6G Celicas Forums

So I've had my Celica for over a year now, and about a month ago I noticed my exhaust manifold had started to crack, right in the middle. I would say between the number 2 and 3 cylinders but I'm not sure that's the correct terminology. (Cylinder numbers go in order of firing order, right?)

Anyway.

Two days ago, I start up my car, and nothing sounds off as it idles. And then I start driving, and I hear a rattling sound much like that of my buddy's Firebird. The problem with that? His Firebird's catalytic converter is hollowed out. And now mine is too, it seems. Same sound, and my engine sounds a tad bit different at certain throttle positions or rpms.

Thus I'm going to replace the entire system, headers, hi-flow cat, and exhaust, but I have no idea where to start as this will be my first-ever performance related modification to a car. So I have a few questions.

Firstly, how much is a hi-flow cat going to run me? I hear prices in the range of $200 which isn't too bad.

Secondly, I have no idea how an exhaust system runs under the car. I know where my cat is and what it looks like, but after that, nothing. So what will I need for new exhaust piping? I would love to order a Tanabe Medallion but they only come in packages for certain cars. Can I just buy a cheap Medallion for say a civic, have a shop cut the old piping and weld new piping in for my car and call it a day? Or is there something more to these to get the correct sound out of it? I want something with a deep hum or a low rumble to it. My friend's STi has a Blitz Performance system that sounds great, but I know the 2.5 Boxer doesn't necessarily sound like a four cylinder.

Thirdly, are there any tuned headers for a 7A-FE? I'm scared to look on EBay, I always see people going "don't get cheap EBay headers" but I have no idea where to start. According to my Dad, I'll need tuned headers (each pipe being the same length as he explained it) in order to see any performance gains from it. If there aren't tuned headers I suppose I could go with...untuned? headers but either way I need something to replace my manifold before it splits completely.

From what I understand, I wouldn't even bother w/a high-flow cat, our exhaust systems are so small anyway that a high flow cat is just pretty pointless. I've been told by a few different exhaust shops that a cat is a cat, the only thing that makes it high-flow is a larger in and out port. Since you can't go above 2.25" anyway, the added expense just isn't worth it.

On the other hand, you can reasonably expect to pay around $100 for a cat anyway, so 95CelicaSt's suggestion on the Magnaflow cat is a good one.

Its what I put on the mr2.

And 2.5" is fine. They can taper the pipe to fit.

http://www.magnaflow.com/02catalytic_conve...universal=50005

It's like $200 - a direct OEM replacement is almost $300 though lol.

Edit: I lied - I don't think that's what I need, would this be it though?

http://www.magnaflow.com/02catalytic_conve...universal=54955

This post has been edited by Espo: Jul 29, 2010 - 2:59 PM

well my stx is my beater but ill give it some love because though it aint rwd its still a celica.

my manifold was cracked like u said so heres what i did

bought a alpha werks header for a 7a corolla from ebay, $42 dollars
bought a big oval polished aluminum muffler from craigslist, $30 dollars
took off the 2nd cat to inspect it, clogged, gutted it (no emmisions here)
test fitted the 7a header, fit good but was too short to reach the cat and the header doesnt have the 2nd o2 bung for your sensor
cut the section of pipe after the flex pipe on the stock manifold/pipe assembly off
cut the flange off the rolla header,scrapped it
cut the flange off the stock mainifold pipe but left a bit of pipe on (enough to weld to)
went to the exaust shop and had them weld the stock pipe onto the header to the cat but had the pipe rotated so that the 2nd o2 bung is on its side instead of strait up. $25 dollars
forgot the damn muffler so its still not on yet but was told id be $50-75 for the piping to be welded on (since i have my own muff and looking for a resonator)
went to autozone bought a new o2 sensors
went home and extened the wires for them
enjoyed my fun test drive

if u need pics i can take em 4 u

This one http://store.summitracing.com/partdetail.a...mp;autoview=sku

Or this one http://www.summitracing.com/parts/MPE-5995...mp;autoview=sku

Thanks again, 95. You've been a great help. Looks like I'm all set then - I only have one cat I assume right? Because I read somewhere recently about a second cat - don't know if that's just a gt thing or what though.

There's 2 cats. stock exhaust manifold goes 4-1, pre cat, downpipe, then 2nd cat, but if you're getting an aftermarket header, you only need to worry about the one cat before the exhaust.

Definitely getting an aftermarket header. Thanks Hector.

yea, that ebay header honestly sort of 'wakes up' the 7A and gives what I felt like was a much stronger midrange and cured that top end fade, it felt like mine wheezed out much closer to rev limit than it used to.

espo i made a thread for you and others about moddiing the rolla header.

http://www.6gc.net/forums/index.php?showtopic=75318