NJTman

Yesterday I did a long trip (3.5 hours each way) to a buddy of mine, with the wife. A/C was on, and the windows were shut so we could hear ourselves think. If I was alone, the window would have been open, and my ears would have been bleeding from the music.... but I digress..


At a certain RPM range.... (don't know what it was because I don't have a Tach yet ) there is an annoying resonance in the truck coming from the exhaust. I can make it go away by moving the pedal either down or up, but unfortunately, @ 70MPH, I'm constantly fluctuating the pedal to make it stay away.. You can hear it throughout the truck's movement forward, as I've even noticed it while accelerating. It sounds like an owl coo-ing.

I was thinking some kind of wrap on the muffler, but I just can't see how that would be any good for the DE Exhaust temps.

Any thoughts on how to address this resonance ? Would be nice to have a conversation with someone without hearing that darn hoot OWL below my truck...



TIA

#2isgreen

That's yer problem right there bud! Get that dang muffler outta there! It's not much louder...

MARF75

X2

Crossy's son

Yea that's why we got rid of the Diamond Eye muffler on the 92, it had an annoying drone that would drill your ears out at highway speed.

Now it's straight piped (temporarily my dad said 4 months ago) and I swear no more resonance.

NJTman

Most appreciated to all who responded. Muffler is coming out.


Did you guys just order a bypass pipe from TY or make something up local ?

Crossy's son

Well usually the muffled systems come with enough extra pipe to get rid of the muffler, but since yours is a CC I'm guessing it didn't come with enough extra pipe?

Napa sells 4" Exhaust pipe, usually I measure the OVERALL length of the muffler with the ins/outs included (account for the pipe being slid over 2" on each side), After i cut the pipe the perfect length i take it to an exhaust shop and get the ends expanded so the 4" OD pipe will slide right up into the new muffler delete

Easy

Jim Lane

Add a resonator to acoustically tune out the noise.

http://store.airflo.com/m090362.html

http://www.xtremediesel.com/mbrpdies...lesssteel.aspx

http://www.thoroughbreddiesel.com/mbrp/resonator.htm

A resonator is not a muffling device but a tunning chamber.

Also all of the padding and insulation on the floor and covering the back of my cab helped to reduce the interior sounds, without the engine running you can get into my truck and close the door and all you hear is the sound of dead muffled silence.

Although my truck is very quiet, I still get a fair amount of mechanical noise from the outside world.

You could apply this to the interior of the cab to make it acoustically dead, if it cannot vibrate it cannot transmit the noise.

http://www.secondskinaudio.com/index...pectrum-detail

Jim

elephantrider

try the fte resonator. works wonders for drone. i have mine right off of the downpipe and there is zero drone, but still sounds great.

Jklawinsky

If you want to keep the muffler then add a resonator or switch to an Aeroturbine. Best muffler you can buy IMO.

Onemoparnut

Get rid of the muffler it will sound much better anyway. jmo.

sootnsmoke

On the stock 92 club cab I had (now Bill's), I never noticed a drone with the stock muffler and exhaust? Maybe there is a baffle or something awry inside your muffler?

On our 91, the previous owner took out the stock muffler and put a straight thru cylinder style muffler (looks like what I used to call a "cherry bomb"). That exhaust sounds nice but there is more noticable noise in the cab.

On my new to me 96 12v which is completely stock with stock exhaust, I could record live opera at 80 MPH with almost no background noise LOL. Its kind of creepy actually.

NJTman

99% sure it's a straight through type muffler..... just 4" in diameter inlet and outlet.


Sent a request to TY diesel about the replacement pipe. Not sure if they can get it yet, as I haven't heard back, but if it's cheap enough, I'm going to replace the muffler with a straight piece of pipe and be done with it.

sootnsmoke

Yep, thats what I would do. Keep it simple.