GOOG Posted November 15, 2015 Share Posted November 15, 2015 I'm thinking about putting straights on my tractor, but can't hack the noise like when I was a young man. Has anyone ever put straight stacks on with a muffler under the truck? Quote Link to comment Share on other sites More sharing options...
keg1 Posted November 15, 2015 Share Posted November 15, 2015 i have straight pipes on my Superliner that have mufflers in them Quote Link to comment Share on other sites More sharing options...
Outbehindthebarn Posted November 15, 2015 Share Posted November 15, 2015 My old 359 with 8V92 had a muffler underneath... When I got the urge, I'd slip the muffler off and insert a piece of straight pipe. Quote Fun is what they fine you for!My name is Bob Buckman sir,. . . and I hate truckers. Link to comment Share on other sites More sharing options...
Freightrain Posted November 15, 2015 Share Posted November 15, 2015 I have muffler under cab. Some days I'd like to make it bark. Most I like to be able to hear myself think! Guess I'm getting old? 2 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
GOOG Posted November 15, 2015 Author Share Posted November 15, 2015 Is one muffler enough? Quote Link to comment Share on other sites More sharing options...
GOOG Posted November 15, 2015 Author Share Posted November 15, 2015 I was in Brooklyn yesterday sitting dead still in traffic. A very fancy Pete went by (going the other way) with straights. Then it occurred to me he wasn't making a sound. He was amazingly quiet. That's what I want on mine. Quote Link to comment Share on other sites More sharing options...
Popular Post Superdog Posted November 15, 2015 Popular Post Share Posted November 15, 2015 If I ever get so old that the beautiful sound that my unmuffled trucks make bothers me,please someone shoot me in the head and put me out of my misery. I've always wanted to have the time and the batteries to start about 25 or 30 just to see if I could make the ground rumble. 4 Quote Link to comment Share on other sites More sharing options...
m16ty Posted November 15, 2015 Share Posted November 15, 2015 My old 359 with 8V92 had a muffler underneath... When I got the urge, I'd slip the muffler off and insert a piece of straight pipe. The urge to hear a un-muffled 8v92 wouldn't last long. I drove a straight piped 8v92 Mack once and ear plugs were mandatory. 1 Quote Link to comment Share on other sites More sharing options...
blackdog2 Posted November 15, 2015 Share Posted November 15, 2015 I'm glad winter com min close the side windows on the super liner and go back to thinken again that how the song goes( thinken problem ) Quote Ed Link to comment Share on other sites More sharing options...
Outbehindthebarn Posted November 15, 2015 Share Posted November 15, 2015 The urge to hear a un-muffled 8v92 wouldn't last long. I drove a straight piped 8v92 Mack once and ear plugs were mandatory. I didn't think it was terrible... had a wicked 'crack' in the note between 1800-2000. I think any Cummins 855 through the ISX's made a lot more exhaust noise. The blower on my '92 was annoying to me though. 1 Quote Fun is what they fine you for!My name is Bob Buckman sir,. . . and I hate truckers. Link to comment Share on other sites More sharing options...
dogg rescue Posted November 15, 2015 Share Posted November 15, 2015 Drop in baffles work great, but they aren't cheap. I have dropped in auger fighting in mine, and it reduces the noise considerably. The thing to do is put a bend in the fighting before you put them in so they don't rattle around. Quote Link to comment Share on other sites More sharing options...
farmer52 Posted November 15, 2015 Share Posted November 15, 2015 I was in Brooklyn yesterday sitting dead still in traffic. A very fancy Pete went by (going the other way) with straights. Then it occurred to me he wasn't making a sound. He was amazingly quiet. That's what I want on mine. Was it a newer unit? If so, the "muffler" is the DPF/SCR system. Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment Share on other sites More sharing options...
david wild Posted November 15, 2015 Share Posted November 15, 2015 Little short muffler under can works great, have had several that way, only way to go, drives DOT in Colorado nuts, even keep receipt that say's muffler, they will argue resonator is not a muffler. Quote Link to comment Share on other sites More sharing options...
mowerman Posted November 15, 2015 Share Posted November 15, 2015 a buddy of mine put 2 strait stacks on his R model,,,it sounds real good,,,and not as loud as the single stack,,,i used to run a straight single stack myself,,and thought it was too loud..good luck,and welcome aboard..bob Quote Link to comment Share on other sites More sharing options...
GOOG Posted November 15, 2015 Author Share Posted November 15, 2015 I wouldn't bet against the muffler being replaced by a "test" pipe occasionally, but it will be initially set up on the quiet side. I've had many trucks on the wild side, just not inclined that way today. Should I go with 6" pipes or 7". I'll use 5" from the turbo to the square tube that will mount the stacks. Quote Link to comment Share on other sites More sharing options...
1MACK1 Posted November 15, 2015 Share Posted November 15, 2015 I run a single muffler under the cabin Then thru a y pipe to twin 6 inch pipes up behind sleeper very quite to sit in all day whilst pulling but I've been told by various people that it still sounds good Some say pull the muffler and install a small resonator but its working well for me so ill leave it till time to replace muffler Other truck has straight thru single 5 inch behind cabin on the off side Sounds great for a short drive but not to work all day Just my opinion Quote Link to comment Share on other sites More sharing options...
BOB DINGSDALE Posted November 15, 2015 Share Posted November 15, 2015 I used to take the muffler off but the jake was to loud.27% and 120 tons on drone you out of the cab Quote Link to comment Share on other sites More sharing options...
Mack Doctor Jr. Posted November 15, 2015 Share Posted November 15, 2015 I think longer stacks muffle some noise. Especially getting it away from the cab. And if you turn the tips away from the cab it helps. R model I drive was 4" and belled out to 5" at the bottom of the stack. Most important for me is getting even smoke out both pipes at the same time. Those V8s where bad for uneven smoke with those funny Y pipes. Quote Link to comment Share on other sites More sharing options...
GOOG Posted November 15, 2015 Author Share Posted November 15, 2015 What I've always done is square tubing across the frame. I'll put a 5" nipple on the bottom as an inlet. Put two nipples on the top for the stacks to connect to. I put a 3"x3" square tube riser just inside the stacks to brace the stack. Then I like to put flood lights on the top of the braces. I'd rather work with the square tubing than with fittings. Just my preference. Quote Link to comment Share on other sites More sharing options...
Refined Trucker Posted November 16, 2015 Share Posted November 16, 2015 I have 7in straights behind 70in bunk on my CX and it is too loud when cruising on long stretches. Its fun on short runs but I'm to the point it needs toned down a bit. I'm going to try a resonator under cab just behind flex pipe that comes off the squeeze pipe from turbo. I have one that is 9in in diameter and think it will fit without cab contacting it. Quote Link to comment Share on other sites More sharing options...
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