Quote:
Originally Posted by lawdogg
I just took an N/A plenum apart today. Those are the longer runners in mitsu's variable runner length design. It's pretty cool how it works. The physics behind it is even cooler - namely the organ pipe theory. When the intake valve opens, it releases a negative pressure pulse (i.e. sound wave) up the runner. When the wave hits the top of the runner, most of it continues into the plenum but a certain % of it is reflected back down the runner as the inverse - a positive pressure wave. When the engine is at the right RPM, that positive pressure wave hits the intake valve right when it closes, thus forcing a little extra air into the cylinder and improving volumetric efficiency (POWER).
The reason for the dual lengths is that at lower RPMs, there's more of a lapse between intake valve openings, therefore the longer runners allow the stronger first or second pulses to synch up ... whereas at higher RPMs, the valves within the N/A plenum open, cutting down the runner length considerably, and working with the shorter lapses between intake valve openings.
Pretty cool huh??  |
+1
This is corrct. Those black pcs in you hand create a velocity stack opening at the begining of the longer but smaller diameter runner. this allows for grater air speeds and volume in the smaller runner. The NA intakes are made by and designed by Mikuni for mitsubishi. Mikuni make most of your bad ass bike intakes and this system they did for the NA is top notch. This is good stuff your looking at. This system can not support the big cams that I have and head work that I did. But I will never be able to get the low end torque back that I lost when removing this system.
Now I can not just put it back, because now all the runner length are wrong for me. Win some, lose some.
