High flow cat or Midpipe... that is the question? I did a search but found little. Wanted to see pros and cons of both. I realize that boost creep is associated with a midpipe so IS IT neccessary to have a ported or larger wastegate and must i have a boost controller? I have also read that a highflow cat only makes a small difference over the stock cat. The mods that I have are as follows: Street port, Apex'i Power FC, Apex'i N1 cat back and M2 downpipe. I will soon have the Blitz intake. I have not installed the downpipe or the Power FC yet and have taken out the boost pill to keep it at 7psi until I have the ECU installed. I would like to wait to have the ecu and downpipe installed until I have midpipe or highflow cat inorder to tune it one time. So will I have to add a boost controller? Will I have to port or get a larger wastegate? Is there anything i'm over looking or dont really need inorder to do this?

 

think the question boils down to how much power do you "need"

 

Well I guess another way of putting it is how drastic is putting a midpipe on? Is it really what some make it out to be with 30 Hp gains and huge boost spikes that boost controllers and wastegates can't handle or is it alright to install without worry. I would like to put one on now being that I'm installing a downpipe but don't have the extra money at this point to get a boost controller and to mess with the wastegate. If it is necessary for both then I will definately wait and play it safe. Just wondering... when i get the boost controller should i get the one that goes with the Apex'i Power FC or should I get something like a AVC-R or Profec B? I thought I read somewhere that the one made for the Power FC is only needed if you've gone single?

 

I plan on going to a midpipe later this Summer so I can't help on that subject.

The car is no slouch with a high flow cat however. My car is 100% street legal and passes fairly stringent emissons testing in Maryland & I'm just about in the 11s.

By the way, high flows tend to be loud. You may have to search around for a catback that quiets it down.

 

I have been looking at high flow cats because I don't want my car to be as loud as those I've heard with midpipe's. Am I mistaken in thinking that the high flow cat is much quieter than a midpipe?

 

I've got a high flow cat with a stock muffler... made a huge difference. We'll see what happens when I get my header and RB muffler.

 

Do you mean that it made a huge difference in how loud the car is or it made a huge difference in the power?

 

A midpipe is louder than a high flow cat which in turn is louder than the stock cat.

From what I have heard, I don't think you want a midpipe without a muffler. The midpipe adds a bunch of power. Just look at the drag times & what you will notice is that everybody running in the 11s has a mid pipe.

I have been told that you give up 5 HP with a muffler on the midpipe but you can hear your stereo. Seems a reasonable trade off.

 

The big question is does your state have emission standards and are you willing to go through the trouble every year

Second is noise a concern

If power is what you want with a deep sound go with RB
Believe me I went my own route w many burnt up exhaust systems before I learned the hardest way of all in my pocket.
RB and a straqight shoud be fine on turbo car; the turbos already help quite down the car alot

 

As for emissions I am not concerned being that I know many mechanics if you know what I mean.... How much louder is a midpipe over stock cat? Minor or huge?