What octane is everyone using?

[Redlinez]

I haven't heard anyone speak of results or experience with the SCT tuner. It's about $100 less than Cobb, but until I hear results, I'd stick with Livernoise or Cobb.

 

[Woem]

Ron98

 

[boost420]

I use Shell V-Power 91 0% ethanol. I also have esso 93 and petro canada 94 available to me. Both 93 and 94 have ethanol, so i be stuck with 91, plus the x10 air miles helps lean me towards shell.

 

[Russell]

98 ron

 

[DaveSignal]

just filled up with 99 today. I already notice better mpg. I am going to switch my Cobb tune to a higher octane map soon.

 

[Ghostwhite]

E50 mix using 91 and e85. Think the octane is in the high 90's

 

[Sourskittle]

E50 mix using 91 and e85. Think the octane is in the high 90's

Heck yes !! "Kill mode"

 

[_RED_]

First tank was 87 from the dealer. Since they 93 only.

 

[Major_A]

I was running 87 Chevron but have now switched to 93 Chevron. Now all I need is a tuner to apply the 93 octane tune.

 

[Jonesdawg]

I am curious if anyone did testing between 87 to 91 on how many more mpg they get going to 91 than 87. I did that years ago with a subaru I had and it made a huge difference. Anyone here in the states test that?

 

[C. love]

i have didnt see much of a difference. Im using E-30 right now and even then MPG's are running about the same which is odd

 

[razorlab]

i have didnt see much of a difference. Im using E-30 right now and even then MPG's are running about the same which is odd

Make sure you do the real world accurate method of MPG calculation of mileage divided by gallons. The MPG display on the dash will NOT be accurate when using Ethanol blends if the tuner did not change the correct multiplier in the ECU. Even if you do change the multiplier, it is based on the specific fuel gravity % and that can be skewed if you don't have the blend matched with the setting in the ECU.

If you just put E30 in the car with the same tune for pump gas the dash MPG gauge WILL be off.

From my data of using Ethanol blends in the FiST so far for over 4000 miles your mileage does drop but how much is dependent on the blend percentage and tuning strategies.

I've lessened the drop on my personal FiST with tuning strategies like lean burn cruise, ignition timing changes at cruise and other things. It's still not 1:1 with pump gas but it is better.

 

[Sourskittle]

And prob actually cheaper per gal too ( in Razor's case ).

 

[C. love]

Make sure you do the real world accurate method of MPG calculation of mileage divided by gallons. The MPG display on the dash will NOT be accurate when using Ethanol blends if the tuner did not change the correct multiplier in the ECU. Even if you do change the multiplier, it is based on the specific fuel gravity % and that can be skewed if you don't have the blend matched with the setting in the ECU.

If you just put E30 in the car with the same tune for pump gas the dash MPG gauge WILL be off.

From my data of using Ethanol blends in the FiST so far for over 4000 miles your mileage does drop but how much is dependent on the blend percentage and tuning strategies.

I've lessened the drop on my personal FiST with tuning strategies like lean burn cruise, ignition timing changes at cruise and other things. It's still not 1:1 with pump gas but it is better.

All true. Thing is Im not using E-30 for MPGS so even the small amount of work it will take to calculate the actual MPG is more than I care to do. Its good to know how it all works and really I know the guage isnt accurate, I just figure its not going to be grossly off


when I did a quick comparo of 87 & 91 i was curious. With ethanol fuel mileage usually isn't better so no point in even trying.


along time ago I compared Ethanol vs 91 in a different car it was a wash. 91 mpg was better MPG wise but Ethanol was cheaper. COST per Mile was essentially the same. So again knpwing that could care less about MPG now. Plus I have a scooter that gets about 75mpg i wanna scrimp I will ride that lol

 

[razorlab]

All true. Thing is Im not using E-30 for MPGS

I hear you. I'm in the same boat.

 

[Jonesdawg]

My apologies. I wasn't specific enough on which gasses. Down here in AZ we have the basic unleaded 87, 89, and 91 gasses plus diesel. I don't really do ethanol unless I am force to use it when it's 10% mixed with unleaded gas. I am curious if anyone has tested the mpg for both 87 unleaded and 91 unleaded. I promise I will be more specific next time...

 

[ed_the_sledd]

I'm confused. As I understand, higher octane allows the gasoline to operate under higher compression ratios /temperature, before spontaneous combustion occurs (ie knocking). A car is tuned for a certain octane, and using anything lower than that will cause the ecu to detect the onset of knocking and then reduce the power output to accommodate the low octane. But if a car isn't tuned for a higher octane, it won't take advantage of that extra power. Our car is tuned for 87 octane, so anything higher would be useless unless you get a tune. The Cobb AP would allow you to take advantage of the 91/93 octane, so it makes sense to invest in the premium fuel. Unless our car can detect the octane that we give it, not sure how any octane higher than 87 is useful unless you et a tune. The best analogy I can use is like having a credit card with an initial $5,000 limit. If the credit card company increases your limit, but never tells you, you'll never use anything over the $5,000, even if it's available.

 

[C. love]

^ not exactly. You can use 87. However when you are driving a car harder you create more heat more heat= possibility of more detonation. So in a hard driving situation you use 91 or better to prevent knock which prevents timing being pulled which then reduces power. So you use better fuel for better results.
Theres more too it and Im sure someone will chime in and post pages so stay tuned

 

[ed_the_sledd]

^ not exactly. You can use 87. However when you are driving a car harder you create more heat more heat= possibility of more detonation. So in a hard driving situation you use 91 or better to prevent knock which prevents timing being pulled which then reduces power. So you use better fuel for better results.
Theres more too it and Im sure someone will chime in and post pages so stay tuned

Mmm. that's interesting. i always assumed that if a car was made to operate on X octane, it would perform perfectly under that X octane. I guess technically you could run 87 octane on a mercedez benz because the car would just reduce the power as soon as knocking started to occur. But Mercedez (or whatever luxury company) specifically requires premium fuel so that the car functions properly (which is also how they get that extra power from their engines). I can't imagine that ford would require 87 octane, knowing that knocking will occur under high loads and power will need to be reduced.

 

[razorlab]

The ECU uses a pretty cool dynamic timing strategy that listens to the knock sensors and will add, keep constant or subtract dynamic timing on the fly depending on the noise it picks up. OEM programming will add up to 6* dynamic timing on top of the standard ignition advance.

Depending on the level of knock noise it sees it will either stop dynamically advancing or pull dynamic advance. This is on top of timing pull the system can do on knock detection.

On 87 octane, the car will run just fine, but most of the time that is not enough to allow the full 6* of dynamic advance and you will not be getting the fuel performance of the car.

Funny you mention Mercedes as some models use the same MED17 ECU as the Fiesta.