2013 Mustang GT Spark Advance

[kris5597]

Hey guys, I am running into an issue, that I've never seen before, on spark advance on a 2013 Mustang GT. This car has a cold air intake kit, catless 1 3/4" long tube headers, and catback exhaust system running good 93 octane. I primarily tune 2015+ GTs but I had this 2013 roll up for a calibration and figured it would be the same or very similar. I am having issues with Knock Retard in the midrange and at peak power and I am not sure why. I can normally command 29-30 degrees of igntion advance with no problem on full bolt on cars, but for some reason, this car keep detecting knock and will not go above what was logged, every pull. Confused...

Any help would be appreciated.

Kris

[jchambers]

You must have good gas where you're at. A typical Coyote around my area (northern Ohio) is maxed around 26-degrees on E10 93 pump, not only from the knock sensitivity standpoint but from a power/torque threshold as well. I don't find any benefit of beyond this unless running a higher octane fuel such as Sunoco 100 or MS109.

[15PSI]

IMHO 29*-30* is too much total spark for that combo on 93. Lower your total down to 25* and re-log it. If you want to test it at your current spark values, try adding some Boostane or Torco Accelerator. Raising the octane to around 100 should support that amount of timing.

[kris5597]

You must have good gas where you're at. A typical Coyote around my area (northern Ohio) is maxed around 26-degrees on E10 93 pump, not only from the knock sensitivity standpoint but from a power/torque threshold as well. I don't find any benefit of beyond this unless running a higher octane fuel such as Sunoco 100 or MS109.

IMHO 29*-30* is too much total spark for that combo on 93. Lower your total down to 25* and re-log it. If you want to test it at your current spark values, try adding some Boostane or Torco Accelerator. Raising the octane to around 100 should support that amount of timing.

Very interesting, on every 2015+ I've tuned, the knock sensor will allow up to 30 degrees of timing with no issues on e10 93 octane on a I/ H/ E car. I have even seen other 11-14s running similar timing with similar setups.

However, that being said, I am only targeting 22-24 degrees of timing max, and allowing the knock sensor to add up to a cap of 30 degrees. I may add a squirt of E85 to the mix and see if it reduces knock and adds timing.

Kris

[tbrtuning]

I run 30-31 on an S550 with no issue. Usually a little less on a 2011-2014 but would at least expect that setup to be comfortable at 28 unless it's really hot out. 2011-2014 exhaust layout makes it very easy to get contact with the frame causing false knock so check that. There's even a clamp people put on the midpipe upside down all the time because it's easier that way. It hits the frame if it's installed like that.

[murfie]

The knock advance/retard system on the 15+ is more versatile and forgiving for small intensity knock than the 11-14. This allowed ford to have a higher stock MBT value to target. The trouble is with the 11-14 you cant tell the difference between low and high intensity knock events, they all look the same to the ECU. It judges only by engine RPM. You can still optimize it as much as you are comfortable with.

With the 11-14's you can raise the borderline values(they were low to accommodate 91 and bad gas of different areas). Because you have a higher starting borderline you can reduce the knock advance rates. They don't need to ramp as fast and you can rely on them less to get your spark where you want it. Removing 1.5* is quite aggressive for light intensity knock, 2015+ is .5*. Work toward that and you should get results more like the 15+. Keep in mind once knock starts it takes more retard to stop it than if it didn't happen in the first place. If you keep your MBT values reasonable and you don't start getting a bunch of knock events you can lower your knock retard rates so knock events have less impact on total spark. You want to leave some room as even 93 varies tank to tank.

Its always a good idea to just pull the plugs and have a look at them. Make sure they all have the correct gap or have any carbon build up preventing optimal spark.

[SultanHassanMasTuning]

full bolt ons with 2011-2014 coyote engines i can push 28/30

just an intake more like 21-23

[kris5597]

The knock advance/retard system on the 15+ is more versatile and forgiving for small intensity knock than the 11-14. This allowed ford to have a higher stock MBT value to target. The trouble is with the 11-14 you cant tell the difference between low and high intensity knock events, they all look the same to the ECU. It judges only by engine RPM. You can still optimize it as much as you are comfortable with.

With the 11-14's you can raise the borderline values(they were low to accommodate 91 and bad gas of different areas). Because you have a higher starting borderline you can reduce the knock advance rates. They don't need to ramp as fast and you can rely on them less to get your spark where you want it. Removing 1.5* is quite aggressive for light intensity knock, 2015+ is .5*. Work toward that and you should get results more like the 15+. Keep in mind once knock starts it takes more retard to stop it than if it didn't happen in the first place. If you keep your MBT values reasonable and you don't start getting a bunch of knock events you can lower your knock retard rates so knock events have less impact on total spark. You want to leave some room as even 93 varies tank to tank.

Its always a good idea to just pull the plugs and have a look at them. Make sure they all have the correct gap or have any carbon build up preventing optimal spark.

Thanks for the response Murfie. I will adjust accordingly.

Kris