I have an EJK on the way and in preparation for this I removed the airbox mod, so thought I would share an observation. I've had this done for nearly 20,000km and didn't think it made a change when I did it. Any improvement was in my head I reckon. I had also assumed the air flap changeover occurred around 4000 rpm but after Azza said that TDMs in this part of the world were different I checked. Mine operates between 2100-2200. There is some hysteresis in it; ie it's different when increasing and decreasing, but it's always in that range. So that explains why no difference at lower rpm.
But one big thing I noticed on removing it is the improvement in jerkiness off the throttle stop. With the mod done, if I wasn't careful to keep revs off idle in a tight corner I could nearly get tossed off when putting revs back on if applied quickly. With the airbox operation restored to normal there in none of that tendency to buck me off. All very odd, so I will be leaving he modification off regardless of whatever happens with the EJK. Will report on that when it's done. G
But one big thing I noticed on removing it is the improvement in jerkiness off the throttle stop. With the mod done, if I wasn't careful to keep revs off idle in a tight corner I could nearly get tossed off when putting revs back on if applied quickly. With the airbox operation restored to normal there in none of that tendency to buck me off. All very odd, so I will be leaving he modification off regardless of whatever happens with the EJK. Will report on that when it's done. G