I'm going to rebuild a S5 N/A. should I use S5 TII rotor housings or stick with my S5 N/A housing? I want to do a nice exhaust port.

 

if you have them, use the TII housings as the diffuser is not present.

 

I would go with the N/A housings... being that it's an N/A engine.

 

I would use the turbo housings if theres no cost difference for you, for the reason that the diffusers are absent in the exhaust port sleeves.

However, this is not the only issue. The turbo rotor housings have coolant ports above the exhaust ports which provide coolant to the intake manifold on a turbo engine, which is used for bringing coolant to the turbocharger. You have to plug these on an NA engine, like so: (the anodized blue hex socket plugs).



I imagine you could get away with just installing the T2 O rings and let the LIM block it off, but this is more prone to failure, I prefer the tap & plug approach.

 

The housings themselves are the same, except that on t2 housings there is an extra coolant pasage that would need to be plugged. IT's easy enough to cut or grind out the NAs exhaust diffuser, or just swap sleeves from a t2 housing. The cost of buying t2 housings outweighs the advantages of them.

 

All the diffuser does is quiet the exhaust noise right? If it all it does I'll grind it out

 

It also restricts airflow

I've been told that the diffuser is a real bitch to grind out.. let alone do a nice and smooth finish..

 

Eh, it wasn't hard to grind them out, took like a half hour for each for me. Here's what I ended up with:






Then after it was ported