Turbocharger for 318 project

Cudafever said

In my case, using the 318 of the OP, the first one is a better choice. Why? because of the different pressure ratio created by higher altitude, that i live at.
Even thought the turbo is often called a altitude compensater it still will affect your choice on a turbo.

If you input 11.8 (average air pressure were i live) in place of the standard 14.696. you will see that it changes the maps. Causes the GT4508R to be running close to the 72% line and never make it into the sweet spot. Were as the GT4292R comes up the 78% line and then runs straight across the sweet spot or best afficany(sp) line.

THANKS for the link MD, been having a lot of fun mixing it all up :coffee2:
http://www.squirrelpf.com/turbocalc/

Click to expand...

With all of these calculators/maps etc , they are only for reference to have a ball park of where you will end up. For example on my set up I have a 410 CU Small Block Stroker. I know from experience that it should make right at 500HP Naturally Aspirated before the Boost is entered into the equation. Solid Roller cam etc............

On Squirrels calculator when I input my specific engine characteristics it is saying I will need 16PSI to get to 800hp for example. I know plenty of combinations pretty close to the same as mine running the same Turbo's that I have that are hitting close to 900Hp to the tires on only 11PSI. It comes down to how efficient your engine is as to how it will actually react in a "Real World" Scenario. Intake Charge Temp "Inter-cooled/Meth Injection", "Head Flow" Compression and camshaft choice will all come into play.