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Dsm killer
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Discussion Starter #1
I was wondering how much horsepower per lb of boost the MKIV twin turbo's make? my friend said that he was told that a car makes 10hp per 1lb of boost is this true or is it more or less for the stock twins?

monty
 

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This is a very non-liniar relation. Meaning that it might be ~10hp when going from 11 to 12psi, but it most certainly will not be when going from 18-19psi due to the efficiency of the turbos at that boost level. I really don't think there is a good rule of thumb.

Daniel
 

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Depends on turbo size too. You can put the stockers at 18psi and make 440rwhp, or you can put a sp74 at 18psi and make 625rwhp
 

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i wish my stockers made 440 at 18psi :) but yah, pressure is different than airflow.

horsepower is roughly 'x' lb/min of air * 10.86 * .85 (or .8 for an automatic)

this will give you rwhp for a turbocharged application. obviously there will be instances where this is low or instances where it is high, but its a pretty good estimating 'equation'

that equation may help you when deciding between two compressor maps
 

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Dsm killer
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Discussion Starter #5
thanks for the equation so it goes like this... X*lb/min*10.86*.8
(im auto)

ScrewDrvr I am talking about stock twins.
 

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monty187 said:
thanks for the equation so it goes like this... X*lb/min*10.86*.8
(im auto)

ScrewDrvr I am talking about stock twins.
yeah except the 'X' variable is a the airflow number OF pounds/min.
 

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Dsm killer
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Discussion Starter #7
so if you were to take your bpu'd car and minus all the rwhp that you get from all bpu mod's except cranking up boost to say 18psi on 100 octane what would be the result of rwhp from just that?
 

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monty187 said:
so if you were to take your bpu'd car and minus all the rwhp that you get from all bpu mod's except cranking up boost to say 18psi on 100 octane what would be the result of rwhp from just that?
Different cars make differnt hp. Differnt compression, different exhaust, differnt intakes, condition of the turbos, weather...etc..etc

There is no one answer for this. One guy made over 480rwhp on his stock twins no nitrous, others struggle to get over 420rwhp.
 

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yeah, greg b. pushes well over 400 to the wheels on 16 psi, i have no friggin idea how he does it (actually if you see this thread, feel free to post tips) where as on 18 psi i have at best 400 wheel.
 
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