Official "custom" exhaust thread, for all engines Options

[njccmd2002]

now that we are talking about exhaust. can somebody teach me the parts of the celi.

now, i know the first part is the catalizer that goes into the downpipe that connects to the flex pipe, but i see my car has like another cat and a tube before the muffler? what are those.

[presure2]

the smaller one is the cat, the bigger muffler looking one is the resonator.

[njccmd2002]

ok so it flows like this.


header -> Cat-> downpipe----> flexpipe---------> 2nd cat------------Resonator----------->muffler!!!

thanks. too complicated!!!

[hurley97]

Did you get a good price on the Vibrant stuff? I carry it if you want to check prices with me sometime.

What's the deal with the two 02 sensors in hurley's downpipe?

-Doc

she bought everything herself for her setup, im not sure what she paid to be honest...i know a 3"vband like that at the local speed shop is VERY expensive..like close to 80$.

PM me a price on the 3" vibrant vbands, ill be using a few of those in the hopfully near future on my own exhaust!

the 2 sensors are:
1 for the OEM pre cat sensor.
1 wideband / postcat sensor for stock ecu
she also has one farther down the exhaust path, after where the cat would go under the car.
im not sure if its an st, or 96+ thing, its the 1st and only 7afte ive worked on, to be honest...lol

Oh a wideband, that would be it.

Yeah V-bands are VERY expensive. The 3" complete set (clamp and two flanges) are $88.95 each from Vibrant, and they don't discount their stuff very much. I can get them for around $74 and probably work in some free shipping with a good order.

-Doc

I got mine from Verocious Motosports for $72.93/ea plus shipping, I paid about $220 on three flanges, of which we only used two.

Anyone want to buy a 2.5" V-Band clamp and flanges for $75 shipped?

the 96+ 7A has no cat in the manifold, just the small one underneath. So the first O2 sensor is in the downpipe and the second is after the cat which is under the car.
the second sensor in my downpipe is just a wideband, as Manny said.

This post has been edited by hurley97: Sep 28, 2008 - 6:07 PM

[elastikman]

ok so it flows like this.


header -> Cat-> downpipe----> flexpipe---------> 2nd cat------------Resonator----------->muffler!!!

thanks. too complicated!!!

I think is more like
header -> downpipe----> flexpipe--------->Cat------------Resonator--------->muffler!!!



Like promise here is the video:

@Headers 4-2-1
@Straight exhaust 2" No-Cat, No-Resonator.
On CELICA 1.8 ST 7AFE

VIDEO: http://www.youtube.com/watch?v=3QfxprvM548

This post has been edited by elastikman: Sep 30, 2008 - 4:35 PM

[97celiman]

i dunno i have 2 cats...maybe its a obd thing??? i dunno just guessing...maybe dr tweak could straighten us out

[njccmd2002]

i tought 97 gt have a cat in the header, thus 2

[delusionz]

I beg to differ on a number of points, but what I have to say doesn't apply to the US folks as they don't have 3s-ge motors and legally require catalytic converters....

But assuming you have a 3S-GE motor as I do, Which comes with decent 4-2-1 headers and a 2.5" system as standard and you live in a country with no emissions laws as I do....

1. The point made about a cannon muffler on a stock system will do nothing at all except sound louder...

-- the standard 2.5" is already big enough for a 2 litre NA motor, still need to upgrade pipe?
-- the cannon muffler flows straight, it doesn't zig-zag from 1 side to the other in an oval
-- the stainless steel cannon muffler has got to weigh less than the large cast iron oem muffler right?

2. the point made about not decatting...

-- the uk 3s-ge guys say their midrange acceleration is freed up
-- a straight pipe weighs 15kgs less than the catalytic converter

[GriffGirl]

For those of us for whom a cat is required, there's always the option of investing in a good quality high-flow cat if you really want to free up that airflow. I think ceramic cats are supposed to be the best, but they don't come cheap.

[DEATH]

A $100 magnaflow hiflow does the trick for almost nothing and very little restriction - IMO the way to go.

[hurley97]

I've been driving my car with a straight exhaust, no cat, for about a month now and the P0420 Cat Below Efficiency code only came on once about two or three weeks into it. I thought it would realize there was no cat much much sooner and more often. I'm waiting for it to come on again to determine the approximate time frame and driving habits that cause it to throw the code.

My backup plan if it threw the code too much was to use some spark plug non-foulers from Autozone and do what some Subaru guys do to pull the O2 sensor out of the direct stream of the exhaust gas which causes it to read leaner than the primary O2 and tricking the computer into thinking everything is fine:

[DEATH]

Oh that is an awesome idea. Will defintely help the OBD2 guys when they install a header.

[delusionz]

Out of curiosity why would you want the o2 sensor reading leaner than it is? When the ECU reports cat below efficiency how does this impact the performance and driveability of the car?
For this trick to work would you not need a separate AFR management system with a separate wideband o2 sensor?

[hurley97]

The second o2 sensor after the cat does nothing but tell the computer that the cat is working. The converter is supposed to filter out the exhaust gas, so a leaner reading means less fuel in the mixture with means the exhaust gas is being filtered well enough. The second o2 sensor does not affect how the car runs.

[95CelicaST]

What I did on my WRX (and I know this has no practical use in the Celica world unless turbo) but I had a small curved pipe welded into my downpipe for the o2 sensor. This way it sits out of the stream, but still reads normally. Let me try and dig up a picture.



This post has been edited by 95CelicaST: Oct 1, 2008 - 8:32 AM

[elastikman]

Hey!
Whats best option ?
1x 18" resonator
or
2x 10" resonator ?
or
other configuration ??

[hockeyplyr24]

hey everyone

figured i'd show ya my muffler. i have a custom catback..but had to get a new muffler welded on and it actually just got done about an hour ago. This time i went with the OBX B10 that they were talking about in the beginning of this thread. I definitely like it, its pretty big, and made it A LOT quieter than my other muffler. heres a couple quick pics. sry if the quality isnt that great its from my iphone







lemme know what you think about it

[elastikman]

Thats a BIG muth*f**er muffler!!! ehehe

[GotToyota]

Nice work, but I personally don't like how many people have their mufflers pointing down, like you do. I prefer the look my Supra had, which was actually tilted up and angled out.

Basically it's this:


Compared to this:


You decide which one looks better.

-Matt

This post has been edited by GotToyota: Oct 3, 2008 - 6:07 PM

[hockeyplyr24]

yeah i wanted it to have more of an upward tilt..but the guy couldnt mess w/the piping w/o charging me..it doesnt look horrible tho..i can deal w/it..plus they are both diff cars and have diff looks..if my piping were any lower it would scrape all the time..my muffler already scrapes


and yeah..its freakin gigantic..didnt think it'd be that big lol