Headers question

[Zezorro]

As some of you know Z4M have little different exhaust then M3. I am curious which headers u guys recommerecommended ? Supersprint stepped 044001,
Supersprint sport 043901, or CPI stepped ? I know most of u say stepped one but I would like to keep stock section 1 so I don't know if this works with them because of different diameter , I am not worry about connection , this can be fixed. I am curious if is not better to choose SS sport of CPI . What do u think guys ?

[Obioban]

CPI's are a non starter-- worse low/mid range power than OE Euro, without a better top end in tradeoff.

The SS Stepped that can use the stock section 1 isn't as good as the version that needs the bespoke section 1.

[ShapeShifter]

Unless you got cams, stock euro headers are the best bang for the buck.

[Zezorro]

Unless you got cams, stock euro headers are the best bang for the buck.

I don't plan any other modifications, just headers and tune.

[ShapeShifter]

I’d go oe euro. You can’t beat quality or fitment.

[Heckblende]

I would recommend Supersprint V1 Stepped for the most gains. However, I am not sure about the fitment on a Z4M. Check out this thread from bimmerboost where they compared the dyno numbers from V1 vs V2 back to back. Also, V1s seem to be pretty good in terms of quality control whereas V2s have had some problems.

https://www.bimmerboost.com/showthread.php?23553-Article-Review-dynos-and-analysis-of-Supersprint-E46-M3-S54-header-options-Supersprint-V1-Stepped-Header-vs-V2-Stepped-He

[digger]

If you can afford SS then it’s a no brainer and if you can’t then euro. I know Obi never misses a opportunity to bag the CPI but would be good to see said data showing the shitness

[E46m3zcp]

I am not 100% clear on what happens with O2 sensors in a cat-less setups (ie. Euro headers with US section 1). I am not very knowledgeable w.r.t. O2 sensors but I know there are pre-cat and post cat O2 sensors and I think the DME uses it to calculate air-fuel mixture? (not sure). I am aware one of the use case is emission related, but isn't it also used for fuel trimming or something performance related ?

In this case you can't "delete" o2 sensors or else you put the DME in a fail-operational state where it's just using some dummy table to get you home (like alpha-N mode)... Right ? So in case of cat-less setups what happens? You remove the post cat o2 and the DME still uses remaining ?

I may be completely off on this, correct me if what I'm saying is wrong. How is the DME not affected by cat less setups ?

[heinzboehmer]

I am not 100% clear on what happens with O2 sensors in a cat-less setups (ie. Euro headers with US section 1). I am not very knowledgeable w.r.t. O2 sensors but I know there are pre-cat and post cat O2 sensors and I think the DME uses it to calculate air-fuel mixture? (not sure). I am aware one of the use case is emission related, but isn't it also used for fuel trimming or something performance related ?

In this case you can't "delete" o2 sensors or else you put the DME in a fail-operational state where it's just using some dummy table to get you home (like alpha-N mode)... Right ? So in case of cat-less setups what happens? You remove the post cat o2 and the DME still uses remaining ?

I may be completely off on this, correct me if what I'm saying is wrong. How is the DME not affected by cat less setups ?

Pre cat o2s are used for engine management stuff. Post cat are strictly emissions related. Catless setups only delete the post cat.

[Arith2]

If you can afford SS then it’s a no brainer and if you can’t then euro. I know Obi never misses a opportunity to bag the CPI but would be good to see said data showing the shitness

It used to exist on M3F. There was objective data showing his point he's making. He always hates on my Megan Headers with no objective data though 😝

[Tbonem3]

Megans and AA are chinesium reps of Euro. So just buy euro which are higher quality metal/design/fab, perfect fitment, barely more expensive, lighter, thinner metal, slightly larger piping ID, slightly more aggressive sound.

[r4dr]

It used to exist on M3F. There was objective data showing his point he's making. He always hates on my Megan Headers with no objective data though 😝

Does anyone happen to have the data somewhere? I'd be curious to see the comparison. My car came with BimmerWorld's PaceSetter headers, not sure how those compare. Especially since they don't seem to have sold them for a while now.

[Arith2]

Does anyone happen to have the data somewhere? I'd be curious to see the comparison. My car came with BimmerWorld's PaceSetter headers, not sure how those compare. Especially since they don't seem to have sold them for a while now.

M3F took a lot of data to the grave with it. The Pace Setters are probably on Buildjournal's write up on our headers. They mentioned a few old ones so check that out. It was generally accurate as M3F is where they got their number from.

Do we have a headers with dyno numbers thread?

[Obioban]

M3F took a lot of data to the grave with it. The Pace Setters are probably on Buildjournal's write up on our headers. They mentioned a few old ones so check that out. It was generally accurate as M3F is where they got their number from.

Do we have a headers with dyno numbers thread?

We have a dyno thread-- it's one of the stickies. It's rough, though, as the larger tuber headers don't really come into their own till you have some additional mods (cams, airbox), as the increased ability to flow becomes more useful.
(which is why I'm running euro on my basically stock M3 wagon, but SSV1s on the full bolt on M3 coupe)

[Arith2]

We have a dyno thread-- it's one of the stickies. It's rough, though, as the larger tuber headers don't really come into their own till you have some additional mods (cams, airbox), as the increased ability to flow becomes more useful.
(which is why I'm running euro on my basically stock M3 wagon, but SSV1s on the full bolt on M3 coupe)

The was definitely a CPI headers thread on M3F. I don't remember if it was in the dyno thread of the CPI thread that we made the discovery of them not being very good. Do you remember the cause of them being less efficient?