- Joined
- Apr 17, 2025
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- Location
- Greenville, USA
- Vehicle(s)
- 2024 Bronco Velocity Blue Wildtrak
- Your Bronco Model
- Wildtrak
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- #1
Hi all, I wanted to share my thoughts and experiences with stacking the JB4 on top of the FPP tune.
Why: I like the revised shift schedule of the FPP tune, but want mo powa!
Let's start with the lessons learned so far. In general, and specifically with the FPP tune,
1. Sport mode adds performance, but tightens the safety windows. For example, you get more fuel by increasing the duty cycle of the HPFP and Injectors, but the safety margin is reduced which will throw codes more frequently if the times are not happy.
2. E-40+ mixes will run and the truck can compensate on the FPP tune, but you quickly hit the duty cycle ceiling with the JB4 stacked.
Running high E mixes but maintaining some safeties is where I believe that the full custom tunes from ZFG, Five Star, etc shine over the piggy back setup. But if you can learn to read the logs, you can do this safely. I didn't try but I bet Burger Motorsports is also pretty good at reading the logs and maybe giving their own tuning advice.
Basically this stacked setup benefits highly from e-30+ and you get generous timing advances, but the HPFP and Injector trims are riding the line on throwing a code. Mine threw lean codes just rolling through my neighborhood and was averaging afr of 15. I had to drive like this some, so I turned the JB4 to map1, and took it easy. Once I had some room in the tank, I dialed back the mix to ~e35 or so and saw improvements , but still running lean and throwing codes. I started over with ~ e-10 and this fixed my fuel trims which I believe was mostly the fuel blend, but also some adaptation I would guess.
E10 let me run map3 and 4 and the fuel trims were great, but at WOT I was hitting the limit of the octane and the computer was pulling timing down to 0 between 3500 and 5000 rpms while trying to boost around 20-21psi. I added more ethanol and tested more and finally workedy way into Map4 on E25-E30 pushing 19-20 lbs of boost...in NORMAL mode.
As soon as I flipped to Sport, the logs showed huge timing pulls. I started to just leave this and run only in Normal, but I can't leave well enough alone, so I started with test hits on Maps 1-4 in Sport mode. Progressively, timing in that upper mid-range was being pulled.more and more with each map and this pushed me to build a map 6.
It took me a few days to get time to do some runs, and I bring this up bc I know the ECU was adapting to the current E25 mix and resetting its targets. I started with a conservative map 6 and saw a lot of improvements. I also saw that the turbos seem to max out around 19-20 lbs of sustained boost. I can spike it higher, but they are generally at their limit. My avg boost per gear per run was around 14psi. On my Map6, setting the 1500 rpm to 6.0 puts the table in absolute target mode, so I can specify peak boost by RPM. The other way is specifying the additive boost amount on top of what the ECU is calling for.
I chose the absolute mode and have been successful with the following parameters:
I'll try to get a clean draggy run and a matching log to post here for your reference. I know that I have some room to tweak these targets, but I can say that these run consistently on MY BRONCO 2.7 today. On a full run, I do see 3-4 small timing pulls between 4000-5000, but I saw that with 92° ambient temps and 110° IATs.
For transparency and comparison, here is where I started and my current final numbers
Start building Map6 with data from a map4 run:
Avg Boost 13.99 psi
Max Boost 19.30 psi
Avg Timing 6.97°
AFR 13.68
Final Map6 with the attached boost by RPM numbers
Avg Boost 16.01
Max Boost 21.40
Avg timing 7.58
AFR 12.97-13.35
I believe that I can increase these numbers a little bit by adding a little bit more octane, but I'm happy that I have a quick, stable piggyback tune running with the FPP tune.
I will probably stick with this and start adding downpipes and intercooler until I get out of warranty and go full custom tuning.
Why: I like the revised shift schedule of the FPP tune, but want mo powa!
Let's start with the lessons learned so far. In general, and specifically with the FPP tune,
1. Sport mode adds performance, but tightens the safety windows. For example, you get more fuel by increasing the duty cycle of the HPFP and Injectors, but the safety margin is reduced which will throw codes more frequently if the times are not happy.
2. E-40+ mixes will run and the truck can compensate on the FPP tune, but you quickly hit the duty cycle ceiling with the JB4 stacked.
Running high E mixes but maintaining some safeties is where I believe that the full custom tunes from ZFG, Five Star, etc shine over the piggy back setup. But if you can learn to read the logs, you can do this safely. I didn't try but I bet Burger Motorsports is also pretty good at reading the logs and maybe giving their own tuning advice.
Basically this stacked setup benefits highly from e-30+ and you get generous timing advances, but the HPFP and Injector trims are riding the line on throwing a code. Mine threw lean codes just rolling through my neighborhood and was averaging afr of 15. I had to drive like this some, so I turned the JB4 to map1, and took it easy. Once I had some room in the tank, I dialed back the mix to ~e35 or so and saw improvements , but still running lean and throwing codes. I started over with ~ e-10 and this fixed my fuel trims which I believe was mostly the fuel blend, but also some adaptation I would guess.
E10 let me run map3 and 4 and the fuel trims were great, but at WOT I was hitting the limit of the octane and the computer was pulling timing down to 0 between 3500 and 5000 rpms while trying to boost around 20-21psi. I added more ethanol and tested more and finally workedy way into Map4 on E25-E30 pushing 19-20 lbs of boost...in NORMAL mode.
As soon as I flipped to Sport, the logs showed huge timing pulls. I started to just leave this and run only in Normal, but I can't leave well enough alone, so I started with test hits on Maps 1-4 in Sport mode. Progressively, timing in that upper mid-range was being pulled.more and more with each map and this pushed me to build a map 6.
It took me a few days to get time to do some runs, and I bring this up bc I know the ECU was adapting to the current E25 mix and resetting its targets. I started with a conservative map 6 and saw a lot of improvements. I also saw that the turbos seem to max out around 19-20 lbs of sustained boost. I can spike it higher, but they are generally at their limit. My avg boost per gear per run was around 14psi. On my Map6, setting the 1500 rpm to 6.0 puts the table in absolute target mode, so I can specify peak boost by RPM. The other way is specifying the additive boost amount on top of what the ECU is calling for.
I chose the absolute mode and have been successful with the following parameters:
I'll try to get a clean draggy run and a matching log to post here for your reference. I know that I have some room to tweak these targets, but I can say that these run consistently on MY BRONCO 2.7 today. On a full run, I do see 3-4 small timing pulls between 4000-5000, but I saw that with 92° ambient temps and 110° IATs.
For transparency and comparison, here is where I started and my current final numbers
Start building Map6 with data from a map4 run:
Avg Boost 13.99 psi
Max Boost 19.30 psi
Avg Timing 6.97°
AFR 13.68
Final Map6 with the attached boost by RPM numbers
Avg Boost 16.01
Max Boost 21.40
Avg timing 7.58
AFR 12.97-13.35
I believe that I can increase these numbers a little bit by adding a little bit more octane, but I'm happy that I have a quick, stable piggyback tune running with the FPP tune.
I will probably stick with this and start adding downpipes and intercooler until I get out of warranty and go full custom tuning.
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