is 21psi , 21psi ? blower vs turbo...
02-26-2013, 11:21 AM
#1
is 21psi , 21psi ? blower vs turbo...
kinda got into a debate with my buddy last night . he wants me to put a big 88mm turbo (or something big like that) on my truck but i didnt see what the point was. i em very open minded about this so please dont think im bias im very open to make more power ! so debate went like this. im running 21 psi right now on my d1 . he thinks if i run 21 psi on a big turbo that i would see serious gains over the d1. so my question in theory IF IAT AND TORQUE/HP CURVE WAS IDENTICAL would the bigger turbo make more power over the d1? and im looking for good hard evidence why.
02-26-2013, 11:27 AM
#2
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psi = pressure per square inch. a measurement of resistance. it's more of a relative term. cfm is the make or break point. i can run 30psi from a tvs 1320, or 30psi from a pt6262. pressure is the same, power difference is in favor of the turbo. the cfm difference is huge, hence the power differerence
02-26-2013, 11:33 AM
#3
Depends on where it is on the map. If that turbo isn't working as hard at 21psi, which it probably wouldn't be, then it will make more power. Also, its not good practice to judge turbos and blowers by CFM, since the pressure is not constant. Better to use lb/min or g/s 
02-26-2013, 11:38 AM
#5
A turbo has close to 40psi of back pressure in the exhaust witch really holds power back vs a pro charger having big headers and open exhaust, but the procharger uses crank power to make power. Because of the back pressure of the turbo the pro charger makes more power on the same boost, but then you pull the power right back out of it having to turn the blower. I'm sure you know this but the difference will change according to boost level, what turbo, ect. At 21 psi I'm sure a turbo would make 1000hp on your engine
02-26-2013, 11:38 AM
#6
i understand that boost is just a measurement of restriction , but why would the turbo make more power if the turbo was pushing more air/cfm wouldn't that cause an increase in manifold pressure also? where does the power come from? i understand that boost is just manifold pressure so does the increase in hp come from more air flow through the valves when open but when closed the waste gate bleeds all the extra air after 21 psi?
plus i dont know if the f1r was going to be the right choice for my set up. that a big blower a requires allot of na power to get going.
02-26-2013, 11:58 AM
#8
i understand that boost is just a measurement of restriction , but why would the turbo make more power if the turbo was pushing more air/cfm wouldn't that cause an increase in manifold pressure also? where does the power come from? i understand that boost is just manifold pressure so does the increase in hp come from more air flow through the valves when open but when closed the waste gate bleeds all the extra air after 21 psi?
02-26-2013, 12:03 PM
#9
Well a na engine can make a lot of back pressure and still run fine, its just how an engine works. You could add more back pressure then boost pressure on a turbo when you turn it up and still gain power. Maybe someone will chime in that can explain it a little better.
02-26-2013, 12:07 PM
#10
i understand that a big 88mm turbo will flow more cfm , no doubt about that but im not buying the "less effort" thing not when big gains are involve like 150-200hp more.remember in post 1 we are assuming iat are the same . im talking peak power here too not hp curve or spooling off the line just peak power.