The finer points of a flipped 3b manifold for a turbo (1 Viewer)

Feb 1, 2009
Portland, OR
So after about 8 hours of reading threads on turbos I've decided to post a question specifically about flipping the 3b manifold. Most people have touched on the concept of flipping the stock manifold. It seems most people opt for the 13b manifold instead. But as the old saying goes, "everything happens for a budget." This is a budget build for me. I'm somewhat happy with the stock power level the bj42 offers. However I managed to find an 02-07 WRX turbo with little shaft play for $50 on marketplace. I'm coming with the idea of "why not just throw it on there" as I have the cruiser halfway torn apart anyway prepping for paint. It appears this turbo might even bolt right up to the stock 3b manifold if I drill another hole in the dog leg thing on the turbo (won't know until I get back home in a few days). I haven't priced all the stuff out yet but I think I could be into the turbo project for less than $150. Here's what I gathered so far from reading about flipping a stock 3b manifold vs buying a 13bt manifold. I'm not stating these as facts just putting together what I have found in researching so far:

-saves $400+ over buying a 13bt manifold
-possibly a direct bolt on to some turbos. D-50 for sure and possible a wrx with another hole drilled

Cons :
-in the way
-won't work or work well with power steering if applicable
-close clearance to the hood (might not be that close if it bolts right up without and adapter)
-more restrictive
-exhaust pulse isn't uniform causing an issues of the turbo being fed constant power.
-might need an extra support bracket

-why does the 3b flipped manifold need extra support and the 13b not? It's the same number of bolts holding it on. If anything I'd think the 13bt would need more support because from the pics it appears the turbo is mounted further way from the engine causing more leverage.
-What issues does the alleged non uniform exhaust pulses cause?
-Anybody have any real figures on what power penality you suffer flipping the stock manifold vs using the 13bt manifold?
-Any real figures on a potential EGT penalty?
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I break things.
Aug 14, 2006
Oceanside and Encinitas, CA
Also, you need to make sure you have room for the compressed side intake piping. With a flip it puts the turbo right behind the first cylinder and your turbo outlet and crossover pipe may sit too high for the 40 series hood, especially with the insulator. The 13bt manifold puts the turbo farther back, and as you said with the fact that it leans it away from the engine, gets it a bit lower than the flip would...

I was always interested in mounting a 13bt manifold upsidedown to get the turbo lower and give the exhaust tubing more room... Especially for RHD trucks. You would need to find a turbo with the right configuration though...

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