Porting Turbos.

Any tips? Never done one before.

Pardon my ignorance, but us that a "thing"?

It's a pump. Seems to me it would move air less efficiently if ported.

Learn me.

Are you just trying to match the gaskets?

I've heard of port matching the hotside housing to the manifold and if fitted with an internal wastegate, porting the wastegate hole to reduce boost creep.

Its pretty much gasket matching and smoothing things back slightly. Anything else would likely impact the efficiency of the turbo negatively.

Here's an example of porting an exhaust manifold for a turbo:

http://www.allpar.com/fix/holler/exhaust-porting.html

If you notice they didn't touch the area where the turbo mounts other than "gasket matching" and cleaning up the mating surface.

Removing the internal roughness is a smart idea, but probably not worth the work. As the tooling ages, internal casting roughness changes drastically. We saw eff gains from changing suppliers at the big C. The old supplier would have worn tooling with rough internal surfaces and the new casting would provide a 2-5% increase in eff across the entire turbo. The changes were tough to measure consistently, but were noticed enough by those monitoring the emissions. We got into some hot water with our engine plant by changing suppliers and not testing them effectively.

SVreX wrote: Pardon my ignorance, but us that a "thing"? It's a pump. Seems to me it would move air less efficiently if ported. Learn me.

I'm pretty sure I don't understand your question. Internal combustion engines are air pumps and they move air more efficiently when ported, I think.

RossD wrote: Are you just trying to match the gaskets?

I don't know.

I plan to match gaskets, but I don't know if that's all I should do.

The junkyard turbo I got seemed like it was built more for convenient casting than absolute efficiency. I was wondering if porting it like I'd port a cylinder head would be worthwhile.

On our challenge Jeep we ported the internal wastegate hole on our turbo to make it larger to avoid boost creep. Ported turbo will hold 7 psi steady. Non ported turbo creeps to 16 psi. Other then that I have no idea what else we would mess with.

I'm in the same boat as PseudoSport: I've ported some rotary turbos to cut down on boost creep and yes that works. I honestly don't know what, if any, gains there are from porting the intake (i.e. hot exhaust entrance) to the turbine. Not sure that I would want to do anything more than maybe port matching and even that it could possibly interfere with the boost creep porting.

Info on internal wastegate porting:

http://www.aaroncake.net/rx-7/s4wastegate.htm

This is for an S4 RX7, the S5 has a different design with 2 ports that's less likely to see boost creep but still can benefit from enlarging and smoothing the wastegate ports.

Our turbo supplier gets all squirrelly when you talk about porting the waste gate. They are not fans of the idea. I forget the exact reasoning, unfortunately. These guys forget more about turbos every day than I've ever known.

I can see porting upto, and from the turbine, and or compressor sections, but porting to get the impeller/compressor a better fit??? This I doubt you can improve on.

Cylinder heads are far more complicated to cast, and often times their cost ratio is much tighter than a turbo would be... so improving on the stock casting can, and does make a difference when done correctly. Ideally to test your porting on a turbo you'd have a jig set up on a flowbench to test different porting on the intake and exhaust sections of the turbo.....

Keith, is that with internal or external wastegates?

I suspect they don't like the idea as they'd prefer people to move up in size in turbos or run less boost or an external wastegate. All of them technically correct, but when dealing in junkyard turbos, one doesn't always have the budget for such niceties. :)

On my old sr20det I just smoothed the casting marks of the compressor outlet and gasket matched the elbow that bolted to the compressor outlet (not pictured).

The gasket was damn near perfect on the housing, but the elbow was way off. It was a noticable difference once on the car, however I put most of that on how bad the elbow lined up initially.

turboswede wrote: Keith, is that with internal or external wastegates? I suspect they don't like the idea as they'd prefer people to move up in size in turbos or run less boost or an external wastegate. All of them technically correct, but when dealing in junkyard turbos, one doesn't always have the budget for such niceties. :)

Internal. And it wasn't due to marketing reasons, there were technical ones. These guys know we'll buy turbos from them regardless.

DaewooOfDeath wrote:

SVreX wrote: Pardon my ignorance, but us that a "thing"? It's a pump. Seems to me it would move air less efficiently if ported. Learn me.

I'm pretty sure I don't understand your question. Internal combustion engines are air pumps and they move air more efficiently when ported, I think.

Who ports an engine?

Heads are ported (to improve flow- they are not pumps).

Intake and exhaust manifolds are ported to improve flow (they are not pumps either).

Engines are dependent on particular tolerances to create compression (cause, yeah, they are kind of a pump). If you opened up any part of the cylinder (pump) you would loose compression, and therefore pumping efficiency.

You could also port a water jacket, or an oil passage. Again, for flow, not a pump.

OK, I understand that you are probably gasket matching. That makes some sense.

PseudoSport wrote: On our challenge Jeep we ported the internal wastegate hole on our turbo to make it larger to avoid boost creep. Ported turbo will hold 7 psi steady. Non ported turbo creeps to 16 psi. Other then that I have no idea what else we would mess with.

This...did this on a Holset wastegate .5" to 1" stopped boost creep which is good at 30 psi and surge stars around 35 psi

I wondering about the exhaust side housing and the cold side outlet. There are some rough castings and tapering sections, particularly before the turbine, that I was thinking of flattening out.

I do have some experience hogging out cylinder heads and was wondering if a similar process might helo my turbo.

I am not talking about grinding away on the close tolerance areas near the impeller or turbine.

SVreX wrote:

DaewooOfDeath wrote:

SVreX wrote: Pardon my ignorance, but us that a "thing"? It's a pump. Seems to me it would move air less efficiently if ported. Learn me.

I'm pretty sure I don't understand your question. Internal combustion engines are air pumps and they move air more efficiently when ported, I think.

Who ports an engine? Heads are ported (to improve flow- they are not pumps). Intake and exhaust manifolds are ported to improve flow (they are not pumps either). Engines are dependent on particular tolerances to create compression (cause, yeah, they are kind of a pump). If you opened up any part of the cylinder (pump) you would loose compression, and therefore pumping efficiency. You could also port a water jacket, or an oil passage. Again, for flow, not a pump. OK, I understand that you are probably gasket matching. That makes some sense.

Did I offend you in some way?