I just finished deleting the Tumble Generated Valve System on my MY01 WRX
as described on NASIOC. All I can say is that it makes a lot of difference in spool up time. I would say at least 10 extra HP. There is more in this mod alone than in i/c hoses, porting exhaust manif., porting throttle body and porting i/c together. A must do on cars with TGVS. But itīs a lot of work to do properly.

Have fun :-)

 

What "version" did you do? I've seen various options on NASIOC from just removing the flap right through to converting to a completely empty ported tube.

Also, did you need to do something to fool the ECU to thinking the tumbler system was still working fine?

 

Sorry for the slow answer Hades.

I took out the valves, cut the axles in halves and removed the partition walls with a saw and a grinder. Didnīt have to fool the ecu as all the motors and sensors are still there. No problems, no cell just a lot of useable power and fun. Later I installed the AVO turbo inlet pipe so itīs time for a re-map now (knock-link has turned into a christmas tree :-) )