Question: Trent's turbo setup (and turbo's in general)

Leadfoot

Leadfoot

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I didn't want to detract from Trent's post so thought I would post here:

Please forgive my turbo "ignorance", but could someone explain the pro vs. con of doing the one big turbo as a primary and two smaller as a secondary vs. the two small as primary and the big one as secondary?


In a typical twin (two turbo two stages), is the smaller turbo the usually the primary or the secondary. I never really paid much attention to multiple turbo setups as I am a puller at heart and most street to med level classes (only one's I would be pulling in), only allow singles, so I never gave it much thought. Now I'm just damn curious and like to try and understand things.

Thanks!
 
SSchmi5519

SSchmi5519

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The smaller turbo in a twin setup makes most of the boost. Thats why the big charger is called the 'low pressure charger.'

I don't have experience with triple setups, but in theory I would take 2 small chargers and 1 big one.

The big charger is there to flow serious CFM at the top end, the smaller charger gets it there.
 
CurtisEmery

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Its the exact opposite of what you think. The large turbo is the HP unit. The two smaller are the low pressure atmosphere chargers. They do this because when you get into really large compound set ups, finding a large enough primary is difficult. So they split the required flow between two smaller chargers.
 
SSchmi5519

SSchmi5519

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CurtisEmery said:
Its the exact opposite of what you think. The large turbo is the HP unit. The two smaller are the low pressure atmosphere chargers. They do this because when you get into really large compound set ups, finding a large enough primary is difficult. So they split the required flow between two smaller chargers.
Click to expand...

I'm referring to the small charger as primary, bigger one as secondary.


Sent from my iPhone.
 
ChevyDieselLLY

ChevyDieselLLY

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Yea don't think of the two smaller chargers in a trips set up as the small one. They are really working together to flow as much or more air then a REALLY big turbo would. Prob bigger then the PBK Trent ran last year.
 
CurtisEmery

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Here I will splain it for those confused primary is always the atmosphere charger(s) secondary is the high pressure compounding charger. In trents set up and all triple compound set ups the larger of the three chargers(secondary) is getting exaust from the engine first. It then leaves the secondaries turbine and splits between the two primary turbos turbines. So the secondary charger spools up first in turn lighting the two primary turbos. Make sense? It works the exact same way as compound twins do. Instead of a really big primary you have two not so big primaries splitting the work.
 
Utahski

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CurtisEmery said:
Here I will splain it for those confused primary is always the atmosphere charger(s) secondary is the high pressure compounding charger. In trents set up and all triple compound set ups the larger of the three chargers(secondary) is getting exaust from the engine first. It then leaves the secondaries turbine and splits between the two primary turbos turbines. So the secondary charger spools up first in turn lighting the two primary turbos. Make sense? It works the exact same way as compound twins do. Instead of a really big primary you have two not so big primaries splitting the work.
Click to expand...

No, primary turbo receives engine exhaust. It powers the secondary, or secondaries in the case of triples.
 
juddski88

juddski88

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I always understood it like CurtisEmery explained since I believed that the Primary was given its name due to it being the primary source of compression, and it compresses through the Secondary (second stage of compression).
 
Chevy1925

Chevy1925

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boy, talk about people gettin confused.

lets drop the secondary and primary vocab for a min and start over.

On trents tripples you have three turbos (obviously lol). the two little turbos both pull air from the atmosphere and compress it up to the bigger single charger. then the bigger one compresses it into the motor. on teh exhaust, the exhaust first goes into the big charger, spin the turbine, then hits the two little turbos similtaniously and exits as two exhausts,

Now comparing a twin setup to a tripple, its like this. the single big turbo on a tripple kit that feeds the motor on the compression side is hte same as the small turbo that compresses air to feed the motor on a twin kit. the two twin turbos on the tripple kit that feed compressed air to the turbo in front of it are the same as the big turbo on teh twin kit that feeds compressed air the small turbo infront of it.

the two small turbos on a tripple kit are thought to spool faster and easier with more CFM than one big charger on a twin kit. this increases drivablilty of bigger charger setups on teh street or drag strip or run bigger setups that others couldnt normally run due to size.

think of the two little turbos as jsut one big ass turbo that spools easy and pushes alot of air



Now what i concider primary is the trubo that is compressing air into the motor. that turbo is the first to light and build boost, then the two little turbos (or bigger trubos in a twin setup) start light as RPM increases and the pressure to drive those turbos increases so they come in second or "secondary".
 
SSchmi5519

SSchmi5519

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ChevyDieselLLY said:
Ok primary = the small one or the first to recive boost from. The secondary = the 2nd one to give you boost or the big one(s)
Click to expand...

This is what I'm saying.

When you have a stock truck, the stock turbo is the primary turbo. When you twin it with a S475 or what have you it doesn't just become the secondary turbo. It is still the primary source of boost.
 
Chevy1925

Chevy1925

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SSchmi5519 said:
This is what I'm saying.

When you have a stock truck, the stock turbo is the primary turbo. When you twin it with a S475 or what have you it doesn't just become the secondary turbo. It is still the primary source of boost.
Click to expand...

hey, quit surfin here. aint you suppose to be doin somethin? :hug:
 
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