Homer3D

#1. Look at your muffler tips. You will see that 2 of them (one from each side) has the control valve right behind the tips.

#2. There are 2 mufflers that are stock. One with NPP and one without.

#3. NPP is the muffler. If you change, you lose that

#4. See #3.

Here is an image for your first question.

Rathmullan

Bless You! You just saved me a bunch of $'s and further frustrating research effort.

BWF07

OK, I think I am convinced to try this mod. I plan to get an aftermarket cat back exhaust system, but it may be a few months down the road so until then I thought this might hold me over.

I do have a few questions however, and the first one is where can I find the hole saws? I have a set, but they are would not reach that deep in. Second is I have only had this 2007 coupe for about 5 months and it came with American Racing Headers, and high flow cats, so will this have any bearing on the mod?

XPLOSYV

did this today and it sounds GREAT!!!!

i did have a question though...do i have to cover the holes? i see that nobody answered the last post here so here's hoping someone is still paying attention

vig1116

the outer holes that you cut to get to the inner pipe? Yes, cover that hole....

XPLOSYV

wow...fast service...will do tomorrow...sounds great open though...are there dangers or what not that occur from leaving the eyesore open? just wondering...

vig1116

No clue, but it can't be good IMO

duramaxsky

Interesting idea. I may do it.

Gerdia

you could have some of the fiberglass inside the can flying out, makes a mess. My cans had fiberglass in that section.

XPLOSYV

yeah, i saw some there during the process...not so much afterwards....what happened is that we covered the holes and revved it up, drove down the street, etc...sounded ok but much better open...1" outer hole...didn't have a bigger circle saw on hand...gonna monitor the results i guess

however, i will say...if you're looking for a little more sound while you put together $$$ for a new exhaust system, this is the way to go

Victory06vert

Did the mod today using 7/8" hole saw in about 20 minutes taking my time. I used 1/2 knockout plugs (Arlington 900) I got from CED. the counter guy gave them to me for free. I high temp rtv'd them in and used a little 2"X2" aluminum tape to cover the plug. Looks great and sounds even better! Thanks for the idea to do this awesome mod for free and an hour of my day!

Mad*Max

bookmarked

Mad*Max

can someone please give more details on the screws to use (e.g. length) to affix the patch and also more details on what kind of patch to use

Markallamerican

I used 3/4" stainless steel screws and sheetmetal.

Mad*Max

do the screws easily pierce the patch and muffler?

Markallamerican

Yes, but I used self tapping ones.

Mad*Max

thanks

Markallamerican

No Problem. You could pre-drill the patch holes first to make it even easier

Mad*Max

okay

Mad*Max

Another question for folks that have already done this mod - is there a reason that the outside hole is larger than the inside ones (2) - do you need to be larger to get better access to drill the inside holes?