JB4 on top of FP tune

Yes, but why is it a bad idea? Why would installing a JB4 on an improved, warrantied Ford tune be bad?

Any actual information would be helpful.

First…there’s no “improved shifting”. The FP tune loads the newest calibration and runs a fresh relearn process…that’s all.
You’d be better off and safer just running the JB4 or the FP tune. Stacking tunes has bad idea written all over it.

He does state he has a ‘21, which shouldn’t have the latest trans calibration. So he may be actually gets g something there with the FP tune.


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I always enjoy your posts, but I'm not following your logic here.

As mild as the FP tune is, I would not stack a JB4 on it at all.

As mentioned the way they cheat the computer bypasses some built in stock safeties.


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My understanding is that the latest version of trans tuning (same as FP tune) didn't start going out on the ST's until mid '22. With the OP mentioning his is a '21 I would assume it's the same as mine and have the an older revision of the trans tuning, which can certainly be described as "less than perfect". So if he does go with the FP tune, he should get the latest/greatest trans tuning and see some improvement.

However, I haven't had the "parking brake" Flash done yet, so I don't know if they wrap in any trans tuning changes with that update, or if it just turns on the parking brake in Park. Once I get the TSB done, I'll read the tune and compare, just for shit's and giggles.

I have access to a FP tuned ST, so I may do a read and compare for fun. I currently have my own tune (HPT and SCT), BoostKing (HPT), Unleashed (HPT) and Gearhead (SCT). So it might be an interesting comparison.

If anyone is curios, here is a friend that did some testing with his '22 Tremor F150 (3.5). You can see it aligns with @TMac statements above. Brett now has the SCT tuner and will begin testing with it shortly (although it doesn't really matter one lick for the ST's). He also noted that with the JB4, it runs rich.


Long time! I hope you are all are doing well. This wont be a super extensive thread, but I wanted to share some initial results with you on the JB4 on my 2022 Tremor. This was done on our in-house DynoJet 224xlc. The truck has 3,000 miles (almost exactly) at this test interval and has no performance modifications besides the JB4 "tuner". Trucks is filled with 93 octane and then run with short cool downs to try to keep consistency.

Initial impressions are: It works very well for what it is. It is not a "tune", but rather a way to make your factory tune do something it wouldn't ordinarily by tricking it. That said, it works very well with the stock tune, and for a non-flash, technically untraceable tuning type device, it's impressive. If you own a 2021+, this is one of the only solutions for tuning as real custom tuning has not been available. It installs in 15 minutes, and you can change tunes using your phone (if you have the bluetooth connect kit), with just a few moves in the app. It has some datalogging capabilities, which I can/will address more later, but at least you can see something.

Mostly this just alters boost, which raises load, which does make power. Spark seems to stay pretty much what I would expect out of these engines, almost nothing. Each MAP is progressively more aggressive. Here is the map guide they supply on their website:

JB4 Map Guide:
Map0: Fully disable JB4
Map1: +3.5psi peak over stock, default map, 91+ octane
Map2: +3.5psi peak, less top end taper, more aggressive version of map1.
Map3: +4psi peak, suggested for 93+ octane and/or modified trucks
Map4: Low boost VALET map
Map5: +6psi peak, suggested for 30% E85 mixtures and/or unleaded race fuel
Map6: Custom tuning map user adjustable
Map7: +7psi peak racing map for unleaded race fuel

So far I have been daily driving on the Map 2 for about a week. It drives really well, no surging. I wish I could tune the trans some to make it better, but it is what it is for now.

I have not run past Map 3 yet. Map 4 is nothing, but Map 5 is made for E30 or higher mixtures. With the stock intercooler, not sure I want to push it, but I may for a run or two on the dyno with some ethanol (one day).

I realized after this I forgot to run Map 1 but if it's less aggressive version of Map 2, then I think we can guess where it would end up.

Power results are:

Stock - 345 whp & 464 wtq
MAP 2 - 361 whp & 486 wtq
MAP 3 - 387 whp & 510 wtq

So for those test, from stock to MAP 3 we see a 42 whp gain. Not bad at all.



When you record, it seems to record "all it is capable of". To that point, there are some good things to log, however some things are missing like knock (which I find crucial). Fueling and boost and throttle as you will see in this image are available, as well as others. The graphing software (mobile and cp) are both primative but effective for checking things. I still have more to learn, but it's not too complex. Boost falls to about 18 something at redline.

Oh, and when I'm doing a run and brake boosting, it only goes up to about 2300 RPMs and no higher. Is that normal?

That is your stall speed of the torque convertor. As you increase the torque output from tuning and other mods, you will be able to get a higher stall speed before the engine can no longer increase in rpm during a brake boost because the engine makes more torque so it can overcome the built in resistance of the convertor. I can get around 2800 RPM with mine.