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Garrett exhaust housing cracked

tomasss

tomasss

former PRVert
Joined
Oct 13, 2008
Location
Sydney, Australia
I sent the turbo from my b204gt for overhaul and the shop sent me these pics today. They are stating it doesn't affect the function of the turbo and they are asking if they should proceed with the overhaul.

What do you guys think? The turbo is most probably original...around 200 thousand kilometers...

<a href="https://imgur.com/s48l2Dm"><img src="https://i.imgur.com/s48l2Dml.jpg" title="source: imgur.com" /></a>

<a href="https://imgur.com/1JRO2yM"><img src="https://i.imgur.com/1JRO2yMl.jpg" title="source: imgur.com" /></a>

<a href="https://imgur.com/kz65haT"><img src="https://i.imgur.com/kz65haTl.jpg" title="source: imgur.com" /></a>
 
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That part of the housing is called the tongue. A minor crack in the tongue can be considered normal in a lot of applications, but yours looks like it has migrated pretty far around the housing and is about to go through to the outside wall (if it hasn't already). Will eventually result in an exhaust leak and could even cause turbine wheel failure, worst case.

Best to replace this housing unless you know a really talented welder who wants to spend a bunch of time fixing it.
 
Looks like time for a replacement housing. As a suggestion because you are across the pond you can more easily procure the cosworth sierra T3 exhaust housing. I am using the .48 housing in my 240 turbo. Fit right on without any issue to my stock T3 center and turbiine wheel. The sierra housing has a 3" outlet and larger wastegate opening and puck. Had to fabricate a bracket for the wastegate actuator. Better flow and boost control than the stock setup.
 
Ok, I will check with my welding guy and also look around for some replacements.
For the cosworth housing - where do you look for these? I just quickly checked ebay and seems to me these things are pretty rare...also it means I would need a different downpipe as the original one is 2.75"...
 
Anyone here is able to confirm if the Lotus turbo above (sticker saying TB0373 465133-3) will fit the stock turbo?

Or, anyone has/knows where to look for the replacement housing from Lotus/Cosworth other than ebay?
 
So, I called one guy that is specialist in Cosworth...he has these turbos in stock...stating it is from Sierra/Escort Cosworth. But he measured the downpipe opening and it is definitely not 3" as dl242gt stated, more something like 2.5". There is "M4" written on the casting.

Could someone confirm if it is the correct one or not?

<a href="https://imgur.com/iNbnhQ0"><img src="https://i.imgur.com/iNbnhQ0l.jpg" title="source: imgur.com" /></a>

<a href="https://imgur.com/7dPcmxJ"><img src="https://i.imgur.com/7dPcmxJl.jpg" title="source: imgur.com" /></a>

<a href="https://imgur.com/jXFggsI"><img src="https://i.imgur.com/jXFggsIl.jpg" title="source: imgur.com" /></a>

<a href="https://imgur.com/ATsOEgN"><img src="https://i.imgur.com/ATsOEgNl.jpg" title="source: imgur.com" /></a>
 
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That housing ^ is 0.83 A/R, which will flow a lot more than the 0.48 A/R that everyone seems to like. It will also make for lazier boost response.
 
tomasss said:
Tb038 465177-0004
Click to expand...

Your stock turbo has a 0.48 A/R turbine housing, with the stepped Volvo T3-style inlet flange, and the outlet flange has a 64.5mm inner diameter, with a 100mm bolt circle for the 3-bolt flange.

tomasss said:
Anyone here is able to confirm if the Lotus turbo above (sticker saying TB0373 465133-3) will fit the stock turbo?
Click to expand...

This alternate turbo 465133-0003 also has a 0.48 A/R turbine housing, but the inlet flange is flat (not stepped like the standard Volvo). The casting material should be there to modify the housing by cutting the stepped diameter. Bolt pattern is the same.

Outlet inner diameter should also be the same, but the bolt circle diameter is 110mm so you'd need to modify your downpipe flange to bolt on.

The internal interface dimensions with the turbine wheel are the same, so no issues with functionality.

Biggest difference will be the wastegate arm & valve is in a different location inside the housing. Your original turbo has the arm rotation axis parallel with the turbine inlet flange (3:00 position looking at the outlet with the inlet flange pointed down). The 451333-0003 has the rotation axis rotated up by 55 degrees (~1:30 position). So your wastegate actuator bracket would need to change accordingly to line up with the new crank arm position. If you were able to grab the actuator and bracket from the 451333-0003, I think you could make it work.
 
tomasss said:
Read that casting carefully...it is not 83 but 63...and according to >this< topic it is as good as 48...
Click to expand...

Fair enough, looked like 0.83 but I see it's 0.63 now. Regardless, still bigger than your current housing and will change the boost response, wastegate %, & turbine flow. Not to say it would be a bad change - performance may improve depending on your engine & tuning.
 
I put a .60 AR housing on the last project and it works great.
The .48 housing is liked because that is what they come with (cheap), a great device to strangle your motor.
It's made for soccer mom's not Maria Andretti
Combine that with a large compressor and you get boost at cruise on the freeway!
And no mileage due to boost afr's and timing.

The stepped manifold can be fixed with an adapter from ATP
https://www.atpturbo.com

I ordered a GT3071 with the .60 / .60 and a 3" outlet
 
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Duder said:
...
Click to expand...
Great and valuable info, thanks...I will keep that Lotus turbo in mind in case the guy asks too much for the separate cosworth turbine housing...

What I still don't get...it has been mentioned several times that the cosworth turbo has 3" output to the downpipe AND it fits the stock downpipe. How is that possible if the original turbo has 64.5mm (roughly 2.5) output to the downpipe? Or is the 3" outer diameter?
 
Duder said:
That housing ^ is 0.83 A/R, which will flow a lot more than the 0.48 A/R that everyone seems to like. It will also make for lazier boost response.
Click to expand...

Actually its an Escort Cosworth .63 turbine housing...like this one here----->
Looks like ordinary Sierra 2wd Compressor side--with that wastegate actuator bracket bolted on the back side like that (4x4 compressor housing has the bracket on the front side..and Escort Cosworth is bigger (and nice for 315 to 400 bhp) and the wastergate actuator bracket is cast in like
500x500.JPG



The outlet HOLE on the turbine housing is 64mm or so...

It is the bolts for the downpipe and the register for the down pipe which is set up to accommodate 3" without bogus reducers....
 
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Ok, understood. That explains why the stock down pipe fits then.
So do I understand correctly, talking about the exhaust housing only: when in the >other< topic two versions (.48 and .63) of the turbine housing were discussed, the rusty one I posted is the second one and will fit and work as described there?

I am really newbie in turbo's, sorry guys for dummy questions..
 
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