How to port a 2g O2 housing

[Zmann42087]

Ok guys, I'm getting ready to port my stock 2g O2 housing this week. I already have a couple carbide burr bits and access to a die grinder. I've been doing a lot of thread reading and I've looked over the vfaq article on porting an O2 housing.

After all that, I still have a couple questions though... namely how do I approach porting the turbo/wastgate side of the O2 housing? I understand that you always want to gasket match when porting, but the turbo/wastegate side of my O2 housing already matches the O2 housing gasket perfectly. Anymore and it won't match. I'm sorry if this is just a dumb question here.. but what should I do? Do I port it even though it won't match? Or maybe I should trim the new O2 housing gasket to match the port job? How about buying an EVO O2 housing gasket? I know the EVO O2 housing has larger openings so maybe this might work?

I'm open to all thoughts and suggestions from guys who have done this before. Also, pictures of your ported O2 housing (namely the turbo/wastegate side) would be great. Thanks!

 

[hopwoodp]

Its good to port the turbine housing and o2 housing together. I have in the past, adjusted the gaskets somewhat. For instance, 7cm turbine housing and an EvoIII o2 housing. I used the bell shape pattern for the wastegate side and continued into the o2 housing. Otherwise there should not be any need.

I prefer to use stone bits for my port work. Carbide is ok but, stone is much easier to control.

Take your time with porting and port in and out, instead of creating circular patterns inside the passages. Be careful around the bends and use careful judgement when porting esp, where the material is thinner than other areas.

Let me know if this helped

 

[Zmann42087]

Its good to port the turbine housing and o2 housing together.

Yes, the turbine housing will be ported as well. I'm buying an FP Big28 turbo this week and I'm going to have it ported by FP.

I have in the past, adjusted the gaskets somewhat. For instance, 7cm turbine housing and an EvoIII o2 housing. I used the bell shape pattern for the wastegate side and continued into the o2 housing. Otherwise there should not be any need.

Not quite sure what you mean here.. how did you "adjust" your gasket? Did you shave/trim it a little bit?

 

[hopwoodp]

Yes, the turbine housing will be ported as well. I'm buying an FP Big28 turbo this week and I'm going to have it ported by FP.




Not quite sure what you mean here.. how did you "adjust" your gasket? Did you shave/trim it a little bit?

Yep, just widen certain parts of the gasket to help optimize the flow. Just use a bit that you are able to keep good control over. Its good to clamp down the
gasket for better stability while porting.

In your case, that shouldn't be too big of a deal. Just make sure you have a good, smooth transition from your turbo to o2 housing to the downpipe. Make sure the transitional changes made to your parts that are getting ported are not too abrupt. Also, its a good idea to make sure that when your porting your o2 housing, that you open up the portion that merges the wastegate port to the main exhaust port, that you try to create a knife edge. Remember that you need to concentrate more on having a smoother flow and a directional flow that will not hinder the flow of exhaust gases flowing through the parts that you are porting.

On the o2 housing, make sure not to make the outlet larger than the opening of the downpipe and that you carefully line up the two pieces when you bolt them together.

 

[kenamond]

Although I didn't try any stone bits, I can say that double-cut carbide burrs are not hard to control. Single-cut will take metal off much faster, but I had one of each, and they were both easily controlled, though the cuttings from the single-cut are NASTAY! The turbine housing will be like butter compared to the O2 housing, though. Maybe the stone works better on the O2 housing...dunno.

And the flapper wheel on a dremel will take out all of the bumps and imperfections left behind by the carbide burrs. You'll need several flapper wheels. The lower the grit the better. I used 80 grit because that's all they had at the store, but 40 would be great for the first pass if they make 'em that coarse.

I got my O2/turbine gasket from ExtremePSI, and the gasket was bigger on both the WG and turbine outlets on both the turbine and O2 housings. The O2 housing was the closer match, but I probably had to take close to 1/8" off in places on the FPB28 side.

When you get the FPB28 back from FP, I'd check out how they ported the turbine inlet. If the WG inlet has corners, I'd grind them down to be more smooth. Since you have all the tools, you could've saved yourself some cash porting the turbine yourself.

And is your ex. mani ported to match whatever FP is doing at the collector (7cm?) If not, consider that...they should match (same diameter). I ported the turbo and ex. mani. to match the 7cm gasket (also from ExtremePSI).

I have plenty of pictures of my turbine port job on the inlet end and the ex. mani., but I didn't get any good pictures of the O2 housing inlet, exit, or "junction" (where WG and turbine exit flows merge).

Fun stuff!

 

[hopwoodp]

Although I didn't try any stone bits, I can say that double-cut carbide burrs are not hard to control. Single-cut will take metal off much faster, but I had one of each, and they were both easily controlled, though the cuttings from the single-cut are NASTAY! The turbine housing will be like butter compared to the O2 housing, though. Maybe the stone works better on the O2 housing...dunno.

And the flapper wheel on a dremel will take out all of the bumps and imperfections left behind by the carbide burrs. You'll need several flapper wheels. The lower the grit the better. I used 80 grit because that's all they had at the store, but 40 would be great for the first pass if they make 'em that coarse.

I got my O2/turbine gasket from ExtremePSI, and the gasket was bigger on both the WG and turbine outlets on both the turbine and O2 housings. The O2 housing was the closer match, but I probably had to take close to 1/8" off in places on the FPB28 side.

When you get the FPB28 back from FP, I'd check out how they ported the turbine inlet. If the WG inlet has corners, I'd grind them down to be more smooth. Since you have all the tools, you could've saved yourself some cash porting the turbine yourself.

And is your ex. mani ported to match whatever FP is doing at the collector (7cm?) If not, consider that...they should match (same diameter). I ported the turbo and ex. mani. to match the 7cm gasket (also from ExtremePSI).

I have plenty of pictures of my turbine port job on the inlet end and the ex. mani., but I didn't get any good pictures of the O2 housing inlet, exit, or "junction" (where WG and turbine exit flows merge).

Fun stuff!

You hit that one on the head. I also wondered why he would have the turbine housing ported when he could do it himself.

One other thing I know that helped smooth out the finish was the flapper wheels like you said. I started with 80 then to 120. But, I used those on the die grinder (1/4" shaft).

I have never used a double cut carbide bur but, those single cut ones really remove the material your porting fast.

Stone does work really good on the o2 housing.

One other thing I will try is small cut off wheels or get a attachment that you could put your own stone discs on(like the dremel tools have) and go over the turbine housing outlet or the inlet and outlet of the o2 housing. But, for any of the tighter areas with bends I tend to use smaller stone bits or cutoff wheels.

On my 20g's turbine housing I incorporated boost creep channels. I basically did what RRE does to some of their special turbine housing port jobs. Cut a V shape in the turbine housing channeling some of the exhaust gases to the wastegate flapper. Then cut into the area above the wastegate flapper and made a smooth path for the gases to follow. On the
other half of the turbine housing I put some channels on the other sides of the "V" that help direct the air straight down and in turn made somewhat of a knife edge effect. You could look inside the turbine housing and see some real definition between these two passages. I did all of that with stone bits and cutoff wheels(small diameter) and finished it off with the flapper wheels.

 

[Zmann42087]

I finished porting my O2 housing... I think I did all right. I focused on opening up the wastegate runner and of course gasket matching. Here are a couple pics... enjoy.

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In case anyone is wondering.. I used a die-grinder with a carbide burr bit for the porting, then I took Kenamond's advice and smoothed things out with a dremel and 80 grit flapper wheel, and lastly I finished with Mother's metal polish to clean everything up.

 

[hopwoodp]

Looks great! Can you get any internal pictures?

 

[S_Ranger]

Great porting job, I wish I can find a cheap electic die grinder around here. Nothing put pnuematics.

 

[Black_Bullet]

I used a simple hand dremel with a small porting bit to port my old 2g housing and took a good while to port it to the maximum i thought it could be ported. I believe I effectively doubled the wastegate holes original size... No hint of boost creep here even with open downpipe it can hold about 14lbs till 8k on my evo3 16g. ( Gradually dropping boost the higher the rpms go up actually due to being a small turbo.) But now I run a evo3 o2housing and i touched it up a little bit but I didnt port the waste gate section at all... Ive set the boost to 15psi and It boost creeps to 17psi in the upper gears ( 3rd and up ) Wont matter as I am turning boost up to 20psi very soon as my daily set up once I get the tune dialed in better....

 

[S_Ranger]

So is it safe to say we can use single cut instead of double cut carbid burr bits?

 

[MrBoxx]

Single-cut should work fine, as long as you finish up with a stone or flapper wheel to smooth things out.

Needless to say, anytime you're working with flying metal shards, you should wear some eye protection, everyone. Getting a sliver of iron in your cornea really does rather suck.

 

[blcknspo0ln]

Single-cut should work fine, as long as you finish up with a stone or flapper wheel to smooth things out.

Needless to say, anytime you're working with flying metal shards, you should wear some eye protection, everyone. Getting a sliver of iron in your cornea really does rather suck.

Agreed, metal shavings rather do suck. Even if you don't get it in your eyes, it can get in your shirt, pants, and even socks.

At any rate, I like using a double-cut (single is good too) and then cleaning up with a nice tree shaped stone bit. If you want to go crazy, you can hand sand with 250, 400, and then 600 grit paper. Oh and another tip is to really reach inside the o2 housing and cut down the divider (viewable from the dp side of the o2) of the two openings.

 

[Black_Bullet]

I think you shouldnt port the waste gate hole any unless it does in fact boost creep, but if its not boost creeping and you make the waste gate hole bigger I believe it can slow spool and cause the turbo to drop off in boost more in the high rpms AND spool a tad bit slower than it wouldve if you left it alone. Maybe im speculating but with a fully ported 2g o2housing *( And I mean I ported the heck out of the entire unit ) Boost would fall to 15psi by 7k from 17 and with the evo3 o2 housing it holds 17 till 7500rpms.....? Or maybe its just me.... Im going to be running 20 psi soon as Ive stated before, ill see how long this 16g likes to hold its boost...

 

[hopwoodp]

I ran above 26psi on my EvoIII 16g and didn't have that much of a drop. I port out my O2 housing to ensure a smooth flow but, I don't really try to hog it out. That will just weaken the housing and it will be prone for cracks much sooner than normal. Also, if you are porting your O2 housing, it is wise to port the whole thing at once and also do what blcknspo0ln said about cutting down the divider. I have done that to all my o2 housing.

 

[Zmann42087]

Agreed, metal shavings rather do suck. Even if you don't get it in your eyes, it can get in your shirt, pants, and even socks.

Haha.. yeah, it was 90* the day I did my porting so I brilliantly decided to wear shorts. Bad choice. Let me tell you, few things are more annoying than having metal shaving in your socks and shoes.

 

[hopwoodp]

Haha.. yeah, it was 90* the day I did my porting so I brilliantly decided to wear shorts. Bad choice. Let me tell you, few things are more annoying than having metal shaving in your socks and shoes.

Another reason I use stone bits.