JaneRX7

I keep on reading and talking to people and they tell me the first thing I should do when modifying my car is to change the downpipe. What exactly is it and why is it so important to change it??

mightyslash

Geez....https://www.rx7club.com/forum/showth...threadid=68640

DJ!

its the pipe that comes off the turbos for the exhust

MySilverRX7

replaces your pre cat converter

GoRacer

iTrader: (2)

There are two catalitic converters. The pre cat and main cat. The pre-cat is used for emissions on cold starts only. After that, the main cat is used for emissions. You can think of your exhaust system as a straw and each cat as a sponge inside the straw. Now think of how much easier it would be to drink your soda without the sponges. The pre-cat has a temporary function but it's restriction does not go away.

http://www.rx7turboturbo.com/robrobi...efinitions.htm

http://www.scuderiaciriani.com/rx7/downpipe.html

blackscorpio

If she doesnt know what a downpipe is what makes you think she is gonna know what a precat is.

The downpipe is the exhaust pipe that connects the turbos to the the catalytic converter. In stock form the FD has a pre-catalytic converter which acts as a second catalytic converter for cold start emmisions. The pre cat. tends to restict the flow of the exhaust off the turbos causing the turbos and engine compartment to be hotter thus reducing the cars reliability. Also the precat tends to clog up with time further reducing the exhaust flow, thus makin the engine bay even hotter I think you get the picture.

apneablue

Your exhaust is divided into three sections...coming from the turbos which are bolted on to your engine...the first thing is

Pre-catalitic converter or Pre-Cat (replaced with Down Pipe for additional airflow and cooling)

that attaches to (with bolts, no welding required):

Catalitic Convert (replaced with Mid Pipe also helps with flow and cooling)

that attaches to the exhaust (replaced with Cat Back...don't think this does much for cool but definately helps with the flow)

how come no one calls the the CatBack the "Post Cat" ?

blackscorpio

CUZ IT DOES NUTHING TO HELP WITH EMISSIONS

Crashunit

always thought the rule of thumb was intake and exhaust first. Them DP amd ECU. BU I dunno thats just me maybe. I kinda take after the 3 Mod rule.

Zoomspeed

people like to do DP first becuse the pre-cat holds alot of heat in the engine bay. so when you elminate it it cools down your under hood temps as well as letting your turbos spool faster. I tihnk the gain forma DP is around 20 HP or so. Although I could be wrong.

jpandes

This is too funny. If the thread starter was a dude, he'd need a flame suit...LOL. I can't blame anyone, though. Women who own FD's are sexy. no matter what they look like. YOU GO GIRL ! ! !

~ John

FD Seeker

You ain't kiddin!!

Jokes on us though... it's probably a dude who already knows this

RiON

was wondering does it make it louder if i jsut put a donwpipe on wiht stock mid pip and exhaust?

NuBiRaCeR

it would be pretty quite if its stock. but the the exhuast flow would be weaker depending on how wide the downpipe is. you should try to get larger pipes for the mid pipe and downpipe, and also high flow cats, for performance.

PS just dont turn out to be a *gay* "RICER" with those big huge exhuast tips and dont do anething else to their exhaust system. and pulling only 5mph when they sound like they going 60.

Zoomspeed

Yeah it'll be a lil louder with jsut a downpipe.

You can't have a STOCK midpipe though cuz a midpipe is what replaces your stock cat.

jpandes

I have a 3" SS downpipe, an N-tech hiflow cat & an HKS cat back exhaust...My car is pretty loud, bordering on Obnoxious. I got pulled over for having a loud exhaust.

I can't imagine having a Midpipe...