TCCoA Forums banner

1 - 20 of 35 Posts

·
Registered
Joined
·
933 Posts
Discussion Starter #1 (Edited)
I'm looking into throwing together a cheap exhaust set up and I have a few questions.

What would be the difference in a mid mount exhaust and a rear mount exhaust if I have the exhaust dump in the same spot (stock location, but probably dual exit using a 1 into 2 muffler)?

With a 3.8 NA unmodified MN12 is there any need to change to a bigger than stock exhaust? Would the different be noticeable?

How much would it cost to have a muffler shop cut out the old cats and put high flow cats in that are slightly further along in the exhaust so that 90 degree bend can be smoothed out a bit (I figure that is where most of the restriction is). And how much should I expect a scrap metal place the pay for the cats (since they contain platinum or what ever)

What would be a good muffler for a set up like this. I think the biggest mod I might do is underdrive pulley's, but that probably it.

EDIT:

If I bought a Thrush Turbo, what would be the best configuration? These are what I thought about.

1) in place of the resonator and just had it dump there, maybe side exhaust it later

2)in place of the stock one, but then I don't know what to do about the resonator.


At Advance they only have a single in single out, but I'd like to do dual exhaust, especially if I go with the side exhaust. Thoughts?
 

·
Premium Member
Joined
·
2,546 Posts
Well... Maybe it's easier for you to find a show to install high flow cats but I had the hardest time finding a shop to even take off the 3rd cat and run true duals.

I would recommend finding some already made downtubes with high flow cats. They will be mandrel bent and then you can have an exhaust shop fab up the rest of the exhaust all the way back. I just don't see a purpose of making some pinch bent down tubes and throwing high flow's on... Granted a Unmodified 3.8 doesn't flow as much as a 4.6 but... I like to only do things once if I can. Which means I think about where I wanna go with the car in the future and plan accordingly. So it may be overkill for the time being but it will suit the future mods.

As for mufflers, I suggest just youtubing 3.8L Tbird exhausts or something to see what mufflers you like and don't like. Or listening to the sound clips here.
 

·
Registered
Joined
·
81 Posts
as for the old cats and how much they go for at scrap yards... if they're the oem stock cats then they should be about $80 a piece... when i was working at a shop in nj thats how much we would get for them. If they aren't the original ones then they are not worth as much.
 

·
Registered
Joined
·
131 Posts
You can gain quite a bit if you reprogram the PCM, which means a flasher. Those are not cheap, but they do help a bunch. They do as much as any of the other little things, they actually make the most of the other stuff. So if the budget permits, plan for a tuner and programming after the other stuff.

In that case a larger exhaust is better than a mild exhaust. You read all the time about the "best" size of (name a part) in the exhaust. All of that is crap if the combinations are really tuned, PCM programmed for the exhaust. The programming needs to change for big changes, and the exhaust is a huge restriction for all vehicles. If you don't do programming, than don't buy nice big exhaust parts, the PCM can't take advantage of them. If you do the programming, always selec the largest exhaust that will physically fit. The headers need to be sized for the engine, sized/tuned for the flow of the heads. That sizing matters, but after headers, it's all restriction. All restrictions past the headers cost power, at all rpm's. That is why straight pipes always make more power, when tuned. Regards,
 

·
Registered
Joined
·
3,902 Posts
To make your exhaust cheaper, I would just stay with stock cats unless they are bad/clogged. You wont notice any performance gains from removing them/replacing them with something that flows just as good. Older GM converters (the big round ones) are supposed to flow less than current Magnaflow (carsound) replacements, but our stock ones are the same style as Magnaflow. I would cut it off behind the stock cats and go to town with a 2 in 2out magnaflow (with x core) midmount, or whatever you like. Glasspacks are even cheaper. I think with an X-pipe glass packs at the rear would sound decent, but it's hard to work with the sound of 4 & 6 cylinder cars. I had mid-mount flowmaster 40 with pipes out the rear on my 3.8 cougar, and it sounded ok for a 6 cylinder. If I could go back, I would have tried my current magnaflow tru x muffler on the 6 cyl.
-Rob
 

·
Registered
Joined
·
1,197 Posts
It all depends on what is cheap for you. If you can, cut the stock off after the factory cats. Summit sells "header extenders" that have the s-bends for about $35 a pair. Add a set of 3 bolt flanges for headers (Summit again, for under $20 and they go all the way down to 2.25" pipe, iirc). Use an X core mid mount muffler (about $100 at Summit) and add a set of mandrelbentexhaust.com's intermediate pipes ($150 shipped). All that's left is to run some 22 to 24" strait pipes/tips/whatever and a couple of hangers. It's actually pretty easy to set up; my current set up is very similar to this but with a true X pipe and dual chambered mufflers. I haven't had time to weld it all up and add tips yet, but it sounds nice, if a bit droney. If I were doing it all over again, I'd just use a Magnaflow X core DIDO muffler and spare the hassle of the X pipe. I can't promise it, but if you're interested in a complete "cat back", I'll probably have mine off to weld this weekend. I can take some pictures and do a quick shade tree "how to" write up. My components, including stainless steel tips, ran around $320 for a true dual 2.5" mandrel bent system.
 

·
Registered
Joined
·
1,197 Posts
That is all aluminized pipe, etc. I thought about going stainless, but the cat sleeps in the garage and doesn't play in the snow anymore. After weld up, I'm going to use hi temp paint on everything. I've killed a chunk of my budget with home improvement and working on a (let the razzing begin) Chevy minivan. I am saving the rest for the new paint job....
 

·
Registered
Joined
·
933 Posts
Discussion Starter #11
Could I yank the resonator and muffler, and replace the resonator with a glass pack? It's a 2" pipe right? 18" long? Is it straight or is there an offset?
 

·
Premium Member
Joined
·
2,546 Posts
Personally I don't like the sound of Glass packs on these cars... But that's just me. I still think Borla's are the best way to go. But that's my opinion. I'd go do a little searching. Maybe goto youtube and check it out different exhausts. You could also try Streetfire. Especially with a 3.8L and not a 4.6L. And no you're car isn't going to sound like a Stang. Just FYI.
 

·
Motorboatin' SOB, Headlight Cleaning Guru
Joined
·
6,910 Posts
i once got a $20 glasspack of summit, had it mid-mounted and ran single pipe split to duals at the pumpkin. no rear muffler. it sounded ok. then i replaced the glasspack with a spintech sportsman muffler. they are not cheap, btw. sounds much better. its been mistaken for a v8 many times. i even fooled some of my gearhead buddies into thinking its a v8.
 

·
Super Moderator
Joined
·
12,088 Posts
I think this post belongs in this thread as well...

Cheap power? let me know when you find it. everything costs money and you will not have a GOOD sounding exhaust for cheap(unless you know someone to cut you a deal). cheap exhaust is cheap sounding....and it makes your car look cheap. enjoy the drone.
If I had a V6 and a limited budget here's what I'd do.

http://forums.tccoa.com/showthread.php?t=120195
 

·
Registered
Joined
·
933 Posts
Discussion Starter #15
I want to leave all cats in place, though Nebraska doesn't check, I'd just rather not worry about it. What if I replaced the resonator with a glass pack, then replace the stock muffler with a Borla or Magnaflow? I want something that will be "quiet" when just cruising along, but will get loud when reved up (4,000 rpm +).

I think this post belongs in this thread as well...



If I had a V6 and a limited budget here's what I'd do.

http://forums.tccoa.com/showthread.php?t=120195
I have looked at that before, but like I said, I want to leave all cats in place and don't like that dual tip thing. Also, would I need to upgrade to 2 1/4" pipe, all I have is a V6 and I don't think it's making enough power to need the bigger pipe.
 

·
Registered
Joined
·
933 Posts
Discussion Starter #16
Any thoughts on the above idea? Glasspack to replace resonator then maybe a Super 44 in the back? How loud do you think that would be? I want something that will be quite under 3,000 rpm, but will by 4,000 will be pretty screaming, or growling I guess. Something deep sounding, at least for a V6. If I wanted to go 2 1/4 from the cats into a 2 1/2 then split again into a 2 1/4 or just 2, would I have to take the 3rd cat out?
 

·
Registered
Joined
·
131 Posts
I have a 4.0 V6 that I finally changed exhaust on last year. I kept a resonator(2.5") instead of a tiny muffler, a resonator quiets more than the small straight through mufflers you are looking at. My exhaust was OEM two 2.25" pipes into one muffler, and out to a resonator and 2.25" tail pipe.

I wanted to try an Edelbrock SDT chamber muffler, hoping for a quieter muffler. The only choice for 2.25" dual in has a 3" outlet, so I ran that to a 2.5" resonator and 2.5" bent tail pipe.It works well and is as quiet as most any aftermarket muffler, but still louder than stock.

Go with the biggest pipes that will fit, if the cost is basically the same. The mufflers all take up the same space, but the pipes can be made bigger usually for the same cost. If I knew that I would retune my truck sooner, I might have done more, forward and bigger. I was replacing a rusted and noisy muffler.
 

·
Registered
Joined
·
933 Posts
Discussion Starter #18
If I could get mine to sound like this I'd be satisfied

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/gyd36GruXKE&hl=en&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/gyd36GruXKE&hl=en&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>
 

·
Registered
Joined
·
683 Posts
when i put my flow master on mine i noticed a big improvement in acceleration i think there might have been something wrong with the stock muffler though
<object width="560" height="340"><param name="movie" value="http://www.youtube.com/v/zUiooWu-L3E&hl=en&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/zUiooWu-L3E&hl=en&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="560" height="340"></embed></object>
 

·
Registered
Joined
·
2,134 Posts
thats the vid i was talkin about (the first one). pretty easy to do, all he did was straight pipe it but leave the cats alone, and dualed it like the stock v8 exhaust. then hes got some minor mods like tune, cai, and underdrive pulleys
 
1 - 20 of 35 Posts
Top