H22-do you need IAB?

[scttydb411]

Here's an illustration of what IAB does for you. This H22 had 2.25" exh, hp header, tuned on CromePro. If you use a p72 you can have the functionality of IAB and you'll gain 3-4 hp and 5 ftlb down low as well as the gains above 5.5k rpm. you can use a p28 and disconnect the IAB and get the result of the red run as shown. Is it worth spending the extra $ on a chipped p72? I don't think so. Just make sure your tuner properly disables the IAB's when it's tuned (I've seen a few "tuned" H22 using p28 that weren't tuned right resulting in the blue run).