Need info on twinscroll setups...

[05scooby]

I'm new to the twinscroll setups.

Looking to learn more about them before I dive in.


I am aware that Im going to need a few new parts.

Sti oil pan, (wrx pan won't clear the twinscroll manifold)
turbo
downpipe.

anything else?

[JTunedMotorsports]

a manifold that accomodates a twin scroll turbo..

[05scooby]

Originally Posted by JTunedMotorsports

a manifold that accomodates a twin scroll turbo..

intake manifold?

[yellow2000S/R]

Originally Posted by 05scooby

intake manifold?

L O f'in L

[mr_eh]

Yes, an intake manifold, duh. You need an intake manifold that accommodates two intakes to dual scroll the twin setup.

(sarcasm is high here)

[RyanG]

a better question would be WHY are you looking at a twin scroll setup?

And dont tell me its because of "lag"

[TROLL]

Wow... guess nobody is allowed to ask a question these days... if you don't have something to contribute to a thread, especially in the tech section, then please don't post.
Why shouldn't he be looking to reduce lag Ryan? I guess its a waste anyway to put it on a "junk" 2.5 liter though right?

Moving on...
Twin scroll setups utilize an exhaust manifold and turbine housing that splits the exhaust path into 2 until it reaches the turbine wheel to aid in efficiency, and thus performance. Twin scrolls originally came from the diesel world which are high displacement motors with low redlines. This means the pulses of air are more powerful and also more spaced out, so separating them with a twin scroll setup makes more of a difference and is beneficial.
On lower displacement higher revving motors which have smaller and more constant pulses of exhaust leaving the engine, twin scroll doesn't have as much of an effect. In theory it should help spool some but I don't know if I've actually seen hard proof of this. It may help some but you have to decide if the extra costs are worth it.

A twin scroll setup uses a twin scroll manifold, uppipe, and turbo with a twin scroll turbine housing. Downpipe, Intake, oil/water lines, intercooler piping would be the same as a single scroll setup but of course the entire system needs to physically fit together as far as downpipe/ic piping placement off the turbo, etc.

[06njsti]

if you dont know what you need for a twin scroll setup you shouldnt be looking to buy one. Its like when people say "I wanna run anti-lag on their wrx/sti" If your asking about something like that its clearly not for you.

[DaveSTi]

call up full-race. they offer a twin scroll gt35r kit that looks to be designed pretty well. Cost to performance ratio just isn't there over a single scroll setup though.

[mr_eh]

Originally Posted by DaveSTi

call up full-race. they offer a twin scroll gt35r kit that looks to be designed pretty well. Cost to performance ratio just isn't there over a single scroll setup though.

it was 800$ more for the ts setup from fr... kinda worth it for what i want to do with the car.

after screwing around with evodan in his ts 35r it really wasnt that difficult to make the decision to try it out on the 240 build

[RyanG]

Originally Posted by TROLL

Why shouldn't he be looking to reduce lag Ryan? I guess its a waste anyway to put it on a "junk" 2.5 liter though right?

did I say that? or even remotely refer to that?

obviously not.. and yes the 2 more 2.5's sitting on my floor still make them junk. besides the op is rocking a 2.0 ;)


99.9% of Subaru owners follow the herd on Nazisock when hearing about twin scroll turbos. All you ever hear about on the forums is "ohhhh the lag on my Vf(whatever) is horrible!!!" ...99% don't even know what real "lag" is. Lag is a downshift away from being eliminated. Those people think a 16g lags...

Twin scroll setups are good if you are looking to make REAL power and still want decent spool. ie 30-42r's etc etc. Not a smaller snail like the oem Subaru ones.. Twin scroll on a small turbo is retarded.. Awesome a turbo that spools quick but runs out of steam up top anyway..Done wrong, a twin scroll could infact HURT spool up and increase boost building time. if you have the $$ and want to make big power and have a decent response spoolwise then yes go with a twin scroll. But by the time someone is ready for something like that they are ready to replace the JUNK 2.5 internals to accomodate the increase in power ;)


and my question still stands..

WHY are you looking at a twin scroll?

[DaveSTi]

oh and dude has an 05 wrx...that's a 2 liter.

[foolio]

Here is a twin scroll set up we did for a customer. Does it make huge power? No not really... but it does drive great and is by no means slow. The car wasnt built to make huge power though. More of a track car/street driven car and not a time attack or Drag car. The set up all depends on your goals and the intentions of the car being built. I like the twin scroll set ups personally.

[superskaterxes]

WTF would anyone build a twin scroll setup, all custom, with an IWG? why? why?

[TROLL]

Thats a stock Subaru turbo with an improved aftermarket header/uppipe... and from seeing the kind of work that foolio does I'm sure it was the best setup for the application, most likely competitive rally racing where peak hp is not nearly as important as useable power through the rpm range.
Whats cool is that turbo has 2 separate wastegate ports to keep the exhaust pulses separate all the way to the turbine, how a true twin scroll should be. Many twin scroll headers share a single wastegate which reduces effiiciency since the two sides join at the wastegate runner.

[CleanNeon98]

Curious...what are the benefits of a twin scroll?

[TROLL]

You can see there are 2 seperate runners leading to the turbo here... its called a divided manifold, or twin scroll, and keeping the exhaust pulses separated this way as they travel to the turbo is more efficient then having them all join as one before they hit the turbine wheel to spool the turbo. This should improve performance at all points of the powerband due to the increase in efficiency.





You can also see the turbine housing is also divided, keeping the exhaust paths separate right up until they reach the turbine.


"The twin scroll design of the APS TSR turbocharger permits separate exhaust gas pulses from each cylinder bank to effectively drive the turbocharger's turbine with the maximum exhaust gas energy possible. This results in quicker turbocharger response and higher horsepower than an equivalent non-twin scroll design."

[CleanNeon98]

So I guess in simple terms, it helps keep airflow/exhaust gasses flowing smoother and improving efficiency. I remember them advertising it on the new Mini Cooper S and never knew what it was.

What are the holes for around the impellar blades on the inlet of that turbo?

[TurboTagTeam]

Think of Rocky Balboa hitting a speed bag.....thats a simple way of how a twin scroll works. The set-up is really only needed on REALLY big turbos with divided housings.

The holes on the intake of that turbo are to make compressor surge les likely to happen.