baz995

iTrader: (8)

In my pursuit to find an exhaust for my 2003 WRX i have sort of managed to work out, downpipe, up-pipe etc but have now come across a new term in my research...twin scroll? i wish buying an exhaust was easier, anyone let me know what this is, do i have it or do i need it :-)

many thanks in advance

rickya

iTrader: (18)

If your car is a UK model, then you dont need a twin scroll downpipe in your exhaust. If it a Japanese import it may have have a twin scroll turbo & hence need a twin scroll downpipe.

baz995

iTrader: (8)

brilliant many thanks for the help

scottydouk

iTrader: (3)

stupid question whats the difference? turbo turbine?

Milamber

iTrader: (2)

If a turbo is automotive ****, then twin scroll is like **** with twin swedish nurses

scottydouk

iTrader: (3)

nice terminology! lol

Milamber

iTrader: (2)

Splitpin

Means simply that the turbo exhaust housing has two separate inlets instead of one. This, as long as the manifold is designed to suit, results in the exhaust gas pulses from adjacent firing cylinders being kept separate right up until they hit the exhaust wheel.

Compare this with the "classic" design of Subaru exhaust manifold in which gas from cylinders 2 and 4 is combined right under the head before running across the front of the engine in the single link pipe. Flow from #1 and #3 also combines before branching into the flow from the link and heading up to the turbo. All those branches create opportunity for the exhaust (or a percentage of it) taking a "wrong turn" or for adjacent pulses to otherwise interfere with each other rather than flowing efficiently up to the turbo.

The Subaru twin scroll design effectively only has one branch in it, rather than the three of the "classic" manifold. It is, in most of the ways that count, simply more efficient.

Milamber's summary works, too, mind.

baz995

iTrader: (8)

just as well it wasnt described on the site i was looking as milambers description or else i would have bought two of em lol