Ok guys and Gals. I'm looking for information and/or opinions. I'm going to have a used Cooper S turbo rebuilt. It's going to be a hybrid rebuild. (It includes the K04 compressor wheel, high flow turbine wheel, HP 360 rebuild and all machining/balancing to perform the upgrade).

When I get this done I'm also going to replace the Exhaust Manifold. I have 2 manifolds at my disposal, A used cooper S manifold and a new JCW tuning kit manifold.

What I'm wondering is if I get the Cooper S manifold ported and ceramic coated will it be better than the JCW manifold? And is there any advantage to porting the JCW manifold?

The reason I ask is I have heard reports a ported Cooper S manifold flow more than the JCW Manifold. But what I don't know is if this comparing 2 ported manifolds or if its just the Cooper S manifold is ported and JCW is not. Also I don't know if the JCW CAN be ported, as in its already maxed out?

So what do people think? Ported Cooper S Manifold or JCW Manifold?


Here are some pics to show the difference between the two manifolds. Dirty/used manifold = Cooper S manifold, Clean/new manifold = JCW tuning kit manifold.

 

Thumper ported my manifold last year, to match the previously ported head. You might check with him to see what kind of flow numbers he gets, if he checks the numbers. I had other work done at the same time, so I can't claim any one specific mod changed performance numbers.

 

I've heard that the header you have in your second picture has shorter, straighter runners than the stock headers. However the proof is in the flow numbers and I'm certain someone who knows more will chime in.

 

We use the JCW manifold on most our big turbo cars. We have never had a chance or have seen anyone flow test them but based on the fact MINI put forth the effort to design/develop it we like to think its has to be better than anything fitted to an S. The casting method used on the JCW manifold is lighter, smoother and more expensive. It was actually fitted to the N18 JCW's stock so it's more than just a tuner kit part.

Most the claims I have seen about ported S manifolds have to do purely with runner volume and not flow. Even then if you look at the areas that could be ported its very limited. Extrude hone would be the ideal method of porting the manifold since its just impossible to port the entire runners on that thing.

Subscribed just to see if you end up flow testing.

 

I went JCW based on the same thoughts as above by eurotechs, they redesign it with a purpose or why redesign. The other kicker is its 2lbs coming off the front lol