Need some Big Turbo help/advice

[FromS60toB61.8t]

Im wrapping up my GTX2867 build and have a few questions about the N75 and running a BOV vs DV.

My turbo doesnt have a charge nipple on the cold side that usually goes on the bottom nipple of the N75. I read on one diagram to just hook that bottom hose up to the intake mani and it will do the same job. Is this accurate? Im also running AEB head and mani which has the 2 vaccum ports on it. Is it safe to use the rear one for the DV and the front one for the N75 or would that mess up readings? Also the diagram said that the long nipple is atmosphere/recirc to TIP. Should i leave that one open or is it required to go back into the Intake? Im going to a 3" MAF with custom intake and would love to not have to weld another bung onto it for the nipple.

Now my question about DV vs BOV is just all for simplification purposes. I know the cars run better with DV but thats just because its located on the hot side instead of the cool side. I plan on relocating the DV right before the TB and for simplification purposes would like to run a BOV so i dont have a big ass hose running along the bay back to my intake. From the reasearch ive done on audis and most turbo cars in general, when the BOV is on the hot side there are stalling out problems when using a MAF (i had this problem when i ran a bov). When its run on the cold side, i havent seen any posts of anyone having any issues. Anyone have input on this?

Theres also what looks like a ground connection that i cant for the life of me remember what it connects to that ill post a pic of later. Its located on the front passenger side, wire is connected to the (impact brace?).

[Seerlah]

You place on your own nipple onto the compressor housing using a drill and tap. All Garrett housings are designed with a spot for you to do this, but do not come factory. ATP also has a boost tap for the silicone couple right off the compressor outlet, if you wanted to go that route. I actually have one that has been laying around for years brand new I never used. And if I still have the pics on my pc, I can post pics later of tapping and placing on your own port.

As for bov or dv, run a dv if you run a maf. If you have no maf, it is purely preference with choosing dv or bov. I personally run no maf with a single piston bov.

And I have a b5, but if it is the same then that is your battery/starter/alternator ground. On my b5, it attaches to the motor mount bracket with a 13mm nut. On the bracket, there will be a stud for the ground terminal loop.

Update with pic and link:

Pic of where you tap. Choose barb size according to your need. Can't recall what size I am running. This was on my GT2871R housing, but had to do the same thing to my CT housing I currently run.



I was also incorrect about there being a designated spot on all Garrett housings. I believe my CT housing had a spot for me to drill and tap. Below is a different Garrett housing, and you can see the 5 different spots in the cast designed for drilling and tapping ports. On my GT2871R housing, I just tapped where was most convenient for me since it didn't have a designated spot in the casting.



And here is the boost tap from ATP. You simply place it on the silicon coupler on your compressor outlet.

http://www.atpturbo.com/mm5/merchant...Category_Code=

[FromS60toB61.8t]

You place on your own nipple onto the compressor housing using a drill and tap. All Garrett housings are designed with a spot for you to do this, but do not come factory. ATP also has a boost tap for the silicone couple right off the compressor outlet, if you wanted to go that route. I actually have one that has been laying around for years brand new I never used. And if I still have the pics on my pc, I can post pics later of tapping and placing on your own port.

As for bov or dv, run a dv if you run a maf. If you have no maf, it is purely preference with choosing dv or bov. I personally run no maf with a single piston bov.

And I have a b5, but if it is the same then that is your battery/starter/alternator ground. On my b5, it attaches to the motor mount bracket with a 13mm nut. On the bracket, there will be a stud for the ground terminal loop.

Update with pic and link:

Pic of where you tap. Choose barb size according to your need. Can't recall what size I am running. This was on my GT2871R housing, but had to do the same thing to my CT housing I currently run.



I was also incorrect about there being a designated spot on all Garrett housings. I believe my CT housing had a spot for me to drill and tap. Below is a different Garrett housing, and you can see the 5 different spots in the cast designed for drilling and tapping ports. On my GT2871R housing, I just tapped where was most convenient for me since it didn't have a designated spot in the casting.



And here is the boost tap from ATP. You simply place it on the silicon coupler on your compressor outlet.

http://www.atpturbo.com/mm5/merchant...Category_Code=

you're the man. I think the quick tap will be my best option. There aren't any markings on my turbo so i was a bit confused. (1st BT build). Thanks for that!

I think ill try out the Tial QR 50MM and see if i need to recirc or not, probably my best bet.

These cars vaccum between -18 to -20 if i recall? Trying to figure out what spring to try 1st.

[Seerlah]

Typical range -18 to -22 inches mercury. And good choice on the qv. If you ever wanted to do full blow off, the qv can be converted.

In all actuality those 50mm are really overkill. You see those on 1000hp applications. But it is so versatile, it is the one stop shop unit. I run a forge 001 and it has a 1" inlet. Serves my application just fine.

[redline380]

I use the boost tap. Works fine.

[FromS60toB61.8t]

I use the boost tap. Works fine.

great, just placed an order!

Typical range -18 to -22 inches mercury. And good choice on the qv. If you ever wanted to do full blow off, the qv can be converted.

In all actuality those 50mm are really overkill. You see those on 1000hp applications. But it is so versatile, it is the one stop shop unit. I run a forge 001 and it has a 1" inlet. Serves my application just fine.

got the QV with a 10psi spring (-18 to -20). Will go stiffer if needed.

[diagnosticator]

The advantage of sourcing the N75 boost reference signal from the intake manifold is the boost regulation of the waste gate will be referenced to the intake manifold pressure after the boost pressure losses in the intercooler core are subtracted. That is, if the pressure loss in the IC core is 2 psig, the regulated boost pressure will be 2 psig higher with the boost pressure reference downstream from the IC core after the boost pressure loss in the core has been removed from the charge air pressure delivered to the intake manifold.

Also, the boost pressure control air signal used for waste gate control sourced to the intake manifold, is a lot cooler air than if the boost pressure reference source is at the compressor discharge, where the charge air is hottest, with lowest density.

Considering the charge air pressure set point, obtaining the boost pressure reference source from the intake manifold instead of the compressor discharge, will increase the boost pressure in the intake manifold equal to the boost pressure loss through the IC core with an IC core pressure loss related delay in waste gate opening point.

Locating the DV to just before the throttle valve, will increase the turbo speed and DV related boost pressure maintenance during gear shifts resulting from the direct discharge air path at the throttle valve, instead of the delayed release of boost pressure when the DV is located away from the TB in the stock location.

The only draw back to locating the DV at the TB inlet, is adding a discharge hose back to the turbo intake that DV location requires.

Releasing BOV discharge boost air to atmosphere will result in excessively rich air/fuel mixture ratios that will negatively effect clutch engagment load pickup throttle response during gear shifts, caused by the MAF metering errors resulting from venting metered intake air to atmosphere. Using Speed/Density fuel management instead of the MAF meter and MAP sensor output, is not justified and will result in additional fuel mixture control errors at other engine loads and speeds.

In addition, a diaphragm DV installed in the reversed from OE orientation provides superior DV response regardless of the DV location.

[FromS60toB61.8t]

The advantage of sourcing the N75 boost reference signal from the intake manifold is the boost regulation of the waste gate will be referenced to the intake manifold pressure after the boost pressure losses in the intercooler core are subtracted. That is, if the pressure loss in the IC core is 2 psig, the regulated boost pressure will be 2 psig higher with the boost pressure reference downstream from the IC core after the boost pressure loss in the core has been removed from the charge air pressure delivered to the intake manifold.

Also, the boost pressure control air signal used for waste gate control sourced to the intake manifold, is a lot cooler air than if the boost pressure reference source is at the compressor discharge, where the charge air is hottest, with lowest density.

Considering the charge air pressure set point, obtaining the boost pressure reference source from the intake manifold instead of the compressor discharge, will increase the boost pressure in the intake manifold equal to the boost pressure loss through the IC core with an IC core pressure loss related delay in waste gate opening point.

Locating the DV to just before the throttle valve, will increase the turbo speed and DV related boost pressure maintenance during gear shifts resulting from the direct discharge air path at the throttle valve, instead of the delayed release of boost pressure when the DV is located away from the TB in the stock location.

The only draw back to locating the DV at the TB inlet, is adding a discharge hose back to the turbo intake that DV location requires.

Releasing BOV discharge boost air to atmosphere will result in excessively rich air/fuel mixture ratios that will negatively effect clutch engagment load pickup throttle response during gear shifts, caused by the MAF metering errors resulting from venting metered intake air to atmosphere. Using Speed/Density fuel management instead of the MAF meter and MAP sensor output, is not justified and will result in additional fuel mixture control errors at other engine loads and speeds.

In addition, a diaphragm DV installed in the reversed from OE orientation provides superior DV response regardless of the DV location.

so correct me if im wrong but from 1st read through i got:

It's actually better to connect the n75 to the intake manifold rather than turbo inlet housing because it makes up for the pressure loss between the two.

Use a DV, located at TB is good but only draw back is routing a hose across the engine bay back into the intake.

My only question is, since i have an AEB intake mani with 2 vaccum nipples. I'm assuming using one for the N75 and the other one for the DV/Boost gauge is no problem correct?

[Seerlah]

Correct. Front nipple closest to the fire wall was used for the fpr rising rate reference line on the b5 in stock form. If you ever wanted to convert to the b5 rising rate ayatem, b5 rail setup and fpr would be placed on (assuming using a stock like fpr). Fpr would require a boost reference line from the manifold, and that nipple is used for it on stock form. Basically sits right next to the fpr. If you ever do decide to convert, you can just tee in a line to the fpr from that nipple being used for your boost gauge.

[FromS60toB61.8t]

Correct. Front nipple closest to the fire wall was used for the fpr rising rate reference line on the b5 in stock form. If you ever wanted to convert to the b5 rising rate ayatem, b5 rail setup and fpr would be placed on (assuming using a stock like fpr). Fpr would require a boost reference line from the manifold, and that nipple is used for it on stock form. Basically sits right next to the fpr. If you ever do decide to convert, you can just tee in a line to the fpr from that nipple being used for your boost gauge.

I've got the 034 billet rail and asked my tuner if i should do a return line but he didnt recommend it for my goals.

How i currently have it set up is the nipple closest to the radiator is going to the N75 and the one in the back is going into my boost gauge and will be T'd into my DV.

[Seerlah]

You can route it however you want. It isn't like an electrical circuit where line location is that crucial. All it is is port sizes, leading to the same space and grant the same pressures.

Out of curiosity, what are your goals?

[FromS60toB61.8t]

You can route it however you want. It isn't like an electrical circuit where line location is that crucial. All it is is port sizes, leading to the same space and grant the same pressures.

Out of curiosity, what are your goals?

400 at the wheels.

tuner said it will be achieved with 1000cc injectors and DW65V fuel pump so we shall see.
Also running snow performance WMI. Only thing im worried about is that my intercooler will be too big. I have a 600HP garrett core.