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Fitting Garrett T3 to 90+ Manifold

89_740Turbo

New member
Joined
Apr 10, 2018
Location
Central New Jersey
My cylinder head gasket seems to be going and is leaking coolant somewhere. I think into the motor since after it's warmed up, the car is burning coolant out the exhaust. It's definitely not burning oil smelling.

I picked up a turbo cylinder head as well as a 90+ manifold. Ontop of this I have a rebuilt and refurbished Garrett T3 turbo. I intended to reuse another pre 90s manifold but since I picked up this 90+ for free I might as well use it but I have a few questions.

The T3 doesn't exactly fit flat onto the manifold so I know either the manifold or the turbo hotside will need to be machined to have it lay flat onto one another. My guess is the manifold needs to be machined. Any ideas?

Additionally, I spoke to my friend Dave about all of this. The 90 manifold has a different size stud than what fits into the T3. Has anyone looked into it and have numbers on paper?

Lastly. I know the 90 manifold will slightly position the turbo in a different spot than before, which I confirmed with Dave. What braided lines have you or anyone used to mitigate this issue so the T3 can be hooked up and work great.

Thank you
 
As far as milling it flat I had good luck cutting the lip off the manifold with an angle grinder, should save a few bucks
 
The 90+ manifold does not need to be milled flat. It has the same raised lip as the older manifold. What you do need is if you plan on using the 90+ manifold are step studs. It's a stud that goes from m8 to m10. The extra weight of turbo is better supported by a larger stud. Here is link to step studs. https://www.amazon.com/10-M10-Double-Studs-Steel/dp/B00KCBLI12

Really appreciate it. That's one less thing off the list. As far as not needing to be flat, maybe there is just gunk in the way because it doesn't sit exactly flat. Have you ever ported your manifold too by the way? Thinking about that while it's off but unsure if it would really make that much of a difference since I'm already going from pre 90 to post 90
 
Here is my 90+ that Josh updated. He milled it flat and then opened it up.
 

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You don't have to mill the manifold flat.

https://www.atpturbo.com

I also opened up the exit hole in the flange and blended it into the runners.
I did it all by hand with a die grinder, it would be much easier to plunge cut the corners in a mill then smooth out with a die grinder.

I drilled out the manifold stud holes and tapped them for 10mm studs.
This was easier than I expected.

A 3" V band outlet eliminates the restrictive stock exhaust.

https://www.atpturbo.com
 
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You don't have to mill the manifold flat.

https://www.atpturbo.com

I also opened up the exit hole in the flange and blended it into the runners.
I did it all by hand with a die grinder, it would be much easier to plunge cut the corners in a mill then smooth out with a die grinder.

I drilled out the manifold stud holes and tapped them for 10mm studs.
This was easier than I expected.

A 3" V band outlet eliminates the restrictive stock exhaust.

https://www.atpturbo.com

May have to send it to Josh since that adapter is out of stock with no eta though the adapter seems like a more efficient way to do it too.

What I dont understand is why mill away this
rdTcvEq.jpg


if it fits directly into the lip here
cxaGfXy.jpg
 
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If your turbine housing has the matching step in it there is no reason to flatten the manifold.

You cant just pull a flat turbine housing up to that raised circle as it will warp the housing when it gets hot.

I've seen the turbine housing and down pipe glow. Like one time when the MAP sensor hose popped off and it went full rich.
 
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