IRTB 4.0
New (4.0 on the left) vs Old (3.4 on the right)
This is my 4th version of the airbox for the IRTB setup. This version aims at increasing the air volume between the filter and throttle plates in order to improve throttle response. Estimated volume increase from about 2.2L to 5.5L.
Though not as insane as with open air-horns, throttle response is still much improved from the 1.5 times increase in volume, so much so that the SDS started to lag behind in quick throttle blip again.
I took the time to revise the vacuum hose layout to get more responsive MAP signal to the SDS. I drilled 5 holes on a 1/2" brass pipe and solder in 5 small brass fittings with diameter good for vacuum hoses. The front end of the 1/2" pipe was covered with a matching plumbing cap. The rear end was soldered in with a brass fitting for the brake booster and PCV hose. SDS catches up better but I think the 1/2" brass pipe is still too big. Next I'll use a 3/8" pipe in place of the 1/2".
For the final touch, the removable sealed air box cover is polished to mirror-shine. And of course, stickers add the final 10 hp (just kidding!), as these $2 stickers from "Canaadian Tire" are locked up in the cabinet right in front of the counter while $100+ power tools are "up for grabs"!
