When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Exhaust J-pipe to eliminate drone. Length/frequency/temperature chart inside.
Found this on another forum and thought it was extremely helpful. I've made an appointment with my local exhaust shop to get a J-pipe (aka 1/4 wave resonator tube) installed to eliminate drone around 2,000 rpm. A V8 creates 133 pulses per second at 2,000 rpm equating to a 133hz sound frequency. According to this chart I would need a J-pipe between 26-28" depending on where the shop installs it. I've already used an IR thermometer to measure temperature along the I-pipe section of the catback and it ranges from 90* near the axle to 190* halfway to the merge. To test the math, I downloaded a sound spectrum app on my phone and went for a drive. Sure enough, it was reading between 130-135hz at 2,000 rpm. Has anyone else installed a J-pipe? How'd it work out for you? Post pics if you've got 'em!
Got the j pipe installed today. The shop did a fantastic job. They had to put the pipe halfway between the mufflers and the headers where the exhaust is about 150° so I asked them to make it 27". When I got home I measured it at 28" but it's still working fine. The drone is GONE. The exhaust does sound a little weird in the cabin with the missing sound frequency but outside you can't tell. Very happy with it.
I have been reading about this the past few days. Just recently installed true duals and the drone is awful ! I hear it works amazing....
I will post back when it's done....I NEED this to work lol !
it certainly worked for me. You'll be able to hear your passengers and your music much clearer and it won't sound like you're driving inside a milk jug anymore.
also I measured the temperature where the j-pipe is welded on and it's actually 160* so the 28" pipe is the perfect length. That worked out nice!
it certainly worked for me. You'll be able to hear your passengers and your music much clearer and it won't sound like you're driving inside a milk jug anymore.
also I measured the temperature where the j-pipe is welded on and it's actually 160* so the 28" pipe is the perfect length. That worked out nice!
Finally got it finished and it worked absolutely flawless !
I ended up at 25 in. and used 2.5in. diameter pipe.
04-11-2024, 01:54 AM
Exhaust J-pipe to eliminate drone. Length/frequency/temperature chart inside. 
