I'm just about to make myself a de-cat pipe, which'll replace both thje cat and the small centre box just after it. Is this a wise course of action? I'm aware it won't pass its mot like this but if I'll get more power........
The reason I ask is, the dreaded max power(or was it revs?) a few years back did a back to back test on an escort RS2000 (k plater I think) and it lost eek! power with a decat pipe, and made 2 - 4 bhp with a freer flowing cat.
Chris, I fitted a 'straight through' cat (basically a cat without it's innards) and it made a noticeable improvement between about 2000 and 3500 rpm, but not below or above that range.
The standard cat needs to be replaced for the MoT, but the advantage of using a straight through one the rest of the year is that the standard (and expensive) cat will probably last for ever, doing about 20 miles a year.