What is the final consensus after all of these years? Is the JCW manifold (squared edges) an upgrade over say a LCI N18 manifold?

Has anyone done actual dynos of before and after results? If both manifolds are ported is any one design really better than the other? I did see the thread with numbers but all of that was measurements without any real world dynos showing differences. Size and volume of ports is misleading as when building custom manifolds for turbo cars I have seen gains with smaller runners vs oversized runners and all kinds of other weird data points so I was hoping someone has more info on actual dynos gains.

I have a 47mm billet turbo will be installing soon and I wanted to optimize flow through the engine while doing it.

Thank you for your time.

 

I'd love to see real world data on the performance of the various manifolds... The Mini community at large seems to have a lot of anecdotal evidence/upgrades that stems more from someone marketing a product than actual data.

I'd love to see a 40/41mm setup with this too, or if there is a point where it makes sense to upgrade, find that point.

Still super uncertain about how many variants there are. Seems like there's N14S, and then "JCW" (assuming this is only N14 JCWs?) and "N18" (Not sure if all N18 or only JCW, S, GP2 etc.)

RealOEM seems to show 11627597031 "FROM" 02/01/2011 - but also lists some N14 cars, and superseded PNs 11627574366 (07/01/2008 — 06/08/2011) Exchangeable retrospectively, and 11627556494 (09/01/2006 — 12/02/2008)

This link https://www.northamericanmotoring.co...ml#post4054249 also calls out a part number 11627593149 as the JCW tuning kit manifold.

Also the option of the RCZ-R manifold/turbo. Not sure how it fits but I've seen it mentioned a few times elsewhere.

 

I would love to be able to get my hands on an entire RCZ-R just for the engine and trans to see if I can stuff them in the Mini. To bad the people on the other side of the world never put the effort out to figure it.

I now have a 11627593149 manifold on the bench to go on with my new turbo. I am tempted to get another one since I just picked up an R58 (and the fact that there are less and less new in the world every day) but I do not have any major plans to go larger than stock on that one for now.

I would love to see dyno results of before and after but for myself being that I would be upgrading the turbo at the same time hard to see a proper comparison. Maybe if I did just the manifold swap on the R58 I could use that as a test.

 

On the exhaust side,I don’t think the exact manifold you use makes too much of a difference. But, I would expect to see gains through port matching and smoothing. If you are getting the head rebuilt, smooth out the exhaust ports, but don’t make them too big. Then, match the manifold to the head. Match the transition as best you can. Do the same at the turbo interface. The more smooth you can get the transition, the better the flow and smaller the losses.

That being said, I don’t have any real world experience with this….