I was wondering if somebody could help me with a question about turbo's.
If i run "x" turbo at 11 psi and it flows 505cfm would switching to "Y" turbo flowing only 450cfm allow me to use a higher psi to flow the same amount of air as "X" turbo. So what i mean is in theory "X" turbo at 11 psi 505 cfm vs "Y" turbo 13psi 450cfm would they produce the same amount of power?
Also if the motor is limited to 11psi on "X" turbo could i run higher boost on the "Y" turbo to achieve the same results without damaging the engine?

 

You have it backwards. Boost = pressure = bad. Turbo X in your scenario is the better turbo. You want more cfm and less boost pressure to make the same power. Of course, turbo x will lag more than turbo y as well. The trick is picking the right combination for your driving habits and desires.

 

displacement effects spool as well, you're 2.4L might spool turbo X a little bit faster than a 2.0. like chkmgnt59 said, you want to find the most efficient turbo for your needs,

 

Boost = bad is not entirely correct.

Turbochargers are designed for a variety of different needs. It boils down to two things, pressure ratio (boost) and volumetric flow (air flow of engine). Each turbocharger is most efficient at a certain pressure ratio and flow rate. Once you know that, you can properly select a turbo that fits your engine needs best.

You cannot simply compare boost and CFM as they are not simply point values, they are areas on a map. Increasing boost might bring the turbo outside of its efficiency range, which has the possibility of introducing negative effects.

In terms of whether or not your engine could take the change, that would largely depend on your engine setup. However, there would be a small influence from how efficiently the turbo was moving the air.

 

how would you go about finding out where a turbo is effcient? If it helps the turbos i am comparing are of the course the evo x turbo at 11psi vs. the ralliart turbo at 11psi.

Btw i only have the 4b11 2.0 motor 2009's got lucky with the 2.4!!

 

x turbo is better. /thread

 

That is the hard part, since not all oem turbo maps are available to the general public.

 

the real problem you tend to run into is that more boost usually pushes a turbo into a range that is less efficient. You want a turbo that makes the desired airflow at it's peak efficiency range for the most efficiency. You can run too big of a turbo at low pressure and get poor performance as well. The best thing to do is figure out the torque band you desire, and then size your turbo appropiately. This is also why a lot of manufacturers drop the boost as RPM increases. the factory evo turbo is efficient with 19 psi at 3500, but not as efficient at 6000. Find a good tuner/shop, tell them your goals, and let them help you find the setup best for you.