Sup HT, need some help.

I'm pretty new to engine mods and what not so forgive me..

I wanted to upgrade my exhaust system so i decided to start with buying my header so i bought the Toda RH 2.5" collector. I'm confused on how i would install it to my stock exhaust that i have.

I still have my stock catalytic converter, and i know that i'm going to have to replace it, but what do i replace it with? I've read about test pipes but i've also read that they make the exhaust sound awfully raspy which i don't like.

So my question is, what do i replace my cat or what do i need to do with it in order to bolt my new header on? Would buying a 2.5" hi-flow cat work? Then again how would that fit onto my stock exhaust? I'm just confused. If someone could shine some light. It'd be great.

Thanks in advance.

 

Custom piping work.
If u dont want the raspy sound. You will need a cat.
Take the header and the highflow car to a local muffler shop. They should be able to figure something out for you.
Goodluck

 

A lot of places sell a 2.5" flange for the exhaust side; you could have that welded onto your stock cat at a local shop.

Or passwordjdm sells adjustable length test pipes.

What vehicle is the header meant for? With a 2.5" collector it sounds it may be for a jdm ITR. You could run a JDM ITR exhaust...it's a nice upgrade and essentially a direct fit for a stock civic.

 

Thanks man. The header is meant for b-series motors and that's what i have.

I might look into buying a hi-flow cat. I'm confused how it would fit though. If my header is 2.5" and my exhaust is smaller, i believe about 1.75"-2". What size of a hi-flow cat would i have to get to make them connect?

 

If you already bought a TODA header, you might as well get your exhaust done while youre down there.
Get a high flow cat and upgrade to 2.5 piping.
And as speedooo said, you can run an itr cat-back, still stockish and able to stay within emissions, but also a significant upgrade.

 

Yeah i most likely will.

But for now if i get a 2.5" hi-flow cat to attach to my header. How would the outlet fit onto my stock exhaust? They're different sizes.

 

get a test pipe and a new exhaust(both 2.5) you'll like the sound way better than a stock ITR or just adapting you'r current one to fit.

 

I don't really want to run a test pipe tbh. Esp since i live in CA.

Would this work:

Toda Header > Hi-Flow Cat > Greddy Evo2 Catback

?

 

ok I can see that then if you live in CA. Toda header>HFC>Greddy catback shound be good or skunk 2 megapower R (if you like it loud)

 

Sounds good. Would i have to get any of these welded?

 

I would recommend having flanges if possible that way if you need to remove/replace any parts.

 

Don't let a shop just weld it all together. Buy the flanges that will match or they may just cobble something up if it's a shop you can't really trust.

I had a civic coupe that the prior owner brought to a shop and they had redone the exhaust so it was two pieces. An axleback, and everything in front was welded together from the downpipe to an aftermarket cat to the b pipe. Then I had to replace the oil pan gasket...what a pain.

 

Wow that must of been a lot of work i can imagine..

Planning not to get anything welded. Thanks homie.