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Jan 2, 2012 | 06:32 PM

#16

1992gen1_fan

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Joined: Nov 2010

Posts: 604

Likes: 2

From: Mo

Quote:

Originally Posted by G1625S

Kind of related. I cut the divider out of a 12cm. Hurt spool and cruising egts. Waste of time.

Do you think the exhaust got turbulent because of the remaining devider inside?

Jan 2, 2012 | 07:07 PM

#17

stillsmokin209

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Joined: Feb 2007

Posts: 238

Likes: 0

From: California

I knocked the divider down in my 12cm housing, along with porting the volute as far as I felt I could go. Also opened up the scroll around the turbine seating area. Spool up is just fine, and is building boost by 1200rpm.

Jan 2, 2012 | 08:07 PM

#18

dieselJon

Registered User

Joined: Feb 2007

Posts: 1,958

Likes: 1

From: Dixon, IL

Quote:

Originally Posted by 92smokin blacky

The hy35 he341, and He351CW have an undividing housing. Im trying to remember on the vgt but if I remember right it is undivided as well. The h1cs and hx35s have a split or twin scroll housing as do a lot of bigger or aftermarket turbos.

I've always wondered why they divided them or why they were undivided other than the wastegate being able to relieve all cylinders instead of 3 unless you drill the hole through the divider. Is it just for spoolup reasons? Cuz the Hy35 and He351 and 341 spool faster than any stock cummins turbo with an undivided housing although they do have the 9cm exhaust housing which is the smallest.

I know some people port their housings and say to do it but wouldn't it hurt spoolup?

Remember though we have a "big" housings. Seperating the pulses helps in spool up.

The HY and HE series have tiny 9cm housing so if there was a divider, you wouldn't be able to properly wastegate the exhaust to get the drive pressures down to manageable pressures. My theory anyways.

In the 4cyl and 6cyl gas worlds. Divided housing are the difference as great as 1k rpms before the turbo spools.
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