Hotside porting ?

[rbrettctd]

I want to port my manifold and either my 14 or 16cm housing. What do I port on them? Is it possible to port the manifold?

[Fnschlaud4620]

all you really need to do is do a gasket match port job.

You need to scribe around the gasket and remove the material that the gasket does not cover up to the scribed line, then remove material until you have blended back into the ID of the manifold, head or turbine housing.

You can gasket match the head( just stuff the port with a rag, so shavings do not fall into the cylinders that have exhaust valves open. or remove the rockers so all valves are closed, then clean with compressed air and/or remove rags when finished). You can do the inlet of the exhaust manifold and the outlet, then the inlet of the turbo.

hogging out a port rarely is worth the time, just giving it the proper shape does the most good.

be most careful on the head, you do not want to break through to the coolant

[PToombs]

The other thing that helps is smooth the inside of the housings. The casting is rough, smoothing helps flow. I did my 16 cm exhaust before I put it on.

[DTanklage]

what seemed to help mine was to open up the ex man flange to dimensions closer to what my turbo is

the rest of the manifold was already ported and polished but rectangles in the flange were a lot smaller than the turbo

helped both spool and egt


the turbo housing is 2" tall


and over 1 1/16 wide...



the ats manifold was not even close to 2"


as you can kinda see in these blurry pix...


and less than 1" wide



cant find the pix of when it was all done? but i had to open the gskt up too and when i was done the manifold was only about 1/16 smaller than the turbo and matched quite nice thank you very much

now, i had been told that this does nothing for performance (by a very exp 2nd gen operator). but i didnt believe that necking the gases down in the manifold was the way to go so instead i let them neck down in the valutes (sp) and on my app i saw improvements in a few areas

[DTanklage]

[rbrettctd]

Very nice. What benefits did you see with the manifold? spoolup, egts, etc.?

[DTanklage]

it helped in both those areas

but i just looked at the 14 ex housing on my old h1c and it is only as big as the manifold used to be

so porting probably wont do anything for ya

polishing will tho...

[dpuckett]

There was a TDR thread about this 3 years or so ago. General consensus was that you want whatever it is going INTO to be bigger than what it is coming out of, to create a venturi effect. So, leave the head alone, port the manifold inlets (all 6). Leave the manifold outlet alone (might clean it up and radius the bends better, but no gasket matching), and port the exhaus thousing. I have done this on 3 trucks now, each with good results.

You DONT WANT to have your outlet bigger than your inlet (i.e. manifold outlet bigger than your housing inlet)- that creates blockage, which will actually HURT performance.

I have also read that gasket matching is not necessary or good for street driven vehicles. Having no experience in this regard, I cant say for sure.

Daniel

[DTanklage]

no good


better


best - imo

the 'mouth' on the s300 is a lot bigger than the hybid turbos. there is 180 cu in worth of ex trying to get crammed thru ea of those small rectangular holes in the ex manifold. sure, the valutes are going to compress the ex gases and increase their velocity, but why compress them once before that process, and then let them expand again? i believe that is wasting some of their energy. pulled my manifold and opened it up and it did make a difference. on my truck, doing only one mod at a time...