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Hybrid CT20b turbo has cracks around the wastegate ports

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I'm in the process of restoring my ST205 GT Four (3sgte engine). And I've noticed the turbo exhaust housing has some hairline cracks around the wastegate ports (twin scroll so 2 ports).

After a panicked hour of google searches it seems this isn't uncommon not just on these but turbos in general to crack around the wastegate ports due to there age and most people say just to run it as it is.

The turbo was working well when I removed it and I can only assume it was like this the whole time when it was running. These turbos are known to boost creep once a larger, flowing exhaust is fitted which this turbo still did so my thought is it can't be loosing too much gas through the cracks.

I'd be interested in people's opinions on running it as is over trying to weld the cracks up and potentially cause more problems. Someone's obviously had a go at welding one of the cracks which hasn't worked so I'm guessing the same will happen if I try and weld these up.

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It's common with rx7 turbos, the flow area is meaningless.

There are some guides on porting FC3S Rx7 turbo wastegates to reduce spiking up to and including swapping flappers to larger diameter so the ports can be opened further. You might consider something similar if it's a concern.

The boost creep isn't really an issue, as it only creeps a couple psi above 15psi and I intend to run higher than that once all set up. I just wanted to make sure the cracks itself wasn't terminal

The cracks are a natural effect of the thermal stresses on the housing. If there's no other concerns you should be fine continuing to use it as long as any of the gases that might escape aren't directed to a sensitive area, which is unlikely, or they join together, especially around bolt or mounting holes.

Turbine housing can almost be regarded as a consumable on those engines, but you may be able to find a replacement inconel housing that wil be a LOT more resistant to cracking.

Alternatively, a GOOD welder, with the correct rods, crack preparation, and pre' and post heat, will be able to weld the cracks to 'like new' condition, but the housing can still be expected to crack again, it's just the result of the thermal stresses on the housing.

Thanks for your input. its not really worth the effort of finding an inconel housing or welding up as eventually I'll be upgrading the turbo setup to something more modern. I just wanted top make sure running it as is wasn't going to be determental to my newly built engine. I've put the feelers out on a few FB groups to see if anyone's got a better housing gathering dust. If not I'll just run it as is

It's really not a concern and if you don't need a factory turbo for class rules get it running and swap to something better when the time comes.

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