Classic Roadster exhaust dilemma

Matt Wech · #1 (**permalink**) 08-07-2014, 02:11 PM

Hello Cobra peeps,
So I have a dilemma. The classic roadster exhaust has baffling in the pipes and they are way too quiet. Given that they are longer than stock, FFR, Superformance, etc... I would have to cut these, remove the innards and instal my own glass packs, etc...I'm being told that once rebuilt they cannot be re chromed due to carbon on the pipes destroying the chrome tank.
Any thoughts on how to make these suckers louder without cutting them or where to buy pipes that would fit my stretched frame?
Many thanks!!

Frank Messina · #2 (**permalink**) 08-07-2014, 02:43 PM

Sounds like bogus excuse to me. There are way too many chrome plated and welded parts out there for that to be true. Did the plater tell you that or a sidewalk expert?

Frank

joyridin' · #3 (**permalink**) 08-07-2014, 03:23 PM

These are rather expensive, but they sound awesome. They aren't killer loud, but a real deep throaty rumble. They make a 30" version for Corvettes.

Spiral Turbo Specialties:

Frank Messina · #4 (**permalink**) 08-07-2014, 03:42 PM

You may want to check those very carefully before plunking your money down. I bought a set of headers and sidepipes from Kooks $$$$$$$ with augers in them because everyone said how great they were. Hated them from the first start and finally replaced them last year. Not saying you won't like them, just check them out so you're not disappointed with what you wind up with.
FWIW I now have Stainless Specialties mufflers and both my engine and I are happy. YMMV.
Frank

PS: Oh, and if you want augers I'll make you a screaming deal on my old muffs.

GLS-BDR226 · #5 (**permalink**) 08-07-2014, 03:45 PM

Contact SSS. Stainless Specialties - Mufflers

They can make a muffler to your specs. I had my BDR stock mufflers cut out and re-welded. Looks like the stock sidepipes but I chose 4" with 3" inside diameter. Really opened up the sound.

GregAgrest · #6 (**permalink**) 08-07-2014, 05:50 PM

I had the same delemia. Ended up cutting to 4 inch tube off , put in a glass pack muffler and used a 4 inch chrome band to hold it back together. It worked fine, sounded better but I didn't like the band because it was chrome and the pipes were ceramic. After six months of that I bought some 32 inch Classic Chambered Exhausts, then had everything ceramiced. Turned out very nice and the sound of the Classic Chambered is perfect. Check them out, they have some sound bites to listen to. Also, somewhere here on CC there was some videos of a guy who has Classic Chambered Exhausts on his Cobra. I think you will like their sound AND you can pick the length of the exhaust. I have a CR too so I know they will work.

Matt Wech · #7 (**permalink**) 08-07-2014, 06:42 PM

Did you cut before or after the tube? I'm guessing you cut from the back side. Was it a simple job to remove the old baffling

joyridin' · #8 (**permalink**) 08-07-2014, 07:23 PM

I have augers. The car sounds great, which is why I recommended them.

MaSnaka · #9 (**permalink**) 08-07-2014, 07:26 PM

Matt,
Whatever you do you should cut out the CR mufflers. Look at them to see how restrictive they are. Then Throw them away or make some yard art out of them. I did and went with Classic Chambered and ceramic coated.

If you want the chrome look those stainless steel pipes look and sound great. They will never peel or flake like I have seen some chrome pipes do.

The CR exhaust is slightly longer but also only 3" diameter compared to all others which are 3 1/2"- 4" diameter. The Classic Chambered mufflers come with 2 1/2" inside opening or 3" inside opening. I opted for the 2 1/2" and faced the little louvers inside so the open end of the louvers was facing the exit end of the pipe. Tickled my insides the first time I fired it up. Not to mention a big jump in power output proven on the dyno. You will need to do some tuning to get your A/F corrected.

John

Double Venom · #10 (**permalink**) 08-07-2014, 10:09 PM

Wow,
The more time changes, the same old problems pop up. I know this is hard to fathom but JC Whitney of all places is your answer. We/I -us did hundreds of "re-do's on CR sidepipes years ago, until I thought for sure everyone had been re-done.

FACT: Dyno before and after- Proven multitude of times; minimum of a true 35 RWHP HP curve with a small block. Much more as the C.I.'s increased.

Your stock sidepipes have a 1" tube configuration in them that is amazingly restrictive!

The solution is not hard nor expensive but does require some accurate modifications. Then you have them jet -coated or as many guys did with great results use BBQ paint to repaint them black or white.

1st measure your bullitt, I think it is 28"s? Go to Whitney find the straight thru burn out proof glass packs. 4"s in diameter. Now the equipment and work needed-Take the side-pipe off and cut the bullitt out cutting the old welds and remove the stock bullitt. (small band saw or even a 4" cut off wheel works fine.) Re-install the headers -temporarily- tack the bullitt in place making sure it is parallel with the bottom of your car. Now take the exhaust tip, align it correctly to re bolt to the frame= tack the other end of the bullitt in place. Remove once again and finish the welding on both ends of the bullitt. Clean welds as necessary, send out have jet-hotted, chromed or simply use high heat BBQ paint to finish them. Re-install with high heat permatex and enjoy a very sweet deep mellow rumble and at least an additional 35 true RWHP.

Hundreds done- never a complaint, only wows and thank yous.

DV - Your welcome.

IF you buy the correct bullitt NO extension is necessary.

cycleguy55 · #11 (**permalink**) 08-08-2014, 02:13 PM

Has anyone tried these - 4" blank case, 3" core, no stubs to cut off before welding. These are the 24" case models, but they're available in a variety of lengths.
http://www.summitracing.com/parts/jex-a4324b/overview/

Double Venom · #12 (**permalink**) 08-08-2014, 04:13 PM

CYCLEGUY,

Those are the exact ones!!!!!!!! Well done!!
DV

jhv48 · #13 (**permalink**) 08-08-2014, 08:12 PM

I have a pair of the stainless steel specialties mufflers with a three inch inside diameter.

Never used. I bought a complete set of sidepipes instead of cutting and welding gear on.

Cost $400 will sell for $200.

Luce · #14 (**permalink**) 08-09-2014, 10:07 AM

Cycleguy, I used those Jones muffs, but longer. Something like 32 or maybe even 36". Loud as he11, but I love it.

I want to make some stainless sidepipes, but before I spent the $1000 plus on the materials I wanted to make sure I could live with the noise of a full 3" bore.

I had less than $200 in the whole set of pipes, then spent $400 ceramic coating them. Best thing is they are a perfect fit because I tacked them up on the unpainted car.

Tim Brewer · #15 (**permalink**) 08-10-2014, 07:58 AM

Augers are famous for detaching themselves inside your mufflers. They'll drive you crazy rattling around inside your pipes.

cycleguy55 · #16 (**permalink**) 09-08-2014, 01:58 PM

My augers (Patriot, 3.5" diameter, 11" long, 2 per side) rattled like crazy when I first put them in and it drove me crazy. I pulled the side pipes apart (seems like about 5 times now) and bent the spirals to a tighter fit on the side pipes, then drove them in with a mandrel (long 1/2" bolt with a large washer) and 24 oz. ball pein hammer. No rattles, better sound - love them.

moore_rb · #17 (**permalink**) 09-19-2015, 10:44 AM

Does anyone know or remember what the internal "flow through" diameter of the original Classic Roadsters muffler insert was/is? (EDIT: Nevermind- DV posted it above: 1 inch )

I've decided to replace my CR's originals with the 4 inch diameter Jones Bullets, but I'm going back and forth between selecting the Jones 3 inch internal insert diameter, versus going with the 2.5" insert diameter....

From a back pressure standpoint, I'm thinking that the 2.5" insert diameter is the correct choice for my car's 325HP 302... At the 6000 RPM redline, my engine can only move 524CFM of air (and that's at 100% VE, which is virtually impossible in a street engine anyway).... So anything bigger than 2.5" is just going to increase turbulence inside the muffler, and make more noise. Plus my engine is fuel injected, and the O2 sensors are mounted right after the 4:1 collectors, so I have to be mindful of flow velocity past the O2 sensors.

Sound wise - The 2.5" inserts in the 4" case means more space for packing, which should equate to more decibel reduction, and a lower pitched "rumble" ; While the 3" inserts will allow more room for the sound waves to bounce around, resulting in a more raspy, crackly, race car style exhaust note. (which I love); But I'm concerned that the 3" inserts might also yield a drone at cruise speeds (an enemy I would rather not do battle with)

Sorry for the long post- I'm just thinking out loud here, and letting you all come along for the ride... lol

cycleguy55 · #18 (**permalink**) 09-20-2015, 02:51 PM

Points to consider:
- 2.5" I.D. will be quieter than 3"
- Longer will be quieter than shorter
- Louvers facing forward will be quieter than louvers facing rear

You already know your mufflers will be a bit longer than most, so that will mitigate the sound level a bit. 2.5" I.D. is probably big enough for your engine, as you've noted.

It seems to me the question becomes one of which do you prefer: a) a quieter rumble; or b) a slightly louder exhaust with a bit of attitude?

Sounds like a real dilemma to me...

moore_rb · #19 (**permalink**) 09-20-2015, 04:23 PM

Louvers facing forward, versus louvers facing rearward is easy- I'll just tack it up both ways on the opposite sides of the car, then have a friend fire it up and rev it while I take a listen from both the left and right sides...

Whichever side sounds better to me, I'll re-arrange the other side to match before I do the final welding...

I love these kinds of dilemmas...

moore_rb · #20 (**permalink**) 09-26-2015, 04:15 PM

My Jones glasspacks arrived this past Thursday, so I broke out the sawzall and cut apart my factory ClassicRoadsters side pipes...

You guys weren't kidding - The inserts inside these mufflers are TINY - only 1-1/2" ID:

Here is one of my $34 Jones glass packs tacked into place (4" diameter, with 2-1/2" core tube, and 30" length:

Then I removed the exhaust, finished the welds, cleaned everything up with a wire wheel and degreaser, then hit it with 3 coats of silver Ultra high temp Barbeque paint. After drying overnight, everything got bolted back onto the car, and you wouldn't know they weren't the same sidepipes - Everything looks identical to the way it was before:

Performance-wise- I agree with DV- WOW, and thanks!. Best $100 weekend car project ever.... There was easily 25-30 more HP freed up, and the throttle response is much improved as well. Awesome.

Sound-wise - The glasspacks make it deeper, raspier, and more "bass" sounding... Oh, and LOUDER - But a good loud - to me it sounds perfect now. It still cruises silently in 5th gear so you can have a conversation with your passenger, but when you romp on it, it can drown out any open-piped Harley in the area

- One side note about the sound- The glasspacks do make it spit, pop and burble on downshifts - I love that myself, but if you don't like that, then these might not be the mufflers for you.

I shot some comparison videos of the sound and loaded them to Youtube. Take a listen:

https://youtu.be/rLjC3GdzjHU