Close up of Wastegate outlet

 

Take a picture of the equipment your using to polish... thanks!

 

5Star, here you go, It's a Crafstman Die Grinder kit and a DIY Port and Polish kit from my local speed shop (cartridge rolls with flapper wheel).
I used this site as a guide:
http://www.sa-motorsports.com/diyport.htm

 

Port and Polish kit

 

I am not being negative here, just giving more advise to anyone that wants it.

See that pretty polish you put on that cast iron? Going to be fairly rough again about 2 minutes after the car is running. Don't waste your time polishing exhaust components. The carbon builds up so fast it just gets back to being rough again. The stones you have pictured in your kit about will be all that is needed for a final finish on the port work. Save yourself time and money for the sanding roles, you really don't need to polish the exhaust components.

David Buschur
www.buschurracing.com

 

That's what they tell me. Nice, huh?

 

That would be awesome. So, you could upgrade your manifold, run the stock turbo, and then later throw the turbo upgrade on there.

 

Or, Mr. bpclements, you port match _that_ manifold, grind out the casting flaws, and bolt the thing right on. Better airflow, indeed. Turbo car efficiency and responsiveness is all about reducing restrictions, especially here in the Rockies where we're all at 5400' above sea level minimum. Did you check out the APS intake manifold? It makes me weak just looking at it!

 

Personally, I don't think that exhaust manifold porting or turbo porting does much. The ports are bigger than the combined area of 2 valves. And there are only ever 2 valves open at a single time. Same goes for the throat of the turbine housing.

 

Josh -
YOu are right in spirit. Yet if the exhaust is mismatched, or offset from the port, you're creating turbulence when you really want nice, laminar airflow. Maybe I should have spoken more strongly of "port matching" instead of porting, which is generally a waste of time on a turbo car. I'd think there would be nothing wrong with removing casting lines, since the manufacturer would remove them if they could justify the $, which they can't. I can, since I only have to do one car. Also, keep in mind that the port cross-sectional area should be at least as large as the circumference of the valve times the max. lift, times the number of valves.

 

Oh yeah, turbulence is definitley worth getting rid of.

 

Oh, but note that the exhaust manifold runners should be larger than the head ports to prevent reversion. Not too large, though, otherwise you kill exhaust velocity.

 

Josh, you're a smart man. Something you touched on is this: one thing we Evo owners don't have to worry about is exhaust scavenging, which has eaten up zillions of engineering hours. I had to do a bunch of research before buying one particular tube header for my '73 BMW 2002. All we have to worry about is delivering the most kinetic and thermal energy to the turbo in the most efficient manner. That's where I get stoked over the APS exhaust manifold. They're only selling the thing as part of their entire system - intake, exhaust, turbo, intercooler, piping - the whole deal. Too bad for us!