Originally Posted by
Rob@Backyardracing
theres a few reasons large turbos make more power.....temp has little actual effect.
the turbine is largely responsable for making more power at the same boost levels, as larger turbos usually have both a larger compressor, and a larger turbine.
the turbine "corks" the exhaust, and restricts flow, which kills power.
so a larger turbine will not "cork" it as much, and hence flow more at the same pressure (allbeit at the expense of spool time).
secondly, the larger compressor has more ability to keep the cylinders full as rpm rises, (where a smaller compressor will tail off). simply put, large compressors "carry" torque higher. and if you make more torque at higher rpm, you make more hp, since hp = toquexrevs/5252.
i.e if you make 200ft/lb at 5000revs you make 190bhp.
if you make the same 200ft/lb but at 7000revs you make 266bhp.