Where to put a high flow cat?

hi guys,

I'm on the verge of installing toda headers on my dc5r with the fujitsubo RM01A, now i know its a massive fine not to have a cat installed but i dont want wruin the toda headers,i've heard you can have the cat installed in the exhaust system,does anyone know the pro's n con's to that and if its a good idea?Also are the high flow cats the way to go?.

Any insight is appreciated.

You will need a cataylic converter otherwise expect to pay a big fine.

high flow cats are very good they wont restrict the air flow an will give you a little bit of a power increase

Cat goes in between the Toda headers and the RM01A. Don't install the test pipe that comes with the Toda headers. Install a cat in that place instead.

My undersanding is that you can get a set of Toda headers, and put them straight onto a DC5 and it'll attached upto the cat back exhaust... no need for a test pipe.

So OP is left with the option of cutting up the Toda Headers or cutting up the RM01A to fit the cat.

Personally opinion, weld the cat to the headers. If you decide to sell and part the car in the future, and you've attached it to your cat back, you'll have the problem that a prospective buyer for your RM01A might not be interested as there headers are going to have a cat already, and then the RM01A is also going to have a cat, thus running 2 cats.

I also agree with that,which is why most ppl get it put in with the header,if i weld the cat to the header ,the header will still need to be cut at the bottom to fit the cat in am i correct? or does the cat connect to the end of the header?

as above, your system should look as follows:

toda headers - high flow cat - rm01a

no need to weld cat on to header or catback. they will just flange up the cat on both ends so your headers and catback bolt on like the factory system. just bring it to the exhaust shop and they'll sort you out.

There is some terrible reading comprehension in this thread, the guy has a DC5. 45SET knows the score though. There is no test pipe or flanged cat that can be removed when running a Toda header on a DC5 without modification, the header bolts straight to the 'cat back' exhaust.

I would get the Toda header cut and and a good quality high flow cat welded in with a donut gasketed flex joint with spring bolts. It is important to retain some flexibility in the header otherwise it can crack. Modifying the header will give you the best resale value of both header and exhaust since most people in Australia will want to run a cat and won't already have one welded into the cat back.

as above...plus:

i have installed this kind of setup before and its not fun...installing a cat to the catback section is hard because of the angles that come off the flange so the best way is to go with modding the end of the headers BUT you have to be precise in which type of cat you buy, because the wrong diameter or shape will give you very little ground clearance. But if you get a cat that has a flush diameter with the piping, any cop or epa officer will not believe there's one in there. Plus from memory you have to factor in the O2 sensors or something.