Exhaust housing bolts torque spec

[Dunebilly]

I'm putting a three inch downpipe with an exhaust elbow and I'm wondering what should the torque specs be for the turbo housing to the 3 inch downpipe I'm using a copper gasket thank you
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[Flyin Brian]

The book says 15 ft*lb. Make sure you clean up the threads and use a lot of antisieze on the bolts.

 

[Dunebilly]

I'm using a Terry Houston downpipe so I am using longer bolts

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[RmvBfrFlght]

I'm using a Terry Houston downpipe so I am using longer bolts

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If you are using the internal wastegate then no gasket should be used. This is between the turbo housing and the downpipe flange. A thin smear of Ultra Copper RTV can be used to help prevent rust from forming (thanks Bison).

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[Dunebilly]

Remove before flight thanks that's what I did I was wondering if anybody has or knows the size of the hex bolt I need for mounting the Terry Houston downpipe on to the turbo exhaust housing please let me know

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[RmvBfrFlght]

The bolts being used are 8 mm x 1.25 pitch x 30 mm long. And I'm not sure that is correct. It is a Garrett housing and I though that they would be American dimensions. Note the picture as I am not sure that this is a TH down pipe, and note the two washers under each bolt head.

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[Flyin Brian]

Mine are 8 mm x 1.25 pitch x 30 mm long as well. I have a Terry Houston style downpipe also with a 1/2" thick flange. I am using 1 washer. You should check to be sure you are getting enough thread engagement. Also, be sure and buy high strength bolts. Breaking off a cheap bolt in your turbo housing is not fun. My bolts are metric grade 12.9. I got the socket head cap screw (hex key) style for clearance reasons. You can get them at Ace Hardware or order online from McMaster Carr.

 

[Dunebilly]

Cool I'll try going to ace and getting those hex Cap bolts I like those better

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[RmvBfrFlght]

I'm with Flyin B, did some more research, and it seems that Garrett used 8 mm x 1.25 mm pitch bolts for the exhaust bolt threads. He is also correct about thread engagement. With the 30 mm long bolts and the two lock washers, the thread engagement is minimal. Also, the lock washers no longer have any tension to them, they are flat (heat!).

If you can, dig up some copper based anti-seize. Holds up much better to the heat then aluminum based stuff.

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