dirtbike64

Can you really get past Emissions with a downpipe? Some people say you can and some say u cant. I know this is a stupid question but wut does "Catback" mean?

rx7eaven

I have downpipe with stock cat and cat back exhaust and passed emissions with flying colors. I am putting on a racing beat dual tip cat back, when it gets here, and I am thinking of going with a midpipe. Midpipes are illegal, you will not pass emission with one but with the downpipe you will be okay.
~Strike

djantlive

Catback is the pipe and muffler behind the catalytic converter. Pre cat is the mini catalytic converter from the engine exhaust to the main catalytic converter. A pre cat is often replaced by a down pipe which is a straight thru pipe without the mini catalytic converter.

I hope this makes sense.

dirtbike64

Will a downpipe replace all the cat stuff? And wuts a cat back exust?

Rx7Boi

A cat-back is a pipe to a muffler going from the cat to the back of your car

Mahjik

iTrader: (1)

No, a downpipe will only replace the Pre-Cat.

A Mid-Pipe or Hi-Flo Cat would replace catalytic converter.

Mid-pipes help out more in the higher end then Hi-Flo's, but you lose some lower end power (from what I hear). Plus, mid-pipes aren't street legal, so you won't pass an emissions test if there is one (unless you slip the guy a $50 ).

I'm using the Bonez Exhaust replacement system which replaces the pre-cat with a downpipe and the stock cat with a hi-flo cat. Then I added on a GReddy Power Extreme cat-back to complete it.

1FAST7

Mahjik, so how do you pass the emissions with your mods???

1FAST7

Mahjik

iTrader: (1)

The Bonez hi-flo is street legal.

http://www.rx7.com/cgi-local/3catalog.cgi?cat=4&part=1

1FAST7

Is the performance increase still really good? And how with racing midpipes you can shot flames, is that possible wit the Bonez replacement?

1FAST7

Mahjik

iTrader: (1)

Performance gain is very good. Not quite as good as just a straight mid-pipe, but still a LOT better than stock. There was a message a while back about someone who replaced their midpipe with a hi-flo cat system to lessen the noise. The person was also surprised to gain back some low-end power with the hi-flo.

Yes, you can shoot flames with midpipes, but you can't shoot flames with a catalytic converter period (and hi-flo's have cats of course). Only with midpipes can you shoot flames.

But then again, if you have to pass an emmissions test in your area, a midpipe will be out of the question unless the car is track-only driven.

1FAST7

about how much does it cost to replace a midpipe. Lets say you have midpipe, and then emissions is comming up. And you want to put back the stock cat. About how much would it cost to switch the two from a shop? THANKS

1FAST7

Mahjik

iTrader: (1)

I would guess around $50-100 depending on the shop. The shop I had do my full exhaust only charged about $150 to install the downpipe, hi-flo cat and cat back.

Honestly, unless you are drag or track racing, I don't see the need to use a mid-pipe over a hi-flo cat.