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Discussion Starter #1 (Edited)
I've reached out to OV in order to ask some questions about their tune. In the meantime, I was looking at their FAQs and there is something that throws me off a bit.

I was hoping members that are in the Know, or better yet have actually had the Tune done, can clarify something. In their FAQs, they specifically state... "Rest assured we don't tune for octane. We tune for the data we see." I also read somewhere that they specifically point out that they do NOT ignore\disable the Knock Sensor feedback.


Then, under the specific question(s) about Octane, "We recommend 91 octane for all of our tunes, especially if you have a skyactiv" and "If we tune you for a premium grade fuel you must use only the same or as close as possible to that grade fuel"


So if I'm interpreting this all correctly, it basically means that unlike other tuners that ASSUME 91 octane, OV allows you to tune to whatever octane you want... however once you do, you are locked into that Octane and running any lower has potential risks.

I guess my concern comes from that Locked in Octane. Our cars come from the factory being able to run any grade of gas. Even members here have stated that switching to 91 makes a difference. Thus it would suggest that the ECU makes use of the Knock Sensors (and possibly other sensors) to allow the engine to adjust for 87,89, or 91 octane safety.

Why would a tune change this? I totally could understand if the statement was..."To get the most out of your Tune we recommend 91 octane"... however to state "We DO NOT recommend using lower octanes like 87 or 89 if you are tuned for 91 octane" worries me.

Last thing I want is to put 87 in my car (maybe to keep the cost of a road trip down for example), and get on the gas to pass someone and something goes wrong!


So could someone slap me on the back of the head so I can see clearly? As it stands now, I'm thinking I would have to tune for 87 to be safe and spend the same amount of money but for a lesser HP increase.
 

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We can always get back to the stock tune that allow u to use any kind of octanes. If somehow u feel like u want to go to track or something u can use file 91 or E85 octane.

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So that's mean that u can always use ur computer to dumb the back to the ecu. It change all the setting to reach what u want for ur car in just few mins.

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In 91 and E85 octanes tuned, u can feel a day and night different. I heard people saying that is not quite a difference to have 87 tuned.

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Discussion Starter #5
So sounds like you guys are saying...

1) That if I did get a 91 tune, and needed to go on a road trip, I could easily flash back to stock, and then go back to the tune when I got home?

2) Rumor has it that an 87 tune vs a 91 tune is NOT a huge difference, but a 91 vs E85 is? I don't have E85 so not worried about that.


The big burning question is if you tune for 91 and then put in 87 what happens? do you risk engine damage?



Also.. I forgot to mention...one of the questions I plan on asking OV is about their "dual tune". Meaning my car has actually 4 driving modes: Auto, manual, Auto + Sport, Manual + Sport.

I was hoping to tune for Economy on Auto, then Power when in either Sport or maybe manual. I wonder if I could tune for different octanes for example, when in Sport + Manual I know I need 91 octane.
 

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What makes the tune effective is the timing advance and spark/fuel maps. The higher the octane, the more you can push the timing. The skyactive 2.0 is extremely high compression, which makes for lots of torque, but it`s tuned down from the manufacturer to be able to run on regular pump gas, leaving a ton of power untapped. When you decide that you are OK with having to run premium (a choice Mazda didn`t want to make FOR you), the engine can be tuned to run at it`s max potential, but can only do it ON premium, and anything less will cause problems (no, putting in lower octane fuel and driving very gently in an emergency isn`t going to blow up the engine, but putting in low octane fuel and driving it like you stole it is going to cause detonation, which has the potential to be catastrophic). Bone stock there is absolutely no need nor benefit to running higher octane fuel. It does nothing to help the car run better. Once it`s tuned, the character traits of a high compression engine are brought right up, front and center. And yes, while the high octane tune is in effect, you`ll have to run it. You can always flash back to the stock tune if you needed to for some reason, and run regular again.

I chronicled my tune pretty thoroughly here a few months ago. I tuned for 93, and the results were remarkable. I took a 3,000 mile road trip last month and still got over 40mpg. I could have just flashed back to stock for the trip and saved a few pennies on the price of fuel itself, but consumption would not have changed. And yeah, if you tune for 93 and put 87 in, there are going to be problems. Tuning wakes the skyactiv up big time, but like anything, there is a trade. If you want to run 87 octane fuel, you can`t have the horsepower. If you want the horsepower, you can`t do it on 87 octane.
 

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I have 100 ron available, which should be about 95 octane in US, so will tuning to 100 ron (95) give me even better numbers?
 

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Discussion Starter #10
What makes the tune effective is the timing advance and spark/fuel maps. The higher the octane, the more you can push the timing. The skyactive 2.0 is extremely high compression, which makes for lots of torque, but it`s tuned down from the manufacturer to be able to run on regular pump gas, leaving a ton of power untapped. When you decide that you are OK with having to run premium (a choice Mazda didn`t want to make FOR you), the engine can be tuned to run at it`s max potential, but can only do it ON premium, and anything less will cause problems (no, putting in lower octane fuel and driving very gently in an emergency isn`t going to blow up the engine, but putting in low octane fuel and driving it like you stole it is going to cause detonation, which has the potential to be catastrophic). Bone stock there is absolutely no need nor benefit to running higher octane fuel. It does nothing to help the car run better. Once it`s tuned, the character traits of a high compression engine are brought right up, front and center. And yes, while the high octane tune is in effect, you`ll have to run it. You can always flash back to the stock tune if you needed to for some reason, and run regular again.

I chronicled my tune pretty thoroughly here a few months ago. I tuned for 93, and the results were remarkable. I took a 3,000 mile road trip last month and still got over 40mpg. I could have just flashed back to stock for the trip and saved a few pennies on the price of fuel itself, but consumption would not have changed. And yeah, if you tune for 93 and put 87 in, there are going to be problems. Tuning wakes the skyactiv up big time, but like anything, there is a trade. If you want to run 87 octane fuel, you can`t have the horsepower. If you want the horsepower, you can`t do it on 87 octane.

Ok..that makes sense... I would have thought that the Knock sensor would have accounted for the timing adjustment however. So say you tune for 91, and you put in 87... your engine starts knocking, the ECU would tone it back and you would be fine.

Hmmm... I can get 89 around here, but I tend to get my fuel at Costco which only offers 91 + 87.
 

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^^^^ Not entirely correct. The ECU can only adjust so much timing retard. It`s designed to trim timing, not correct it. If you`re tuned for 91 and you put in 87 and floor it, it`s gonna knock. Bad. It`ll cruise just fine, but any time it`s under load it`s going to put a demand on the cylinder pressure. It would be really cool if the ECU could account for whatever fuel was in there, and add or retard timing according to whatever was in it. That would mean a true performance gain just from running 93 vs 87. Hmm...wonder why that`s not the case in at least some vehicles.....
 

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See answers below:

So sounds like you guys are saying...

1) That if I did get a 91 tune, and needed to go on a road trip, I could easily flash back to stock, and then go back to the tune when I got home?

IF YOU WANT TO GO THROUGH THE STEPS TO DO IT, YES.

2) Rumor has it that an 87 tune vs a 91 tune is NOT a huge difference, but a 91 vs E85 is? I don't have E85 so not worried about that.

DO YOU ALWAYS BELIEVE RUMORS?? THERE IS A SIGNIFICANT DIFFERENCE BETWEEN A 91 AND AN 87 OCTANE TUNE. THERE IS A BIG DIFFERENCE WITH JUST THE 87 TUNE; THE 91 TUNE JUST AMPLIFIES THE POWER TO ANOTHER LEVEL.

The big burning question is if you tune for 91 and then put in 87 what happens? do you risk engine damage?

YES, POTENTIALLY YOU DO.


Also.. I forgot to mention...one of the questions I plan on asking OV is about their "dual tune". Meaning my car has actually 4 driving modes: Auto, manual, Auto + Sport, Manual + Sport.

I was hoping to tune for Economy on Auto, then Power when in either Sport or maybe manual. I wonder if I could tune for different octanes for example, when in Sport + Manual I know I need 91 octane.

ONLY 2 TUNES WOULD BE NEEDED. THE DIFFERENCE BETWEEN AUTO & MANUAL ARE IN HOW YOU USE THE TRANSMISSION, NOT THE ENGINE PERFORMANCE. YOU COULD DO A TUNE FOR NORMAL AUTOMATIC & THEN A TUNE FOR SPORT.
 

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^^^^ Not entirely correct. The ECU can only adjust so much timing retard. It`s designed to trim timing, not correct it. If you`re tuned for 91 and you put in 87 and floor it, it`s gonna knock. Bad. It`ll cruise just fine, but any time it`s under load it`s going to put a demand on the cylinder pressure. It would be really cool if the ECU could account for whatever fuel was in there, and add or retard timing according to whatever was in it. That would mean a true performance gain just from running 93 vs 87. Hmm...wonder why that`s not the case in at least some vehicles.....
That's what Flex Fuel vehicles do. They have an octane sensor and adjust the timing accordingly based on preset values in the tune.
 
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