Im working on a twin turbo setup for my TPI and i was wondering where everyone gets the y-pipe and oval shaped piece for their throttle bodies.

also, one more question, do i need to have a BOV next to the intake or can i use the ones on the turbos? also, if they are set at 8psi for each turbo what is the net pressure at the intake?
thanks, brandon

 

BOV on the turbos? Do you mean wastegate?

 

i wound do some more resurch befor making a kit

 

Ditto^

FWIW though, the oval connector can be a 4" round pipe reworked with a vise and hammer. The TB is actually slightly smaller than the 4" pipe, but you can make it work. It made two of these junctions so far, one for my TT-IROC and another for a single turbo LT1 in an S10 truck. In both those cases, I sliced a little section (1/4" or so IIRC) out of the ovalized 4" pipe and rewelded it back together for a better fit (I like when both T-bolt clamps have the same gap when tightend down ). You are going to need to be somewhat good at fabricating (or know someone who is) to get this project completed.

The WG on the turbos will be good. If they are both set at 8psi you will get 8psi on the intake manifold (unless you stage them, which would be foolish for low boost).

Add a BOV to the intake pipe. A cheap option is two small DSM BOV's.

 

^Ditto on the research...

I don't understand why people think the boost would add together. Maybe its not that intuitive to others.

Using the standard parallel twin turbo setup that about all of us TT guys use, each turbo puts out the same pressure, but each turbo supports half of the FLOW requirements of the engine. so your total boost is 8 psi wih half the flow from each.

I used a 4" to 3" silicone reducer on the throttle body and a y-pipe from ebay for a 3000GT (it has a 90 bend in it that I cut off, and a short tube to slip a hose over for the BOV).

the silicone couplers seemed to work their way off with the worm clamps, so I superglued it all together then clamped it. It held so well I couldn't take some of the pipes apart to ship when I sold it. Had to get a bigger box!

 

You can form a piece of 16 gauge sheetmetal or slightly shortened 4" pipe for the throttle body attachment. I mig weld a lip in a few places at the end so the hose can't pop off and clamp it with T-bolt clamps. Use a piece of 4" silicone hose.

You can use screw clamps but make sure you clean the throttle body and pipe with brake clean/acetone/laquer thinner first. For extra insurance give them a light spray of hair spray. It is a good temporary glue.

I use one stock Bosch Audi/Porsche/VW compressor bypass valve on a twin low boost setup and it handles the extra air fine.

I use an air compressor with a small air regulator with a Tee to the boost gauge to set the wastegates. This gives you a reference point to start with. I tend to leave the gates sort of open initially and run the engine to see how it boosts and adjust from there.

 

These guys sell the twin turbo inlet pipeing

BBS turbo

 

sorry i was in a hurry when i typed that lol i meant the wastegates on the turbos and the bov right before the intake

 

alright thanks guys, one more question, will pretty much any BOV work or do i have to get one specifically for a twin turbo setup?

 

i guess im just a little confued about the BOV situation, do i need a BOV that handles twice the flow as say a single t four banger? and am i understanding right that if this is the case i can use two of those BOV's?

Basically i need to know what the best route to go with this is so i get it right the first time, thats why im asking

 

Get a Tial 50mm BOV - it seems to be the favorite of the turbomustangs.com members. The one valve should handle your requirements. I would install it in the section of the inlet pipe between the Y-collector and the throttle body. When ordering the valve, you have to specify the correct spring rating to match your combination. This spring value should be determined by your engine's vacuum reading at idle. Check out the link below for details.

http://tialsport.com/documents/w3_tial_bov50_sp.pdf

 

The Tial is a very nice unit, but IMO too expensive for a budget turbo system (they are around $250). I have one on my T66 turbo LT1 S10, but that wasn't quite a budget build By comparison, the DSM BOV's can be had for under $50.

A BOV is not even an absolute necessity, so don't get too worried about it (some early factory turbo systems didn't even use one and went for hundreds of thousands of miles). Junkcltr stated above that a single Bosch BOV did the job for him. If you do still run into compressor surge, you can add a second one to handle the extra flow. Many of the larger aftermarket valves will probably handle the required airflow for a mild SBC TT system. Again, don't beat yourself up on the BOV selection, it is not as hard as you are thinking it is

 

I just purchased a Tial from B&G Fabrications for $195.00 + shipping. Their phone # is 740-686-2897. My only issue was that it took about a month to get it. I don't really know why it was delayed, but I wasn't in a rush so it didn't matter. You are correct that it may not be cost effective on a budget application. I went with the valve based on experience of others with high HP combinations.

 

alright thanks guys!

 

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With an automatic transmission, BOV is not really needed, since You are not lifting on the throttle when shifting...