Calculate total lb/min air on a compound setup

zfaylor said:
I am not saying you are wrong since I don't actually know chit about turbochargers in the grand scheme.


A single s475 can make 800hp+ in a single configuration but in most compound setups things get out of control in a hurry as far as boost numbers and heat before you approach that number.

Is it because of the restraints on the secondary used typically in s475 setups? An s363 over an s475 vs maybe an s366 over an s475 for example?


I have to say compounds definitely appear to be harder on parts as well. Transmissions, rods, cranks, etc. appear to suffer with the low rpm power compounds usually present.
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JSP has posted a good example of compounds vs single in the past. In his 364 over S480 it made 1000whp, pulling the s480 out of the compounds and using it as a single netted him the exact same 1000whp. The compounds definitely had a broader powerband though.
 
zfaylor said:
I am not saying you are wrong since I don't actually know chit about turbochargers in the grand scheme.


A single s475 can make 800hp+ in a single configuration but in most compound setups things get out of control in a hurry as far as boost numbers and heat before you approach that number.

Is it because of the restraints on the secondary used typically in s475 setups? An s363 over an s475 vs maybe an s366 over an s475 for example?


I have to say compounds definitely appear to be harder on parts as well. Transmissions, rods, cranks, etc. appear to suffer with the low rpm power compounds usually present.
Click to expand...

You can always control boost via a wastegate, and from what I've seen with heat readings, compounds actually seem to run cooler at the same boost, because the compressors are much further in their efficiency zone.
 
JQmile said:
You can always control boost via a wastegate, and from what I've seen with heat readings, compounds actually seem to run cooler at the same boost, because the compressors are much further in their efficiency zone.
Click to expand...
No doubt twins run cooler at the same boost but do they make the same power at that boost level?

In another thread it was stated that compounds total airflow is simply the primary airflow. If that is the case total manifold pressure is going to be much higher more times than not with, for example, a s475 as a primary vs as a single to obtain the same airflow?

Just trying to educate myself a little more. Ive ran compounds in the past and gotten away from them since smaller single chargers have always hit harder with less overall boost. S366 box charger made more power on my ppump 24v than my he351/ht3b compounds. Same fueling. Currently my 95 is much more powerful with an s464 than my hx35/gt4294 was. Of course both cases i went from tight secondary to decent flowing singles.

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We are considering a GT 60 for the secondary. Most use an HX 82. Does anyone have any experience with the GT60? What we like about it is it appears to have a bigger exhaust wheel then the HX 82.
 
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