in the stock exsaust system what is the biggest bottle neck? the manifold, y pipe?, cat, catback pipes., muffler? what order would you put them in worst to least restrictive. im just interested if anybody has got some numbers.

 

It's hard to say. I'd probably rate it going from the rear to the front. From the back of the cat it's not the greatest. Then the cat becomes the problem(mainly if your still running the stock cat). Then comes the y-pipe and manifolds.

Now this is just my opinion, I don't claim to be an exhaust expert. Your going to get different opinions every where you go. Your best option is to look at the exaust the way it is now and see what you can afford. You will benefit from any exhaust mod you do.

In other words, save up and start hacking away!

Eric

 

Id get guess manifolds are pretty restrictive, and i'm just going by the fact that headers give u the biggest performance increase of any exhaust mod. Then the cat i assume is the least restrictive, i mean think about it, how much HP do expect to get from no cat on a stock engine. The Y-pipe and cat-back pipes is a toss-up i think, it all has do with the diameter of the pipe, and of course mandrel bending. So in my opinion, which of course i'm no expert, and who ever knows more correct me if i'm wrong would go something like this.

5- most restrictive 1- least restrictive

5- Manifolds
4- Cat-back pipes
3- Y-pipe
2- Muffler
1- Catalytic Converter

 

The stock manifolds and y-pipe are by far the most restrictive. For one if you look at the stock y-pipe design it's horrible.

Second, we all know that you don't really need 3" i pipe till you hit a certain HP and some 3rd Gens don't really "need" it as much as headers and y-pipe.

 

I would switch muffs and cats almost

least on most cars


don't know much about how bad your muffs are though

 

My opinion, take it for what its worth. I replaced it all anyway.

1. Y-pipe
2. Manifolds
3. Stock cat
4. Stock muffler
5. The rest of the pipes

But seriously, just replace it all! Its expensive to do all at once, but you not only get a big SOTP difference, especially from the headers/y-pipe, but you'll need upgraded exhaust to support more power later.

 

The first thing I did was a muffler. Mine was rotted. The second thing I did was headers, y pipe and no cat. I just did it as needed and money. I still have the stock size pipe and muffler, but it is a better flowing one.