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Going with Magnaflow glasspack...need help with exhaust q's!
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Author:  slantin_77 [ Sat Mar 29, 2014 7:58 pm ]
Post subject:  Going with Magnaflow glasspack...need help with exhaust q's!
Ok, I'm planning my exhaust right now and I'm trying to figure out what size piping I should do (I'm eventually going turbo and I don't want to redo my exhaust) and its between 2.25 and 2.5". Also, I wonder if I should get one glasspack and Y it off after it, or Y it and go with 2 glasspacks (one for each pipe since Im having dual outlets). If anyone has any insight on this, please let me know. Thanks!
Author:  Aggressive Ted [ Sun Mar 30, 2014 10:34 am ]
Post subject: 
How old are you? Is this for fun?
are you building the exhaust system for noise?

Will this car be taken on long trips? say over 6 hours or 500 miles?

or are you concerned at all about building it for mileage?

There are a lot of folks on this site that have built a wide variety of systems. I have spent a lot of money on just that!
Author:  Joshie225 [ Sun Mar 30, 2014 11:53 am ]
Post subject: 
Is there a bona fide need to replace the exhaust now? If not, wait until you do turbocharge the truck. You are aware that dual exhaust is of no power benefit, costs more and weighs more, correct?

With a stock or mildly modified engine 2.25" exhaust is fine. With a turbo engine 2.5" may not be enough depending upon the power output. Turbochargers cut the noise quite a bit so you may be fine noise-wise with a glass pack muffler, but until then it may be much louder than you, or the public, would desire.

If you must do the exhaust now I would hang a large case (not a small case glass pack) single 3" in/out muffler and 3" tail pipe and feed into it with a 2.25" pipe off the manifold. http://www.summitracing.com/parts/wlk-17698/overview/ If you must have the look of dual outlets you'll want to split after the muffler, or have a dual outlet muffler, and possibly suffer being seen as a poseur.
Author:  1974duster kev [ Sun Mar 30, 2014 6:15 pm ]
Post subject: 
I used to run true dual exhaust 2 1/4 from my clifford shorty 3 into 1 headers hated my glasspacks threw them in the trash (sounded like fart cans on a honda but on a larger motor) can and put two flowmaster style mufflers. Dual exhaust was more of a because I made it and wanted to considering a single larger exhaust will work just as well or better. If your worried about making something that will work with a turbo setup then you may want to reconsider because I can almost promise that whatever exhaust setup you go with now won't work for the turbo setup or need some major re working to fit the turbo and new downpipe. All in all I liked my dual exhaust setup it loped well with a cam and sounded pretty cool. I run a 3 inch downpipe all the way to the rear axle now and no muffler and love it. The current turbo exhaust Doesn't drone it is quieter than most NA cars with mufflers but sounds like a beast when you stomp it with the WG dumping under the k frame and has a decent lope at idle even with the turbo cam.

Kev
Author:  slantin_77 [ Sun Mar 30, 2014 7:35 pm ]
Post subject: 
I'm 30 years old, which I dont know why that is relevent to my post. Im just doing it basically for noise. I always put some kind of exhaust on my vehicles just because its what I like to do. I have a Borla muffler on it now that I got for free and I can barely hear it. Before the muffler I couldnt hear it at all with the stock muffler. It shouldnt be too terribly loud with the 2 glasspacks. It was actually pretty tame with just the cat converter! I dont know when the turbo build will be done, so thats why Im doing the exhaust. The Grand National (which is the car I got the turbo from) had a 2.25" system from the factory and a lot of upgrade catback kits are 2.5", so thats why I went with the 2.5".
Author:  Aggressive Ted [ Mon Mar 31, 2014 7:32 am ]
Post subject: 
If you can handle it, then go with the FM40 you will love it. Actually the Thrush version is quite affordable @ $35.00. That design helps on mileage too!
When I was younger and not taking long trips over the mountains it was a lot of fun. Folks would pull up or stop by and ask if it was a V8.
Author:  Joshie225 [ Mon Mar 31, 2014 8:57 am ]
Post subject: 
Quote:
I'm 30 years old, which I dont know why that is relevent to my post.
Your age was called into question because the quality and volume of noise you're contemplating is usually only tollerated or desired by kids.
Quote:
The Grand National (which is the car I got the turbo from) had a 2.25" system from the factory and a lot of upgrade catback kits are 2.5", so thats why I went with the 2.5.
My 132hp SOHC Neon had 2.25" exhaust from the factory. Just because GM choked the Grand National doesn't mean you should choke your engine.
Author:  slantin_77 [ Mon Mar 31, 2014 9:07 am ]
Post subject: 
I'm just saying that I am not building a high-horsepower slant six boosted setup...a lot of boosted cars that aren't running super high numbers run 2.5 easily. Could I go 3"? Sure. Do I need to? No.
Author:  Aggressive Ted [ Mon Mar 31, 2014 11:53 am ]
Post subject: 
Take a look under my car, it's 2.5" diameter. That is FM70 in the back and a FM HP2 up front. It used to have a single FM40. Now it's very stealthy and works very well with a stock motor providing very consistent mileage.

Click on the red link below my name to view photos. You can go into slide show mode and blow them up.
Author:  slantin_77 [ Mon Mar 31, 2014 12:46 pm ]
Post subject: 
I know the chambered mufflers sound pretty good at idle but they do sound rather obnoxious when revving and at highway speeds. I've heard plenty of sound clips of the Magnaflow glasspacks on Jeeps and such and they sound pretty mild.
Author:  SpaceFrank [ Mon Mar 31, 2014 2:08 pm ]
Post subject: 
I have a mild cam (I think), a Holley 350 on a super six intake, and a single 2.25" pipe running out the passenger side behind the doors. On a straight pipe with no muffler, it was annoyingly loud and probably not legal at higher RPMs. It also made horrible burbling noises when letting off the throttle, which I assumed was an indication that I needed more back-pressure. I cut the end off the pipe and added a 22" Magnaflow glasspack. At typical cruising RPMs, it's almost polite now.

For reference, I'm a 28-year-old who frequently makes bad decisions.
Author:  slantin_77 [ Mon Mar 31, 2014 3:35 pm ]
Post subject: 
^Thank you! You wouldnt happen to be able to get a sound clip of it would you?
Author:  slantin_77 [ Mon Mar 31, 2014 3:42 pm ]
Post subject: 
BTW, here's a few clips of my truck with the factory muffler cut off and just the cat, then of a Borla muffler clamped on. Both are surprisingly quiet...

http://youtu.be/i-ErQAPBTbA

http://youtu.be/WocCh_Llmy4
Author:  6inarow-makemego [ Mon Mar 31, 2014 5:46 pm ]
Post subject: 
Here is a short videos of my /6 with glasspack. I like it, even with a bit of a drone at higher RMP. It is same glasspack on my Flathead 6.

Slant 6: https://www.youtube.com/watch?v=jw68-MZn__M

Flathead 6: https://www.youtube.com/watch?v=_Yt29U7738o

Everyone likes something different!
Author:  Aggressive Ted [ Mon Mar 31, 2014 6:34 pm ]
Post subject: 
slantin_77,

Idling is one measure, next try it at 3000 rpm for 2 to 4 hours. The rasp comes on at about 2500 rpm to 3000. The rasp and howl will become annoying with a load on a long trip.
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