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Are these THE side pipe mufflers to get? Flowmaster 13530320 Slimeline

39K views 122 replies 39 participants last post by  conger 
#1 · (Edited)
(re-posting from my build thread)

I had been looking for side pipe mufflers for some time. The noise level has always been an issue for me. I wasnt willing to spend the $$ on mufflers and then have the packing blow out and have to go through the process of cutting out the glass pack and starting over again. The plan was to go with a rebuildable muffler. The only one I was aware of, was made by Burns Stainless, but the pair of mufflers ranges from $900-1200. I had a friend with them and they worked incredibly well... and rebuilding was easy enough from what I found. The price was keeping me from making the jump. I had even considered making mine rebuildable.

I was literally a day away from spending $1200 on rebuild-able Burns Stainless mufflers when I found the new Flowmaster 13530320 Slimeline. We heard about them at SEMA a few years ago, but no one at the booth knew anything about them. Searching their web site netted nothing as well. Before making that last call to Burns, I decided to do one more search and found a few discussions online, including here along with a part number. Tennessee Tim installed them and it appeared he was pretty happy. With that, I was ready to take a chance on them.

https://www.youtube.com/watch?v=Xuww8Yjyzsk

https://www.youtube.com/watch?v=HlDiQkWNhIY

They are SS, have no packing to burn out and have a lifetime warranty and at $209 each they are fairly priced. From what I gathered they are very effective at taking the sharp tone out of the exhaust which is what we need. I had to wear ear plugs with the FFR pipes, and even then my ears rang after driving the car.

They have an added benefit of having a special insulation that really cuts down on the heat of the outer shell. Anyone that has had a "cobra bite" and the resulting lifetime scar understand the importance of this.

So on with the install:

Made up a support to get the new mufflers in the exact spot desired.



After welding them up. It was a bit tough as the fit-up wasnt as tight as one would prefer.







Ive had the oppty to put maybe 300 miles on the car since installing the new mufflers and Im really happy with the change. As mentioned before, earplugs were a must, and even then my ears were sore. After the new mufflers, I havent worn them and my ears dont hurt :D The sound is just perfect to me. Still sounds like a cobra but without the sharpness.

Against my better judgement, after coming back from a spirited drive I decided to try to quickly touch a pipe where your leg would contact it. First quick tap... wow, no skin left on the pipe... tried a bit longer, then longer still... and no burn. Yes its still hot and I dont know if I could leave my hand on it for more than a second, but its cool enough for your brain to register and tell your leg to move it before getting a 2nd degree burn. This alone is worth the price of entry.

The only drawback to these pipes is they are fairly heavy. If you are really concerned with weight, then the Burns are probably a better bet.

Overall, I couldn't be happier and I have several friends that are buying them as well once they heard them on my car.

Appearance wise, I think they look much much better than the normal sized glass pack. I was a bit worried that they would be to big looking, but after installing them, I like the looks better.

David
 
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#2 ·
Great post.

I have an extra set of sidepipes that I plan on trying a muffler swap in...but mine aren't stainless. I wish flowmaster made a non-stainless version.

I might have to look for a used set of beat up stainless side-pipes over the next few months.
 
#3 ·
If you cannot get a set of older, used SS pipes, you can weld stainless to carbon steel. If you use tig, use a 309 filler wire and leave the arc on the carbon side to add filler then weave the puddle over onto the stainless. Make sure when welding stainless to use Solarflux Type B on the inside or purge with argon to prevent sugaring the inside of your welds. Use multiple, opposing beads (at least 6 for that diameter) and let the pipe cool to <300F in between pairs of beads. Just have them ceramic coated afterwards and you'll never tell they're different metals.

I have to thank Dave for this thread also. I have a set of used stainless pipes I was going to do an auger install on, but this looks easier. I wont be able to use my DRUMMERMIKE heatshields but it sound like they won't be necessary.
 
#4 · (Edited)
Any chance you could record the sound? Looks great on the car.
 
#5 ·
#9 ·
#10 ·
Great price. I paid the $209 each last year.
 
#12 ·
They look good! Like the idea of a bit less noise as I am already deaf in one ear and not from driving a roadster!
 
#16 ·
David,

I see in one of your pictures the sidepipe support bracket and hardware on your lift, below the sidepipe. Did you reinstall this and if so, did you make a new mounting bracket to weld on the muffler section or transfer the old one? Did you use a reinforcing pad around the mounting bracket on the muffler wall?

 
#20 ·
David,

I see in one of your pictures the sidepipe support bracket and hardware on your lift, below the sidepipe. Did you reinstall this and if so, did you make a new mounting bracket to weld on the muffler section or transfer the old one? Did you use a reinforcing pad around the mounting bracket on the muffler wall?
I cut out and re-used the existing bracket from the FFR mufflers. I needed to relocate the holes in the 2" tube, but its installed as it was originally with the exception of only using one bold at the muffler.

David
 
#18 ·
Just ordered a set myself.:yes:

Thanks David for posting.:thumbup:

George
 
#21 ·
I will be completing the build on my 347 in the next couple of weeks. It's then going on my engine dyno for some thrashing. I will be doing some exhaust testing. Plan is to get it tuned and basic numbers with the FF5 mufflers. Then I'll cut them off and get numbers with open exhaust and finally install the flow master mufflers and get final data. I'll try to post videos with db readings and dyno results for all configurations. If anyone has something else they'd like me to test, ship it to me and we'll see what it does.

Bob
 
#23 ·
I have done a lot of exhaust research lately for my build and if I were going for quiet these flow masters are the way to go. Especially since they are on sale now.
Since I don't have to comply with any DB levels, and I have concerns about HP loss using them, I will be using Classic Chambered, either the Cobra pack, or the insert for custom side pipes on my Daytona.
 
#24 ·
Just bought a set. I think its really funny when my concern is that they might not be loud enough....
 
#27 ·
Trust me, they are NOT quiet. They still will get plenty loud when you are in the gas. They just arent super sharp sounding which to me is what is annoying and hurts the ears.. I was worried they may be too quiet as well. Part of me like super quiet and stealthy and another part of me likes people to look as I rumble by...

I would call the loudness a very good compromise for a cobra.
 
#25 ·
Thanks forum for once again helping me spend more money :)

Ordered them today from Jegs, now I have a month to figure out if I am going to cut mine up or not???
 
#26 ·
bobl
Can't wait till you get some real #'s with the different sidepipe combo's. I too have a loud 347 with super-ported j-pipes. Maybe the new F Ms will lower the DBs on my combo too? Thanks for doing testing, and please post results soon. Good luck.
Butch
 
#29 ·
I am excited to see the results of actual testing. Oh how I would like to see your pipes, a set of Breeze Quiet Pipes and Gas-n-pipes all tested on the same engine.

If anyone is thinking about not using the hangers, here is my advice. I didn't use them after reading a few threads that recommended not installing them. I ended up with a cracked 4 into 4 header on the #1 tube. To back that up, my friend that also ran with no hangers, just welded his #1 tube yesterday after it broke all the way in half. My hangers are installed, and he is doing his. Not 100% proof, but proof enough for me.
 
#30 ·
I am excited to see the results of actual testing. Oh how I would like to see your pipes, a set of Breeze Quiet Pipes and Gas-n-pipes all tested on the same engine.

X2 on that. Gas-n also offers a 3" core option for higher horsepower engines on their website but I don't recall reading anything about them on FFCars.
 
#31 ·
I just ordered mufflers. They are now 2 weeks out. I bet jegs never expected a run on mufflers like this...

Bob
 
#32 ·
I got a note from Jegs today, currently out of stock and giving me a ship date of 1-21-16. That's three weeks to ship.

George
 
#36 ·
Has anyone tried the 24" slimline mufflers? Are they louder?
 
#37 ·
Nuke....forget supporting the side pipes. They don't need it. My MkII has 36000 miles since it went on the road in 05 w/ no hangers. You can jack up the side of the car w/ your jack under the pipes just ahead of the turnout. Or you can jump up and down at the same place w/o hurting the pipes.
 
#38 ·
David's side pipes turn out about where the Gas-N pipes do. However the Gas-N use a 24" muffler but has a much longer tip which nets about the same length. The one thing I don't like about my Gas-N pipes is the long tip. 3 snake bites in the family thus far and all have been with contact on the tip, not the muffler. The muffler portion is a bit cooler than the tip. I'm sure it would still bite you. I love the sound and looks of my Gas-Ns but a longer muffler and a shorter tip would be better I think.
 

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#40 ·
I was wondering...will there be a corrosion issue with the two different metals? Is it a decent long-term repair with steel turnouts and collector?
 
#42 ·
Of course there will. 2 electrically dissimilar metals in an electrolytic solution is the definition of a galvanic cell. How dissimilar they are and how much a correct dissimilar weld buffers that solution are the details I am unsure of. If you did this with steel collector/turnout, you would want some form of coating to inhibit the steel general corrosion and make it all look the same anyway, so that would inhibit the galvanic corrosion externally and then you just have to worry about what happens on the inside of the pipes. Not that there's any water in engine exhaust.:001_rolleyes:
 
#41 ·
Ordered mine from Jeg's the 29th and received them Tuesday, drop-shipped from Flowmaster. Unfortunately, I am in SC thru next week. Otherwise, I now have a nice little winter garage/basement project. Garage for fitting/layout and I will move the welder into the basement so I am reasonably warm while I suck in the hexavalent chromium fumes.:001_tongue:
 
#50 ·
I have the used stainless pipes marked up and may work on cutting them and adding the slimlines this weekend.

In laying them out, it looks like I could cut 1.5-2.5" from the inlet to the muffler and 4.5" from the outlet. Still leaves these pipes being about 4" longer than they are now. Should fit almost perfectly such that the tip of the turnout is right at the rear wheelwell flare.
 
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