for the ECU to take advantage of this. I know this is kind of a half answer but it is what it is.
Even with 93 octane though the car may not see maximum timing tables, it may require even higher octane. The question is where is the diminishing return at. For the S65 powerplant in the M3 its 95 octane, anything above this and you are wasting your money. I think its safe to bet that the ECU in the Coyote powerplant is somewhat similar. If you are at sea level with cool ambient air and temps and you are running 93 octane,the other variables are in place, you will get to a higher timing table for the ECU as the chance of detonation with these positive variables will allow the higher timing table. The engine tries to adjust to the best timing table before knock occurs.
Keep in mind in hot weather you won't be able to use the high end timing table as the ambient air temp, along with other variables just won't support this table as detonation will be detected and the knock sensors will make the ECU pull back timing. Running higher octane in this condition can alleviate this somewhat.
Also, where in the country are you located. Are you usinig a Cali blend of fuel? Here in Cali our 91 is not the same as other 91s around the country. We can't even get 93 octane here. I have to blend 4 gallons of Sunoco GT 100+ to get me just over 93 octane, and yes there is a difference. It was worth 10rwhp for my M3 to go to 93 octane vs. 91.
Dave
Even with 93 octane though the car may not see maximum timing tables, it may require even higher octane. The question is where is the diminishing return at. For the S65 powerplant in the M3 its 95 octane, anything above this and you are wasting your money. I think its safe to bet that the ECU in the Coyote powerplant is somewhat similar. If you are at sea level with cool ambient air and temps and you are running 93 octane,the other variables are in place, you will get to a higher timing table for the ECU as the chance of detonation with these positive variables will allow the higher timing table. The engine tries to adjust to the best timing table before knock occurs.
Keep in mind in hot weather you won't be able to use the high end timing table as the ambient air temp, along with other variables just won't support this table as detonation will be detected and the knock sensors will make the ECU pull back timing. Running higher octane in this condition can alleviate this somewhat.
Also, where in the country are you located. Are you usinig a Cali blend of fuel? Here in Cali our 91 is not the same as other 91s around the country. We can't even get 93 octane here. I have to blend 4 gallons of Sunoco GT 100+ to get me just over 93 octane, and yes there is a difference. It was worth 10rwhp for my M3 to go to 93 octane vs. 91.
Dave
4/11/12, 12:12 PM
#27
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Here in CR there are only two options:
Super (95 octane)
Plus91 (91 octane)
I have never used anything but Super, but I only had european cars which ask for 95 or higher
Super (95 octane)
Plus91 (91 octane)
I have never used anything but Super, but I only had european cars which ask for 95 or higher
4/12/12, 03:43 AM
#30
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According to the other posts here, you should drop down to 91 if the have it because there is no benefit to anything above that. I know some Sunocco stations near me have 91, but I don't know if you have those.
4/12/12, 04:03 AM
#31
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Hmmmmm. I get jumped and attacked for using 5w-30 on an oil change; the manual states 5w-20. Now, the manual recommends 87 octane, but the usual rat pack are not jumping on this and stating to stick with the recommendations?
If a tune requires it, then I'd go with that recomendation; if no tune (factory settings), then it just has to be the factory recommendation. We're not supposed to question the design/development engineers.....
If a tune requires it, then I'd go with that recomendation; if no tune (factory settings), then it just has to be the factory recommendation. We're not supposed to question the design/development engineers.....
Last edited by Bucko; 4/12/12 at 04:04 AM.
4/12/12, 05:11 AM
#32
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Originally Posted by 50_lover
According to the other posts here, you should drop down to 91 if the have it because there is no benefit to anything above that. I know some Sunocco stations near me have 91, but I don't know if you have those.
4/12/12, 08:31 AM
#33
Legacy TMS Member
Hmmmmm. I get jumped and attacked for using 5w-30 on an oil change; the manual states 5w-20. Now, the manual recommends 87 octane, but the usual rat pack are not jumping on this and stating to stick with the recommendations?
If a tune requires it, then I'd go with that recomendation; if no tune (factory settings), then it just has to be the factory recommendation. We're not supposed to question the design/development engineers.....
If a tune requires it, then I'd go with that recomendation; if no tune (factory settings), then it just has to be the factory recommendation. We're not supposed to question the design/development engineers.....
4/12/12, 08:33 AM
#34
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Originally Posted by Bucko
Hmmmmm. I get jumped and attacked for using 5w-30 on an oil change; the manual states 5w-20. Now, the manual recommends 87 octane, but the usual rat pack are not jumping on this and stating to stick with the recommendations?
If a tune requires it, then I'd go with that recomendation; if no tune (factory settings), then it just has to be the factory recommendation. We're not supposed to question the design/development engineers.....
If a tune requires it, then I'd go with that recomendation; if no tune (factory settings), then it just has to be the factory recommendation. We're not supposed to question the design/development engineers.....
4/12/12, 08:37 AM
#35
