Dynomax vs. augers vs. stock glass paks?
 

Dean,
Now that you've had the new 3" SSS (not Dynomax :)) mufflers installed for a while, what do you think? Are they too loud and what performance difference did you notice with the change? Did you notice any loss of torque with less backpressure or more power up in the 4K+ rpm range?

One of my ERA sidepipes is possibly starting to rattle inside and I'm considering cutting them open and going with an auger or Dynomax 3" mufflers. I'm still looking for someone with an ERA with stock sidepipes (2.5" ID) that may have changed them out for comparison to either the auger style or the Dynomax. My car is fairly loud today with the stock 2.5" ID glass paks and my particular cam, but a little louder would be okay too and possibly worth trying.

Your thoughts?



Thanks

Duane, you might want to re-check the photos and text from the beginning of this thread. I did NOT install Dynomax mufflers. These are custom stainless steel mufflers with 3" ID. They sound great and there are at least 4-5 others on CC that have done the same modification since this one. The Dynomax will be very loud, like running an open pipe. No loss of back pressure...with a jet change to compensate for the freer breathing, the car runs great.

Regards,

-Dean

Edit
 

Hi Dean,
Yeah, I must have read your post three times and knew they were SSS, but kept thinking of Dynomax from something else.

I listened to the auger type yesterday. They sounded good, but seemed to have less crackle, and definitely let less air out by just feeling the exhaust as compared to the glasspak straight-through setup. Maybe that is by design, who knows. The augers do have a deeper shound and a metalic ting sound to the sidepipes which is kinda neat too. I've only heard 20" type augers with 3/4" center pipes. It would be neat to try 18" augers with 1" ID center pipes too. I guess the only way to know is to test them and compare to know for sure. Thanks. Duane

Sidepipe modification done. Fine tuning next.
 

Hi Dean & All,

Well, after much analysis - I DID IT. The new 3" round ID cores went on yesterday and I cranked it up yesterday for the first time. They are back off now for painting. I went with 20.5" (.5" longer) and cut off my old muffler cans and reused my header-collector, tailpipe tip, and mounting brackets.

Observations and Conclusions:

- Sounds nothing like my original 2.5" ID ERA exhaust pipes. Totally different.
- Much deeper and less crackle sounding; More deep pop, sound pressure.
- At least 25% more air coming out at idle by a quick hand check.
- The new muffler cores weigh about HALF. Those old ones are heavy.
- LOUDER at low frequency exhaust note range (more DB)
- QUIETER at high frequency exhaust note range (less DB, less annoying)
- More noticeable torque response at midrange for sure, a nice suprise.
- I think I need to rejet, checking on this now. Need to measure. 2-3 up?
- To me, Its maybe 20% louder but only at low frequency which is nice.
- Seems easier to talk with a passenger now with mid/high frequency gone.
- Exhaust note/type is more similar to a factory SPF sidepipe than ERA, KMP.

After looking at this muffler setup a bit more all said and done, there is actually some engineering to it; and more than I originally thought. The shorter ID glasspack inside a larger center section creates a chamber expansion-contraction-expansion effect which completely changes the exhaust note; it cuts out almost all of the high frequency note. This is very similar to some expermintation I did with my Harley Fat Boy exhaust a few years back with the exact same type results. Once I get the sidepipes painted up, decide on what carb rejetting is actually required, I'll have a better idea on performance gains. Overall, I'm really glad I had my factory ERA pipes on there for a while first to make a real hands-on comparison. Its fun to try something different. There are about 10 guys around here waiting to hear the results. Pun intended. Can't wait to get them back on again. See Ya. :)

i also give a thumbs up on this set up. although i only heard them on the engine test stand as of yet, the sound awesome. a good amount of low end gurgle that sounds like "serious business". nothing but nice tones from these mufflers. plenty of flow. hope to get the car on the road next week if lucky.

Dr. Jekyl / Mr. Hide
 

The cool thing about them is you can cruise along at say a steady 2,500-3,000 rpms and they are not bad at all, but when you romp on it WOW, its a deep roar.

I would not say they are quiet, and would now classify them as medium loud at cruising and very deep and loud at wide open throttle. Not for the faint of heart. Most importantly that annoying rapp papp papp papp sound is gone now, like going from Harley motorcycle slash cut pipes to dual Thunder Headers if you like that deep sound. I sure do. Much easier on my ears on longer drives at crusing speeds. Your cam size has something to do with it too though. Larger cams do get a bit louder with these pipes.

So far we have about 10 of us that have tried them. So far so good. :D

Sorry a little off the subject but do you recall the directions or where I could fine how to make those black ramps

Dean (Red Barchetta) and I were terrorizing our local streets on Saturday, so I got a close-up and personal test from outside the car. Here are my unscientific observations:

1) The car no longer sounds like a small-block Ford, it now has it's own distinctive sound
2) Without a dB. meter, I would say that when he gets on it (which happens frequently) it would be the loudest street car I've heard life-to-date,
3) At idle to cruise it would fall into the "acceptable" range,
4) My wife likes the sound of his Cobra better than mine with a 496 FE with glass packs:cool: .

I've heard the car from inside and now outside and I think this setup is a winner.

Brian

Which is why I wear ear plugs rated at 30db. :)

Thanks, Brian. Cruising :LOL: through our little town was sure a whole lot of fun. The look on people's faces as two wound-tight Cobras work each stop light was one for the books.

-Dean

I see that you guys are in the Yorba Linda area. I am in Ontario just south of the 60 and west of the 15. I made my own mufflers using Car Chemestry baffles and Vortex cones-no other packing. My car is also quite loud "at speed" but not too bad at a low cruise. Maybe we can get together for a beer sometime. E mail me if you are interested. -Bob bremillard@msn.com

Sidepipes
 

scottj,

With using a 3.5' perforated muffler core, are you running a 4.5' OD sidepipe?

Also you mention the noise is similar to a straight pipe, I dare say the only way to quieten for certain situations is to plug a chambered type baffle up the the end or inside the muffler, but that would have to go down to maybe 2.5" for the street, and still have the lack of response with a big cammed engine like mine!

Another thought for packing a muffler is a product here called KAWOOL is the white mildly toxic (strong coffee) fluffly dense wool they wrap around boilers can stand a great deal of heat, but its normally behind a metal skin not in direct spark type exhaust flow!

Do the newer Backdraft side pipes have a straight through muffler?

Any idea of inside diameter? The new pipes from Backdraft are $1,350 but they may not pass the tennis ball or baseball test.

If they are just 2.5 or so I will get the big stainless mufflers grafted on my collectors.

Any suggestion or advice is welcome.

Thanks,

Russell

I currently have my BDR in the shop to get Stainless Specialties mufflers welded in place of my old BDR mufflers. The new mufflers are 3" ID. I'll post the results. The cost of just the mufflers from SS was about $730. SS did an outstanding job on the mufflers.

The current price of the BDR sidepipes are now $1,650.

Stainless Specialties made custom mufflers for my under car exhaust,they fit perfectly and sound incredible 2 1/2" ID They have also made the mufflers for two of our Harleys and a set for the Boss Hoss V8 motorcycle all sounding just the way we hoped they would.Great Co!!

Please post photos and keep us in loop.

Are you doing your own welding? What inside diameter are new BDR Muffers?

Thanks,

Russell

Is this the company in Fargo, ND?

No, Stainless Specialties is in Cleveland, TN. I just recently cut off my old auger type mufflers on my Kook's sidepies and replaced them with 2½" ID Stainless Specialties perforated core muffs. I loved the way Dean's sounded but was a little nervous about the sound volume so went with the smaller ID.
I went from this:
http://img.photobucket.com/albums/v6.../DSC01627R.jpg

To this:
http://img.photobucket.com/albums/v6.../DSC01630R.jpg

Re-Coated and Mounted:
http://img.photobucket.com/albums/v6.../DSC01662R.jpg

The improvement in performance is remarkable. I love it. What's even more remarkable is that I was able to go to square jetting for the first time ever and actually leaned the motor down a bit. The sound is good but I keep earplugs at the ready as they get really loud above 2500 RPMs and sustained blasts warrant ear protection.
Frank

Frank- how the hell did it ever run with that much restriction ! :eek:

Did they come from FFR !

I have the same Stainless Specialties mufflers in my "Gilmore Side Pipe Kits", and love them. Amazing difference in quality, performance & sound.

Old pipes-
http://i509.photobucket.com/albums/s...ertubes010.jpg

New-
http://i509.photobucket.com/albums/s...ompleteKit.jpg
http://i509.photobucket.com/albums/s...oreKit1036.jpg

Thanks for the information. Tennessee is lots closer to Arkansas thn North Dakota.

Russell

Very nice.
How much power could you gain if they were tuned lenght headers?
JD