Bhigdog Posted January 26, 2018 Share Posted January 26, 2018 It sounds like your're in a STEM program. Good for you. At least you're not looking at a "career" of serving Vente Grande Mocha Latte Supremes sporting a pony tail , facial piercings and a shitty attitude..............Bob 1 Link to comment Share on other sites More sharing options...
Beemon Posted January 26, 2018 Author Share Posted January 26, 2018 7 minutes ago, Bhigdog said: It sounds like your're in a STEM program. Good for you. At least you're not looking at a "career" of serving Vente Grande Mocha Latte Supremes sporting a pony tail , facial piercings and a shitty attitude..............Bob Yes sir, I got my Associates in Mechanical Engineering this past spring. I just got certified into my degree this last semester at the 4--year so I'm on track to graduate 2019. Link to comment Share on other sites More sharing options...
Bhigdog Posted January 26, 2018 Share Posted January 26, 2018 18 minutes ago, Beemon said: Yes sir, I got my Associates in Mechanical Engineering this past spring. I just got certified into my degree this last semester at the 4--year so I'm on track to graduate 2019. I've noticed your posts. You seem a together young man. I wish you well..........Bob 3 1 Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted January 26, 2018 Share Posted January 26, 2018 Ben, I believe, unless it MUST be correct, you are overthinking this. Twer me, I would find the most successful muffler shop in town and tell them what I want. Probably way less moola. Looking forward to your graduation in a year. Without that BIG debt some have. Totally unnecessary. Ben 1 Link to comment Share on other sites More sharing options...
avgwarhawk Posted January 26, 2018 Share Posted January 26, 2018 15 hours ago, Beemon said: Mr. Johnson's prices are more than fair, I just wish my text books this semester weren't $500. I went to the University of MD College Park. Up the road is Crofton Raceway. I would bet on the ponies. My winnings I would pay for my books. True story! 1 Link to comment Share on other sites More sharing options...
avgwarhawk Posted January 26, 2018 Share Posted January 26, 2018 10 hours ago, Beemon said: Yes sir, I got my Associates in Mechanical Engineering this past spring. I just got certified into my degree this last semester at the 4--year so I'm on track to graduate 2019. Sir, they can take away everything but your good name and education. Keep at it! 2 Link to comment Share on other sites More sharing options...
KAD36 Posted January 26, 2018 Share Posted January 26, 2018 2 hours ago, avgwarhawk said: Sir, they can take away everything but your good name and education. Keep at it! ....and your experience. Keep at it x2! 2 Link to comment Share on other sites More sharing options...
JohnD1956 Posted January 28, 2018 Share Posted January 28, 2018 The drone could be the pipes touching the frame anywhere they pass through it. See if you can find those spots and bend the pipe a little to insulate the system from the car. 1 Link to comment Share on other sites More sharing options...
Beemon Posted January 29, 2018 Author Share Posted January 29, 2018 On 1/26/2018 at 6:04 AM, Ben Bruce aka First Born said: Ben, I believe, unless it MUST be correct, you are overthinking this. Twer me, I would find the most successful muffler shop in town and tell them what I want. Probably way less moola. Looking forward to your graduation in a year. Without that BIG debt some have. Totally unnecessary. Ben I probably am overthinking it. However, the cost to replace the mufflers or any part of the exhaust system, the cheapest quoted was more than what I can get from Mr. Johnson. Dual exhaust is expensive to build and fix. 21 hours ago, JohnD1956 said: The drone could be the pipes touching the frame anywhere they pass through it. See if you can find those spots and bend the pipe a little to insulate the system from the car. This was the first thing I checked when I got the car back. The only place it rubbed was at the rear passenger quarter panel, which drove me nuts. I few raps with a hammer fixed that problem. Despite the cheap work, it doesn't come close to any other part of the system. The drone is from 2500-3000RPM, roughly 60-75mph. It's very noticeable, even with the wind whistle around the A-pillar at those speeds, there is a deafening change in pitch that makes the whole car rattle. And I know it's not the driveshaft, because I checked it for out of round when I replaced my differential, and also tried to replicate conditions in Low. I just "test drove" it from home to my dorm tonight and there was a good patch of smooth blacktop at one point where it was apparent that there wasn't any wobble, etc. I also had the wheels re-balanced, drums turned and balanced, etc. The harmonic frequency of the cylinder heads must be the same between 2500-3000 RPM as the exhaust pipes. I thought I had also bougth the 18" mufflers, but I guess 14" mufflers were installed so now I have to find my invoice next time I go home. In any case, budget wise, I'll see if I can squeeze in a resonator right after the rear axle on both sides like a 57+ for the time being. Link to comment Share on other sites More sharing options...
JohnD1956 Posted January 29, 2018 Share Posted January 29, 2018 Could the drone be the engine fan? Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted January 29, 2018 Share Posted January 29, 2018 I hate drone! Some mufflers cause it, some do not. Had a '78 Dodge PU. I had heard some exhaust over the years I liked. Was always " XXXXX" mufflers. So finally installed XXXX on the Dodge. Absolutely hated them! At about the same speed as Ben mentions. THEN learned XXXX and others make more than one series. DUH. Right now the glass packs on George are droneless. Ben Link to comment Share on other sites More sharing options...
Beemon Posted January 30, 2018 Author Share Posted January 30, 2018 I do not think it is the fan, I don't believe I would feel it under the seat. It is also a new heavy duty clutch fan, so the RPM it spins when not engaged is much lower than engine RPM. This is also a constant bass note with vibration. If it were the fan I would think it would be intermittent. Exhaust frequency and done have a number of variables. Firing order, valve size, collector shape and material, ID and wall thickness of the pipe, length of the pipe, location and length of the muffler, expansion joints etc. On modern cars for packaging with the catalytic converter, it's usually CC, resonator and then muffler at the tip, occasionally muffler and resonator swapped. The location of the components can also be critical, though I've not seen any comprehensive information on the web about this other than "I work at a muffler shop and this is what we do." Glasspacks are essentially a modern OEM resonator. It's an expansion tank that allows gases to change the direction along the wall of the tubing and decreases harmonic frequency. Definitely not designed to muffle sound, that's for sure. they must sound nice. Link to comment Share on other sites More sharing options...
KAD36 Posted January 30, 2018 Share Posted January 30, 2018 (edited) So..... dopey question - you can replicate the drone in L or N at same rpm? Apologize if I missed that. In college days a ordinary citizen 20 dollar walker reverse flow muffler was on my car and it was stupid quiet. Any chance of returning/replacing? This also reminds me of a possible event where one friend may have whacked his Buicks muffler with a very large ball peen hammer, installing a sufficiently large dent that eliminated both resonance and annoying baffle rattle. This was done with little thought as to location of where to hit it or the probability of success of the approach. Prior to conducting the repair we ensured we were not thirsty. Because dehydration is unhealthy. And we all want good health. Lapse in judgement aside, it was rather extraordinary that he didn't miss the freakin muffler and take out the rocker panel or one of us. "Hey....it's fixed!" "Good. Now put that down" Unsure how long that muffler lasted... Edited January 30, 2018 by KAD36 (see edit history) Link to comment Share on other sites More sharing options...
Beemon Posted January 30, 2018 Author Share Posted January 30, 2018 4 hours ago, KAD36 said: So..... dopey question - you can replicate the drone in L or N at same rpm? Apologize if I missed that. no no, I had mentioned I had a bass note and light vibration at that RPM, so I tested in Low to see if it was the drive shaft instead. Turns out that wasn't the case. And Walker mufflers are expensive, the good ones anyways. From others online, it looks like the small basic 14 inchers drone without resonators, too, and the big mufflers are in the $60+ range. I figure for that price, instead of gambling I'll try some resonators first at the tail pipe. Link to comment Share on other sites More sharing options...
old-tank Posted January 30, 2018 Share Posted January 30, 2018 Do you have carpet and trunk liner as original? My projects all had a drone when 'testing' before final assembly. Link to comment Share on other sites More sharing options...
Beemon Posted January 30, 2018 Author Share Posted January 30, 2018 Yes I still have the original carpet and trunk liners in place. They are in decent enough condition but they probably don't do much lol Link to comment Share on other sites More sharing options...
KAD36 Posted January 30, 2018 Share Posted January 30, 2018 (edited) Hangers all snug on the pipes? Check the rubber mounts so they don’t allow too much motion? No vibrations in exhaust pipe behind the muffler over the rpm range? Just trying to ascertain if its resonating inside the muffler or elsewhere Edited January 30, 2018 by KAD36 (see edit history) Link to comment Share on other sites More sharing options...
Beemon Posted January 31, 2018 Author Share Posted January 31, 2018 it would be hard to tell if it was resonating under load at 2500 RPM after the muffler Rubber mounts are all good and snug. The only original mount in the car is the exhaust tip hangar, as they're attached to the exhaust tip. Link to comment Share on other sites More sharing options...
avgwarhawk Posted February 3, 2018 Share Posted February 3, 2018 Installed the new muffler and tailpipe. I had to reuse the pipe between the crossover and muffler. The new pipe was not bent in the correct angle. Could be mine is a manual and routes differently than a Dynaflow. Any, it is quieter than the Walker. Engine appears to run a bit better. Perhaps back pressure is greater. The muffler takes up the enter section where it's located! I'll post a video with sound later. 1 1 Link to comment Share on other sites More sharing options...
avgwarhawk Posted February 5, 2018 Share Posted February 5, 2018 Beemon, Sound of the new larger Goliath of a muffler. I like the sound. Appears to run better(back pressure): 1 Link to comment Share on other sites More sharing options...
Beemon Posted July 13, 2018 Author Share Posted July 13, 2018 GoWanted to revive this thread because I just got a package from a Mr Martin Johnson. I'll be installing tonight! I'm really excited about this one. 60 percent of the noise driving down the road was no weatherstrip and 40 percent was the muffler. I'm ready for my quiet ride! 4 Link to comment Share on other sites More sharing options...
avgwarhawk Posted July 16, 2018 Share Posted July 16, 2018 Cool! Let us know who it works out. 1 Link to comment Share on other sites More sharing options...
Beemon Posted July 16, 2018 Author Share Posted July 16, 2018 Thank you all for getting me in touch with Martin Johnson. I can't be more happy with these factory original mufflers! 2 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now