My CB7's current cat is specifically designed for the F22A4 stock motor and is still literally new. However, I'm planning to swap in an H23 blue top in a few months. Anyhody know if the bolt patterns/fittings will be the same or will I have to get a cat specifically for a Prelude motor? I would hate to waste my money on a new cat if my current one fits fine...

 

The header is a different length, so if you use a H22/H23 header then you will need to cut it to fit the Accord exhaust. I can't recall how much I had modified. Keep in mind, the exhaust piping stock is going to be more restrictive than that motor is used to.

Will it work? Sure
Will it work as well as one designed for the motor? No

 

So my current exhaust system needs bigger diameter, check. But what about my cat? For obvious reasons, the cat and exhaust sizes won't match up then, right? So that would mean I would have to ditch my cat and customize the exhaust piping to match the cat that I will need for my H23?

 

You have many many options...

1) Just weld on an adapter when you modify the H22/23 header and go from say 2.5" to 2.25" or whatever it is and leave the rest of the exhaust stock

2) Cut the header, weld that adapter then weld on whatever size exhaust you want (ex. 2.5 > 2.25 > 2.5)

3) Go aftermarket and toss on a test pipe + O2 defouler and run whatever exhaust and not worry about spending more money on another cat

 

Option #3 won't fly in the communist state of California. I will be here for another year or two then I will be moving away from this ****... Lol

Looks like option 1 and 2 is all I'm left with...

 

You could also buy an aftermarket header, "high flow cat", and get a nice full LEGAL exhaust. Although that may be difficult, I'm unaware of California's limits on exhaust systems. Northerner'

 

That engine is "functionally the same" as the h22a1 so you can BAR it. You will need the exhaust manifold from any h22. It doesn't matter what year as this part is the same for all h22's. Get the h22a1 downpipe and that should match up with your existing cat. The A4 and h22 use the same size diameter piping and the flange should be the same as well. Worst case scenario you will just have to have it welded together, but it will fit with your A4 exhaust. The A4 and h22a1 both use the same aftermarket cat.

btw when i say A4 I mean f22a4

 

Thanks for the useful insight. The exhaust system restrictions around where I'm at are a joke. I'm not sure about whether or not they have be a "recognized" brand or not, I'm sure just as long as they are not extremely loud (as in decibels) or have very reflective parts to where anyone behind you will get blinded...

 

I got the most basic system exhaust system possible as I think my exhaust guy fabricated it on the spot that's why it was so cheap and mine is just barely loud but nothing serious. I never have any problems with cops. I think as long as you don't specifically ask for a loud exhaust you should be fine. Keep in mind for emissions purposes nothing behind the cat to the muffler is illegal. It only comes down to sound decibels as to if it's too loud it's illegal.

That's why they talk about "catback" systems. These systems don't actually include the "catalytic converter" as you would think. It's everything behind it.

 

What about the ebay N1 style exhaust system? Would you recommend this? Just for functionality's sake?