wvinson
Ram Guru
thats why I had my shop do mine
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2025 I6 - JB4 Tuner
- Thread starter bshelton8
- Start date
I'd like to share lessons learned and some experience with the JB4 tuner. I have a 2025 Ram 1500 Limited with the HO Hurricane. I installed the JB4 and yes it makes crazy HP and really throws you back into your seat. Instant smile. BUT.... As with anything there some problems. One, there is a known software issue with the Rams running the HO. There is a rapid response update that supposedly fixes it. What happens is that the catalytic converters cannot handle the amount of heat and the software issue causes some unburnt fuel to reach the converters where is ignites. Over time the Honeycomb inside structure begins to melt and slowly clogs the converters. You will see a major reduction in power and eventually CEL. The JB4 speeds up this process and will completely clog both converters in about 6 months. If you have the update then it will take longer but the amount of heat these engines produce are too much for the stock converters.
The second issue, the engine compartment also gets very hot and the metal JB4 casing will get so hot that you can't even touch it. When the tuner overheats it will cause some brief connection issues. If this occurs when you are getting into the throttle it will blow the turbo hose off and the motor will stall. If your motor starts losing power suddenly and chugs along barely running then it probably blew off the turbo hose.
If you decide to continue to run the JB4 I wouldn't use anything higher than map #2. Map #3 and higher needs blended fuel and even then it will exceed the max PSI value and you will eventually run into problems.
Suggestions... buy some wire and connectors to lengthen all 3 JB4 harnesses and keep the tuner inside the truck. Never use anything higher than Map #2. Daily driving keep factory settings on the app and only use the maps when needed.
Overall the JB4 does what it says very well but has negative side effects on the motor. All depends on how you use it.
wvinson
Ram Guru
So, are you saying that if you don't get the rapid response update and don't have the tuner that all HO engines will melt their catalytic converters. That sounds a little absurd. The HO engine has been out for 3 years running in the Grand Wagoneer.
BowDown
Spends too much time on here
C6 Corvette ZR1s were having an issue with melting cats with repeated long pulls. It takes a while to get to that point but there's been no fix short of going cat-less or less/shorter full power pulls.
High flow cats didn't last any longer, actually shorter. The only thing that helped the cats was adding fuel to cool the cats, that maybe something the tuners need to reconsider
High flow cats didn't last any longer, actually shorter. The only thing that helped the cats was adding fuel to cool the cats, that maybe something the tuners need to reconsider
BowDown
Spends too much time on here
No, the engine can be in its ideal range under boost, probably in the 11-12's but that be too lean to keep the cats from overheating under high load conditions.
Adding fuel to help the cats would reduce power. Possibly switching to a metal matrix cat.
An E blend would help but you'd need a flex fuel sensor that could detect ethanol content and adjust the tune accordingly and a corresponding tune. Your only other option would be buying drums of ignite or something sooner that had a consistent E content then tune for that but that would eliminate your ability to use pump gas
That’s what I’m saying, tune may be a bit too spicy for the sake of marketing. Reducing power is not as sexy, but neither are melted cats.
