I have read every muffler thread on the HAMB. Probably putting glasspacks on my Merc. Want them to be rather quiet, if possible. I have nice neighbors, and a wife that I like to talk to (most of the time). Thinking 2inch diameter smithys, but what length and where to place for quieter at idle, minimum drone on the freeway, but some rasp on accel and I do like the popping on deceleration. Thank gents for not busting my balls, I have loud exhaust on my other ride.
The longer they are, the quieter they will be at idle and low throttle. They will still have a nice bark when you get on it, though. Brockman Mellowtones are available in many lengths, probably even make some custom ones for you, if you like. With glass, steel, or no packing. Of course glass would be the quietest. I once did a big block car with LOOOONG steelpacks and it was pretty acceptable sound wise. The short ones would have been deafening! H pipes pretty much cancel any "advantage" from glasspacks. By that I mean, you aren't going to pick up a lot of HP with 'packs, so you run them for the sound alone. The H pipe will completely screw up the sound they should make.
I was going to say 28-30", run them right back against the axle and run your tail pipes out past the bumper. If you don't want popping when you let off of it make sure that your exhaust system is air tight, like in weld all the joints. The popping sound comes from air getting into the exhaust pipe before the muffler.
I use Jones Glass Packs, as resonators. Here is a page from Summit for reference guide http://www.summitracing.com/search/...t-Line/Jones-Glasspack-Mufflers/?autoview=SKU With slip on end or weld on.
Well I'll join in. ten years ago I put 30" Brockman Mellotones on my '60. They are still there, and are still smooth sounding. It has an authoritative rumble, but is quiet inside and won't upset people. Unlike when I drove my '62 to the muffle shop with nothing from the manifolds back! LOL You could see the love it or hate it looks on peoples' faces!
Thanks gents; what about putting them in backwards? How does that affect sound and flow? BTW: the folks on the HAMB are amazing in their generousity and wisdom. Yeah there are some kooks on here too, but we know who they are
Nothing new in this post, but imo get as long a glasspack as you can get/fit and run the pipes clear out the back.... I don't like X and H pipes, to me they just don't sound like a hot rod is supposed to sound like. I mean really, those of us with V-8's don't care for single exhaust much, and lots of folks with inline engines split the exhaust for a better sound, and now all of a sudden the hip V-8 crowd wants to run the pipes back together... I will agree that in some testing the X and H has shown to provide some slight power/torque increases over "true duals" but to me the change in tone negates this slight power increase. Since I don't race competitively, if I really want that "lost power" that I am "just giving away", I will pick it up somewhere else.
What ever will fit in the space you have is going to determine what the longest Smithy's you can use. I have 22" ones on mine and am happy with the sound level.
Pretty much what he says except the H pipe is more about balancing the pressure between sides. Most engines require some back pressure to run more efficiently. The purpose of glass packs or steel pack mufflers is to reduce backpressure. Since they provide a straight through flow, they also allow more sound to resonate. Keep in mind that most municipalities have a maximum decible ordinance. In all cases, it is up to the descretion of the arresting officer. And, there is the stress that continued loud noices enact on our ears. I have run glass packs on most of my cars with out any trouble. But, then I prefer a mellow tone, just enough to say performance and not draw unwanted attention from the gendarmes.
I have an "H" pipe and use 28" glass packs. Good sounds and great rumble for a 261 Chevy six Normbc9.
Bumping back up, I picked up some steel packs at a swap meet, they were custom built by a guy who worked for an muffler manufacturer and are around 16" long perforated inner tube and jam packed with metal filings. I plan to run them on my chrysler full sized (read land yacht) with a 383 and stock exhaust. They will replace stock muffler before the axle and then up over the axle to six inch slash tips past the bumper So with that in mind, being a full size car not a 31 coupe, how much louder over stock do you think I will be? Concerned they're going to be to loud for inspection. Cheers
My Nomad has been running a pair of (brand unknown) 39" long glasspacks since 1986. Plenty quiet at idle and low speeds, plenty loud when I get on it! I bought the car in 1991 from a muffler shop owner (since retired) and I have not seen any other glasspacks as long as I have. I have no idea where he got them.
Are the longer glasspacks mellow enough to have a conversation in the car without yelling? I also am shopping for a pair but want to make sure they are not obnoxious when cruising at 2000 RPM, on the throttle is fine to be louder. I know different engines give different results, this would be with a basic stock 275HP 350 chevy.
On my 318-powered Sweptline Dodge pickup, I'm installing two 30" glasspacks right behind the cab, with the tailpipes exiting in a 45* downturn in front of the rear axle. This is a 2-1/4 exhaust from the exhaust manifolds back. Should have the sound I'm looking for. I've been having the same thoughts as the OP, but I want a little more noise than he does. True, going all the way back to the rear bumper and then having downturns would make it quieter. A longer glasspack with bumper exits would be about as quiet as it gets with glasspacks. Shorter (20" or so) make for a loud system, especially if no tailpipes are run.
i have 26'' brockmans on my wagon with a 413 in it. It is definately not too loud, but I get compliments on how it sounds. no real interior noice to speak of, you can carry on a conversation and whatnot.
I have 48" thrush glaspacks on my gasser pipes to the bumper, even with a radical motor the sound is not to loud.
4 foot long glasspacks? I can fit 30" long overall , looking at design I would have to guess the "can" style like a smittys would be quieter than a cherry bomb straight through style..although I remember running thrush straight throughs in the 80s and they were ok with a SB, unreal loud with the BB.
Back in the 80's, my dad needed to replace the rotted out muffler on his '74 Chevy 1/2 ton truck (250 inline six). The local auto parts store had 48" long generic glasspacks (sold out of a garbage can! I kid you not!). They had them with 2 1/4" in/out, and at $10 new, he couldn't pass them up (most people couldn't. They were quite popular for a number of years). The truck took on a whole new "attitude". Nice deep, mellow rumble replaced the "rolling raspberry" sound that plague most sixes. So, they do exist, or maybe, did. This thread came up in a Google search for 48" glasspacks and, so far, I'm not seeing any. Could be, the 4 foot Cherry Bomb is a thing of the past. (of course, no law says you can connect two 24" mufflers together. Would essentially be the same thing and pretty easy to accomplish). ...also, in reference to the OP's question, one thing that will make the exhaust note a little quieter is to point the tips down at the ground. Simple 45 6-8 inches before the end of the pipe, then cut the tip to 45 degrees. Sends the "pop" at the ground and thus, everyone hears a reflected signal (getting into a little acoustics tech, so hang tough. I'll try to be brief). Any time power has to change direction, it loses a little of itself. Same thing happens when you bounce an acoustic signal off a surface (like the ground). What you hear is a little less than what it was originally, when it exited the pipe. Also, a single exhaust system will be a little quieter than a dual exhaust system. This is due to two things; lack of the "stereo effect" and "persistence of hearing". Having two pipes exit the back of the car, isolates the exhaust note heard from each bank of cylinders. Since 4 cylinders have fewer exhaust pulses, compared to all 8, its easier for your brain to pick up the individual "pop's" of each cylinder. The attack of that "pop" thus becomes more apparent and you hear it as a more "harsh" sound. Pop-Pop-Pop-Pop..., etc., etc.. Cram all 8 exhaust pulses created by your V8 engine down one pipe, and its harder for the brain to discern each individual "pop", thus it all runs together as one long drone, wuuuuuhhhhhhh. This is the same phenomena that allows us to watch a movie, because we can't discern each individual picture, so it all runs together as a single action. That's Persistence of Vision. The effect I described with the single exhaust system, vs. the dual exhaust system, is (therefore) Persistence of Hearing. There's also the fact that the pipes on the dual exhaust system are far apart from each other (essentially, the width of the vehicle). This allows the ears to discern which pipe is emitting an exhaust note and that also makes it easier for the brain to discern those individual exhaust "pops". This is known as The Stereo Effect and just plays on the whole reason why we have an ear on each side of our head. It's so we can tell what direction a sound is coming from. ...off course, we're talkin' hot rods here (for the most part) and dual exhaust is WAY cooler than "yer dad's" single exhaust system, so if the OP decided to stick with dual exhaust, I wouldn't blame him. =)
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