[rickinaz]

Has anyone done this? Results?

[Alpine435i]

I'm sure it will be fine...but you're gonna have to find a way to clear your check engine light.

[psher481]

I could be wrong but I think if you have to pass an emissions test you could have issues. I'm in NY and would like to add a dp but not sure if a HFC will 1) pass NY emissions and/or 2) throw a CEL that would have be cleared before the inspection (and dealer visits).

[rickinaz]

Actually, a fellow forum member pointed out that the post July 2013 builds have a 4" (catted) pipe as stock. That's why those N55s make an extra 15 bhp with the MPPK. No need for a bigger downpipe.

[sonicsonic]

Originally Posted by rickinaz

Actually, a fellow forum member pointed out that the post July 2013 builds have a 4" (catted) pipe as stock. That's why those N55s make an extra 15 bhp with the MPPK. No need for a bigger downpipe.

True!
But with catless downpipe you can earn more power.

[mike@x-ph.com]

You will get more power with catless downpipes no matter which tune you have.
Its just a lot easier and faster for the turbos to reach desired boost target

[tibookM3]

But you'll always have a CEL with catless DP right?

[DVC]

Originally Posted by rickinaz

Actually, a fellow forum member pointed out that the post July 2013 builds have a 4" (catted) pipe as stock. That's why those N55s make an extra 15 bhp with the MPPK. No need for a bigger downpipe.

Really? So no benefit to an HFC down pipe on a 2014 335i??

So for a 2014, what is the consensus on the most effective way to get a little bit more performance (i.e. reduced turbo lag, increased throttle response, and maybe a little bump in power), as well as a more aggressive sound - without CELs?
(I have MPPK and MPE, so I'd prefer to work with these upgrades... )

HFC down pipe - no appreciable gain?
Charge pipe - no appreciable difference other than being less prone to failure under high boost?

Any other restrictive piping that can be upgraded from the down pipe to the axle-back MPE?

[tibookM3]

Originally Posted by DVC

Really? So no benefit to an HFC down pipe on a 2014 335i??

So for a 2014, what is the consensus on the most effective way to get a little bit more performance (i.e. reduced turbo lag, increased throttle response, and maybe a little bump in power), as well as a more aggressive sound - without CELs?
(I have MPPK and MPE, so I'd prefer to work with these upgrades... )

HFC down pipe - no appreciable gain?
Charge pipe - no appreciable difference other than being less prone to failure under high boost?

Any other restrictive piping that can be upgraded from the down pipe to the axle-back MPE?

I know Terry from BMS says plenty of power can be made with stock catback exhaust so that probably isn't the best place to look. I'm curious about a non-CEL down pipe as well, if its worth it or not. I prefer to not have CELs and not have a ton of parts I have to remove for service...

[rickinaz]

Originally Posted by DVC

Really? So no benefit to an HFC down pipe on a 2014 335i??

So for a 2014, what is the consensus on the most effective way to get a little bit more performance (i.e. reduced turbo lag, increased throttle response, and maybe a little bump in power), as well as a more aggressive sound - without CELs?
(I have MPPK and MPE, so I'd prefer to work with these upgrades... )

HFC down pipe - no appreciable gain?
Charge pipe - no appreciable difference other than being less prone to failure under high boost?

Any other restrictive piping that can be upgraded from the down pipe to the axle-back MPE?

You and I are in the same boat. I suspect that catless 4" would still flow more, and create more power, but not as much as replacing a 3.5" stock catted pipe.

The elephant in the room is the environmental impact of going catless, and I don't see that discussed much. I am not a tree-hugger, but I also want to do my part for the greater good. [End of soapbox speech] With the 4" catted pipe, there is something of a cake and eat it too situation.

[DVC]

Originally Posted by tibookM3

I know Terry from BMS says plenty of power can be made with stock catback exhaust so that probably isn't the best place to look. I'm curious about a non-CEL down pipe as well, if its worth it or not. I prefer to not have CELs and not have a ton of parts I have to remove for service...

Originally Posted by rickinaz

You and I are in the same boat. I suspect that catless 4" would still flow more, and create more power, but not as much as replacing a 3.5" stock catted pipe.
The elephant in the room is the environmental impact of going catless, and I don't see that discussed much. I am not a tree-hugger, but I also want to do my part for the greater good. [End of soapbox speech] With the 4" catted pipe, there is something of a cake and eat it too situation.

The environmental impact and whether it throws a CEL probably overlap for the most part... so I think we're all in the same boat there.

I've heard some conflicting info as to whether the stock piping back to the exhaust is a choke point or not... (and now it seems like the possibility of a larger down pipe on the 2014s is yet another variable in getting the real story here).

It would be great to get some definitive info on what replacement parts will actually improve performance (throttle response and turbo lag, or more power) as well as sound, without throwing CELs.

[The Nerd]

Originally Posted by DVC

The environmental impact and whether it throws a CEL probably overlap for the most part... so I think we're all in the same boat there.

I've heard some conflicting info as to whether the stock piping back to the exhaust is a choke point or not... (and now it seems like the possibility of a larger down pipe on the 2014s is yet another variable in getting the real story here).

It would be great to get some definitive info on what replacement parts will actually improve performance (throttle response and turbo lag, or more power) as well as sound, without throwing CELs.

I actually feel a difference on the top end of the rpm band since going to a full catback exhaust (still stock downpipe).

[psher481]

Originally Posted by DVC

It would be great to get some definitive info on what replacement parts will actually improve performance (throttle response and turbo lag, or more power) as well as sound, without throwing CELs.

+1

I'm really considering a HFC downpipe. It seems like the most cost effective solution for increased gains without a tune (I have the new MPPK). Tough to pull the trigger on the purchase without really knowing what the gains should be, as well as whether it'll throw a CEL or not.

[rickinaz]

Originally Posted by psher481

+1

I'm really considering a HFC downpipe. It seems like the most cost effective solution for increased gains without a tune (I have the new MPPK). Tough to pull the trigger on the purchase without really knowing what the gains should be, as well as whether it'll throw a CEL or not.

If you have the new MPPK (and you mean post July 2013) you already have a 4" downpipe.

[psher481]

Originally Posted by rickinaz

If you have the new MPPK (and you mean post July 2013) you already have a 4" downpipe.

yeah, not sure what kind of performance gain you would see if swapping out the stock 4" downpipe for an aftermarket one. have to assume that there would be some gains involved, right?

[rickinaz]

Originally Posted by psher481

yeah, not sure what kind of performance gain you would see if swapping out the stock 4" downpipe for an aftermarket one. have to assume that there would be some gains involved, right?

I would guess that the majority of the gains that BMW left on the table were from the 3.5" restriction.

[DVC]

The cats in the stock DP probably add some restriction too... maybe it would be the best bang for the buck to just replace the stock cats in the 2014's 4" DP with a single, less restrictive cat.