Center muffler for flow on stock exhaust?

[mmarfan]

So I moved into a nice neighborhood and for the benefit of my neighbors not getting mad at 5:00am I decided to remove my Corksport exhaust and put my stock exhaust back on. Even though a have a CP-E downpipe w/ cat, There is pretty much no exhaust sound anymore, so goal #1 accomplished.

Unfortunately, I noticed a substantial decrease in power doing this (~25hp). The nice flow that the Corksport 3" pipe had all the way back is now restriced BADLY by the 2 1/4"? stock exhaust.

What I want to do is put a large 3" muffler between the mounting points of the exhaust and just before it bends around the rear differential to gain most of the lost flow back, then reduce it down to the stock exhaust. I believe the sound should still be very minimal. Has anyone done this? FYI there is a cat in the stock cat location so nothing can be mounted there.

[oh_yeams6]

If you are looking to reduce sound get a resonator or two welded into the corksport. The closer they are to the engine the more they will help, this has been dicussed many times.

Get the vibrant 3" in/out http://www.google.com/url?sa=t&rct=j...1n-LtuZ8euTX4A

Also, the stock catback is not going to reduce power by 25, but maybe 5-10

[mmarfan]

I'm not buying the 5 - 10 hp loss on the stock exhaust. There is just too much difference. It may be a torque loss over hp. Is there dyno proof of that claim?

I've looked around the forum on this topic, but haven't found exactly what I want. The closest I've seen someone do is a 3" back into the stock mufflers, which is originally what I wanted to do. Unfortunately, the exhaust shop I went to could not do this.

I just want better flow with no noise.

[6Y MAZDA]

According to the guru's at MSF, the stock exhaust is actually not very restrictive at all. According to them, if you are looking for power, upgrading the exhaust is the last place to look for it. A lot of them are actually running stock exhaust. Main reason for exhaust is sound.

[6Y MAZDA]

My biggest concern for you is you are running a DP with no HPFP internals and no AP. ZZB is imminent.

[IHeartGroceries]

I don't think CS's, or any 3"+ system can ever be made quiet.

I am having trouble visualizing your description, but do you mean adding a single muffler to the midpipe section of the car? Under the cabin?

You cant fit one there, can you? I guess you don't like the idea of a single exit exhaust?

You ever consider a cut-out? Maybe a cutout fabbed into the OE system, or something like the Magnaflow CB with a cutout?

[jm211]

imminent, i dont know about that. More like 5 seconds ago.

i have single out and is noisy. leaves a black eye on exhaust valance too.

[mmarfan]

Originally Posted by IHeartGroceries

I don't think CS's, or any 3"+ system can ever be made quiet.

I am having trouble visualizing your description, but do you mean adding a single muffler to the midpipe section of the car? Under the cabin?

You cant fit one there, can you? I guess you don't like the idea of a single exit exhaust?

You ever consider a cut-out? Maybe a cutout fabbed into the OE system, or something like the Magnaflow CB with a cutout?

Yes, adding a muffler under the car in the mid section of the exhaust, under the cabin. I just can't think of why going from the 3" to the stock 2 1/4" is ok for power? The flow area a reduced by almost 50%! I would just like a smoother transition between the sections to help with flow.

I have not measured officially yet, but I do believe there is (barely) room to mount one there.

As for the single exhaust, I don't like the "black eye" as mentioned above.

[mmarfan]

Originally Posted by 6Y MAZDA

My biggest concern for you is you are running a DP with no HPFP internals and no AP. ZZB is imminent.

Yep, been running the DP for 40,000 miles. No problems with the HPFP. It's funny, I'm on the original pump one to that is usually junk.

What is AP and ZZB?

I did have the CP-E DP crack on me and had to get it re-welded, but so far, so good.

[ctmazda]

AP=AcessPort
ZZB=ZoomZoomBoom usually as in throwing a rod.