Roacho2

yo,

so my exhaust manifold cracked large... and i bought a header to put in it's place.

i don't plan on putting in an full exhaust system anytime soon.. my question is if i get a new catalytic converter, will it make a difference without getting a catback?

i'm stock on an Si with an AEM COI

spracingsports

a high flow cat will most likely help a little, but not as much as it would with custom exhaust...

btw ... what is a COI????

Roacho2

it's a big goldfish.

:P

imported_t_dot_SiR

i have the opposite thing...
i have a customize catback exhaust system
but i have a stock header....
not much difference...

**except now i have problem passing emission!! hahaha)

imported_bevboyy

The there are three points to look at:

1) diameter of piping used
2) use of low restriction resonator
3) use of low restriction muffler

The cat is actually free flowing by design. Just get one that matches the diameter of piping you are going to use on your system.

The most amount of restriction found is in the resonator - followed by the muffler.

Don't go too large of a diameter of piping. You'll loose bottom end (the stuff that moves you off the line..)

Roacho2

so if i get a good resonator and muffler, i can get away with spending $300-$400 instead of $850 for larger piping, muffler, and new catCon..?

and i'll still get some more boost..?

imported_My93Civic

Just take off the resonator and get a Catalytic converter or take that off too..Just get a custom 2.25" catback exhaust.

Roacho2

i put the header in... no heat shield... i guess i don't need it?

imported_My93Civic

The heatsheild is there for a reason; leave it on. Keeps the engine bay cooler than if you have it out too. Also helps the heat heat up the exhasut manifold (header).

You need it.

Roacho2

my old heat shield doesn't fit over it........

imported_My93Civic

EH? Okay then you don't 100 percent need it. But if you can put it on its advised.

imported_My93Civic

What Ractive header you got there?

Roacho2

i dunno man... it's look like chrome... i'm guessing polished stainless steel.

four pipes come down much longer than the stock, become two, those go all the way down almost to the catalytic where it becomes only the one pipe.

the o2 sensor is only in one pipe would isn't ideal.

it's pretty crazy how hot it gets after 10 minutes of driving. water was immediately evaporating when it hit it.

I'm going to call my vendor and ask about a heat shield for it i guess.

imported_BoOsTd

dont worry about it, exhaust gas is hot, therefor a headder will be extreeml;y hot... just leave it its normal. you wont find a heat sheild for after market headders.. besides headder wrap which is not nececary for you.

Roacho2

no necessary for me cause i will never turbo my engine and such?

i don't race my car... but i do drive like an idiot at high revs sometimes..

imported_My93Civic

In reality, my preference would be to have it because of what I stated above and plus it wouldnt get too dirty....

But is it 100 percent needed? No. But if you can get one, great.

What car you have?

I think you have the Ractive H101?

Roacho2

i have a 98 civic si.

i have the box in my trunk i can check at lunch if you really want.

so i want my header as hot as possible and my engine bay as cool as possible?

i'm looking at safety/breakdown issues, or a bit of hindered performance?

imported_My93Civic

Don't worry Roacho2. Nevermind what I said, in all reality it makes little difference.

Just when you get to drive it tell me if you feel a difference in performance for the Ractive header against stock.

Roacho2

there were two cracks in my stock. i booted around with it last night... 3500+ rpms I think I feel a little more than I used to.

I got a cold air, so they should be working well with eachother.

somes days, i feel like i'm getting sick performance, and other days, it feels like ****... kinda weird... i might be on crack or something..

i can take pictures if you want. it looks kinda funny.. my engine is dirty and whatnot... then there are these shiny massive pipes coming out of it.. haha

imported_kane2k

The heat shield just protects local parts that are susceptible to heat like wiring, insulation, etc. There's really not that much to protect at the front of the car. Having a heat shield does not reduce your engine bay temperature, it just distributes it so that the extremely hot header isn't exposed.

I wouldn't worry about trying to get another, just visually inspect and ask yourself what could melt. You can tinfoil wrap anything that you think might be vulnerable and that can't be moved.