I'm not new to getting 11-15 Mustangs tuned, but I'd like some thoughts on this latest deal. I have tunes from 2 tuners(no names...lets call them tuner A and tuner B). Both are very well known and very well respected. I know that both of these guys truly know what they are doing.
Tuner A datalogging shows routinely -2 degrees of knock indicating a very safe tune as the PCM is adding timing. My fuel economy over stock and compared to tuner B is dismal. So, it's also pig rich. I know all the emissions controls and cat over temp protection are in place. In general, this is a good tune.
Now, tuner B. My datalogs show +3.5 degrees of knock. At WOT, starting around 3500, it starts at -1 degree and steadily climbs +1.5, +2....all the way to +3.5. It feels 30-50hp stronger than tune A. Drivability, part throttle cruising/responsiveness are better. Not a ton better, but it's noticeable. Fuel economy is also 3-4mpg better. I sent tuner B my logs and he said he'd be surprised if it was actually 3.5 degrees. He said to go out and make a couple more runs and then send him a pic of the plugs to see what we are actually getting.
Now, does that seem like a fair request? My gut tells me that worst case, if I am actually getting 3.5 degrees of knock, those 2-3 extra pulls ~could~ scatter this motor all over the highway. Is that enough that I should be concerned about for a couple of pulls? It would seem to me that the PCM seeing +3.5, even if it is being liberal with the readings, indicates that tune is right on the ragged edge. Meaning, that if I get a tank of bad gas in 6 months, it could be great until then...and then boom! To be fair, he said that he could pull some timing out of the tune if it actually is knocking. So, what are my risks with 2-3 more pulls with that much knock...if it is actually that much?
Tuner A datalogging shows routinely -2 degrees of knock indicating a very safe tune as the PCM is adding timing. My fuel economy over stock and compared to tuner B is dismal. So, it's also pig rich. I know all the emissions controls and cat over temp protection are in place. In general, this is a good tune.
Now, tuner B. My datalogs show +3.5 degrees of knock. At WOT, starting around 3500, it starts at -1 degree and steadily climbs +1.5, +2....all the way to +3.5. It feels 30-50hp stronger than tune A. Drivability, part throttle cruising/responsiveness are better. Not a ton better, but it's noticeable. Fuel economy is also 3-4mpg better. I sent tuner B my logs and he said he'd be surprised if it was actually 3.5 degrees. He said to go out and make a couple more runs and then send him a pic of the plugs to see what we are actually getting.
Now, does that seem like a fair request? My gut tells me that worst case, if I am actually getting 3.5 degrees of knock, those 2-3 extra pulls ~could~ scatter this motor all over the highway. Is that enough that I should be concerned about for a couple of pulls? It would seem to me that the PCM seeing +3.5, even if it is being liberal with the readings, indicates that tune is right on the ragged edge. Meaning, that if I get a tank of bad gas in 6 months, it could be great until then...and then boom! To be fair, he said that he could pull some timing out of the tune if it actually is knocking. So, what are my risks with 2-3 more pulls with that much knock...if it is actually that much?