Exhaust Drone Question - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**LockDoc** · 09-27-2020, 07:48 PM

Quote:

Originally Posted by bigmoe

LockDoc when you measure the length where exactly are you measuring? You could measure total length of pipe before bending or just top to bottom of the J.
I've got a lot of drone with my shorties and Magnaflow 3 chambers. Truck is going in this week for tailpipes (now just turn downs) and I hope that will reduce or eliminate my drone which is deafening at 18-2000. I keep it in a lower gear and higher revs when I can to avoid it.

I measured mine at the longest point after bending and cutting to fit the existing tail pipe.

LockDoc

**Boog** · 09-27-2020, 07:53 PM

Somewhere there is a formula for determining the length and placement of a j pipe.

**LockDoc** · 09-27-2020, 08:06 PM

Quote:

Originally Posted by Boog

Somewhere there is a formula for determining the length and placement of a j pipe.

I posted it in post #8, below the picture.

LockDoc

**HO455** · 09-27-2020, 08:48 PM

The bend in the pipe is for packaging purposes. It's hard to find room for a 32 inch pipe at 90 degrees to the rest of the exhaust system.
The length is figured in the formula as a straight pipe. That being said this isn't something has to be dead on exact to work. In fact lots of folks have used the formula to get in the ball park and then made the pipe adjustable to really dial in the cancellation effect.

**Sheepdip** · 09-28-2020, 09:49 AM

Quote:

Originally Posted by Steeveedee

Worse comes to worst, put a pair of Cadillac mufflers on it. Those will give no rumble whatsoever. Ever heard a loud, stock Caddy? A couple to fit a 500 Cu In engine would be sure to give you enough flow! When I go to do mine, that's the route I'm taking.

Many moons ago when I was in high school there was a fellow that had a really pumped up 68 GTO with insane compression and cam overlap.

After getting a ticket for loud exhaust he installed Caddy mufflers. It really took the loud out at the rear exit but it made this unique sound while idling.
My best description is it sounded like you were tapping on a empty gallon paint can with a spoon all the way down the exhaust system and seemed like you could almost hear each cylinder fire individually.

Never heard anything like it since... but those caddy mufflers worked.

09-27-2020, 07:53 PM	#27
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,514	Re: Exhaust Drone Question Somewhere there is a formula for determining the length and placement of a j pipe. __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

09-27-2020, 08:48 PM	#29
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,350	Re: Exhaust Drone Question The bend in the pipe is for packaging purposes. It's hard to find room for a 32 inch pipe at 90 degrees to the rest of the exhaust system. The length is figured in the formula as a straight pipe. That being said this isn't something has to be dead on exact to work. In fact lots of folks have used the formula to get in the ball park and then made the pipe adjustable to really dial in the cancellation effect. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377



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