boost +hp?
Senior Member
Joined: Sep 2002
Posts: 2,550
Originally Posted by jspecracer7' post='795079' date='Jan 19 2006, 05:01 AM
Who told you that?
10 psi on a stock turbo vs. 10 psi on a greddy T78. Now 20 psi on a stock turbo vs. 20 psi on a greddy T78. So they both will yield the same HP gain per psi?
HP gain per PSI is dependent upon turbo effeciency in that range of boost. Some turbo's are more effecient down low ...say 15psi and below. Some turbo's are more effecient at "high boost"....say 21 psi and above.
Yep, It's all about the volume or air and fuel @ that boost level that can get into and out of the combustions chamber in the amount of time it has to do so that will determine your HP as boost increases. As Jspecracer7 said, every turbo performs diffrently and this is why you have to choose a turbo that fits your application for the car.
Senior Member
Joined: May 2003
Posts: 635
From: Orange County, NY
Originally Posted by Il RX8 lI' post='795111' date='Jan 19 2006, 12:49 PM
And absolutely no variation.
Yea, it's like this:
13b-TT= 50k Miles
13b-T=150k miles
13b=200k miles
12a=250k miles+
See a trend? :P
Senior Member
Joined: Mar 2004
Posts: 453
From: A2, MI
Not just the size of the turbine and it's efficiency range determine it either... a simple way of looking at it (very simplified) is that if you have a 1.5L motor running 15psi, you are packing 2x the air and fuel into it as if it was NA, so its kinda like running an NA 3L engine, minus the power loss required to drive the turbo. if you have a 2L engine running 15psi, thats still 2x the air and fuel, however now its like running a 4L engine. Still 15psi, but a greater volume of air and fuel, and thus more power per psi of boost. basically, nothing can be generalized with turbos, besides their effect on the longetivity of rotary engines as stated above.
Senior Member
Joined: Oct 2003
Posts: 504
From: ummm, Oregon
and it does matter on the turbo,
for example on my audi a GT30R with an a/r ratio of .63 would put my audi at about 575 hp and having full boost around 4k rpm's compared to stock at like 200....
at the same time a GT30R with an a/r ratio of .82 would make somewhere around 600+ hp, but would not spool up untill much later maybe 5.5k rpm
both these turbo setups would run the same boost it all matters on the setup and the turbo sizing....
for example on my audi a GT30R with an a/r ratio of .63 would put my audi at about 575 hp and having full boost around 4k rpm's compared to stock at like 200....
at the same time a GT30R with an a/r ratio of .82 would make somewhere around 600+ hp, but would not spool up untill much later maybe 5.5k rpm
both these turbo setups would run the same boost it all matters on the setup and the turbo sizing....
Senior Member
Joined: Jan 2005
Posts: 842
From: AL
Originally Posted by PhoenixDownVII' post='795146' date='Jan 19 2006, 04:00 PM
Yea, it's like this:
13b-TT= 50k Miles
13b-T=150k miles
13b=200k miles
12a=250k miles+
See a trend? :P
