hey everyone, I'm still new around here, and search is not really working for me so please move this post or redirect me to an existing thread if required.

That aside, what I'm trying to figure out here is how I want to go about setting up my exhaust. I'll start by stating that I want to build this exhaust myself I have many years of welding and fitting experience so that is not an issue. I want to make a system that is not crazy loud but also sounds nice and throaty. I'm going to use the OEM exhaust manifold. What I have currently came on the car and It is the OEM manifold with a universal cat and a bullet style Magnaflow on the back. it sounds decent but is really loud. What I'm thinking of doing is running the OEM manifold to that same Magnaflow that's on the back in place of the cat as a resonator/presilencer (Magnaflow 10416) and then another oval Magnaflow on the back (11216 or 12589 or something). would this quiet it down a bit with a nice sound or would the volume stay the same? any help is appreciated as well as suggestions on components or placement. I make this thread simply because I can't find any other info on custom exhausts using the stock manifold. everyone uses an RB or other header. Im not really going for major power increase as my car is stock with a stock 12A so having a header is of no concern to me at this point in time. In the future, I would like to get a full RB system but it's out of my budget at the moment.

I've included a drawing of what I'm trying to describe here.

 

Since you are running a stock 12A, you could probably get away with a 2-inch exhaust system which should support up to 144 HP.

• 2-inch would most likely quiet down your exhaust sound
• 2-inch would make your system compatible in size with RB exhaust if/when you want to upgrade various components

 

There's a good chance that most options will be quieter than what you have now, assuming you stay below 2.5", and like @RX7_Renesis said, 2" would be sufficient and keep the noise down even more.

I would seriously suggest you look at the RB universal pre-silencer for use in the resonator position. They're good quality units and are stainless packed, as opposed to the glass or rockwool used in most other units which tends to burn out on our engines rather quickly. I'd honestly suggest an RB muffler as well, although that might not be as throaty as you're looking to go. Using the stock manifold keeps the noise down a lot already and smooths out the tone, so in general you can take any advice for a header system and just assume it'll be a little less raspy and toned down and go from there.

When I was NA and had an RB header, the RB muffler and pre-silencer made a nice pairing but wasn't terribly throaty. Still plenty loud for me but I'm sure some would still find it quiet.

 

the other thing is that RB uses thick-wall tube, it keeps the noise in the pipe more, so its quieter unless you're right at the tailpipe.

if you use mandrel bends 2" would be ok, 2.25 thick wall might be better. you want pipe that has an ID that is the same or bigger than the manifold exit

 

Good point, I forgot to mention that. I have 1/8" wall mild steel pipe on my vehicle and even still a little of the "pinginess" gets through. Definitely stay away from the thin stuff like 20, 18, and even 16 gauge if you want a quiet exhaust that doesn't tick. For comparison sake, 1/8" wall is 11 gauge.