Primary Turbo

G

Gambler

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Dec 28, 2011
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248
Anyone out there running a 475/83 or 87 1.10 a/r?
I'm currently running a 475/96 1.32 a/r. Looking for input on a better and responsive DD. I realize I could step up to 5x.016's, which is in the works. I also know the smaller turbine wheel and housing is more expensive, but not worried about that.

Thanks in advance,

Jody
 
What turbine housing is on your II 62? I have found it better to run a tighter turbine housing and open the gate sooner to allow more exhaust flow to the primary.
 
Low end response should be your secondary, if it's mid to top end response bothering you then you might want to tinker with your primary. I never had any problems with the response of an s475/96/1.32 coupled with an he351cw
 
Chrisd91 said:
Low end response should be your secondary, if it's mid to top end response bothering you then you might want to tinker with your primary. I never had any problems with the response of an s475/96/1.32 coupled with an he351cw
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Mainly bottom end...I checked w/ II and they said for a compound setup, the 62 I have comes set at 25 psi.
 
Maybe you need to tighten up the wastegate a little on that 62, try it at 30 psi and see how it runs.

I too agree, messing with the big turbo is not going to make a noticeable difference on the bottom end throttle response/smoke control.
 
Chrisd91 said:
Low end response should be your secondary, if it's mid to top end response bothering you then you might want to tinker with your primary. I never had any problems with the response of an s475/96/1.32 coupled with an he351cw
Click to expand...

Chrisd91, what kinda fuel were you running w/ that setup? The 351 is a 60 w/ a 9 cm housing, right? I wouldn't suspect it would be laggy...
 
What are you considering being laggy? I'm running a 63/68/.83 T4 as a secondary and it runs fantastic. Also to mention, 90% smoke free.
 
Gambler said:
At what point does the primary actually take over, approximately?
Click to expand...

The primary takes over when it's fully spooled, so technically it never fully takes over, it slowly comes in and shares the work load till it reaches full load. This all depends on the size of the primary and how/when the smaller manifold turbo is wastegated.

As an example, with my HE351 over S480 setup, the HE351 is 95% responsible for my excellent driveability in the 0-25 total psi range. It's true the S480 starts making measureable boost around 15-18 total PSI at the intake manifold but it's just barely starting to light.

Around 25-30 psi total boost, the wastegate starts to open and HE351 increasingly performs less of the air compression work and S480 proportionally performs more of the air compression work.

From all the setups I've ran, the big atmosphere turbo makes little difference in the initial 0-15psi total boost pressure range and in my opinion, the 0-15 psi range is 90% of the in-town driveability.
 
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