Question about Magnaflow muffler

[chris15]

Within the next 3 months or so I'll be turboing my n/a PT, but am getting the ball rolling early (fuel system upgrades, oil lines, etc.) and would like to swap in a Magnaflow muffler because I've read that they make some pretty good flow-through mufflers.. so first question: could someone provide me with a model # and/or the dimensions of the mufflers you guys use? I'm not inept, and I realize that 2.25"-in/2.25"-out is required, but I'm referring to the dimensions of the muffler casing itself.

Also, so I don't have to create another thread-- in the meantime, without the turbo installed, would anyone care to explain the effects of reduced backpressure on the n/a PT? (Will I see reduced fuel mileage? Drop in low-end power? Slower throttle response?)

Thanks guys, I appreciate you all sharing your knowledge!

[daviddrift]

Back pressure on the engine can reduce its power. Improving the overall flow of air through the engine will increase the engine's efficiency. Improving the turbine wheel and housing design of your Muffler, reducing bearing friction or improving the overall efficiency of the turbocharger will reduce engine exhaust back pressure.

[quicksilverdon]

Welcome.
I put exhausts on both my N/A PT (Bassani) and my turbo (BTG) and I was getting 24+ overall on my N/A and I'm getting 25+ on my turbo, so clearly it can't hurt mileage.
I'm confused about you magnaflow questions - they make one for the PT - why wouldn't you buy that one?

[grungerockjeeper]

Personally, after turboing your PT Id just have a muffler shop saw the muffler off and straight pipe it right back. Theres another thread in here about that, and after reading everyone's posts, I determined that $400 or so for a good performance muffler vs $50 for the chop and pipe job was a no-brainer.

My results:

It does breathe a bit better, maybe a SMALL increase in mileage. It is a good bit louder, but its a good rumble, not a ricer sound at all. I get a lot of compliments on the sound of it, actually. You will hear all the little burbles, pops and backfires when decelerating. When I take off, I can see people trying to figure out where that nasty snarl is coming from, and when coming to a stop downshifting thru the gears you'll hear all kinds of stuff. I got a nice loud backfire pop right beside some old lady in a camry, I think she filled her granny panties!

[Mean Green]

If you are going to stay around stage 1 numbers (235 hp) then the 2.25" exhaust system is fine. If you are going to go beyond that then you'll need a 2.5" system, preferably a turboback system. A mufferless system isn't for everybody. For some it is too loud or after awhile becomes too loud. You don't need a lot of noise to be fast, just as long as the muffler is flow through. With an aftermarket turboback mufferless system on my neon srt-4, after two years, I got tired of alerting everybody 3-4 blocks away that I was coming. I installed a Camaro style Magnaflow flow through muffler and now I'm stealthy quiet, still fast as hell and leave V8's in my rear view mirror. Know what you want now so you don't end up doing it twice. IMHO loud is nice, but stealthy is better.

[808]

Just an FYI for the previous posters, Chris detoured a different route from turboing his PT. His latest updates are in the regular Wheels, Tires, Suspension forum. Though he still might be interested in a new exhaust system.
Damn, Chris, correct me if I'm wrong cuz I don't wanna feel like bigger dumbass if you're still planning on the turbo

[chris15]

Thanks for the feedback guys.

Oh, and you're not completely wrong-- that particular project is just up on the shelf for now. This is still good info, and could possibly help others researching the same things. I searched around for awhile and couldn't find anything about this particular setup.

I think I'll probably just search for a Magnaflow exhaust to use on the N/A for now, that way it'll be relatively useful when I do turbo the car.

My plans for the future include a full rebuild of the bottom end, some head work, a manual tranny swap and a transplant of the srt-4 turbofold setup onto the PT. The car has sentimental value to me, and I've decided I've done way too many mods I don't feel like doing over again, so I won't be trading up to a GT.