Divided or straight??

[RedWagon]

Ive been looking at turbos and saw it said on the selection divided or straight for a t3 or t4 turbo. Whats the difference and what are the bennefits?

 

[RvlutionMtrsprt]

A divided exhaust housing paired with a divided manifold will combine the exhaust pulses from cylinders 1&4 and cylinders 2&3. This twin scroll design will spool the turbocharger faster. Remember that you must have BOTH the exhaust manifold and exhaust housing.

 

[absolute_DSM]

A divided housing is a better choice if your exhaust manifold is also divided.

In a non divided setup, the exhaust pulses each of the 4 cylinders come together and contact each other causing a loss of kinetic energy which could be used to propel the exhaust turbine faster.
Basically, the longer cylinders 1 and 4 vs 2 and 3 exhaust gases are seperate, the better your turbo will spool. Each set of cylinders will have its own "spiral" until they contact the turbine. (twin scroll)
Also, having a non divided housing effects VE. One cylinder will be on an intake stroke and another will be on an exhaust stroke. The intake stroke can actually suck in the exhaust gas on the valve overlap (less if you have afermarket cams or work with your cam gears).

All this means : faster spool up at low RPMs, less back pressure at higher RPMs. From some things Ive read even a 5% gain in power can be seen.

 

[RedWagon]

alright this info is helping out. So if I wanted a manifold to have a twin scroll setup which company makes one for DSM's? Would the Evo 8 manifold work?

 

[csgsx23]

No the evo manifold will not work.

 

[RvlutionMtrsprt]

You can get a tubular stainless steel divided manifold from ETS, Shearer, and Full Race (I think).. maybe a couple others. If you're lucky enough to find one of the 300 HKS manifolds floating around, they're divided too. You could get the Evo 8 manifold to work if you're willing to do the custom work necessary, which really isn't going to be any different than all the work you're going to need to do in order to switch to a T3 or T4 setup. But if you choose that setup you will be limited on turbocharger selection.

 

[pitbull419]

This depends on a few things.How much are you trying to spend?
What turbo will you be running?External or internal wastegate?

 

[RedWagon]

im probably going to run an external WG and I love how punishment and Shearer's tubular SS headers look and thinking about buying one of them. Im just looking around right now for a good streetable big turbo since there isnt a track around here for like 70 miles or more.