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Fully Built 1995 TT6
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Discussion Starter · #21 ·
In the picture below, you will see my engine bay shortly after it was put together initially. If you'll notice, the turbo's center section is clocked in such a way that the oil feed / drain ports are about 40° from vertical By vertical, I mean your oil feed would be the highest point on the turbo's center section. If you have it this far off vertical, the oil pools at the bottom of the turbo, because it is gravity drained.

This causes a LOT of smoke, enough that it might make you think your car is on fire. Not very fun when you've invested a stupid amount of money into a car, for it to look like it's on fire whenever you roll to a stop...

Now, depending on your manifold design, you might be in for a good time, trying to get the oil feed close to vertical. Personally, I wouldn't go more than 20° from vertical, if at all possible. Get creative, but also realize that you need to deal with extreme heat in that region. Careful hose routing (try to keep the drain hose as vertical as possible too, because, again, gravity is all you get to drain the oil out of the turbo) will keep MOT folks happy, hopefully. More hopefully, you won't run the risk of burning through an oil drain hose and err... having a source of hot oil exposed to a super hot manifold, which... I shouldn't need to elaborate, but that's a bad situation. ;)

View attachment 257274
So oil feed needs to be as close to vertical/12oclock as possible and return 6pm?

Water feed 3pm and 9pm?

I will make sure the lines as are far from heat as possible and will also use heat jackets for the hoses.
 

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So oil feed needs to be as close to vertical/12oclock as possible and return 6pm?

Water feed 3pm and 9pm?

I will make sure the lines as are far from heat as possible and will also use heat jackets for the hoses.
Yes that is correct...you want the feed and drain to be vertical or as close to as possible, depending on your manifold design etc.

If you are also going to use water lines, then thats a slightly different story, as you want to have the CHRA at a slight angle to help with thermal siphoning, where the water inlet is slightly lower than the water outlet. If my memory serves me correctly, Garrett has an article on their website showing the optimal orientation for the water lines.
 

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Ree is on the right track. My old Comp turbo only had one water inlet and one outlet. The Garrett I now run has two inlets and two outlets, so that you can have your inlet lower than the outlet.

Garrett does have a tech article on their site that will explain the reasoning for clocking the CHRA as we're describing. Worth a read. :)

Heat protection is absolutely worth the effort!
 

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Ree is on the right track. My old Comp turbo only had one water inlet and one outlet. The Garrett I now run has two inlets and two outlets, so that you can have your inlet lower than the outlet.

Garrett does have a tech article on their site that will explain the reasoning for clocking the CHRA as we're describing. Worth a read. :)

Heat protection is absolutely worth the effort!
Wow, I had no idea that Garrett had designed a twin in/out CHRA.

Do you know if the water galleries have a common centre, or is there two distinct passges?
 

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Wow, I had no idea that Garrett had designed a twin in/out CHRA.

Do you know if the water galleries have a common centre, or is there two distinct passges?
Pretty sure it's a common center, the idea being to allow for thermal siphoning when you shut the car down. Mine sounds a bit like a kettle bubbling on occasion. Plugs are used in the two unused ports.
 

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