The Stovebolt Site Forums The Shop Area The HiPo Shop my new exhaust is obnoxious

I just got fentons and dual exhaust installed with cherry bombs, which sound just fine till about 2500 RPM whereupon it commences the most horrid crackling/reverbation I have ever heard, the mufflers are quite far forward, would moving them back help. All I know is it is unacceptable. The guy said the mufflers will burn out and mellow the crackling, but I have my doubts

What length are the mufflers? I try to get real long ones. About 30 in. If the pipes are too big it will make a lot of noise. 2 in. is large enough for a 6. As far as burning out they only get noiseir in time.

they are probably at least 30 inches, I haven't actually measured them, all I know it is really not what I was expecting. But then again with the way the world is now days, I should be surprised to actually get what I have paid for. I don't know what to do, I am not at all happy. As a matter of fact, the situation is really close to being completely unacceptable.

A balance tube between the two pipes ahead of the mufflers will change the sound apprecably. I never tried it on a 6

I don't believe moving them would help. Way back in the mid 60's I had a '60 two dr. Biscayne with Fenton’s and Walker glass packs, which were the same thing as the Cherry Bomb, just a straight thru muffler with no baffling. I though it was kind of cool back then to rattle the neighbors windows in first gear leaving for work in the morning. When I joined the Air Force I was stationed in Wichita Falls, TX where I did a lot of high speed highway driving and when I hit that resonant point with the engine it would drive me nuts.
Today I don't need the attention and if I were to put duals on a Stovebolt, it would definitely be with nearly stock mufflers or at least mufflers that did some muffling.
DG

I had the same problem with my Suburban. Read about it here.

I added a pair of Walker #17852 near the end of the pipes. It now has a nice mellow sound going through the gears and it relatively quiet on the highway.

Glass packs are loud. That's why Cherry Bombs slogan is "Disturbing the peace since 1968"

I have dual (about 30") bombs on my 1-Ton. I like the way they sound, but I only wind the truck up when it's fully loaded. As a general rule, I don't drive above 50 mph either. I can see how it'd be loud if you did allot of highway driving at modern speeds.

At idle, the truck is very quiet.


Now, all this being said, for my panel truck, I'm going to stay with a stock muffler.

I must be getting old and sedate! Hahaha!

loud would be one thing, but this is horrid sounding. I've heard engines with no mufflers at all sound better, louder but at least there was some substance (for the lack of a better description) to it. This is just awful, I mean it echos off buildings and sounds an awful lot like a hot 2 stroke now that I think about it. which would be fine if I was racing motocross. Guess I will have to go talk to the fella and see what can be done. It sounded better on the way to the shop with open headers, no pipe at all.

well I just went out for an hour spin on the freeway, and after the paint and what ever else burnt off the exhaust it does indeed sound better. The crackling only comes in at full throttle, and who knows what RPM (I'll be able to tell when my tiny tach comes) but whatever the case the RPM it occurs at is increasing. So maybe the fella does know what he is talking about.

If it helps, General Lee had glass-pack mufflers!

with credentials like that how can I go wrong...(the general lee)

One reason why it sounds better after a while: you're losing your hearing.

That's funny Panic.

its not loud, its obnoxious, it just doesn't sound right.But it is getting better.

Dual pipes on an inline 6-cylinder have a 120-degree separation between exhaust pulses, and each pipe gets an alternating flow, and sound. At certain RPM, as you've figured out by now, the resonance in the pipe from end to end gets really obnoxious. You can change the resonant RPM, but not eliminate it entirely, by installing small mufflers (resonators) somewhere in the exhaust flow. The position of the resonator in relation to the main muffler will definitely affect the quiet and loud points.

Even with a quiet muffler, a dual-pipe six has a distinctive sound. The really obnoxious ones back when I was a teenager had steel-packs, not glasspacks. They were straight-through flow, with steel wool instead of fiberglass as the sound-moderating medium. A 216 with a split manifold and a set of "Smitty" steelpacks would rattle windows a block away when it was wound up!
Jerry

I'm running a 235, Fentons, dual exhaust with 22" glasspacks, dual 97's on an Eddie Edmunds intake. There is a cross-pipe about a foot below the Fentons. It is very mild sounding. No problem in the cab at speed either. I attribute the overall mild sound to the cross-pipe. I bet it would have that popping sound you mentioned if it weren't there.

>>the mufflers are quite far forward,<<

I reread this thread and could not find where you mentioned what is after the muffler. How far do the pipes extend and where do they exit?
The quietest mufflers you can find, will be loud and raspy if bolted directly to headers or mounted close to exhaust manifold and there is no tail pipe after the muffler. Exiting under the bed, turns the bed into a vibrating megaphone.

they are 24" mufflers, 2" pipe probably 3 feet from the headers, there is probably 6 feet of pipe straight out the back. But after about an hour on the freeway they seemed to have mellowed out, I'm going on another cruise this weekend hopefully it will remove the crackle for good.

My 24" cherry bombs are generic and I don't know if they are steel or glass pack. I installed an X-pipe between the headers and the bombs and it mellowed it right out.

I run a muffler and love the sound of it. I have a sound clip but my camra dose not catch sound that great. But feel free to see if you like the sound.

Well I got my tiny tach friday, put it in yesterday, and today I'm gonna take my little kid to our friends house, (she loves the "giant truck"), I finally get to see what RPM I have been turning this engine all these years, see if the mufflers mellow out any more, and give mommy a little break. I'm very excited about today...I'll let everyone know at least by morning how it went.

I still don't know how fast I have been turning this ole engine, the tiny tach took a big one before I even got to the freeway. Either way it sure sounds better, there is a little crackle right at the end,its just fine.

the guy from tiny tach called in response to my email and told me how to fix the tach, nothing that is in their instructions, I can tell you that.But what ever it works now.

Dang Grandpa! That sounds like all six main bearing are coming loose.

HAHA Ya that video makes it sound just bad. Ill have to try it agine on a less windy day. Just could not get it right.

I had Cherry Bombs on my 57 with the dual exhaust. The drone at about 50mph made the truck almost unbearable. I swapped out the glass packs and went with stock GM mufflers. I still get a nice throaty rumble at the tail pipe at idle, and the drive is much more satisfying.