TO4 turbine housing swap possible? *Pics Inside*
 

I have this turbo, my dad gave it to me. The compressor would be fine but the damn turbine housing is HUGEMONGO. Can you say an A/R of ~1.3.
Is there a way to swap turbine housings. I have no idea what vehicle this turbo came off of, but I'm going to assume it came off a big diesel.

The wheels are perfect and the shaft has minimal play, not out of spec by any means. This turbo is alot like what lazzer had and used for his compressor swap. Does anyone have any idea what kind of housing I might be able to swap onto this badboy? I could just sell it to recoupe some cost of a different turbo. Or I could find a smaller T3 and swap the larger compressor like lazzer. Open to all opinions and options outside of bolting it onto the miata to see when it would spool. I'm guessing 5k rpm. It would be great to find out that I could just swap on a smaller A/R turbine housing.
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I'd pick up a t3 in a 63 or 48 AR housing then use the coldside from that turbo to build your hybrid.

Or.. get a bigger t3 turbine housing and have a machine shop make the wheel fit correctly.

pretty much the same here...not only will you have to find a t3 exhaust assembly but you'll have to get it balanced too...but heck i would just sell that turbo and buy a new one!!!...just to save the trouble and time..

Why not block off one port and reduce the A/R that way? Would it work, I think it might. :D It's an interesting idea, if nothing else.

Mark

wouldnt that sort of screw up the flow in a major way?

lol Mark sounds like a great idea. Do you think I can use packing peanuts to block the port?

I think i'll just sell it. Anyone want it?

Oh yeah, local balancing to high tollerances is $30-35 if I wanted to do it, no big deal.

at that price...i say it'll be fun to see how the turbo performs...that turbo with a t3 turbine wheel would be nice but its hard to find just the exhaust side assembly though!

That's just like the compressor I just swapped out on my Saab T3 with the .48 turbine. Works great so far. Mine looked like this after I cleaned it up. I didn't get pics of the t3/t4 I made with it yet.
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Here's the t3/t4
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I have an extra T3 laying around too btw. Interested? Oh and also... I didn't balance the hybrid. Sounds smooooth.

Can you give me specs and pics of the CHRA and turbine outlet?
Internal gate?

CHRA? cartridge? It's oil cooled. Compressor .42, Turbine .48, Internal gate. Your T4 compressor would fit on it.

Yes

How do you figure? If you block of half the port and there is no flow in that port, how does that screw up flow?

Mark

That's not really how a twin scroll turbo works...

Save that turbo for your tractor.

The turbine wheel needs X cfm of air flow passing over the blades to work efficiently. Amount 'A' comes from one port, Amount 'B' come from the other port and together total X. It's a divided housing to keep turbulence down inside the turbine housing. It's still too large a turbine for 1.8L of exhaust gas to spool.

Yes, but by blocking one of the ports you effectively reduce the A/R of the turbine, which is what we were talking about, not the trim of the turbine wheel.

Mark

yes theoretically by limiting the inport to 1 you will increase the exhaust velocity but i dunno if you are gonna run into choke flow issues doing that. I sure wouldn't try. Chad don't you have a s60 laying around somewhere?

Yes you would but the wheel still needs a much larger volume then the Miata can flow even if the velocity is increased. The T4 radius is to large to get any real velocity. If I took the wheel from that turbine, and machined a T3 turbine housing to fit, it might spool it eventually. =) hmm I might look into doing that if there's enough metal in the T3 to allow it.

Nope if i did have a s60 around it would be on the car already man. Might rig something up with this TO4 compressor.

Well yes I understand your point about the wheel, although at 5000 RPM I suspect that there might be enough flow. Especially when you raise the velocity. It would be interesting to know where that point is and what reducing the A/R would accomplish in this case... all academic of course and not 100% practical.

Mark

WTF are you talking about? Do you have any clue how A/R is calculated?

A/R is calculated by dividing the turbine discharge diameter's cross-sectional area by the distance between the center of the wheel's shaft and the center of the measured inlet.

Blocking a port on a twin scroll turbine is the stupidest idea ever, won't work like you think it will and discussing it is not worthy of this forum. I can't even believe I'm reading that blocking part of the turbine inlet (which is what you're doing regardless of whether it's twin scroll or not) will help spool. Not to mention, if it worked like you thought it did the A/R would INCREASE, not decrease. Jesus.

That turbo belongs on a tractor. Otherwise it's a paperweight.

EDIT: Sorry to be harsh but it's early and I couldn't take it anymore.

:bigtu:

If anyone wants to hybrid their t3... i have an entire t4 coldside ready... housing/backing plate and compressor wheel.

Now wait a second.... I almost was tired enough to concede your point but then my brain actually turned on, it's obvious that you are still a few cups of coffee behind.

If you have a cross sectional area of 1.00 and a radius of 1.00 we have an A/R of 1.00. Agreed?

If we reduce the cross sectional area of the port by 50% it is now 0.50
Over the radius which remains 1.00. Are we following along still?

Then if we divide A/R, 0.50/1.00 = 0.50 A/R

Now I am just a fucking psychology student, not a fucking engineer, but tell me where did I go wrong?

Not to be harsh, but the math seems fairly straight forward.

Mark

PS - I don't think you are being harsh, if I fucked up as bad as you say. Despite being a psychology student feel free to take me to task when I am wrong, you won't hurt my feelings and I might learn something new... which would be great.

Mark your logic is correct, however, the design of the housing wouldn't allow it to be as efficient as a "real" .50 a/r housing. The size of the wheel alone takes much more cfm to turn it then the smaller wheel found in say a T3 .48. But it would look cool. =)

I realize that it would not be as efficient as a real .50 A/R housing. I was more writing it down to think about the effects than I was suggesting that someone actually implement it.

We agree that the turbine wheel is simply too big for the application here. It would still be interesting to see the effect. People are right in stating that I have no idea how a twin scroll housing works, I never said I did (Remember Mark the Psychologist, Not Mark the Engineer!). All I know about twin scroll divided tang housing is that you can get them to spool earlier than the identical non divided tang housing.

Mark

Well how well do you guys think this would work with a .48 turbine T3? The .48 would spool fine I'm sure. But would it pull to redline is more what I'm interested in? I have no problem hybriding the two turbos just wondering how well they might work together.

What psi are you planing to run? My T3 (.42/.48) would pull hard into redline running 12-14psi. I'm planing on 15-25psi to reach 300-400hp on the new engine. Hence my need for the larger compressor. The .42/.48 will get you at least 10psi by 3000rpm. If not check for a potato in your tailpipe. ;)

Are you planing on using the T4 compressor? If your goal is only 250hp a T3 should be fine.

You are wrong because the "inlet" by which A/R is measured is actually the nozzle area of the turbine scroll, not the inlet of the turbine housing itself. If you were correct then everyone who ever ported a turbo would be changing their A/R, which they are not. If you block half of the turbine inlet then your turbo will spool up slower. Period.

Ok, paint me a bit of a picture here, because as I stated, I am not an engineer. While I understand that you are saying changing just the inlet size will not change the A/R (or will it because the A/R would no longer be constant and it should be according to Garrett.) where exactly does the nozzle area begin.

Once again, try to understand I don't have an engineering background but would love to know exactly how this is calculated so I don't have to guess at how it works. I know a little about turbos and I can pick a decent turbo to match my goals but that doesn't make me an expert. So feel free to share your knowledge, I am willing to learn something new today.

Thanks,

Mark