Honda D Series Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter · #1 ·
I know not many people bother in using a divided manifold, so what do you do with the turbo housing, has anyone knife-edged the divider and noticed a difference?

Many thanks :)
 

·
Registered
Joined
·
2,515 Posts
Is it a true twin scroll, or just a divided housing?
 

·
Registered
68 Camaro
Joined
·
4,583 Posts
i misread i thought you had messed up the divider...



is your question about whether the dividing part affects airflow?
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #6 ·
Pic is of a H1C, if I remember rightly they're twin scroll...

I just just wondering if people left the divider as-is, or if they knife edged it a bit to help flow?
 

·
Registered
Joined
·
2,515 Posts
Pic is of a H1C, if I remember rightly they're twin scroll...

I just just wondering if people left the divider as-is, or if they knife edged it a bit to help flow?
If you have a twin scroll turbo and *don't* use a divided manifold, you're totally selling yourself short on midrange / spool time.

I wouldn't touch the divider, and save up for a divided manifold. :)
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #10 ·
On a proper manifold it's common practice to use two wastegates yeah, but I've seen plenty of people on a single gate with no problems.



Shifty, that was my thoughts too - Just there seems to be a few people running the Holsets now and wondered what they were doing with theirs :)
 

·
Registered
honda/firebird form.
Joined
·
6,966 Posts
im running a h1c 18.5cm holset. grinding the divider to a sharp edge isnt going to do anything.. its pointless. twin scroll manifolds usually have 2 wastegates. pretty much always have 2 wastegates.. i mean on 2 runners the wastegate will open and limit exhaust flow to that one side, but how about the other 2 cylinders..?? its still going to be spooling the turbo, which will cause a boost spike which anyone running turbos do not want.. im using a ported out cast mini ram right now... im using the zex 59500 cam with a ported head and i get 24psi around 6k... but once off antilag its not as laggy as you think... redline is set at 9k so i have plenty of powerband
 

·
Classic Man
Civic
Joined
·
16,355 Posts
rounding it would be better for the flow, but a pro would have to chime in on that.

sharp adds more turbulence
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #13 ·
The way I've seen it done is a runner from either side to a single wastegate. Not sure how well it works, but one of them is on an 800bhp 2.0 Cosworth engine.

Just enquiring really as I'm going to be running an HX35 from GSRacing - Home - They use the 12cm housing so shouldn't be too bad. So basically, either run a split pulse manifold or just leave it as is? :)
 

·
Classic Man
Civic
Joined
·
16,355 Posts
seems kinda ass backwards to have a custom made divided manifold with dual wastegates for a holset build........................
 

·
Registered
Joined
·
2 Posts
my friend and i are using similar setup on our sr20det, no problem so far for. he is using alchemy manifold and i am using the speedaction top mount.
 
1 - 16 of 16 Posts
Top