That's because people confuse divided inlet with twin scroll. There's only one company out there that makes an "aftermarket" twin scroll turbo and that's the Borg Warner EFR series
Twin scroll EFR housing
Divided Entry Not twin scroll
The sole purpose you go twin scroll is for low to mid range transient response not for power. Hence why you see twin scroll setups on a lot of road course cars but hardly ever on strip car. A proper setup open scroll turbo will always make more power then twin scroll setup. The reason being is that Twin scroll setups have increase back pressure compare open scroll and hence the reason why you have to run a higher A/R ratio on twin scroll setups to lower the back pressure. That's why Borg Warner sells that massive 1.45 AR T4 housing for the EFR turbos.
In low rpms range you have limited of number of exhaust pluses to drive the turbine wheel. In an open scroll setup what ends up happening is while one exhaust pulse fires the previous exhaust pulse has cause negative pressure area that new exhaust pulse has to overcome. This takes energy away from the new exhaust pulse. Twin scroll solves this problem by separating the pluses and not allowing them to interfere with each other however it comes at a cost. The cost is higher RPM power due to the increase back pressure cause by the twin scroll housing. Furthermore at high rpm range pairing the exhaust pluses is irreverent since there's so many pluses driving the turbine it doesn't matter anymore. Same can be said for bigger motors such as V8s. So it all boils down to what your looking for. High rpm High HP Open scroll. Low Mid range power and transient response twin scroll.
A few things here... so youre saying that the twin scroll housing pte uses is only divided in the beginning entry?
Also a twin scroll doesn't make as much hp up top?
You have data or photos for any of this?
Space constraints due the the tilt of the motor. QSV are popular on the 2j crowdWhy not a quick spool valve instead of just a divided housing open scroll turbo? I don't think I have seen anyone do that with the n54.
Um what? All the Garrett housings that are "Divided" are divided all the way from the flange to the turbine wheel. So are the MHI Twin Scroll housing, etc, etc, etc. None of these are just "divided" at the flange then open up, that would do nothing. Honestly, it would be helpful to have the correct information before posting. If you need me to post pictures I can.
LOL, that link is also referencing open or single scroll to a Twin Scroll or divided. Talk about misinformation...
That's a divided housing not twin scroll like the EFR housing. Divided housing aren't anything new. My Mr2 turbo had a divided housing but it wasn't twin scroll. A twin scroll housing has the exhaust volutes separated from entry to it hit the turbine.
As far as power goes go venture over to the Honda and Evo Forums. This topic has beaten to death a million times over or better yet go talk to Andy. There's a reason why he doesn't sell twin scroll bottom mounts.
heres just one example of it
Space constraints due the the tilt of the motor. QSV are popular on the 2j crowd