Cherry Bomb Glasspacks - Impala Tech
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post #1 of 18 (permalink) Old 06-29-2011, 12:39 AM Thread Starter
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Cherry Bomb Glasspacks

I was thinking about getting cherry bombs and was wondering what size to get to have a sound that was somewhat loud when accelerating but not obnoxiously loud all the time. Also, do they last longer than they used to or are they about the same? Please include the length, width, and opening to use with 2.5 inch pipe.
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post #2 of 18 (permalink) Old 06-29-2011, 10:37 AM
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All glass pack mufflers burn out with heat; so the further back on the tail pipe you can install them, the longer they will last. Greater life span is obtained by using them as exhaust tips on a straight exhaust pipe that exits out from under the rear bumper.

All glass packs are straight through "mufflers". I use the word muffler advisedly as they are used in racing because they neither muffle nor restrict exhaust flow when kept large and short. The only resistance they offer to the exhaust flow is from the louvers punched in the internal pipe to ventilate it that hang down into the exhaust gases to restrict laminar flow. If you run a three inch glass packs with an adapter to fit it onto your 2-1/2 inch pipes you reduce that restriction promoting both the amount of noise and the rate of exhaust flow.

Chevrolet only used a glass pack muffler as optional equipment on only one car; the Corvette, in the form of side pipes. The mufflers where five feet long and 2-1/2 inch in internal diameter.



I had a set (GM called them chambered exhaust mufflers) installed on my Baldwin Motion Phase III 1968 Camaro and they drove a twenty three year old me nuts with the noise (I could hear the same level of noise that every one I drove by heard, which doesn't happen when the exhaust exits out from behind the car). I took them off and then used the actual high performance muffler that Chevrolet used on the Corvette in 1968 and it was also used on their early highly successful turbo charged Corvair. That muffler offered the same flow rate as the glass packs, but with half the noise level.

Flow Master copied this design and offered them for sale as their 40 series muffler.




Here is what a standard Walker automotive muffler looks like inside.



The gasses enters at the lower right hand side pipe and runs into the wall of the back of the central chamber through a reduced diameter pipe inside the muffler. It then has to go into the pipe with the perforations and flow through to get up to the top pipe by again hitting a wall in a closed off front chamber. The middle pipe with all of the holes in it cancels out the high frequency noises. Notice that there is blind alley on the left off the central chamber, that goes nowhere. That is to reduce the lower frequency noises. The gap in the top pipe is so that exhaust pulses (momentary pressure spikes) cancel each other out as the majority of the gas has to take a longer path through the muffler. This is why they are so restrictive to exhaust flow. The muffler made by Walker, muffles almost all noise that enters it and evens out the flow of gas to a continuous stream with no pulses or pressure waves (you hear those pulses frequently in school bus exhausts because of the long, long pipe from the engine to the muffler way in the back of the bus away from the funnel tank magnifies the pulses through harmonic resonance).

Note that the gasses have a nearly straight shot through the baffled exhaust muffler made by FlowMaster (you can not buy original GM mufflers for the Turbo Corvair or early model Corvette only repops). The muffler is based upon echos. Just as an echo dies away the noise of your engine is canceled out but the gas flow is not restricted in the baffled Flow Master design.


Big Dave

Last edited by Big Dave; 06-29-2011 at 11:10 AM. Reason: Added standard muffler
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post #3 of 18 (permalink) Old 06-29-2011, 05:22 PM
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Kris, I remember using the one of the longest Cherry Bombs on my 68', I think they were 20 something inches. They rumbled at idle and just started to crackle when I got into it. I installed them in the stock location and they lasted til I took them off due to a resto. 3 years later.
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post #4 of 18 (permalink) Old 07-19-2011, 09:39 PM
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Possibly a dumb question as they sell them but are the cherry bombs something they can give you a ticket for? Excessive noise.
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post #5 of 18 (permalink) Old 07-19-2011, 10:11 PM
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I don't know about Kansas but in N.Carolina police determine the cruising noise level more over the idleing or startoff. Only exception is if you run just straight pipe to the axle. I know a guy who had a 65' with this setup and he used to rattle the sheetmetal on the local self carwashes, he finally installed the shortest glasspacks (CherryBombs) after spending twice the fines on noise ordinance.
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post #6 of 18 (permalink) Old 07-19-2011, 10:22 PM
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Quote:
Originally Posted by Pimpzilla View Post
Possibly a dumb question as they sell them but are the cherry bombs something they can give you a ticket for? Excessive noise.
That will depend upon where you live. In Florida the state legislature in their infinite wisdom passed an ordinance that requires a Db meter to measure loud radios, loud truck tire or loud motors in cars. The object was to stop kids from annoying our elderly citizens who can't hear anything without their hearing aides on, but they wanted a quiet state.

Trouble is they never acquired any money to pay for training law enforcement personnel in how to use a decimeter; that they also forgot to buy for every department and jurisdictional boundary in the state. As a result we now have no noise ordinance what so ever instead of the old system of a cop's point of view when it came to who or what was disturbing the peace. So since we have no emission enforcement in this state, no noise ordinance, or even a basic safety check you can drive a top fuel nitro methane blown dragster to the corner store and back so long as it has a tag on it.

However not every state is as progressive when it comes to automotive restrictions. I am pretty sure my carburetored 1985 Impala with a high compression 582 big block Chevy under the hood wouldn't be legal in California. It definitely wouldn't pass emissions, and probably not the stock appearing visual examination.

Big Dave
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post #7 of 18 (permalink) Old 07-22-2011, 03:15 PM
 
 
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Noise is dependent upon the indivdiual listening. What one police person may like, another may not.
I ran Walker Continentals on my '64 Impala in the late '60's.

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post #8 of 18 (permalink) Old 06-26-2012, 12:04 AM
 
 
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40 seriers flow master get really loud through excelleration and highway driving. 70 series are a bit quieter, but still give you a decent sound.
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post #9 of 18 (permalink) Old 06-26-2012, 08:22 AM
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As the others have said. It depends on how you will drive the car and attract attention. It also depends on your local noise laws and how the police enforce them.
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post #10 of 18 (permalink) Old 06-26-2012, 09:06 AM
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Welcome to the Team Dan!

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post #11 of 18 (permalink) Old 06-27-2012, 08:02 AM
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Smile

Even tho cherry bombs are straight thru they give high back pressure
due to the hash marks........buy turbo muffles for a better tone & higher gas mileage.

Donnie
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post #12 of 18 (permalink) Old 06-27-2012, 08:44 AM
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David Vizard published his five year study on mufflers and headers that he had conducted on hundreds of products using every American made V-8 to test the restriction and affects of mufflers and pipes on performance.

He covered basic fluid dynamics and thermodynamic theory earlier in the book so that you will know how they affect gas flow. The book is easy to understand and has lots of pictures and graphs along with average back pressure readings and the effect that a pipe size has on flow.

He still leaves noise abatement as a personal choice but rates various brands that do not restrict flow by dB measurements (surprisingly the cheaper the muffler the louder it was so you don't have to pay a lot to get a loud exhaust system).

I recommend reading all of David's books as he is an excellent technical writer, isn't paid by any manufacture to tell only half truths the way the car mags that rely upon advertising about any product and backs everything he does up with dyno results and track testing.

Big Dave
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post #13 of 18 (permalink) Old 06-29-2012, 05:06 PM
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Quote:
Originally Posted by weldvair View Post
Even tho cherry bombs are straight thru they give high back pressure
due to the hash marks........buy turbo muffles for a better tone & higher gas mileage.

Donnie
cherry bomb also makes a turbo style muffler (saw it on summitracing's site) that isn't too horribly priced. Cant vouch for the noise it makes though.

this guy is running summit's turbo mufflers:
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post #14 of 18 (permalink) Old 05-10-2013, 08:00 PM
 
 
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My 67 has duals with 18" glass packs. I love the rumble. Longer length glasspacks have a more mellow tone. 12" glasspacks are super raspy.
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post #15 of 18 (permalink) Old 07-13-2013, 05:16 PM
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Cheery

MY 64 impala with 454 is running cheery bomb glaspacks, it sounds pretty sporty and no drone at cruising speed. I like em better than flowmasters which i have on my other 2 hot rods. MADE A recent discovery, when i installed a k&n type air filter with the same k&n type filter lid, it really changed my exhaust note,l the car starts a lot faster, and sounds much bettter, try it , you will love it.

Last edited by 64ImpalaRed454; 09-08-2014 at 12:48 PM.
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post #16 of 18 (permalink) Old 07-15-2013, 12:35 PM
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Where I live there is a Db limit. I had turbo mufflers on my 66 Chevy II, I got busted for too much noise and when the DMV checked it the Db level was over 90. They said too loud. Some states want mom and pop mufflers on your car.


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post #17 of 18 (permalink) Old 07-26-2013, 02:15 PM
 
 
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I have Cherry Bombs on my '63 vert, and i love them! they are about 3 1/2" by about 24" long. the exhaust pipes are 2". I have the 327 in it which may make a difference in how it sounds. My dad had them installed at least ten years ago, but he didnt put a lot of miles on the car either. I plan on having the exhaust redone in the near future, and i'm definitley putting the same ones on. It sounds good at idle, but really sounds good when I get on it. My buddy has a '65 with a big block and has new Flowmasters on it. I like my exhaust better....I certainly dont think its too loud.
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post #18 of 18 (permalink) Old 08-03-2013, 08:02 PM
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cheery bombs

I'm with you on that got em on my 64, no drone like my 2 other rods with flow masters, cheery bombs sound good with no drone.
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