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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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#51 ·
I was playing around with my tape measure and found that the collector and turn-out will really be trimmed down. I honestly think it'll look better!
 
#52 ·
Lobak?

How do these pipes sound relative to the Lobaks with a vortex cone in the collector? I went with that approach 10 years and 30,000 miles ago and I still have my hearing. One drawback with the Lobak is that, after that many miles, the internal helix vibrates and 'buzzes' at certain RPMs.
 
#58 ·
I wanted to circle back and let folks know that I LOVE LOVE these mufflers. With the FFR side pipes, I needed to wear earplugs or my ears would ring after driving the car. I have not worn earplugs since installing these mufflers. The car still sounds great but its just not harsh. Much quieter while cruising...

Incredibly, after driving the car hard, I can literally put my hand on the muffler where my leg would touch it and it's hot, but it doesnt burn me. Doing that with a normal pipe would leave sheets of skin on the pipe!

David
 
#59 ·
David,

I finally got mine and am excited about these pipes. They look like a quality made product, however, mine were not marked either. Thanks for circling back and following up on this thread. :yes:


  • Sound
  • Safer to the touch
  • Will look good after a bunch of polishing

With these new pipes they have taken away the disadvantages of side pipes.

All of it 'Sounds' good to me, George
 
#60 ·
I took my pipes out of the boxes today. One was a nice satin finished piece with dressed welds. The other was raw unfinished thing without a brushed finish and black jagged ends. Called Summit and they're going to ship a replacement. I really hope it's not going to be another nasty piece like I have now! What have you been getting?
 
#61 ·
Both of mine needed the welds cleaned up. 3 of the ends were not that bad, but one of the them the weld was pretty heavy and took a lot of grinding to clean up. I also needed to grind on the inside of the welds to open them up enough to slip the collector and turn downs in.

Still, I am overall happy with the quality of the mufflers. I mock them up on the car today and started it up. It was a lot smoother sounding but still loud enough to get your attention.

I just need to get them welded up now :smile2:
 
#62 ·
Both of mine were pretty ragged looking welds and needed grinding on the inside. I figured I've got to clean them up and weld to the collectors anyway, so it didn 't make much difference.
 
#64 ·
Both of mine were like the one on the right, though not quite that bad. I also did not have any stickers to indicate the inlet side, so I had to measure the cones. To the eye they looked about the same.
 
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#65 ·
That is a HUGE difference! For an under car exhaust, I guess the ones on the right would be OK but even if you fix the welds, the finish is very difference. Not too sure how excited I am about ordering them now...but they still looks the the best option for my new pipes.
 
#66 ·
I got the crappy ones

Yeah its funny that I was not mad about the state of my mufflers until I saw that picture. My welds are pretty bad and they are def not polished. Also there is only a 1 inch difference between the cones anyway.


Not exactly pretty



 
#67 ·
So one of your mufflers has a sticker showing the inlet? Is that the short cone side? Mine are both the crappy welds. Big difference.
 
#71 ·
External diameter on the muffler is 4.5 inches
 
#72 ·
The Summit Racing listing for the Slimlines shows "Muffler Finish: Natural", so while some may have come through as polished, does not look like that is what is being offered.
 
#77 · (Edited)
I ground the welds down on one of mine. What it appears you actually have is the cone insert seats against the rim of the outer shell, which is stainless. The cone is not stainless. The weld is not stainless. Apparently the nicer ones were tig welded with stainless, whereas the others(crappy ones) appear to have been mig welded. If you were wanting to make everything stainless and polish it, you would need to grind the nasty weld off and reweld correctly with stainless. I'm not sure how the metallurgy shakes out on that in the long run. It almost looks like they changed how the cone is constructed.
 

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#79 ·
Proper stainless welds should be purged with an inert gas or a paste that upon heating releases said inert gas. To avoid the weld being contaminated with porosity.
 
#88 ·
i received my mufflers today, they are a fairly decent mill finish, but definitely not polished. It doesn't look like it would be too difficult to polish them.

They did not have any indication of inlet or outlet, so have we determined which end is which. The cones are consistent on both mufflers at 15 1/2" deep on one end and 14 3/16" on the other.

Thanks,

BigUgly
 
#90 ·
One consideration to go with the 30" is it puts the muffler (where it is double-cased) further back and actually in the area where your leg/calf usually locates when getting out of the car. What's cool about these is that they run much cooler where they are double cased and reduce or eliminate the accidental snake bite. The smaller 24" puts your leg more around the turnout which is single walled and is much hotter and more prone to biting. The assumption here is that we all exit our cars the same way and I know we don't. I have the Gas-N pipes and love them except with 3 snake bites and most likely counting from different people I have considered these slimines but would only go for the 30s.

Trevor
 
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