 
     |
| Yet another 3800SC exhaust build (Page 1/3) |
|
gtoformula
|
MAR 25, 08:55 AM
|
|
This past weekend I put over 400 miles on my car (1986 GT 3800SC 5spd). The exhaust noise was intense and I've decided to install a new system. In the image below you can see how the mufflers are currently arranged. I didn't install this system, but it is basically a down pipe from the rear manifold, to a "T" split, two bullet mufflers and then dual tailpipe tips (no resonator). I have researched several threads on exhaust builds and have listed them below ... gathered several ideas from these and will use them to create my own.
Here's basically what I'm going to do:
- my system will end up looking a lot like the system JamesCurtis put together (link below). It will have a flex pipe coming off the first bend by the manifold flange.
- I am going with a Magnaflow #12158 muffler. Seems like it is quieter than the FlowTech Afterburner and is just a bit longer (1"). I like the Hedman Hot Tips that Darth Fiero used, but I can reuse my current tips and save some bucks.
- revin had a great idea in using the exhaust donuts that are available on eBay. These provide a nice mandrel 180* small radius which will save room and eliminate some welding too.
Here's my shopping list:
- 2 1/2" Summit flex pipe #SUM-652510 $38.13
- 2 1/2" ebay exhaust donut $38.00
- Magnaflow muffler #12158 $105.62 (2 1/2" inlets and outlets)
- Dynomax Performance 2 1/2" exhaust pipes #42596 $10.97 (muffler to tailpipes)
- Dynomax Performance 2 1/2"-2 1/4" exhaust reducers 41961 $4.97/@ (tailpipes/tips are 2 1/4")
I'll cut off the flange that is currently welded to the system and bolts to the manifold. The exhaust donut will be cut in half ... one half will form the U-bend connecting the muffler inlet to the flex pipe outlet. Part of the other half will be used to connect the manifold flange to the inlet side of the flex pipe. The straight exhaust pipes will connect the muffler outlets to the 2 1/4" reducers. The current tailpipes already have 90* radius bends so all that I'll need to do is weld them to the exhaust reducers.
I'm hoping to end up with a much better sound. I don't expect, or want, a quiet system ... that's not why I bought the car. What I do want to get rid of is the way loud, and not great sounding, bullet muffler system. I'll have about $215 with all the basic parts and will enlist my neighbor's welding skills. As always, your thoughts, ideas and opinions are welcome.
_
JamesCurtis
http://www.fiero.nl/forum/Forum2/HTML/129145.html
revin and Darth Fiero (first image)
http://www.fiero.nl/forum/Forum2/HTML/123782.html
Alex4rmula
http://www.fiero.nl/forum/Forum2/HTML/121048.html
qwikgta
http://www.fiero.nl/forum/Forum2/HTML/123378.html
|
|
|
|
solotwo
|
MAR 25, 07:48 PM
|
|
|
I bought a car last year and was told it has 3" . I asked about changing to 2 1/2 and was told ":you dont want to do that". so how does yours run with 2 1/2?
|
|
|
|
gtoformula
|
MAR 25, 08:19 PM
|
|
| quote | Originally posted by solotwo:
I bought a car last year and was told it has 3" . I asked about changing to 2 1/2 and was told ":you dont want to do that". so how does yours run with 2 1/2? |
|
Can't say yet. I am in the process of ordering parts. You may want to review the thread links i included. Most of them are running 2 1/2" systems. 3" may be a good idea if you're running heavy mods, but probably not necessary for my low mod set up.
|
|
|
|
solotwo
|
MAR 25, 08:54 PM
|
|
| quote | Originally posted by gtoformula:
Can't say yet. I am in the process of ordering parts. You may want to review the thread links i included. Most of them are running 2 1/2" systems. 3" may be a good idea if you're running heavy mods, but probably not necessary for my low mod set up. |
|
My car came with a bone stock 3800SC
|
|
|
|
gtoformula
|
MAR 25, 09:03 PM
|
|
| quote | Originally posted by solotwo:
My car came with a bone stock 3800SC |
|
Mine too. This will be one of the mods I do. All the mufflers installed in the thread links are 2 1/2" except the Flowtek Afterburner and it only a had 3" inlet with dual 2 1/2" outlets.
|
|
|
|
gtoformula
|
APR 01, 01:14 PM
|
|
OK. Got the parts last night and disappointed with the muffler. The Magnaflow is a beautifully constructed piece, but I don't think that the inlet/outlet arrangement will work. The Summit specs say that it is reversible, but not for how I intended to install it. There is a center inlet on one side and two offset outlets on the other side. I had intended to use on of the offsets (on the side that has two) and use two outlets ... one from each side. It doesn't look like it is plumbed for that set up. Gotta return the muffler and maybe some of the pipes and start over again.
Requesting recommendations:
Flowtech Afterburner part #50363FLT. This will work regarding the inlet/outlets, but it has one 3" inlet and two 2.5" outlets. The 3" throws a curve into my pipe plumbing and that muffler will also be louder than the Magnaflow ... I think.
Spintech 333SC - just spoke with them on the phone. Their inlet/outlet arrangement is perfect for what I have planned. One offset inlet with two opposed outlets (one on either side straight across). The standard dimensions of this muffler are 4"x10"x15"L. I have heard that 15" may be too long (13" to 14" being preferred). Spintech offers a 13" version that will obviously be somewhat louder. Opinions on whether I can go with the 15" or play it safe with the 13"?
|
|
|
|
nosrac
|
APR 01, 03:47 PM
|
|
|
You got the wrong magnaflow. The correct one is the transverse Camaro muffler.
|
|
|
|
Tom Slick
|
APR 04, 08:13 PM
|
|
here is how Darth did mine, since you were asking.
[This message has been edited by Tom Slick (edited 04-04-2014).]
|
|
|
|
JamesCurtis
|
APR 05, 03:06 AM
|
|
I'm sorry I posted a photobucket photo. It is a broken link for me. Here's a photo below to show you what I have:
It has a bit of a drone to it when it's wrapped up at 2500 rpm on the highway/interstate. I've been thinking of running a system that followed the stock fiero route to get a little more length in the pipe. I also don't like how low this exhaust sits below the cradle. My muffler is definitely the lowest point of my car due to the lack of a tight radius coming off of the rear manifold down into the muffler.------------------
|
|
|
|
Diamond Dave
|
APR 05, 04:16 PM
|
|
|
Nice job Tom how does it sound? I love my magnaflow. Sound is incredible.
|
|
|
