The wall thickness is actually 1.2mm. That seems really thin to me. I just spoke with Racing Beat on the phone asking about ways to make my setup quieter. He suggested I remove the Magnaflow because it might be the reason for all the noise in my interior. This is after I mentioned the noise outside the car is actually not that bad.

 

Just got home. They insisted there's no way I will be able to blow apart their presilencer and if I do to bring it back in. Hopefully he's right. We shall see.

 

I wish you good luck that it holds together. I guess we'll see how well mine holds up too.

Oh and I've decided to leave the Magnaflow installed but add a 16 gauge tube on the outside. The other choice would have been to cut it open and swap to a 14 gauge tube - that's too much work and more expensive (would have to buy some tube). I also incorporated a slip-sleeve design to protect the core during heat expansion like Racing Beat's that I got to fit just right in there, which would become mis-aligned if I mess with it/rebuild it. Nah I'll just add a second tube on the outside to make it a .120" double wall shell.

 

Jeff, so you're just going to wrap the entire magnaflow muffler with another tube to thicken it up? I don't think I understand?

I sure wish Racing Beat made those universal mufflers/presilencers with 2" diameter as an option. Looks like all they have right now is 2.5" and 3". If they offered a 2" size I would be ALL OVER that. It would really open up people's options for custom 12A exhausts. Right now it's either the Racing Beat complete exhaust system for over $700 or you buy something from Magnaflow and pray that it will hold up. If Racing Beat would make a 2" universal muffler that would allow me to ditch all this Magnaflow crap in my custom exhaust, and just use RB parts.

Anyone know if they are considering this? Could we nudge them that direction?

Jamie

 

The problem with the universal presilencers is the wall thickness is VERY thin (like 22 gauge!), as they were intended for turbo applications. This means they are technically too thin for an NA setup. Racing Beat's old school 2" and 2.5" round presilencers are 14 gauge and work very well at keeping the noise out of the interior.

The universal mufflers have the same paper thin wall thickness I suspect, but because it's a muffler, they've assumed you already have an adequate presilencer earlier in the system and aren't complaining about the noise like I am. This lets then get away with thinwall here too, regardless of whether NA or turbo.

Yes I'm thinking about adding a 16 gauge tube on the outside of the magnaflow so I can keep it in the system instead of removing it (hey, it IS a muffler after all, and every little bit of muffling helps) and prevent noise from leaking out through the shell, as I suspect is happening right now.

Noise is also probably leaking through the very thin wall of the universal presilencer, so maybe I'll grab some steel sheet and bend it around to make a nice comfy wrap for it.

14 gauge 3" tubing used as exhaust pipe will get replaced with .120" wall tube in front of the presilencer when I redo the header in coming months. As for now I think I could double it up with some more 14 gauge or some spare 16 gauge I have left over from PercentSevenC's turbo exhaust build. I'm kinda jealous of how quiet his setup turned out, almost like the Racing Beat streetport exhaust in volume and character. That's what I wanted mine to sound like. Maybe I was a bit naive, huh?

 

Great info Jeff, I understand where you are coming from now. So you are currently using a Magnaflow and a Racing Beat universal?

Jamie

 

wft do you want 2" for? the RB SP system is bigger than that....

 

RB road race header, dual pipe flange, collected to 3", RB "large" universal presilencer, two 3" core 4" round 14" long Magnaflows joined together, 3" flange, up over axle, 3" RB universal muffler, dumpy.

 

Welp got the RB muffler installed. Its quieter than the first day the magnaflow was installed, even before all the glass melted. Sounds awesome. Almost no interior drone. Its the quietest its ever been. Sounds fantastic though its still loud as hell at WOT like I like it. Its clearly better built than the magnaflow, so we shall see how she holds up.

Current setup is;
ISC header>ISC collector>RB large presilencer>dynomax bullet presilencer>magnaflow 8x4x16muffler
Magnaflow work perfect in the main muffler area. Mine has been on my car for over a year now and is still full and sounds great.

 

Going to dyno it again?

 

Glad you like it. I love mine. Makes one wonder how RB can get away with selling those things at such a low price, given the build quality. How's your Dynomax bullet holding up?

Jeff: 1.2mm wall is 18 gauge.

 

Ok, ok. Thanks for that info Percent.

Adrian, thanks for letting us know how it sounds. It's enouraging to think I might only need to wrap my Magnaflow. Less work for me.

 

Too broke to dyno it, plus I don't see a reason to as the mufflers are almost identical in construction. Took it to willow springs for their Friday night drags. It's on the front straight of the big track, so there is absolutely no traction. Its also only 1000 ft. Car ran 12.5's @ 87 MPH all evening.

 

12.5 in the 1/8?

 

You don't read very well do you... 3 words before 12.5 it clearly tells you it was a 1000 ft track. Shall I do the math for you? 5280 ft=1 mile. Therefore 1/4 mile is 1320 ft and 1/8 mile is 660ft. Well maybe you're not American and you use the metric system and all this feet talk is foreign to you, but its most likely because I'm an ******* and I expect everyone to know this stuff. ;D

Kinda slow I know, that should put me in the mid 14's in the 1/4 mile, but willow springs is at 2500ft, by no means a drag strip with no traction, and running that shitty airfilter, street timing, I know I'm not making the same 190whp that I was making at sea level. My guess is at this elevation, with the airfilter, and conservitive timing, I'm at about 170whp. I know at sealevel with the airfilter and conservitive timing I was making 180whp. I figure a 10whp loss for the elevation.

 

Didn't know Big Willow did friday drags, might have to check that out with the REPU this summer. Do they stop at sundown?

 

It's every other weekend. They recently moved it from Wednesday to Friday nights.
They ended at ten pm.

 

Reading comprehension owns me. I thought you meant 1000ft as in altitude. I had just never heard of a 1000ft track.

Ive only been to the 1/4 in the car once since the autocross was at a drag strip. I ran a 15.1 at (98ish?) on a 95 degree day with high humidity. I didn't adjust tire pressure and with the 9lb flywheel and 6 puck clutch it was either spin spin spin or bog.

 

Lol oh I see what you did there. Elevation here sucks. 2500 ft makes everything slower!

 

Yeah the humidity down here doesnt help but at least we are near sea level. I was disappointed but I should be able to get it down to the 14s pretty easy on a night run when its cooler out. I ran a 2.8 60 ft. Crappy thing is I ran a 15.9 with just an RB Streetport on the stock 190000 mile motor.

I have been thinking about putting in the regular lightweight flywheel and selling the aluminum one when I go back to a regular clutch. Also I am working on a 3 inch exhaust and will report the results of the dyno difference between that and the RB when I am done.

 

damm man dats sweet

 

Update it's been a few weeks and the RB muffler has seen over 1000 miles and it's not a peep louder and it appears to be holding up well to my abuse.

 

RB muffler status update. it's seen over 6k miles and asside from scraping everywhere(may super low fault)it's still in great shape.

 

Thank you for posting an update! Sounds like the SS shell is pretty durable and the slip fit at one end allows expansion of the core so it won't buckle.

 

that's the problem with DunoMaz mufflers, collapsing cores...