PTE divided vs. undivided mitsu housing comparison!

[blcknspo0ln]

So here we are. I started off with a PTE BB 5031RLE turbo with an undivided turbine housing. Now that my plans for the 08 seaons are becoming more apparent, I decided to stick with my 50trim turbo and see what she can do. A fellow member (1fastpos/Remy) sold me a PTE divided turbine housing used with an SCM61. Little did I know, and was surprised to find out that these turbine housings are slightly different. So here we go:

Side by side:

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Divided turbine housing (unported) against OEM gasket:

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Undivided turbine housing (unported) against same OEM gasket: WTF

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Safe to say, the divided turbine housing offers a much larger exhaust area. Next, turbine housing inlets against the gasket are nearly identical and are nearly 7cm. I would give or take 1.5mm tolerance around the circumference on the gasket.

Unported divided on the left, ported undivided on the right:

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Ported undivided housing:

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Unported divided housing:

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Again, the inlet of the housing matches pretty closely to what it needs to be, but a good amount of housing needs to be ported to utilize it's potential.

 

[blcknspo0ln]

What's next? porting the housing and converting it to external!

My little porting station :

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Weapon of choice: double cut carbide burr

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Starting to port:

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End result, I never usually port the exhaust portion of the housing, but decided to just for the sake of "seeing what happens". I chickened out and only removed maybe 1mm worth of metal.

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About an hour later I got into a fight with the flapper and here's how it made out. I win.

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[blcknspo0ln]

I enlarged the flapper entrance a bit:

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Went to town with the turbine inlet. Learning from the destruction of my last housing, porting too thin was not going to be an option here. I focused on opening up the entrance to the flapper exit, but was very careful not to port too much. On the other side of the housing, a good 1.5- 2.5mm of metal was removed.

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After the burr, i smoothed it down with a stone tree burr. Once I get to home depot and pick up a couple buffing burrs, she should be good to go.

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Last thing to add is that the hole in the housing (where the flapper arm used to be) needs to be welded.

 

[Black95TSIawd]

I don't see any pics. Newbie!!

 

[Boosted98gsx]

Bad idea to go that deep into the turbine outlet. You have just screwed up the tolerances between the blades and the housing.

 

[J-speed99]

Bad idea to go that deep into the turbine outlet. You have just screwed up the tolerances between the blades and the housing.

I was thinking the same thing.

 

[Steve93Talon]

Divided turbine housing (unported) against OEM gasket:

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Undivided turbine housing (unported) against same OEM gasket: WTF

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What turbine wheel did the SCM61 have? I'd say it has a larger one than your turbo, hence why the outlet is bigger (the common one is the SCM6152). If so, that housing aint gonna work for you. Did you ever try putting your center section in it to make sure the distance between the wheel and housing is the same?

 

[Savage Talon]

A scm6152 comes with a T350 76 trim stage 5 wheel. What does your 50 trim have, a stage 2 turbine? That is why the housing's are diffrent.

 

[twicks69]

Another important point that you guys missed was the gasket sealing surface between the turbine housing and the O2 housing -- this will be a boost leak, causing severely slow spoolup because you now have exhaust gas leaving through the downpipe before the getting to the wastegate.

I think you have learned a valuable lesson, that hopefully didn't cost much more than the time put into it, and the lesson itself.

The SCM61 can be obtained with a few different turbine wheels, hence the outlet diameter differentiation.

The housing you ported will likely not be usable -- unless you want to hand grenade a turbine wheel, as well as making slow spool/boost problems because of the exhaust leak into the downpipe from the O2 flanged wastegate.


Years back, I changed over from internal to O2 mounted external on a mitsu flange turbo, and ported the gap -- oops. Welcome to uncontrollable boost.

 

[blcknspo0ln]

Yes thank you for the comments guys. Stupid me assumed that the turbine wheels would be the same when I put 'wanted to buy' ads up for just a PTE divided housing. Live and learn I suppose, at least I got a good deal on the housing so I'm not out too much cash.

Tim, as far as the housing, it was an accidental touch by the burr while I was doing the port job, I checked and it will still seal when the housing and o2 are put together with a gasket.

Oh well, back to the drawing bored

 

[twicks69]

Yes thank you for the comments guys. Stupid me assumed that the turbine wheels would be the same when I put 'wanted to buy' ads up for just a PTE divided housing. Live and learn I suppose, at least I got a good deal on the housing so I'm not out too much cash.

Tim, as far as the housing, it was an accidental touch by the burr while I was doing the port job, I checked and it will still steal when the housing and o2 are put together with a gasket.

Oh well, back to the drawing bored

gotcha!