Just wondering how many of you have replaced your catalytic converter(s) and restored a good deal of power in the process? My other Accord (2007 Accord 2.4) has almost twice the milage at 300K and has almost double the power. In my other Accord, I can easily chirp the tires right off the line pretty effortlessly. It JUMPS right on demand. so I am thinking this newly acquired (original owner; very well take care of) Accord needs a new CAT(s), a valve adjustment, fuel filter replace, ignition coil replace, battery replace. transmission fluid flush, fuel injector and valve cleaner, such as BG44K, and decolonization of the intake. I expect to see great improvement from these items. Just wondering if anyone here has tried CAT replacement and noticed a big bump up in power and throttle responsiveness. I am also wondering if anyone that has done a valve adjustment over 150K on the engine (mine has 170K on it) and if so, did you notice a bump up in power afterward? Thanks.

 

Bump. Anyone???

 

You'll get a couple percent of ponies with the valve adjustment, the other things you listed should help too. Typically if the car has alot of miles with no care and things like the air filter are dirty or you have partially clogged injectors or alot of different things are worn out, you can lose a substantial amount of power. It varies a ton of course on how much but it sounds like you might be down a good 20 or so.
As far as cat's go, unless they are horribly clogged your not gonna see much power increase from replacing it. Its just a metal box with some kind of honeycomb matrix inside that is coated in precious metals. They tend to flow enough in any condition for the engine to operate pretty well. I hollowed out the cat on my '94 Accord with an f22b1 VTEC motor and noticed pretty much no change in power other than some slightly better throttle response and the sensation driving it like I did SOMETHING but no 20hp or even 5hp.

Things I'd do:

• Air Filter
• Spark Plugs
• Fuel Filter
• Transmission Fluid Flush & Change
• Oil and Filter Change
• Valve Adjustment
• Clean the Throttle Body
• Battery
• Run Fuel Injector Cleaner Through the Fuel System (Alternatively you could spend about $100, remove your Injectors and have them cleaned by a company that performs cleaning services.)
• Inspect & Replace Accessory Belt & Tensioner
• Clean the VTEC Oil Filter

Your probably good on ignition coils, the '03 & up Accords have COP or "Coil On Plug" so theres a dedicated ignition coil on each spark plug. These are a solid state, enclosed, electronic coil so there no internal "contacts" to wear out and typically they are either are working or not.