Jb4 + downpipes = bad??

[Likeanowl]

So I’m finally getting my vrsf downpipes put on. Upon calling the tuning shop though the tech told me jb4 is notorious with causing issues with catless downpipes. He didn’t go on to specify but did say he’s seen and heard of several people coming in with “issues” related to the jb4/catless dp combo. Can anybody verify this or back this up? Once the pipes are installed my only mods will be jb4, catless dp’s, and intakes.

Hopefully this isn’t a huge drawn out thread, just looking for any validity to his statement and if so, what issues. Thanks.

[Sd335i2007]

I haven't personally heard of this. Was the shop trying to get you to purchase a different tuning platform as a result of this?

[FriedPiston]

Sounds like the shop is highly misinformed. The JB4 does not cause any issues with catless downpipes. As part of BMS' effort to be C.A.R.B. compliant, they removed the JB4's ability to auto-clear the CEL caused by catless downpipes. This change mainly applies to the North American region.

You can still clear the catless downpipes trouble code with JB4, but it just won't do it actively in the background.

[Djdnav]

Originally Posted by FriedPiston

Sounds like the shop is highly misinformed. The JB4 does not cause any issues with catless downpipes. As part of BMS' effort to be C.A.R.B. compliant, they removed the JB4's ability to auto-clear the CEL caused by catless downpipes. This change mainly applies to the North American region.

You can still clear the catless downpipes trouble code with JB4, but it just won't do it actively in the background.

To add to this:

Although the p0420 CEL is an eyesore if your JB4 doesn't have auto clear functionality, it doesn't affect performance or operation.

[Likeanowl]

Yeah they did mention working with ecs tuning once or twice. He didn’t specifically try to sell me another tune, but he did try pretty hard to convince me that with just jb4 and catless downpipes I would be in for some trouble. Even said they make customers using just jb4 as their only “tuning platform” sign a paper stating they acknowledge they will get some “issues” and can’t hold them liable.

Just very curious what these “issues” might be, and again, if anybody can back this up or if it’s just a bullshit scare tactic/sales plot.

[luchocamp]

no issues, in my Youtube channel starting a very detail info about stock flash using all JB4 maps, map0, map1, map2, map7 ...them I will covered flash only bm3, them bm3 + jb4, them mhd and after that mhd + jb4, stock, fb0, clutches, upgrades turbos etc

[mike@x-ph.com]

The car will run fine, the Jb4 does not auto-clear the CEL so you have a warning light at all time

[FastM3CT]

Originally Posted by mike@x-ph.com

The car will run fine, the Jb4 does not auto-clear the CEL so you have a warning light at all time

Mike is spot on with this... No performance concerns at all...

[Likeanowl]

Questions regarding the jb4/cel light. I haven’t updated the firmware since last year so will it still leave the cel light on?

[horsepower_and_hounds]

Originally Posted by Likeanowl

Questions regarding the jb4/cel light. I haven’t updated the firmware since last year so will it still leave the cel light on?

Do not update the firmware.... if you current set up masks the CEL then don't update. Te roll out of the emission-less tampering is so Burger can continue to market their product in the US without fines...... It will still work but I personally would not update

[Likeanowl]

Originally Posted by horsepower_and_hounds

Do not update the firmware.... if you current set up masks the CEL then don't update. Te roll out of the emission-less tampering is so Burger can continue to market their product in the US without fines...... It will still work but I personally would not update

Bingo. Thank you my friend!

[M3ZCPNYC]

Originally Posted by Likeanowl

So I'm finally getting my vrsf downpipes put on. Upon calling the tuning shop though the tech told me jb4 is notorious with causing issues with catless downpipes. He didn't go on to specify but did say he's seen and heard of several people coming in with "issues" related to the jb4/catless dp combo. Can anybody verify this or back this up? Once the pipes are installed my only mods will be jb4, catless dp's, and intakes.

Hopefully this isn't a huge drawn out thread, just looking for any validity to his statement and if so, what issues. Thanks.

Fake news!!!!!

[TurboSid]

Had the combo on two M4's over 5 years. No issues

[Likeanowl]

So a bit of an update to this. Got my downpipes put on today by them. First thing they said is my oil pan is leaking... minor leak, but still leaking.

Then basically made me paranoid. Repeatedly mentioned that jb4 is essentially tricking the car into making more boost which is dangerous and basically will blow my engine. I can’t even count the amount of times I was told “man... just be careful. Don’t drive it hard. We aren’t responsible for anything. Don’t push it. Don’t drive it hard on the highway.” Or some variation of those things. They now have me thinking #1 do they know something I don’t that’s about to become a huge problem? 9r #2 I HOPE not... but possibly tamper with something causing me to have to come back for a huge repair.

They did keep saying that “these cars need to be tuned properly to have catless downpipes or you’re gonna have issues we aren’t liable for.” Also kept referring to a specific tuning company they always work with I’m assuming to sell me a tune.

I’m honestly so paranoid now I won’t even put it in sport mode. I have no idea what to think.

[Fuel-It!]

The JB4 is one of the most widely used tunes out there, your shop clearly doesn't understand how it works and has confused it for RaceChip and other junkbox tunes out there.

Post up a JB4 log and lets see how it's running and ensure it's safely tuned!

[Djdnav]

Originally Posted by Likeanowl

So a bit of an update to this. Got my downpipes put on today by them. First thing they said is my oil pan is leaking... minor leak, but still leaking.

Then basically made me paranoid. Repeatedly mentioned that jb4 is essentially tricking the car into making more boost which is dangerous and basically will blow my engine. I can’t even count the amount of times I was told “man... just be careful. Don’t drive it hard. We aren’t responsible for anything. Don’t push it. Don’t drive it hard on the highway.” Or some variation of those things. They now have me thinking #1 do they know something I don’t that’s about to become a huge problem? 9r #2 I HOPE not... but possibly tamper with something causing me to have to come back for a huge repair.

They did keep saying that “these cars need to be tuned properly to have catless downpipes or you’re gonna have issues we aren’t liable for.” Also kept referring to a specific tuning company they always work with I’m assuming to sell me a tune.

I’m honestly so paranoid now I won’t even put it in sport mode. I have no idea what to think.

There you have it. Forget what they told you. Literally thousands of people run jb4’s without the world burning down. Some joker at a car meet gave me the same line about bm3, and how the car would blow bla bla I should pay him $1000 to install a jb4. I obviously laughed in his face.

[Likeanowl]

Originally Posted by Fuel-It!

The JB4 is one of the most widely used tunes out there, your shop clearly doesn't understand how it works and has confused it for RaceChip and other junkbox tunes out there.

Post up a JB4 log and lets see how it's running and ensure it's safely tuned!

Unfortunately I don’t have any way of data logging it. That would be great though. I wish I could. Just really really uneasy right now. Have me second guessing even owning the car. I’m currently out of a job for at least the next year still due to covid and if anything major went south I’d basically be on my way to bankrupt.

[Ejones4541]

The JB4 has integrated data logging...in the mobile app or the desktop app.

[Likeanowl]

Is it Mac compatible?

[TurboSid]

You should do more research before purchasing. All of your questions have been answered for many years.

[Fuel-It!]

JB4 software and directions are posted here: https://www.n54tech.com/forums/showthread.php?t=25401

[sicck_m4]

I have been running full bolts with JB4+BEF E85 10k miles. No issues. When I installed my downpipes, I put a spacer to recess the o2. No CEL once so ever.