Engine/Transmission (1994 - 1998) three piece exhaust manifold

[MLee]

I am contemplating installing a three piece manifold. And was wondering, those of you that have installed one, What was the inside of the tubing like? Smooth, or rough, does it need some smoothing to help flow? I don't believe it is ceramic coated inside.

 

[hsmith]

You know, it has been so long since I installed mine, I really don't remember the texture of the inside walls. Next time I pull mine off I am going to port match it to the head and turbo.

 

[JDKammin]

My ATS manifold is pretty smooth for a cast piece. Looking at it, I think it should flow much better than stock. Plus, it will not put stress on your heads mounting ears.

 

[bmoeller]

The ATS was pretty smooth on the inside. They DO flow more air than a stocker.

 

[DPashko]

My Ats and my BD one were pretty smooth. The ports on the Ats one on the cylinder head side were pretty much port matched. the turbo side was pretty small so i removed alot of material to match it to the turbo. BD one was pretty good.

 

[MLee]

Appreciate your input, Thanks.

Sounds like there might be a little mismatch in the ports, will have to look this over.

 

[JMcCoy]

My ATS manifold needed a lot of material to be removed. The interior corners were cast with pockets behind the ports. I spent hours removing material and smoothing them out. I only made the ports acceptible. I didn't go overboard and attempt a mirror finish. I was very disapointed with them. Also I could not believe that ATS expected me to remove the old rusty studs, that fasten the turbo, from the old manifold. They were to be reused along with the rusty nuts. That said, I am happy with how it now performs. The turbo spools up noticably quicker.