Could some of the twins experts help explain some how to's about building them??? More specifically about oil lines, wastegates, and anything else I might be missing??

I believe I understand the piping, and how the small and big turbos work together but what else is involved??

Fresh air comes into the big turbo and is compressed and fed into the small turbo. This compressed "cold air" is fed to the intercooler, to the intake, combustion, and out the exhaust flange into the "hot" side of the small turbo. The hot air exits the small turbo through the "hot" pipe and into the exhaust flange side of the big turbo. This hot air exits through the hot side of the big turbo into the down pipe and out the exhaust. Is this correct??

I understand the small turbo is usually wastegated and the big turbo is not. The small turbo wastegate is fed into the big turbo to help it spool by feeding it more air. This is the part I am confused on. How is the wastegate routed or piped to the big turbo. Does anyone have a picture??

Oil lines?? Where are they plumbed from and where do they dump?? Oil supply?? Oil return?? Anything else I am missing?? Where do most guys put there boost guage at??

Thanks,
Chad

 

clc900:

Your description of the flow of air through a twin turbo
system like the ones used on alot of our trucks looks
pretty good to me.

Some of the twin turbo systems used do have the
top (manifold) turbocharger "wastegated" as you
described, but some do not. One of the advantages
of a wastegate is to control total boost and drive
pressure on the system. I don't have a picture to
show you, but maybe one of the other members
will be able to post one. You can go these websites
to see pictures of some twin turbo systems and how
they are set-up:

www.scheiddiesel.com
www.piersdiesel.com

You mentioned oil lines to the turbos. Both the top
and bottom chargers have to have an "inlet" oil line
and a "return" or drain line to the oil pan just like you
do with your single charger. They are "plumbed" in the
same way a single charger is, with the inlet line on the
top of the charger and the "return" or drain line under
the turbo. Usually, stainless steel braided line is used
with the oil lines on the twin turbo systems (both top
and bottom) because of space limitations.

Hope this has helped you some.

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John_P

 

119 views......1 reply......SSSSHHHHHhhhhhhh....were takin about twins here, dont want to give up any secrets. Come on guys help a poor boy out.

 

every thing you have asked has been covered many, many times. i don't mean to sound like a a$$ but many peolpe get tired of typing. try the search button, mike

 

gunracer:

Good point about the twins,....................

---------
clc900:

BTW,........Your Welcome!!

----------
John_P

 

Chad,
There are usually 2 oil ports on your filter head.
Also, on the return there should be 2 bosses in your block for return for trucks after 97-98 (one is being used by one of the drains).

 

Gunracer, no you dont sound like an ***. I can understand that some get tired of answering the same question over and over. I tried the search and didnt find some of the specifics I was looking for. I guess I will keep searching.

John, sorry I didnt respond to your post. I found it very informative. Thank you!!

Pourindiesel, mines a 94 so I dont think it has 2 ports. Thanks though, I will check it out.

I havent searched this one but whats the diffrence between an external wastegate and an internal wastegate?? If it been covered before I should be able to find it in the archives.

I have searched this one and havent found any comparisons between the Piers street twins and the Haisley twins. Haisley uses a S400?? I am not familiar with this turbo. Does it have another name? If not what does it compare to??

What does EEP use for their street twins??

Thanks for the replys. I didnt mean any disrespect in my last post, sorry if it seemed that way.

 

clc900:

You are welcome!

Your 94' Dodge CTD is similar to my 96' "clc". As Justin
said the oil filter "head" (right above the oil filter) should
have two (2) ports so you can obtain oil lubrication for the
second turbo there.

You asked about wasetgates, internal and external. My
top charger is a Piers HX-40/16. It has an "internal"
wastegate that you will also find on your Holset HX-35/12
that came "stock" on your truck. These "internal" wastegates
control the maximum amount of boost that the turbo has.
On a bone "stock" 94' like yours, that is probably around
18-20lbs. New, my 96' had about that amount of boost.
The "internal" wastegates can be "adjusted" by turning
on a threaded "turnbuckle" style adjuster that is attached
to the side of your turbo. "External" wastegates are
wastegates that are mounted as stated, "externally",...
such as to the side of the turbo exhaust housing or
in the case of my twin turbo truck, welded directly in
the center of the ATS Manifold. These "external"
wastegates are used to "bleed off" excess drive
pressure and boost and help the engine breathe
better. A friend of mine recently installed a Tial
External Wastegate on his 2002 Dodge CTD with
twin turbos and saw a 60 H.P. increase by just
adding that wastegate!!

You can go to this website to see what an external
wastegate looks like:

http://www.hopupracing.com/ti38wa.html

If you are looking to build your own set of twins a
good "starting combination" IMO is your HX-35/12
on top and a Holset HT3B/26 for your bottom turbo.
This "combination" would save you money as you
only have to buy one turbo and the Holset HT3B
is pretty reasonable. I would however suggest
going to a 16cm housing on the HX-35 to keep
your EGT's and drive pressure down. Go to some
diesel rallies and look at the twin set-ups some
of the members run. Ask them how their system
performs on their truck etc. and that should give
you some good references of where to start.

One other suggestion,........the associated twin
turbo "piping" is tricky to get just right. That is
one reason why the various vendors don't give
out alot of information. They put alot of R&D into
their systems and want their particular "set-ups"
to work right for their customers who are willing
to pay the money for the systems. There is alot
more to the twin turbo systems than you think.

Anyway,.......good luck "clc!"

----------
John_P

 

Thanks "John_P"!!!

Im a little confused though... I see that you have 2 trucks and maybe you were describing both in your last post. First you say your top charger is a Piers 40 with an internal wastegate. Then you say your twins truck has the external wastegate. Do you have both internal and external wastegates?? Why??? If your top charger of your twins is a 40 what is the bottom?? What does Schieds S4 compare to?? I am not familiar with it. Are your Schied twins designed more for towing, street, or competition??

Wastegates......dont external wastegates have to mount between the exhaust manifold and the turbo exhaust inlet???

Oil lines....I see where the oil supply comes from. Where do most guys hook the 2 return lines for the two turbos???

 

clc:

Sorry for the confusion.

Yes, I am using the Piers HX-40/16 on both of my trucks.
They are both attached to the exhaust manifolds. On
my 96' Dodge CTD I would call the HX-40 my "top charger."
The Piers HX-40/16 is an internally wastegated charger
just like your HX-35/12 is on your truck. So to answer
your question,......YES,....on my 96' Dodge CTD with the
twin turbo system I am utilizing two (2) wastegates,...
that being, the "internal" wastegate on the HX-40 and
the "external exhaust wastegate" on the exhaust manifold.
The reason for that is what I stated above,... to lower the
boost pressures, lower the drive pressures and to help
the exhaust gas temperatures also.

My bottom turbocharger is Scheid's "hybrid" Schwitzer.
You can call Mike Wood @ "Scheid Diesel" (Effingham, Ill.)
for more specific information on that charger if you want
to. His phone number is: 1-800-669-1934.
As far as what kind of system it is (towing, street or
competition), so far my truck has done pretty well in
all of those areas. I towed over 10,000 lbs. behind it
up I-77 through Va. and W. Va. recently and the 96'
performed well on the 5-6% grades on that highway
with plenty of power and acceptable EGT's. The only
drawback was I have alot of black smoke (obviously )
under heavy acceleration,....but my fuel is set pretty high
too.

Finally, you asked again about the oil return lines. I would
refer you back to "Pourin Diesels" post about those return
lines. The twelve valve trucks only have one "port" near the
front of the engine where you have two on most of the 24V
truck engines.

-----------
John_P