Boost - 1psi = XX HP
Sep 27, 2005, 06:32 PM
#16
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it has to do with turbo sizing, motor size, motor efficiency, turbo efficiency, IC efficiency, etc. on average 1psi = 10hp. but again that is totally based on turbo cfm, barametric pressure, air temperature and the like
Sep 27, 2005, 06:35 PM
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a lb of psi is a lb. it doesn't matter if it's from a giant turbo or a small turbo. 1 lbs = 7 hp. whether that's to the wheel or to the crank, i'm not sure. i believe it would be measured at the crank though.
A stock 2003 comes with 271 hp to the crank w/ 19 psi of boost. 19psi x 7hp = 133 hp. Subtract that 133 hp from the 271 hp a stocker makes and that is 138hp. that means with no turbo, the normally aspirated 4G63 makes about 138 hp... sound about right? So I can see 7hp being crank power.
A stock 2003 comes with 271 hp to the crank w/ 19 psi of boost. 19psi x 7hp = 133 hp. Subtract that 133 hp from the 271 hp a stocker makes and that is 138hp. that means with no turbo, the normally aspirated 4G63 makes about 138 hp... sound about right? So I can see 7hp being crank power.
Sep 27, 2005, 08:42 PM
#18
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Originally Posted by SP00LIN
a lb of psi is a lb. it doesn't matter if it's from a giant turbo or a small turbo. 1 lbs = 7 hp. whether that's to the wheel or to the crank, i'm not sure. i believe it would be measured at the crank though.
A stock 2003 comes with 271 hp to the crank w/ 19 psi of boost. 19psi x 7hp = 133 hp. Subtract that 133 hp from the 271 hp a stocker makes and that is 138hp. that means with no turbo, the normally aspirated 4G63 makes about 138 hp... sound about right? So I can see 7hp being crank power.
A stock 2003 comes with 271 hp to the crank w/ 19 psi of boost. 19psi x 7hp = 133 hp. Subtract that 133 hp from the 271 hp a stocker makes and that is 138hp. that means with no turbo, the normally aspirated 4G63 makes about 138 hp... sound about right? So I can see 7hp being crank power.
um pretty it does matter if its from a big or small turbo, a large turbo will move more air at a lower psi. like having a 2'' pipe at 19psi vs a 4" the 4" has way more air in it at the same psi, and as we all know moving large amounts of air is what a turbo is for.
Sep 27, 2005, 09:22 PM
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Originally Posted by dbdude
Ok. we are asuming he is talking about stock. I really dont see how you guys say stock boost is around 19psi. I just put in a new autometer gauge and my boost only reads 10psi in higher gears and 9psi in lowergears. But it never tappers. I installed it exactly how it is in the how to section. (fuel presure reg). I even went to the dealership and asked the mechanic why it dont go past 11psi on my boost gauge. I told him that everybody claims that stock boost is around 18-19psi. And he said noway. That 12psi is already too much for stock. They said the only thing they can do is a leak test. But i just let it go.
Sep 27, 2005, 09:33 PM
#20
Originally Posted by kataklyzm
theres your problem right there... mine sucks too...reads 2psi when its sittin on a table...POS
ROFLOL! Thanks I needed that!
my Defi D is within 2 psi of my MAP sensor for my Utec. They read 18 and 20 respectivey up here at 5280 ft. I just need to figure out which one, if either is right and adjust the other.
Sep 27, 2005, 10:19 PM
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Originally Posted by SP00LIN
a lb of psi is a lb. it doesn't matter if it's from a giant turbo or a small turbo. 1 lbs = 7 hp. whether that's to the wheel or to the crank, i'm not sure. i believe it would be measured at the crank though.
A stock 2003 comes with 271 hp to the crank w/ 19 psi of boost. 19psi x 7hp = 133 hp. Subtract that 133 hp from the 271 hp a stocker makes and that is 138hp. that means with no turbo, the normally aspirated 4G63 makes about 138 hp... sound about right? So I can see 7hp being crank power.
A stock 2003 comes with 271 hp to the crank w/ 19 psi of boost. 19psi x 7hp = 133 hp. Subtract that 133 hp from the 271 hp a stocker makes and that is 138hp. that means with no turbo, the normally aspirated 4G63 makes about 138 hp... sound about right? So I can see 7hp being crank power.
Density plays a very important role here. Density does NOT equal pressure. If a very hot air flow (very low density) is pushed at 10lbs per square inch into a motor... and a seperate experiment was conducted with the density of the air being the only dynamic factor... changing the air from being very hot to ice-cold (very high density)... the dense air will make a very large amount of more power than the less dense air.
Density and cfm and all that good stuff is what makes bigger turbos produce more power. This topic has been discussed and beaten to death. Please reserach before posting random gibberish. =]
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