How V6 turbos work

[LukeZ]

Do the stock turbocharged 6-cylinders in our cars draw exhaust from one manifold, or both sides of the engine? (If its both manifolds, do they just Y-pipe together?)

Does the wastegate somehow feed back into the exhaust system after the turbo, before the catalytic converter?

I couldn't find a diagram online. If you have one, please post it haha. I was just wondering.

 

[UNGN]

There is a "crossover pipe" that ties the two sides together. On the '86-87 Buick Turbos, the headers are three pieces, right side, left side and crossover pipe.

The funny story about TR headers happened about 20 years ago in Greer, SC. A guy took his '87 Grand National to Steve's Muffler Shop, wanting dual Exhaust (to get rid of the crossflow muffler. Steve's crew saw that there was already a 2.5" pipe coming from the right side, so they cut the crossover pipe, capped it and ran a second 2.5" pipe back from the driver side header.

The owner like the sound of his new dual, even took it to the track, but couldn't figure out why it wouldn't spool and was much slower than before. One of his friends pointed out that only 3 cylinders were spooling the turbo, the other 3 were going out the back of the car.1

After hearing this story and wanting duals install on my 1986 T-type, I went right to the source of this "BS story, Steve's muffler shop to talk to Steve himself about Duals. He quotes me $150 and then says "wait... Is this one of those Turbo Cars? We can't put duals on those"

Story confirmed I whip out a diagram I made of a 2.5" cat back dual exhaust. Steve bent it up and charged me $150 and it's still on the car.

I've attached an Illustrated parts catalog pdf that shows the two headers and the crossover

 

[UNGN]

The Wastegate allows exhaust to bypasses the turbo. Exhaust bypassing the turbos can't spin the turbos. Most modern cars cycle the wastegate to hold a given boost level. Old school cars like a buick have the wastegate open at a certain boost level controlled by limiting the amount of boost going to the wastegate and a by making an adjustable rod/spring to hold the wastegate closed. By adjusting spring tension(by changing the length of the wastegate rod), you could adjust maximum boost level (until you ran out of spring or rod).

 

[LukeZ]

Very informative, thank you very much UNGN