Hollowing your cat will provide a little bit of quicker spool up for the turbo. If you don't have a turbo most likely you will have a loss of low rpm torque with a little increase in high rpm hp. Also, your exhaust will become much louder (not for me) and could it land you a $100,000 fine or several years in prison if you are caught(no prison for me, thank you). Not worth it for 2 hp + or -. In fact, in a test in SCC, they found that without a cat they lost 1 ft lb and no hp by removing the cat on a project car. So what I'm saying in the street driving use most cars see, removing the cat is not a good idea. Do what I did, I bought one at http://www.summitracing.com. It is a high flow cat with 2.5 I.D. piping to match the rest of my exhaust. It will be on next week and I'll let you know the difference. The best thing about the cat is I bought it on wednesday night online for $67 delivered, and it arrived this morning (Saturday). Woah, sorry about the rant! I just don't think there are any advantages on cars like ours in removing the cat
A forum community dedicated to Mazda MX-6 owners and enthusiasts. Come join the discussion about restorations, performance, upgrades, modifications, classifieds, troubleshooting, maintenance, and more!