14b vs. evoIII at same boost level

[racetracker]

quick question i was curious as to why people that change there 14b to a evoIII or bigger say that there car pulls so much harder at the same psi im just confused maybe this is dumb but why would one turbo make more power at the same boost level if they are both running say 14 psi why would one be more efficent

srry for spelling thanks guys help me understand

 

[2-0turbo]

the evo WILL pull harder at any SAME psi as the 14b because it will always deliver the air at a cooler charge than the 14b.... as long as you are comparing equal psi. Density is the key factor here, there is more air per given volume in cooler air, just because they are both at 14psi, the cooler air has more air than when warm.

Think of an elevator, 10 skinny people will fit, but only 5 fat people can fit, now think of the skinny people as the cooler air, and the fatter people as the hotter air, warmer air expands taking up more room, therefore less people (hot air) can fit

I'm not sure if you got it right first or not, but this is the answer. DENSITY is the name of the game. Everyone needs to forget CFM--it is worthless. Mass flow is where it is at. If you have a real trick air/water IC setup and you are running icewater through it, 14PSI in the intake manifold at say 50F is SUBSTANTIALLY more mass than 14PSI at 300F on a hot summer day going through a stock sidemount.

Also, please note that most lb/min rating for compressor wheels are reported all at some standard conditions. They are not real-world mass flow rates that your engine is consuming. There are a ton of factors that play into the actual lbs of air consumed by your engine.

 

[Caithness]

Everybody is forgetting the benefit of a better-flowing hot side. A bigger turbo with a less restrictive hot side will lower exhaust manifold pressure, increasing VE and allowing more air volume to flow through the engine at the same intake manifold pressure. This along with the slight increases in compressor efficiency at the low boost levels we're talking about and you've found your "extra" horsepower. This is also why Honda guys run massive turbochargers at 10 psi, confounding DSMers the world around... because they don't choke up the exhaust at high rpm and the compressors are more than capable of keeping up to provide efficient airflow to very high rpm.

 

[DSM90AWD]

Everybody is forgetting the benefit of a better-flowing hot side. A bigger turbo with a less restrictive hot side will lower exhaust manifold pressure, increasing VE and allowing more air volume to flow through the engine at the same intake manifold pressure.

Very good point, but will only be of help if your backpressure pre-turbo is excessive (i.e. > 1:1.5 ratio of boost to backpressure).

http://www.dsmtuners.com/forums/showpost.php?p=1670844&postcount=15

Not sure what the difference in backpressure of a 14B w/6cm vs 16G w/7cm housing would be at lower boost levels, but definitely a benefit near the limits