Turbo Flow rates and IC piping
I did some research and found some useful info on turbo flow rates and when the IC pipes start to restrict and when the pipes are an overkill that creates turbo lag.
Quote:
*.4 Mach is the point at which air becomes turbulent and losses in efficiency start to occur exponentially. The key is to stay under that speed. You want to use the smallest piping possible that still flows enough to meet your needs. Larger than necessary piping increases lag time with no measurable gain
The velocities are in miles per hour and mach, and the flow rates are in cfm. Measurements for the piping are in inches.
2" piping
300 cfm = 156 mph = 0.20 mach
400 cfm = 208 mph = 0.27 mach
500 cfm = 261 mph = 0.34 mach
585 cfm max = 304 mph = 0.40 mach
2.25" piping
300 cfm = 123 mph = 0.16 mach
400 cfm = 164 mph = 0.21 mach
500 cfm = 205 mph = 0.26 mach
600 cfm = 247 mph = 0.32 mach
700 cfm = 288 mph = 0.37 mach
740 cfm max = 304 mph = 0.40 mach
2.5" piping
300 cfm = 100 mph = 0.13 mach
400 cfm = 133 mph = 0.17 mach
500 cfm = 166 mph = 0.21 mach
600 cfm = 200 mph = 0.26 mach
700 cfm = 233 mph = 0.30 mach
800 cfm = 266 mph = 0.34 mach
900 cfm = 300 mph = 0.39 mach
913 cfm max = 304 mph = 0.40 mach
2.75" piping
300 cfm = 82 mph = 0.10 mach
400 cfm = 110 mph = 0.14 mach
500 cfm = 137 mph = 0.17 mach
600 cfm = 165 mph = 0.21 mach
700 cfm = 192 mph = 0.25 mach
800 cfm = 220 mph = 0.28 mach
900 cfm = 248 mph = 0.32 mach
1000 cfm = 275 mph = 0.36 mach
1100 cfm max = 303 mph = 0.40 mach
3.0" piping
300 cfm = 69 mph = 0.09 mach
400 cfm = 92 mph = 0.12 mach
500 cfm = 115 mph = 0.15 mach
600 cfm = 138 mph = 0.18 mach
700 cfm = 162 mph = 0.21 mach
800 cfm = 185 mph = 0.24 mach
900 cfm = 208 mph = 0.27 mach
1000 cfm = 231 mph = 0.30 mach
1100 cfm = 254 cfm = 0.33 mach
1200 cfm = 277 mph = 0.36 mach
1300 cfm max= 301 mph = 0.39 mach
And the flow rates of most Mitsu turbos
Flow Rates @ 15psi:
TDO4-9B-6CM2 265 CFM
TDO5-12A-8CM2 320 CFM
TDO4-13G-5CM2 360 CFM
TEO4-13C-6CM2 360 CFM
TDO4L-13G-6CM2 360 CFM
TDO4L-15C-8.5CM2 390 CFM
TDO5H-14B-6CM2 405 CFM
TDO5H-14G-8CM2 465 CFM
TDO5H-16G-7CM2 505 CFM
TDO5H-16G-10CM2 505 CFM
TDO6-17C-8CM2 550 CFM
TDO6H-20G-14CM2 650 CFM
TDO7S-25G-17CM2 850 CFM
TFO8L-30V-18CM2 1200 CFM
If you have the pounds per min rate or lb/min of a turbo the conversion is done easily:
lb/min x 14.27 = CFM
Example: Big16g has max flow rate of ~39-40 lb/min
40lb/min x 14.27 = 570 CMF
Which means that even 2'' pipes do not restrict the MAXIMUM flow made by Evo3-8 B16g.
Now imagine the lag you get from 2.25 or 2.5'' pipes on 14b!
These conclusions are based on low level boost 8-15 psi on stock internals motor.
Credits go to gstryyder on DSM Tuners and boomtown on EvoM.net