QUIET down the strrroker... tried DynoMax, MagnaFlo and thinking of...

[rguest3]

2-into-1 exhaust with 2 1/4" Pipe - Flowmaster Super 50 - 3" Outlet

2-into-1 with 2 1/2" Pipe - Gibson Superflow (758219) - 3" Outlet (Pictured)

Neither one has any drone what so ever. Both are fairly quiet.

The Gibson is my favorite and even fits perfectly in the original heat shield (77). I have also installed this set-up behind Nice 351s and 347s.

 

[nvrstuk]

Thanks all... I'm still wobbling... lol

 

[tabyers]

The good thing about the walkers is that they have so many options for shape and size as they supply so many as oem. I used one for a v10 van, which was very long, but relatively slender and round shaped. It was essentially the biggest thing I could fit in a bronco. I tried to reinvent the wheel through research but in the end it I felt it was consensus that the biggest walker quietflow and possibly a resonator, which did help a bit, was all I could do for myself if I was going to insist on sitting right on top of v8 headers, which of course I do.

 

[blubuckaroo]

With duals, an "H" pipe quiets it a lot.

 

[SHX669]

When you find something that works Brian let us know. I'm wanting to quiet down the '76 to a tolerable level - for me any way -lol . It's running a 2 into 1 Magnaflow setup ; two 2 1/2" inlets and a 3" outlet pointing down and exiting just behind the rear axle housing.

 

[Broncobowsher]

I run a 2-into-1 setup with a resonator and walker quiet flow on my 351w. I installed an exhaust cutout switch and have been having fun with that for the past 6 months or so. Some things I've noticed:
1) SO happy I went the route I did. The truck buttons up to sound like a truck. It's not silent, but it's quieter than many other trucks on the road.
2) I've played with the exhaust dumps a lot and I can feel no power difference with the dumps open or closed, which leads me to believe that the walker is quite flow-happy all the same.
3) While the cutouts are nice, whether partially cracked or fully open, they get loud very quickly - there isn't a smooth cline of sexy throttle sound, just little loud, then LOUD. I mention this because I can understand the desire for a softer rumble at times that other exhausts offer. However, having a true dual setup and open aired bronco like we have, I CAN say that having the ability to shut her up is nice.
Good luck and let us know what you wind up with and how it sounds.

This is what I did years ago. http://classicbroncos.com/forums/showthread.php?t=138301
Much like you describe, never felt any power difference with it open or closed. Sold that truck before I ever automated the opening with throttle position. It did get some interesting looks during visual inspection when I ran it through emissions. (It passed emissions on the first try);D

 

[nvrstuk]

Will do...if it quiets down this thing it'll quiet anything!

Best true test was this EXACT same system just bolted up to my stroker instead of the mildly built 351W for years... amazing sound level increase! So the same system for what I felt sounded good on my 351W is great if you are into impressing people from 1/4mile away... all the time...

In fact, my wife commented one night that she heard some kid out really hot rodding when she took the dog out at 11pm...I asked where, she pointed across the fields towards town where I had just really hammered on it coming back from a Bronco buddies house... that was over a full section away (over 1 mile).


That exhaust you built for the Durango is pretty ingenious...

 

[Godwick]

This is what I did years ago. http://classicbroncos.com/forums/showthread.php?t=138301

Much like you describe, never felt any power difference with it open or closed. Sold that truck before I ever automated the opening with throttle position. It did get some interesting looks during visual inspection when I ran it through emissions. (It passed emissions on the first try);D

Bowsher, that post is what inspired me to do what I did. I had just gotten my bronco and began wrenching and thought (and still do) think all the trick and sleeper stuff you can do with these cars is one of the coolest things about them.





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[ntsqd]

I've run this muffler: https://www.summitracing.com/parts/wlk-17698 on a couple 350ci sized engines and really like it. I have one for the Bronc-up as well. I run them 3" thru, but I know of one behind a 302 that uses a 2.5" tail pipe to keep resonance at bay.

Your comment about a larger displacement engine causing a system be louder was one that I've been pondering since spotting this thread.

 

[nvrstuk]

Well... the tech guys at Walker, Thrush/DynoMax) which are all Walker and Flowmaster all said the same thing when I talked to different guys than I have before (last week)...

"Good luck"...!! Seriously...like I've found out, what sounds good in a stock 351W or larger engine and then stroke it, build it pretty seriously and you aren't comparing apples to apples or even fruit to each other any more...

One of them suggested running a resonator after the muffler to help with any drone. Two of them said the length of muffler will help "some"...really? Almost double the length of the muffler and it will help "some"?

I ordered a 24" long case today...I'll see if I can stuff it in there...1/2" clearance on length...after I start it up I'll report back...

 

[Godwick]

Good luck. Would be awesome to have a master list of exhausts and sound/performance in the site somewhere.


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[nvrstuk]

Cool idea on the exhaust link... be a lot of variables with recording levels, etc but very helpful

Quick update on air flow and db...

Friend had a 5.3 in a Yoda. Put a 6.0 in it with a blower...exact same exhaust system.. HUGE difference in noise level...just what I went thru... it's all about air flow.

 

[Yeller]

yes airflow and compression (kinda go hand in hand...)

2 cheby motors, same basic exaust, same muffler, same cubic inches, 1.3 change in compression ratio. both sound pretty rowdy, the high compression one parks next to the lower compression one (me) and I can't hear or feel mine running sitting in it, bump the starter with it running, both rigs idling and we're carrying on a conversation. Both have a single standard 50 series flow master.

Interesting note about the higher compression engine in this comparison, (I built both buggies from scratch) I really expected it to wear on you over long day trail riding, it never did, and it was pretty loud but had no drone and conversation was easy as long as you weren't leaning on it. However in that car if you were leaning on it, you were not talking, you were too busy holding on for life and developing a permanent grin that is a language all its self

 

[DJs74]

FWIW, a few years ago I was so obsessed with finding the right sound and tone on my '78 F150 / 466 BB that I set up my exhaust with a series of 3 hole flange reducers on both sides so I could change the mufflers out in minutes (6 bolts / nuts)... and I did about 8x until I ended up with a set of Dynomax welded mufflers. They ended up being my choice and started off as the perfect sound (to me anyway) but as they burned, the drone started sneaking back in. They sounded a lot like the old round thrush with the bird on the side... my favorite muffler of all time!

I had fenderwell headers on the truck so it was a straight shot back but you could probably do the same inside the chassis.
I put 3" / 3 hole flanged reducers on both ends of the muffler and the same on the exhaust pipe where a weld would normally be.
Then, a new muffler just requires a new set of 3 hole flange reducers - they will already be on the exhaust pipe.

Did I mention I have stock in Summit Racing... just in mufflers, reducers and exhaust turndowns alone! At one time, I had about 5 sets of mufflers (with reducers at each end) on the shelf but friends and family needing mufflers has just about depleted my inventory.

I still have one set of Thrush Welded oval mufflers I stick on the stroked racer once in a while so my neighbors don't stroke and there is one event nearby that requires DOTs and mufflers so I hang onto them in case I get to run there.


DJs74

 

[WheelHorse]

Has anybody quieted essentially, a big block in a bronco down to levels where you can have a conversation inside?

Why not grab a set of used 5.0 coyote mufflers and adapt them to fit underneath with tailpipes?

Or if you are really concerned they wouldn't flow enough go with GT500 mufflers. Stock Coyote vs GT500 muffler comparo sound video

 

[5001craig]

Where I go I need to be 94 db @ 20" @ 2,500 RPM's. I'm pretty sure I'm over that but I was looking at sound meters today on amazon and found-out you can get an app on your phone for a couple bucks. I did that and will be measuring mine this weekend. 94 db isn't very loud. I'll post-up the results here after the weekend.

Not scientific but gives one an idea what different mufflers run. I would love to have someone want to test mine. Maybe you could check some of your buddy's rigs.

 

[nvrstuk]

http://www.mustangandfords.com/parts/m5lp-0212-ford-mustang-muffler-comparison-test/

I think these clips give you db levels...94 ain't very loud... remember, db like the Richter scale is logarithmic so sound volume goes up fast...

 

[Local Boy]

For whatever it's worth...

I'm rocking a 408 that's 600+ Hp and just finished the exhaust...

I went with Borlas and resonators after the mufflers and it is perfect... with full 3" pipes

Sounds very similar to this...even through these are Dynomax mufflers...
https://www.youtube.com/watch?v=84zxvfZGax8

I did not want loud...But with 408's you can only quiet them down so much before you choke them...

Aloha

 

[nvrstuk]

That's a LOT of air moving thru that beast! : ) Congrats on your build...be interested in your cam specs if you're willing to share.

What brand of resonators did you use? I"m trying to find a short straight section of pipe to have "available" if I need to put some resonators in... very interested to find out if you tried the system first w/o the resonators and how much difference they made when added as I've never found anyone yet on a big cubic inch motor that's tried that... be very interesting to see if they helped by 5db or so...

thanks for your input.

 

[Local Boy]

Thanks!

I'll have to dig up the cam specs...old age just won't let me remember the details any more...

No, I did not do a "before and after" the resonators.... Just dove in head first and did it...and very happy I did...I'll have to check on the brand as well...

I wanted to get rid of that echo, in the exhaust, that you can hear in big inch motors with 3" full exhaust (some people like that...I wanted a more clean sound) as well as reduce the volume...This seems to have worked on both accounts for me...

I can put up a video of the exhaust, just like the one I referred to (above).... in a few weeks... if it can help you...

Aloha