A few exhaust questions.....

[celly]

Magnaflow muffler and pipe size/what is a "cat-back"?

Hi all:

This is my first post on the site (a great site I might add). I have been lurking for a little while and getting tons of great info. The SEARCH function is a good one.

The end result is that in the past week, I have ordered an Apten dual-program chip (87 and 91 program), a MAC air intake (both aren't here yet), and yesterday I had a Magnaflow muffler welded into my existing pipes and had a stainless steel tip put on. So that is where I am today (and plan to keep it that way for a while).

My first question is related to pipe size. I kept the standard 2" pipes. The muffler shop guy concurred that the system would be a bit quieter with stock pipes over a 2.5" pipe. How much louder would it be with my Magnaflow? I don't want anything too loud. Also, are there significant performance gains from increasing my pipe size or are most of the gains related to acoustics. The guy in the muffler shop told me that the bulk of the performance gains are in the muffler itself, and less to do with the pipes although there are some gains. I have a 2000 Sport with SOHC engine, FYI.

I have a more general question surrounding the whole "cat-back" concept. I really tried to find more information using Google and other messageboards and from what I can gather, "cat-back" means mods done "behind the catalytic converter". So what really is a "cat-back system". Is it just terminology to mean a new muffler and pipes (with those fancy bends)? Does simply getting a new performance muffler and welding it into your existing pipes also entail "cat-back", or is there something else I need to add to say I have a "cat-back"?

Anyhow, any insight would be appreciated. Once again, GREAT SITE. I've got to use this site sparingly or I'll be broke in no time!

Cheers.....

Brad

 

[Bashman]

First of all, welcome fellow Canadian!

In regards to pipe size, you will get marginal improvement with a 2.25 - 2.5" pipe due to it being slightly more free flowing, anything over that and you begin to lose without a supercharger.

I have a Magnaflow on mine with 2.25" pipe. I love the sound. It is very quiet at idle and when cruising but increases nicely when on the gas, not a harsh sound at all. I drove down to Performance Unlimited in Calgary to get it.

As for the cat-back, it's a term usually used for a kit that includes the muffler and new pipes from the catalytic converter back (with all the fancy bends) or when you replace/enlarge your piping as well as the muffler. If you have your muffler welded into the existing pipes then you have a Magnaflow muffler, not a cat-back.

 

[celly]

First of all, welcome fellow Canadian!

In regards to pipe size, you will get marginal improvement with a 2.25 - 2.5" pipe due to it being slightly more free flowing, anything over that and you begin to lose without a supercharger.

I have a Magnaflow on mine with 2.25" pipe. I love the sound. It is very quiet at idle and when cruising but increases nicely when on the gas, not a harsh sound at all. I drove down to Performance Unlimited in Calgary to get it.

As for the cat-back, it's a term usually used for a kit that includes the muffler and new pipes from the catalytic converter back (with all the fancy bends) or when you replace/enlarge your piping as well as the muffler. If you have your muffler welded into the existing pipes then you have a Magnaflow muffler, not a cat-back.

Bashman, I'd seen a few Canucks on this site and it's especially nice to find a few Albertans. Thanks for the welcome and thanks for all the info.

I've done a lot of reading up on pipe size. I'm really leaning towards 2.5" pipes as the "ideal" diameter for my SOHC engine. I've heard some say 2.5" pipes and Magnaflows are too loud without a resonator. Others like the sound and say it's not bad. So much of this is personal preference after all. I'll re-consider getting a pipe transplant once I get the MAC intake on and drive it as such for a little while. If anyone out there owns a Magnaflow muffler with 2.5" pipes, I'd love to hear your opinions, especially if you have a SOHC V-6.

I appreciate the clarification re: cat-back. I figured it was something like that. ;-)

Enjoy the long weekend......