I need to take a look at the MHI housing again. Maybe I should port the scroll that is point the exhaust gas at the angle to help spool (that blows at high angle, which is inefficient at high flows). When the wastegate is opened, it will bleed off more of the pressure from that port and keep the pressure on the high flow port that blows at small angle. I'm not sure how else to explain.

 

4 is the port that directs exhaust gases at higher angle to help spool turbo. As impeller spins up, it becomes bottle neck because I think it actually drags/hinders the impeller speed, so if I modify 1 or 2 (I need to look again), then when the wastegate opens, it should help with restriction.

Thinking about this some more, port 1 & 4 (same port) could be in a slight vacuum if port 3 is spinning exhaust wheel at it's max...

 

More to picture in our minds (angles are not exact, but you get the idea).

 

Thinking about this, exhaust pulses go back and forth between 3 and 4. Back pressure builds to spin the exhaust wheel. When desired boost is hit, wastegate opens to let exhaust gases to bypass the wheel. So both ports will relieve pressures behind wheel and the higher pressurized port will bypass more exhaust gas. I would think that port 4 will be the bottleneck because of the angle it hits the wheel. It actually looks like the flow turns around and when wheel is spinning in upper speeds, it's causing more energy loss than having it get bypassed.

 

You're overthinking it. Porting the ever loving snot out of it isn't going to help much, your only option to allow a black to breath up top is to move to an FP ss housing. The majority of what spools a turbo is thermal energy, not the exhaust pressure so porting it isn't going to change spool as much as you think it may. I think you need to find how far you really want to take this preliminary engine because it's pretty easy to get carried away with adding more/better parts and blow your original budget out of the water.

Also, about cylinder heads, there isn't much point in putting larger intake valves on a 4g63 head. The intake valve/bore ratio is already around the optimum number meaning it's already past the point of diminishing returns because larger valves just shroud each other more and get shrouded more by the combustion chamber. Exhaust would probably see decent benefits from a +1 valve but not monumental gains.

 

Guess I'm stuck with inefficiency of MHI since I need engine bay to appear stock. I'm open to any ideas to compensate with other things.

 

The new FP SS hotside appears to combine both ports. So there's no point to segregate in exhaust manifold.

 

My evo 9 bare block is shipped today.
I plan on opening up the oil passages.

 

Way to go Don

Great engine project you have well underway.

Are you foregoing the install of the stock block and going in w/the built block?

 

I'm going to put my head back on my stock block once it's done. I just bought a spare complete head and bare block to build spare engine with.

I'll get my car back together in a few weeks and continue driving the stock bottom end until this spare engine build is complete. Then I'll swap out and get it tuned with FP Black (I just can't see stock bottom end using a Black).

Once I'm on spare engine, I'll take my time building my factory engine. I have a spare intake and exhaust manifold to play with porting. I'll also plan on slightly porting head since both engines will eventually be 2.2L.

 

I also picked up a spare evo 9 ecu. I think I'll have my stock tuned super conservatively 91/E85 and the spare set up for all out E85 racing at track.

 

Why would you use two physical ecu's for that? Just flash between the maps. 5,000x faster and easier.

 

Road course tune is typically the conservative tune.

 

I want a conservative low boost 91/E85 tunes on my car's ecu where it will run fine with a bad tank of gas and where my wife doesn't need to understand my gauge readings . Our ecu can only store 2 maps right? For my spare, I'll use at track for all out spanking high boost on E85