Magnaflow muffler installed.

[Y2K Silverado]

Here's my first post on the subject.

 

 

quote:

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I've been running a 2002 Tahoe exhaust on my Silverado for about 4 months now. It actually performs pretty well, no drop off in performance from the Flowmaster I was using. It's just so quiet, I need to hear a little rumble from the a$$ end. I'm going to keep the Tahoe taipipe, it's stainless and is 3" mandrel bent pipe. I'm going to have the pipe cut right at the muffler, two pipes come out of the stock Tahoe muffler, they're both 3". They are 5 3/4" from center to center, the Magnaflow I'm getting has dual outlets that are 5 3/4" center to center. I'm going to have the muffler shop just slip the muffler dual outlets into the tailpipes dual inlets and weld it all up. This months Sport Truck magazine shows a 03 Silverado gaining like 12 hp and 15 tq from a Magnaflow muffler installation. I'll let you know how it turns out.

 

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Well, I may have finally found a muffler that has what I want. It has a DEEP mellow rumble, you can barely hear it at idle and it has NO resonation so far . The installation went off with out a hitch and was installed as I described in the post above. Hard to tell if I've gain any power just driving back from the shop but I didn't loose any, especially low end. I happy (for now ).

Jim

[Chris97K1500]

I was wondering if you knew the part #.  My Brother in law has a 99 5.3 Z71 and he's been wanting dual exhaust, but his wife doesn't want him to spend the money.  Maybe doing what you did could be a compromise.  Thanks, Chris

[Shaners]

I'll have to look into a MAgnaflow.  I would prefer little or no resonance and no loss in low end torque, and I want to replace just the muffler and keep the stock exhaust pipes.

 

In the "Sport Truck" article did they say if the gains in HP and torque were acroos the full RPM range?  Or were the gains in the higher range at the sacrifice of low RPM power?

[Y2K Silverado]

The part number is 12588, it's their large case muffler, 5x11x22. The Sport Truck dyno graph started at 3600 rpms, both hp and tq were higher than stock at that point. I've always wanted to see a graph that started from very low rpms or just have them run through all the gears. Seems like they dyno in 3rd gear and most don't start until 3K rpm's or higher.

Jim

[tps0424]

I went to a Magnaflow Preferred shop yesterday and they told me that the two exhaust pipes from the cat to the muffler would not be able to go into the Magnaflow 12588 because they were too far apart.  (Never measured anything, he just looked for 5 or 6 seconds) He said that I'd need to run 2 mufflers (true duals) instead.  His price was $548.46 out the door, installed.

I KNOW I've seen at least one other person on this board running that muffler.  Is there some modification to the exhaust pipes to do first or is this guy just trying to make more money?

[Shaners]

This is the Magnaflow muffler I've been looking at.  The part # is 12599.  It is dual 3" in and dual 3" and the pipes are 5 3/4" on center.  I'll have to check under the truck to see how far apart my stock pipes are...

 

[tps0424]

I put down the wrong part number.  I'm looking at the same muffler as you are but in the 2.5" dual in/out.  I know we have 3" exhaust now but I heard going dual in/out with the 3" would cause a loss of torque.  I think it was 'Tweaker' who tried 3 or 4 different versions before deciding the 2.5" dual in/out was the one that actually improved performance in the low end.

Let me know how far the pipes are on your truck.

[Shaners]

Magnaflow also has some mufflers with 4" on center dual-in/dual-out configurations.  They may be 2 1/2" inlets/outlets though... and I hate to neck/restrict down.  

[Y2K Silverado]

You guys with the 6.0L engines, I think Magnaflow makes a muffler specifically for that engine. I think it's a dual 3" in and a single 4" out, I would contact Magnaflow directly for the part number. OR you could run true duals! You do have the two pipes after the cats already, cut the muffler off and put in two mufflers and run duals. Sport Truck a couple of months back put a JBA dual set up on a 6.0L, they also installed JBA headers. The 6.0L gained like 25 hp and 32 TQ.

Jim

[Robinhood]

Y2K Silverado,

 

I've followed your history of experimentations with different mufflers and exhaust configurations(Magnaflow, Flowmaster and Walker Quiet Flow). In your opinion which muffler gave you the most quiet in-cab sound. I ask this because I just installed a Borla muffler in place of the stock one keeping the single side exit. My only complaint is the in cab resonance at cruising rpm (1500-1700). If I decide to change out this muffler again I'm looking for advice on what would be the most quiet.

 

Thanks for any advice you can give.

[Y2K Silverado]

Hey Robinhood! Of those three, Flow 70 (which was a dual 2.25" out muffler), Walker (same as Flow) and this Magnaflow (single 3" pipe), the Walker is by far the quietest of the three on the freeway, can't hear it. The Flow and this Mag are about the same, not bad at all. Around town, The Mag is the loudest (not real loud anyway) under acceleration but gets real quiet when you reach speed. The set up I have now actually resonates the least, not much at all. It's the louder muffler of the three but that's noise, no resonation. Try this! I also had a Dynomax Bullet racing muffler installed in front of the muffler. On my extended cab there is a straight section of pipe that's about half way between the muffler and the Y collector after the cats. I had it welded in there to help with the resonation. I first did it with the Flow and took it off when I was running the stock Tahoe exhaust. I had it put back on when I installed the Magnaflow muffler. It does help, it may take enough resonation away that you can keep the Borla muffler you're running. Here's a link the the muffler at Summit Racing. The part number is WLK-24222.

http://store.summitracing.com/partdetail.asp?part=2383

Hope this helps!

Jim