[Stars1315]

I've been doing a lot of reading about the JB4 tune over the past couple days. I'm a little confused about map 2. I can't seem to find a clear answer on the cats.

So what exactly is the deal with the exhaust? Is it necessary to change the cats for DPs? If it is okay with the cats on, how much do I lose? Is there an option for keeping the cats on somehow?

I'd like to keep the cats on because I don't like the smell and don't want to worry about emissions at all if I can avoid it. How are high flow cats? Any good?

Trying to understand all this stuff as I shop around for a 335 I like. I plan on dropping the JB4 in almost immediately and running map 1 till I figure out exactly what I am doing with the rest of the car.

New to the forum and newish to BMW btw. Had one in the past, currently looking for another. On that note, if anyone knows of someone selling a 2011-2013 335xi on craigslist or something with sub 50k miles on it in NJ feel free to point me in their direction.

[LGCubana]

If you can wait a few months (hopefully no more than that), the MHD OTS Flash tune is the soup du juor. They are currently in beta and have a slew of "Pioneers" paying to be in the beta program.

The consensus is that a flash only tune is better than a piggyback (e.g. JB4), which has to fool the car's sensors and DME.

If you do go the route of the JB4, it's still recommended to invest in the MHD platform, to flash BMS' exclusive BEF, that supports the JB4.

If you do the MHD OTS flash 1st, you can still go forward with the JB4 at a later date, as the JB4 still needs the MHD platform to flash their BEFs (made exclusively for the JB4)

Maybe check you regional subforum, to see if you can hook up with someone (with an N55) that already has one of the products installed, to see what it's like.

If you go N54, then the MHD Flasher has already proven itself to be a stable and popular solution.

[bahn]

Originally Posted by mreto727

I've been doing a lot of reading about the JB4 tune over the past couple days. I'm a little confused about map 2. I can't seem to find a clear answer on the cats.

So what exactly is the deal with the exhaust? Is it necessary to change the cats for DPs? If it is okay with the cats on, how much do I lose? Is there an option for keeping the cats on somehow?

I'd like to keep the cats on because I don't like the smell and don't want to worry about emissions at all if I can avoid it. How are high flow cats? Any good?

Trying to understand all this stuff as I shop around for a 335 I like. I plan on dropping the JB4 in almost immediately and running map 1 till I figure out exactly what I am doing with the rest of the car.

New to the forum and newish to BMW btw. Had one in the past, currently looking for another. On that note, if anyone knows of someone selling a 2011-2013 335xi on craigslist or something with sub 50k miles on it in NJ feel free to point me in their direction.

Map 2 recommends a catless dp because the stock downpipe is very restrictive. This restriction causes exhaust gas temps to rise quickly at higher boost targets. High exhaust gas temps can shorten the turbos life span by overheating the bearings. You can run map 2 (I did for a year) with the stock downpipe, just refrain from doing 3-4 pulls in quick succession. This should help keep the EGT's down. If you want to keep a cat then a high-flow would be a good option.

[Turbod]

^^^ I was going to write something similar to this. Just make sure you have the proper fueling for that boost level.

[Stars1315]

Originally Posted by LGCubana

If you can wait a few months (hopefully no more than that), the MHD OTS Flash tune is the soup du juor. They are currently in beta and have a slew of "Pioneers" paying to be in the beta program.

The consensus is that a flash only tune is better than a piggyback (e.g. JB4), which has to fool the car's sensors and DME.

If you do go the route of the JB4, it's still recommended to invest in the MHD platform, to flash BMS' exclusive BEF, that supports the JB4.

If you do the MHD OTS flash 1st, you can still go forward with the JB4 at a later date, as the JB4 still needs the MHD platform to flash their BEFs (made exclusively for the JB4)

Maybe check you regional subforum, to see if you can hook up with someone (with an N55) that already has one of the products installed, to see what it's like.

If you go N54, then the MHD Flasher has already proven itself to be a stable and popular solution.

Thanks for the info!! I read through everything, but it all is a bit confusing to me still. The MHD OTS is a new tune in beta separate from stuff like the JB4 or cobb? And if I get the JB4 I need the MHD anyway? I thought he JB4 works very well on its own?

[opjose]

Originally Posted by bahn

You can run map 2 (I did for a year) with the stock downpipe, just refrain from doing 3-4 pulls in quick succession. This should help keep the EGT's down. If you want to keep a cat then a high-flow would be a good option.

So is MAP2 OK to use with a high-flow CAT?

Also out of curiosity, if you enable the JB4's can flap, does it deactivate when MAP0 is set.

[Johnny Boost]

Originally Posted by opjose

So is MAP2 OK to use with a high-flow CAT?

Yes

[mike@x-ph.com]

Map 2 is good with high flow cats, keep in mind high flow cats are not emission legal

[maddmatth]

MHD for N55 is already in a very good state. I ran it on my car for a bit. Haven't tried the latest map revisions as my car has an issue where it isn't holding boost, want to fix that first (actually discovered that thanks to MHDs logging and comparing to other cars).

I recommend you start with MHD. Do get an aftermarket charge pipe first, a tune will make the stock one explode.