Down pipe question

Does a aftermarket down pipe get rid of both cat converters.Or just the one in the stock down pipe. Any problems with emmisions ? I have seen them look underneath on my last car to see if the cat is there.

Thanks
Mike

 

A full length downpipe includes the downpipe as well as the midpipe, and replaces both cats.

A shorty downpipe only replaces the stock downpipe and leaves the last cat in place.

With emmisions, it depends on the test they do.

Check exhaust fumes (aka sniffer test): If you're catless, you are screwed. AT LEAST one high flow cat SHOULD get you through this one.

OBDII scan: You need to eliminate the check engine lights caused by removing cats with engine management or CEL eliminators.

Visual: Need an actual cat down there, or at least it's gotta look like one. Daddy's SCP sells a midpipe that looks like it has a cat, or you can "gut" your stock pipes.

 

Generally around here they just plug into the OBDII port. As long as you do not have any CELs and you haven't reset the ECU in a few drive cycles, you pass.

The Helix Catted has a nice, clearly visible cat, and is presently my favorite DP.

SS

 

is it a bolt-on? or is there more to the install?

 

The Helix catted downpipe is a very nice and easy fit. Keep in mind, though, that if you are hooking it up to a stock catback you have to different types of flanges mating together, and will probably have to double up on gaskets and/or throw some extra sealant on to keep it from leaking. Not a big deal at all, but something to remember when installing it.

I also want to add this: yes, the catted downpipe is a bit costlier, but keep in mind that it'll have a huge impact on how much nastiness your car spews out, and the environment needs all the help it can get...

 

i have the helix catted dp on my 03 wrx... its a nice bellmouth... like moose said, i had to double gasket it in on the outlet side order to make sure there were no leaks... and yes, its a bolt on

 

I should mention that I ended up reversing the stock 'doughnut' gasket and adding the Helix supplied one.. it fit well and there are no leaks. Using the Helix gasket alone didn't work too well.