Exhaust Manifold Modifications

[mooserage]

So I have a brand new Evo III manifold that has been hanging around for quite a while waiting to go on the car and I'm finally going to put it on. I was hoping some of you guys can answer some questions for me.

-Does anyone here do porting work on exhaust manifolds, or know someone good who does? I definitely want to at least take the step out, i'm not really sure if there is anything to be gained from porting it out since I think I have pretty reasonable power goals.

-I have an an EGT, should I have the manifold tapped for this? Or have a bung welded on? Or is this not as useful of a tool in the day of wideband O2s and I shouldnt use it? Also is it going to be a point of weakness or possible failure?

-Should I have the manifold coated?

If I think of any other things I'll post them.

The car spends 90% of its life as a daily driver, it will likely never see anything larger than the 16G thats on there, maybe a 68HTA someday, but that is it. I am aiming more towards reliability and durability rather than short term performance. But, for the other 10% I love enjoying this car and putting my foot down, so I can't neglect that either. Thanks in advance!

 

[DynastyLCD]

i would feel as if an non-ported Evo 3 manifold will do just fine for a 16g.

the wideband will always react 50x faster, and more accurately than the EGTs. i learned that after i put my EGT gauge in and started to watch both readings for similarity.

coating, that's your preference. it will keep some heat inside the manifold, but mainly it will freshen up the look of the engine bay.

what o2 housing do you plan on using? i think you could see the most benefit from having the o2 match the manifold's flow

 

[thedsmguy]

I normally just do cleanup on the runners of the manifolds, since the head size is usually the same as the manifold runner size anyways. But I do hot the piss out of the collector area going into the turbo as well as expand the turbo by removing lip and smoothing flow.

 

[mooserage]

Thanks for the replies guys, yeah it seems like the manifold won't need a lot of work, just some cleanup. It sounds like the parts after the manifold are where the flow gains are to be made. The O2 is a regular OEM O2 as far as I know, not an Evo3. I think getting an Evo3 would be nice, but having to change the exhaust around for it isn't something I want to do right now. So the EGT and the coating are really just a matter of preference, I may go with a coating just for corrosion prevention, but even then I'm not sure it's really that necessary. I actually really like the silverish coating that is already on the manifold.