Im one of the 4" Mufflex cat back owners looking to help quiet down my Hooker longtube equiped 383. Right now Im running the Spintech muffler which I know is hurting my HP, but more importantly I want to get the db's down. I know its a stout exhaust system but I think there has GOT to be a better way to get thoes db's down at least a bit more. I was looking on Magnaflow's web site and found there race series mufflers. http://www.magnaflow.com/02product/02race.asp Im thinking the 14153 muffler might work better than the Ultra flo 4" muffler that most of you guys have been talking about just beacuse it looks like it might pack a little bit more sound deading material in it. Any of you guys know anything about Magnaflows 5"x8" OVAL RACE SERIES mufflers?? Thanks in advance!

The 14153 is the one I'm planning on getting after seeing them being used on an Ultima GTR. Really like the sound out of them and the Ultima usually uses a regular SBC or LSX motor. http://www.youtube.com/watch?v=CKX2KZruc3E

That thing did sound pretty sweet! If my memory serves me correctly, my Spintech muffler case is around 16" long, so im thinkin this might be a pretty straight foward muffler swap, seeing how the 14153 is 14" long.

well I have tried the Split-flow from dynatech which is a Borla XR-1 style muffler, just about the same thing but cheaper. IT was very loud but had a great sound

I switched to that 16" long dynomax ultraflo round and it was quieter but still pretty loud. My car idled around mid high 80's dBa's. I measured it. It was even louder at part throttle but its hard to tame down a 383 with longtubes and 11 to 1 compression when using a 4" single. The ultraflo has larger holes in the core and more sound material packed in than the dynatech

That 14163 round case version looks to be identical to the Ultraflo and not be all that quiet.

The 14153 does look promising, but will depend on the core and the holes it has in there. My dynatech was a oval 4.5x7 or so inch case, just as long at 16 inches i think. It had small holes. Not so quiet. So that 14153 may not be that quiet either but could be the best option right now

Orr89RocZ, I have been following what you've been saying in the other 4" exhaust threads, so I appricate your input. Ive read alot about Magnaflow owners complaing about how they wished there car was louder at idle, but opens up nicely with more rpm's. I guess what I would really like to accomplish is to get most of my idle db's down.

Yeah i havent seen those mufflers on any cars. I didnt even know they made a 5x8 oval or else i may be running that muffler by now. My state cop neighbor told me to quiet down my car and i put on that ultraflo and it came down abit but still is ridiculous at low part throttle. Its the nature of the beast tho.

You have to look at the core inside and see how large the holes are and that will help determine how quiet its gonna be

what would be very cool is a flapper valve that works on vacuum that will open up on WOT but stay somewhat closed at idle. Help deafen the sound i bet. Like the Z06 has

You have a state cop as a neighbor!?! Boy, that must suck when you have to start the Z, LOL I guess that explains your drive to quiet you car down.

I hear what your saying about the holes in the core, makes sense. I suppose if the 14153 muffler dosent make it any quieter, it should at least pick up 10 to 20 hp, according to what everyone has been saying about the Spintech muffler, LOL.

It might not be the most cost effective way, but throwing a Ultraflo in the I pipe could help quiet things down a bit more.

It is certainly not cost effective, but I will have a nice data point for you all in the next two months.. I have the 4 inch on my car now and a magnaflow catback waiting to go on.. as soon as my car is out of paint I am going to dyno the 4inch spintech, then come back and dyno the magnaflow catback.. should provide some good info.

My neighbor is cool tho. He told me i had to quiet it down one day when he was in a bad mood and generally states he doesnt mind me coming or going... as most of the time its not too early in the morning or too late at night. So thats good. I know alot of my car isnt quite legal but depends on your definition of the rules/laws

I also fully intend to do some more dyno testing myself. Last time on the dyno I put down 413 rwhp thru my Spintech muffler. Late last year my thrust bearing wore out in my old cast steel/hyper piston 5.7" rod motor, causing me to re-build the motor. Now its just about finished, but now its a all forged H beam 6" rod 383, with a little bigger cam (XFI) my old cam was a TPIS ZZ409, I do plan on dyno tuning my new motor and then once I get use to the sound of my Spintech muffler again, I would like to install the Magnaflow 14153 muffler to see if it quiets down the Z AND see if she makes more HP on the dyno.

i had that muffler on my mufflex and it came off the same day. it was loud!
had a very different sound, really nice. no interior resonance, but wasnt quiet at all for my tastes.
im looking into a dynomax can muffler thats 22" in case length, or maybe a magnaflow can thats 30" in case length if i can fit it.

Your talking about the Magnaflow 14153, its loud hun? I was hoping to just replace my Spintech muffler with another muffler, and I dont know how much more room there is to fit a 30" muffler in the stock muffler spot? Does putting a round Dynomax muffler in the I pipe interfere with the driveshaft and ground clearance? Thanks!

the magnaflow has less interior resonance than the spintech for sure.
its been a while since ive had a spintech on the car, and it was very very loud.
the magnaflow matches the spintechs noise on the outside, only smoother.
with the windows up the magnaflow would be decent, but i dont have a/c in my car, so it had to go.
i have a bullet in my I pipe. dented the floor pan up a lil and i have the same clearnance with it as i do my mac subframes.
angle is off on the camera, but you get the idea.
its higher than the y pipe is.

Thanks stage20, I do appreciate the help here! Less interior resonance would be nice, I have the same mac subframes as you do, what bullet do you have in your I pipe? (length wise I guess) Are you running a muffler in addition to your bullet, or just the bullet? I guess if it takes running the Magnaflow muffler and the dynomax bullet in the I pipe to get the db's down, then thats what its going to take. Ya know?

My 6" round case is pretty close to the ground but i havent had a problem yet with it.

Is it that loud, like race track loud or what?

Eric

My muffler was alot quieter than open headers but its pretty darn loud. I have a bunch of vids of it but they dont really do it justice. The track vids you can hear it screaming down the track pretty good. And hear it idle in the burnout box a good 30 yards from the camera Its almost as loud as most race cars there but certainly not open header or straight pipe loud

i had the bullet in the I pipe when i did the magnaflow.
my exhaust is a 3" y pipe into a 4" bullet. there is only one 4"
5" OD 12 inch case, 16" overall.

ive had every muffler under the sun except a few, and the dynomax ultra flow 17536 stock replacement has been THE most sane setup on the car over anything else.
my problem lies now is i have 625-650 flywheel hp, crazy camshaft and compression that is just popping and banging around. now this muffler isnt quiet so im ditching it.
it cost me 15rwhp and 10rwtq on the dyno. i dont think the muffler is the restriction as much as necking back down to 3" pipe and then 3" inlets.
i think im going to go with the larger bullet muffler pictured above, but a longer version. might even put another one out back if its not to my liking.
here is the pic of the magnaflow with the y pipe. i hadnt had a chance to paint it yet.
i sprayed the taipipe real quick to hide it.
here is the for sale thread that has a pic in it.
http://www.thirdgen.org/techboard/en...s-muffler.html

its gonna be HARD to quiet down that car without sacrificing some power. you might be better off with a dual exhaust with a large muffler on each bank or atleast a long y pipe with some sort of muffler on each bank then another large 4" piece.

I think this answers my original question, if I need a few more db's taken off, Ill do the bullet in the I pipe as well. Thank you!!

the stock replacement dynomax 17536 that i ran is the ticket, but it killed 15hp and 10ft pounds on the dyno, so its see ya later!
it lost nothing on my head cam 6.0. i guess thats what another 130hp does for ya.

dynomax claims 596 loss free hp. i figure 625-640 crank, so it makes since its a bit of a restriction now.

All in all, 15whp isnt all that bad but does suck to lose it.

That muffler tho is a 3" setup.. Thats suprising you made as much power as you have thru that muffler. Maybe 3" isnt all that bad?

it flows well.
15hp is a huge loss for me.
my 6.44 just became a .48 or .49... figure in the 35 pounds the muffler, hangers, and tailpipes weigh and thats getting in the .50's.
im all about ET.

was [this] close to ordering the 36" mangaflow round muffler, only to find out the 4" muffler has a 3.5 inch inside diameter in the muffler!!!!!!
looks like ill be ordering the 30" long one and hope its enough to keep it somewhat calm.
ill post up some results by the weekend.
id like to do it friday if i have off.
thanks.

Length should help. Dynomax ultraflo round also comes in a longer but thicker case, like 9" circle case compared to my 6". That may keep things quiet as well

i cant fit a 9" under the car.
i could put the 9" one in the stock location, but i made a template and a big round thing loooks wierd back there.
the magnaflow is on the truck for delivery today. im going to get it welded up friday and see if i can live with it.
ill post up my results.

raining. board. having some fun.
lil bit large. 30" case 7" diamater. 4" in/out
:mrgreen:


nws for language.
dan was yelling extremely loud the 2nd time.
http://www.youtube.com/watch?v=FPInqcK4Mec

Would one of these do the trick?

http://store.summitracing.com/partde...5&autoview=sku

I'm interested in your results, as i think i may beable to fit that muffler in the I pipe region. That is if my car is loud again this year but i think the lower compression and two turbos should not be that loud

http://www.youtube.com/watch?v=tQ72l4Q0a_E
oh man.
this one is a better example.
i cant tell you how hard im screaming. should have faced the camera, it would have been louder, but you get the idea.

muffler is 16 pounds if it matters.
my 4" bullet is 8 pounds, and it does nothing for sound quality.

http://videos.streetfire.net/video/4...ack_644412.htm

its decent for what it is.
hard to tame 625+ n/a hp.
its kinda big block sounding.
no rasp or drone, but not as quiet as i wanted it. dont think it will get any quieter though. muffler wouldnt fit under the car, so its back in the stock location.

NOt to bad at all. Still pretty loud i bet but what are you gonna do with 600+hp? lol

Definately sounds like a big block car tho

to me, im more partial to the dynomax crackling sound.
its more my tone.
this setup sounds a bit like the flowmaster, without the hollow, tin can, this muffler wont make any power type sound.

id like to throw a dynomax can on there just to see if there is a difference in sound.
ill let this one be for now.

Im going to bring back an old thread with some sound clips-
Mufflex offers a 4" Magnaflow race muffler with there systems now for the 3rd and 4th gen cars, the tone sounds better then the flowmaster and the spintech.

3.5" bolt-on LS1
http://www.youtube.com/watch?v=TFVe-9lKGac

4" system with a catted y-pipy on a 383 LT1
http://www.youtube.com/watch?v=ln5qco-cvkk

I'm going to bring it back again.

Does anyone know if any company besides Spintech makes a single 4" in, dual 3" out crossflow type muffler? Something that could simply replace the Spintech in the Mufflex system?

Better yet...does anyone know if Mufflex has changed their policy on selling just the 4" I-pipe seperately?

no 4" in with 3" outs that i know of. i have looked for one in the past. ended up with a dynomax ultraflow on the back. exhaust guy flared the end of the muffler out as far as possible, then used a short piece of flared pipe to connect the two.
it didnt lose any power on my 6.0, but was worth 15 at the tires on my 408.
i have a mufflx I pipe, with a bullet muffler in it, as well as the over the axle pipe.
it has the big magnaflow welded to it right now.
id sell it all, but shipping may be quite a bit.
could cut the muffler off and sell you the pipes.

I just bought the Mufflex 4" w/ 14153 Magnaflow muff for my TTA.
I never heard one on a TTA but sounds great on V8's online.lol One member has this catback and is running 10.2's with more left in it. He hasn't posted any sound vid's with the Buick powered T/A.