T3 flange mismatch (pics)

[20psiGMC]

Here’s a couple pics of the port mismatch between the ATR header flange and a standard “T3” Garrett, for those interested. Below is a shot of the ATR header flange (loose) on top of the new T3 flange (welded to header). If the ATR header was used as-is with a standard T3 housing, the sealing surface on the sides would be between .125” and .150”, greatly increasing the chances of exhaust leaks. I assume there is a housing out there that matches the ATR well, but the T3 flange (as I know it) does not. Just something to be aware of… hope this helps somebody :smile:

 

[4C FED]

Mmmm Beefy!
I like it. How much was the flange?
Are you going to run a gasket also?

When I was lookin' at mine the other day, I thought about blending the underside of that one section that has the bolt in the exhaust path (there is a lot of covered pipe there). But, considering the thickness of the ATR flange, I decided it might not be a good idea.

 

[20psiGMC]

Thanks Rick!

I have two cans of soda into the 347SS flange. The biggest benefit to where I work is access to all sorts of neat materials and a mulit-million dollar machining center. You’d be surprised what a cup of coffee or can of pop can get you :wink:

Yup, I’ve got a gasket sourced. I sent the service requirements and dimensions to one of our sealing vendors and told them I wanted something bullet proof. They sent back a couple of examples made out of “Thermiculite” .0625” and .125” thick. I’m going to use the one that’s .125” thick. Supposed to be good for 1800deg+ service and far more pressure than my turbo can produce….

I know what you’re saying about the bolt hole. The smaller size of the T3 opening gave me more room to port. Even at that, what I tried to do was come up with a smooth, rounded “bell mouth” to the backside of the flange. You may be able to do the same without getting too close to the hole. Here’s a pic looking up the crossover pipe that shows some of the porting:

 

[4C FED]

Isn't it great to have access to a great machine shop.
I to have that access, but try to use it sparingly due to concerns of abuse.

We just got one of those high pressure water cutters. It can cut 6" plate steel real nice.
I might have to buy a 6 pack or a lunch to get this job done. :smile: