[RMJ335i]

I have 2009 335i and running BMS DCI, AA 5" FMIC, BMS Chargepipe with diverters and VRSF Catless Downpipes.

How will a JB4 handle the downpipes regarding throwing codes? Also, how does the JB4 adapt to the mods that im currently running?

I know with Cobb it adapts based on specific stages requiring specific mods.

Thanks for your help in advance!

[evon54]

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[musc]

You will need a backend flash to eliminate the cat codes with DPs while running the JB4. There is really no adaptation other than you can running a little more aggressive map with more boost. It's kind of like switching flashes with the Cobb except the Map levels are built into the JB4.

[335NJ]

JB4 will auto clear the cat codes, with auto clear enabled. You will not pass emissions testing if your state requires the O2 monitors to be "ready" unless you have a DPFix.

JB4 Map 5 auto tunes based on fuel, weather, and mods. Map 2 has preset tuning parameters that don't change for the most part.

[RMJ335i]

Originally Posted by 335NJ

JB4 will auto clear the cat codes, with auto clear enabled. You will not pass emissions testing if your state requires the O2 monitors to be "ready" unless you have a DPFix.

JB4 Map 5 auto tunes based on fuel, weather, and mods. Map 2 has preset tuning parameters that don't change for the most part.

Thank you for the input , this helps quite a bit. When i reached out to BM directly they just told me they didnt support downpipes since they are illegal.

[musc]

I wouldn't recommend auto clear if you are just installing the JB4. You need to know what the codes are when trouble shooting.

[RMJ335i]

Originally Posted by musc

I wouldn't recommend auto clear if you are just installing the JB4. You need to know what the codes are when trouble shooting.

I am just trying to avoid faults due to catless downpipes....based on using my search tools it appears to be the only way. Also, what I found is that the JB4 only autoclears a couple of codes that are related to mods and the others will passthrough as active codes. Hopefully this much is true

[335NJ]

Originally Posted by musc

I wouldn't recommend auto clear if you are just installing the JB4. You need to know what the codes are when trouble shooting.

Auto clear, as stated above, will only clear certain codes. Important, or possible engine damage risk codes (misfire, etc) will throw a CEL.

[Aashenfox]

Pardon my noob, but could I ask for someone to expand on two sub topics here...

1) Backend flash along with a JB4? Is this specifically to eliminate O2 related CEL? Or does it have any other benefits?
2) I think I remember VRSF selling a O2 CEL fix, a little cable with a dongle of some kind on it...isn't that an option for the OP?

And lastly, since we're talking about JB4, something I've wanted to know for a while...when we do the JB4, does it remap the gas pedal response? I've noticed as others have, that I have to push the pedal in a LONG way before the car actually goes, as standard. The JB4 adjusts this, right? The huge deadzone...

[Mike@N54Tuning.com]

Originally Posted by Aashenfox

Pardon my noob, but could I ask for someone to expand on two sub topics here...

1) Backend flash along with a JB4? Is this specifically to eliminate O2 related CEL? Or does it have any other benefits?
2) I think I remember VRSF selling a O2 CEL fix, a little cable with a dongle of some kind on it...isn't that an option for the OP?

And lastly, since we're talking about JB4, something I've wanted to know for a while...when we do the JB4, does it remap the gas pedal response? I've noticed as others have, that I have to push the pedal in a LONG way before the car actually goes, as standard. The JB4 adjusts this, right? The huge deadzone...

Yes JB4 improves the pedal feel.

There are two DP fixes on the market, VRSF and Wedge. Both same price.

Back end flash for JB has nothing to do with CEL for DPs.

Mike

[Aashenfox]

Thanks Mike.

[musc]

Originally Posted by Aashenfox

Pardon my noob, but could I ask for someone to expand on two sub topics here...

1) Backend flash along with a JB4? Is this specifically to eliminate O2 related CEL? Or does it have any other benefits?
2) I think I remember VRSF selling a O2 CEL fix, a little cable with a dongle of some kind on it...isn't that an option for the OP?

And lastly, since we're talking about JB4, something I've wanted to know for a while...when we do the JB4, does it remap the gas pedal response? I've noticed as others have, that I have to push the pedal in a LONG way before the car actually goes, as standard. The JB4 adjusts this, right? The huge deadzone...

You can block the CEL from catless downpipes with a backend flash but that is not its primary purpose. The flash gives you control over timing, air/fuel, fuel scalar, etc. I wouldn't run a JB4 without it unless you are just doing Map1/Map2 on 91/93 octane. Even then there are 'pump' flashes you can run as well. With the backend flash you don't have to run autoclear.

[Aashenfox]

Thanks, perfect explanation. So the backend flash is in addition to the JB4. I was planning on going FBO and running map 7 on 96 octane having bolted in a plug n play JB4. Would you suggest a backend flash for that? If so, who performs that? How would I go about it? Thanks.

[brewnami]

Originally Posted by musc

You can block the CEL from catless downpipes with a backend flash but that is not its primary purpose. The flash gives you control over timing, air/fuel, fuel scalar, etc. I wouldn't run a JB4 without it unless you are just doing Map1/Map2 on 91/93 octane. Even then there are 'pump' flashes you can run as well. With the backend flash you don't have to run autoclear.

Umm... How long have you been running a JB4? Auto clear works perfect, I've been running near FBO for two years and always have that on. It will only completely hide emissions related CEL's, other issues such as misfires or more serious issues will still throw a CEL, it will just turn off again after a certain amount of time. But you can scan the code(s) with the JB4 and/or another device when you stop driving. I don't know which backend flash you're using, but it's most certainly not required to run a JB4 outside of map 1 or map 2.

OP, when you buy a JB4, run map 5 with your current mods. It's the auto tune map that will take into consideration all the mods you have, fuel, temps, etc and tune your car accordingly. More power than map 1 and 2. You don't need a backend flash at all unless you want more power or run more than 6 gallons of E85, though the amount map 5 and your LPFP will like will vary slightly between cars. My 2007 ran better with slightly more E85 on map 5 than my 2009.

Use auto clear with the downpipes. You will still throw codes for non-emissions related issues.

[musc]

Originally Posted by brewnami

Umm... How long have you been running a JB4? Auto clear works perfect, I've been running near FBO for two years and always have that on. It will only completely hide emissions related CEL's, other issues such as misfires or more serious issues will still throw a CEL, it will just turn off again after a certain amount of time. But you can scan the code(s) with the JB4 and/or another device when you stop driving. I don't know which backend flash you're using, but it's most certainly not required to run a JB4 outside of map 1 or map 2.

OP, when you buy a JB4, run map 5 with your current mods. It's the auto tune map that will take into consideration all the mods you have, fuel, temps, etc and tune your car accordingly. More power than map 1 and 2. You don't need a backend flash at all unless you want more power or run more than 6 gallons of E85, though the amount map 5 and your LPFP will like will vary slightly between cars. My 2007 ran better with slightly more E85 on map 5 than my 2009.

Use auto clear with the downpipes. You will still throw codes for non-emissions related issues.

I moved on from the JB4. I have seen it clear transient codes like misfires before. Maybe they have addressed this in firmware updates. It's just curious that it is not officially listed as a menu option anymore. Even in recent posts on the other forum I have seen Russell tell people to turn it off so they can diagnose what is going on with the car, etc because it is clearing codes. But hey, use it if you like.

If you are comfortable not having control over fueling and timing then by all means don't run a backend flash. Again, backend flashing allows you to adjust this as well as delete the cat CEL, tuner codes, etc.

[RMJ335i]

Originally Posted by brewnami

Umm... How long have you been running a JB4? Auto clear works perfect, I've been running near FBO for two years and always have that on. It will only completely hide emissions related CEL's, other issues such as misfires or more serious issues will still throw a CEL, it will just turn off again after a certain amount of time. But you can scan the code(s) with the JB4 and/or another device when you stop driving. I don't know which backend flash you're using, but it's most certainly not required to run a JB4 outside of map 1 or map 2.

OP, when you buy a JB4, run map 5 with your current mods. It's the auto tune map that will take into consideration all the mods you have, fuel, temps, etc and tune your car accordingly. More power than map 1 and 2. You don't need a backend flash at all unless you want more power or run more than 6 gallons of E85, though the amount map 5 and your LPFP will like will vary slightly between cars. My 2007 ran better with slightly more E85 on map 5 than my 2009.

Use auto clear with the downpipes. You will still throw codes for non-emissions related issues.

Thank you for the input. I have been running the Auto-Tune map with auto clear on and every other day or so I still get the half engine SES light but it goes away within a min or so.

Im dropping my car off at the dealer tomorrow so I will put it on map 0 and turn autoclear off so they can diagnose my wastegate rattle issue.