DocRace N55 Top Mount Manifold

doublespaces

Administrator
Oct 18, 2016
9,050
4,158
0
AZ
Ride
2009 E93 335i
Looks like @DOC_Race has a top mount kit cooking for the N55 folks, what do you think?

This N55 manifold was put to the test on the shop car. Will be shipping a couple kits out I'm a couple weeks. Stay tuned to see what the full kit looks like

2017-09-01 18_09_40-DOC_Race (@doc_race) • Instagram photos and videos.png


Source @omarmarji
 

Krazi3azn

Private
Nov 7, 2016
29
13
0
Canada
This is what I read couple weeks ago, posted the link below

"Here is a rare shot of the manifold. Notice it has a v-band connection going up to the turbo. This makes installing the kit that much easier by just tightening one nut for a full connection. This was something that we wanted to do on the N54 but because of how the O2 sensors were setup with the twin turbos it required us to do twin scroll. We have free range on the N55 because they came factory with a single turbo. Some might be thinking we're going to lose some spool by going away from twin scroll but lets hold off on speculation until there are some results. We can always go back to twin scroll if needed."

https://docrace.com/blogs/news/n55-f30-top-mount-turbo-kit-development
 

Abacus38

Lieutenant
Nov 2, 2016
638
381
0
31
Tampa/Orlando, FL
Ride
2007 Ti Ag 335i
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
E2288AFE-3208-434F-A4BE-6C5EB16D60D0.jpeg

0A579317-F4FA-4832-B928-7CC530817C67.png


Divided Entry Not twin scroll
ATP-HSG-063_450-2.jpg


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.
 
Last edited:
  • Informative
Reactions: doublespaces
Oct 27, 2016
412
261
25
30
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
ATP-HSG-063_450-2.jpg


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?
 

doublespaces

Administrator
Oct 18, 2016
9,050
4,158
0
AZ
Ride
2009 E93 335i
Why 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.
 

Abacus38

Lieutenant
Nov 2, 2016
638
381
0
31
Tampa/Orlando, FL
Ride
2007 Ti Ag 335i
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?

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
https://www.evolutionm.net/forums/a...s/291810-twin-scrool-vs-open-scroll-test.html

Why 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.
Space constraints due the the tilt of the motor. QSV are popular on the 2j crowd
 

[email protected]

Lieutenant
Nov 5, 2016
596
606
55
Bay Area
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...
 

Abacus38

Lieutenant
Nov 2, 2016
638
381
0
31
Tampa/Orlando, FL
Ride
2007 Ti Ag 335i
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...

I said aftermarket not OEM. Garrett, MHI, and Borg Warner OEM setups are divided all the way through. As far as after market stuff only EFR turbos are true T4 twin scroll. The exhaust volutes are completely independent of each other. I wish I still had a photo of when we chop an old housing up. I might just go buy cheap t4 Borg housing and have it cut in half again to show you guys what I'm talking about.
 
  • Like
Reactions: doublespaces

doublespaces

Administrator
Oct 18, 2016
9,050
4,158
0
AZ
Ride
2009 E93 335i
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
https://www.evolutionm.net/forums/a...s/291810-twin-scrool-vs-open-scroll-test.html


Space constraints due the the tilt of the motor. QSV are popular on the 2j crowd

0.68 AR here