2012 Mustang GT, 93 octane, total timing question

[Carbd86GT]

I posted this in Tuning section on the main page also but figured I'd post here as well with people more familiar...

Kinda simple, just questioning if I may have fueled up with some poor quality fuel in my last fill. The car, 2012 Mustang GT, full exhaust (no cats), cold air intake and a tune.

What type of total timing do these engines see with quality 93 octane typically? For some reason I was thinking that 25-26 degrees seems about right but it looks like near the top of the pull there is some knock activity so it starts to pull a little and I'm only seeing about 21-22 approaching 6k RPM. I have attached a log, it's a 3rd and 4th gear pull. Starts at 2.7 sec and ends at 7.7 sec.

Thanks

View attachment log0001.csv.zip

 

[5lho]

I posted this in Tuning section on the main page also but figured I'd post here as well with people more familiar...

Kinda simple, just questioning if I may have fueled up with some poor quality fuel in my last fill. The car, 2012 Mustang GT, full exhaust (no cats), cold air intake and a tune.

What type of total timing do these engines see with quality 93 octane typically? For some reason I was thinking that 25-26 degrees seems about right but it looks like near the top of the pull there is some knock activity so it starts to pull a little and I'm only seeing about 21-22 approaching 6k RPM. I have attached a log, it's a 3rd and 4th gear pull. Starts at 2.7 sec and ends at 7.7 sec.

Thanks

View attachment 71342

It all depends on the gas you can get. "Quality" 93 is hard to get. I find where I am, I'm better off tuning for 91 and giving a little margin. My car pulls just as hard on a 91 tune as it does on the 93, with more readily available quality 91 fuel. The 94 I get here is so full of additives, it loses zip over the 91. Even on nitrous at the track, I run 91 octane and Lucas octane boost and it does better. Your total timing of 25-26 degrees is in the 91 range. There is only a couple degrees between a 91 and 93 tune. It only looks like it is pulling one degree, which isn't terrible, especially since it added 4 just before pulling. There is a knock transition zone on this engine at 4500-5000 sometimes.

 

[Carbd86GT]

It all depends on the gas you can get. "Quality" 93 is hard to get. I find where I am, I'm better off tuning for 91 and giving a little margin. My car pulls just as hard on a 91 tune as it does on the 93, with more readily available quality 91 fuel. The 94 I get here is so full of additives, it loses zip over the 91. Even on nitrous at the track, I run 91 octane and Lucas octane boost and it does better. Your total timing of 25-26 degrees is in the 91 range. There is only a couple degrees between a 91 and 93 tune.

Yeah, I get that but I was just curious what others were seeing on their pump gas tunes. I'm asking because I've never logged this tune and when I'd glance at the nGauge before I don't ever recall it showing knock activity. I noticed it last night (fueled up yesterday morning at the same station I have been for the last 5 months) so I did this quick log this morning to see if it would duplicate. I'm going to throw some octane booster in just to see if it changes anything and then maybe try a new station to rule it out. But if 21-22 degrees is "normal" on 93 octane then I'm not going to bother screwing with much of anything.

 

[WIST2013GT]

Mobil 93 here in Wisconsin and I see 29 on my last log AED tuned.

 

[Carbd86GT]

Mobil 93 here in Wisconsin and I see 29 on my last log AED tuned.

That's about what I was expecting it should be commanding given fuel being decent. Going to throw some octane booster in later to see if I can make the knock go away. Got a date with the track on Friday and don't want to be held back.

 

[Vert]

Since I'm boosted i only see 18.

 

[JTS_7]

Not going to see a huge difference between a few degrees timing NA power wise. Octane booster will help allow the knock sensors to add more.

I would focus more on cam timing.

 

[jn2]

The reason you aren't seeing 26-27* throughout the whole pull because you are getting KR. Can yo get me a actual HPT scanner log please? Reading it off that excel sheet sucks...but from what I can see:

- You peaked 27* of spark advance when the ECM was using Knock advanced to add 4* of spark timing(as seen in row 324-327) I am willing to bet your tuner did not increase the advance limit so 4 is max advance(I have mine set to 8)
- Knock advanced tapered down as the ECM detected knock and you ended up at 1* of KR, which means you ended losing 5* total(the 4 added, and 1 pulled), which brought you down to 22* of spark advanced(as seen starting in row 357)
- You were back at Zero KR around 5,700 rpm, which is when you were seeing 26* of spark advance(as seen starting in row 485)
- At row 485 it looks like you shifted as well because your RPM dropped to 4,600 in the next row


Anyway, get me a HPL format scan from the HPT scanner and I can do a better job at reading, not that i can't read the Excel sheet, I just lack the time to hunt down what I'm looking for.

However, your tuner should be able to fix this quite easily and get you going, this is assuming you didn't put some lower quality octane in. The other fix is to pump in 2-3 gallons of e85. This should get you a e20 mix, which will give you better predetonation resistance and confirm whether you are seeing KR from bad gas or too much timing in those ranges. If it still shows the same amount of KR then you may be getting false knock from something rattling or tapping.

 

[Carbd86GT]

The reason you aren't seeing 26-27* throughout the whole pull because you are getting KR. Can yo get me a actual HPT scanner log please? Reading it off that excel sheet sucks...but from what I can see:

- You peaked 27* of spark advance when the ECM was using Knock advanced to add 4* of spark timing(as seen in row 324-327) I am willing to bet your tuner did not increase the advance limit so 4 is max advance(I have mine set to 8)
- Knock advanced tapered down as the ECM detected knock and you ended up at 1* of KR, which means you ended losing 5* total(the 4 added, and 1 pulled), which brought you down to 22* of spark advanced(as seen starting in row 357)
- You were back at Zero KR around 5,700 rpm, which is when you were seeing 26* of spark advance(as seen starting in row 485)
- At row 485 it looks like you shifted as well because your RPM dropped to 4,600 in the next row


Anyway, get me a HPL format scan from the HPT scanner and I can do a better job at reading, not that i can't read the Excel sheet, I just lack the time to hunt down what I'm looking for.

However, your tuner should be able to fix this quite easily and get you going, this is assuming you didn't put some lower quality octane in. The other fix is to pump in 2-3 gallons of e85. This should get you a e20 mix, which will give you better predetonation resistance and confirm whether you are seeing KR from bad gas or too much timing in those ranges. If it still shows the same amount of KR then you may be getting false knock from something rattling or tapping.

Thanks for the info. How do I go about getting you an HPT scan log?

As far as knock advance, I've seen it as high as 6 but it was during aggressive part throttle operation.

I strictly use chevron 93 octane from a station that's a couple blocks away. Like I said earlier, I've never thought to log before so that I can review, but I watch KNOCKR and Timing pretty closely while I'm fooling around just for curiosities sake and I don't ever remember seeing knock activity previously.

I picked up some NOS "racing" octane booster that I'm going to try first. I'll use a full can with 8 gallons of 93 and see if anything changes. I am just trying to trouble shoot first before bothering my tuner. Would hate to waste his time if it's just bad gas.

Again, thanks for the help and I'll gladly get you that scan if you can point me in the direction of some instructions.

 

[5lho]

Thanks for the info. How do I go about getting you an HPT scan log?

As far as knock advance, I've seen it as high as 6 but it was during aggressive part throttle operation.

I strictly use chevron 93 octane from a station that's a couple blocks away. Like I said earlier, I've never thought to log before so that I can review, but I watch KNOCKR and Timing pretty closely while I'm fooling around just for curiosities sake and I don't ever remember seeing knock activity previously.

I picked up some NOS "racing" octane booster that I'm going to try first. I'll use a full can with 8 gallons of 93 and see if anything changes. I am just trying to trouble shoot first before bothering my tuner. Would hate to waste his time if it's just bad gas.

Again, thanks for the help and I'll gladly get you that scan if you can point me in the direction of some instructions.

Chevron is shit where I am, even the 94 stuff. I had a lot of KR issues when I was boosted on my last coyote. Change gas to Shell, even 91, and the problems cleared up. I've only found two octane boosters that actually do anything: Lucas and Torco. Torco is a bit better but harder to find.

 

[Carbd86GT]

Chevron is shit where I am, even the 94 stuff. I had a lot of KR issues when I was boosted on my last coyote. Change gas to Shell, even 91, and the problems cleared up. I've only found two octane boosters that actually do anything: Lucas and Torco. Torco is a bit better but harder to find.

I've heard decent things about the NOS for off the shelf stuff. Torco is probably the best but I would have to get it shipped. Going to try this to see if it even does anything. May also try another gas station. Got a new race trac that just opened up a couple blocks away that also has E85, but injectors will be in the budget next month so I can make that switch.

 

[Beernuts]

Try Costco 93 if you have a membership.

 

[Carbd86GT]

Well, I added a can of NOS octane booster and about a half tank of 93, let it all mix on the drive to work and such. On the way home I did another log and it seems like it was poor quality fuel. Saw 28* up to 7100 rpm (KNOCKR also showed -2.75 with 28* timing). Ran through that fuel and then fueled up with straight 93 from a new Race Trac station and while I didn't log it, KNOCKR was showing -4 near 7K RPM so I would think this is around 29* total. I think I'll start fueling up there as they also have E85 once I get my injectors in.

jn2, thanks for the help.

 

[5lho]

There ya go...like I said, it's all about the gas. People forget this is an 11:1 motor to start with, that can run on 87 pump in stock form.

 

[jn2]

Well, I added a can of NOS octane booster and about a half tank of 93, let it all mix on the drive to work and such. On the way home I did another log and it seems like it was poor quality fuel. Saw 28* up to 7100 rpm (KNOCKR also showed -2.75 with 28* timing). Ran through that fuel and then fueled up with straight 93 from a new Race Trac station and while I didn't log it, KNOCKR was showing -4 near 7K RPM so I would think this is around 29* total. I think I'll start fueling up there as they also have E85 once I get my injectors in.

jn2, thanks for the help.

Running ethanol will def remedy it. I usually do 4 gallons of e85 and the rest 93, this gets me a e30 mix

 

[Derek@Lethal]

Running ethanol will def remedy it. I usually do 4 gallons of e85 and the rest 93, this gets me a e30 mix

Interesting. You believe the stock fuel system is enough for this and you've done this on a "93 octane" tune?