While it's obvious that too small a pipe will choke performance, I'm curious about the other side ofht ecoin: How does an intercooler pipe size that may be too large affect performance?
I'm currently running a smallish FMIC with 3" piping on my Toyota 22RTE truck:
The system works OK, but I believe I can do better. I recently picked up an intercooler that should offer better cooling and flow due to a larger frontal area and a more flow-friendly design, however, the new IC has 2.5" inlet/outlet piping.
My question is, what effects can I expect from downsizing from 3" to 2.5" piping? Will the greater velocity from the smaller size improve response, or will the smaller piping choke flow at WOT? I'm currently making 220 rwhp @ 15 psi (91 octane gas, no water injection), so the current 3" setup is probably oversized for my needs. However, I will be adding WI in the near future and hope to be able to run a leaner mixture and more boost (the motor is built for a solid 300 rwhp)...but 3" may still be too large for my motor, and i wouldn't mind tuning the system a bit for better low end response. And if I'm going to move to the new intercooler, I'd just as soon do it when I'm plumbing the WI...
Thanks for whatever feedback you can provide.
-Jeff