Everything (almost) went to plan, I had to lengthen the oxy sensor cable, no biggie as it was to be expected, it fitted ok but very slightly makes contact with the block ( I can live with that for $200 ) but I did snap one bolt where the headers bolt to the front of the cat. After a few choice words and with time slipping away I thought, stuff it I’m going for a drive!
Over all impressions were positive, seat of the pants feeling was maybe a little more throttle response but that could be the power of suggestion from the deeper engine note, but there was a horrible buzz at about 3000rpm, it was there before hand but I thought it was the heat shield on the original headers.
So having run out of time I booked it into the local exhaust place today to get the bolt fixed and trace the noise.
I got the phone call today to say that it is the cat buzzing at certain rpm's, would I like to change anything else while they are working on it?
I can’t really afford it but yes, yes I would!
So from my new headers, a new 2 1/4" free flow cat, 2 1/4 pipe into a resonator, 2 1/4 " mandrel bend into a 2 1/4" straight through muffler ( brand name escapes me at the moment ).
While the job is currently unfinished the shop did tack weld it all together for a trial hearing, fantastic bark with out the fart that seems pretty common with hot 4's but still plenty of leaks (obviously) and way to loud - they assure me once all welded up it will quieten down and that the same system sounds pretty good on other MX5's they have done.
Will up date this after I pick it up tomorrow
