S54 Header Design talk

[3staxontheradio]

digger
Tweaking primary lengths and want a sanity check on what part of the merge should be considered where the primary ends. Marked here are there the centerline of the tube crosses the cut plane and also where the flow sees significant expansion into another primary. The difference is 40mm which is meaningful. My inclination is to use the yellow number where the flow expands.

[332]

these are suppose to sound better? more power? both?

[Bry5on]

these are suppose to sound better? more power? both?

Sound better and keep AFR behavior the same between cylinders as you rev through the range. And there might be a few extra horsepower.

[Bimma360]

digger
Tweaking primary lengths and want a sanity check on what part of the merge should be considered where the primary ends. Marked here are there the centerline of the tube crosses the cut plane and also where the flow sees significant expansion into another primary. The difference is 40mm which is meaningful. My inclination is to use the yellow number where the flow expands.

You can properly ignore me here b/c I don't know what I am talking about haha. But a long time ago I saw a exhaust company that sold merge collectors(I forget the name), where the center point of the 3 into 1 (the pointy bit left of your yellow circle) extended further up (like basically all the way up up to the end of your green line. They did custom headers and had this whole write up about their merge collectors and how they did a better job of merging the gas together.

[332]

I'm sure you guys have seen the Jedders thread. Is this gonna break the internet?

[3staxontheradio]

no idea what that is? link?

[digger]

digger
Tweaking primary lengths and want a sanity check on what part of the merge should be considered where the primary ends. Marked here are there the centerline of the tube crosses the cut plane and also where the flow sees significant expansion into another primary. The difference is 40mm which is meaningful. My inclination is to use the yellow number where the flow expands.

I would use the yellow

[digger]

I'm sure you guys have seen the Jedders thread. Is this gonna break the internet?

Is there a newer thread or are you referring to the original S62 header thread on bf?

[332]

Is there a newer thread or are you referring to the original S62 header thread on bf?

https://www.einhornindustries.com/st...r_Headers.html these, just a cool 6k

[digger]

https://www.einhornindustries.com/st...r_Headers.html these, just a cool 6k

yeah those are the same from 2015

https://www.bimmerforums.com/forum/showthread.php?2172040-Unicorn-Headers-for-the-S62-M62-M60-powered-E39s

[digger]

You can properly ignore me here b/c I don't know what I am talking about haha. But a long time ago I saw a exhaust company that sold merge collectors(I forget the name), where the center point of the 3 into 1 (the pointy bit left of your yellow circle) extended further up (like basically all the way up up to the end of your green line. They did custom headers and had this whole write up about their merge collectors and how they did a better job of merging the gas together.

you probably mean a spike which are commonly used with non merge collectors that use parallel pipes and a formed merge rather than pipe merging at an angle

[davidinnyc]

@3staxsontheradio after all the research you've been doing, are you seeing any meaningful flow difference between Euro/CSL LHD and RHD header bank 4-6 due to the flat spot? I know this is something people might still have questions about, but perhaps you can put any flow questions to bed.

[332]

@3staxsontheradio after all the research you've been doing, are you seeing any meaningful flow difference between Euro/CSL LHD and RHD header bank 4-6 due to the flat spot? I know this is something people might still have questions about, but perhaps you can put any flow questions to bed.

That flat spot doesn't matter, its a nothing burger.

[Cronenberged]

@3staxsontheradio after all the research you've been doing, are you seeing any meaningful flow difference between Euro/CSL LHD and RHD header bank 4-6 due to the flat spot? I know this is something people might still have questions about, but perhaps you can put any flow questions to bed.

Engine Masters did a test on this. They dyno’d perfectly good manifolds, then beat the crap out of them with a hammer, dents all over, and re-dyno’d them again, there was no difference.

[332]

Engine Masters did a test on this. They dyno’d perfectly good manifolds, then beat the crap out of them with a hammer, dents all over, and re-dyno’d them again, there was no difference.

The head is the restriction on these cars, mostly the exhaust ports. Get your headers off and get the Dremel out...