The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 09-27-2020, 07:48 PM   #26
LockDoc
The Older Generation

 
LockDoc's Avatar
 
Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,270
Re: Exhaust Drone Question

Quote:
Originally Posted by bigmoe View Post
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
__________________
Leon

Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles

(My Dually Pickup Project Thread)

http://67-72chevytrucks.com/vboard/s...d.php?t=829820

-
LockDoc is offline   Reply With Quote
Old 09-27-2020, 07:53 PM   #27
Boog
laying low
 
Boog's Avatar
 
Join Date: Mar 2001
Location: Searcy, Ark. USA
Posts: 12,888
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
Boog is offline   Reply With Quote
Old 09-27-2020, 08:06 PM   #28
LockDoc
The Older Generation

 
LockDoc's Avatar
 
Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,270
Re: Exhaust Drone Question

Quote:
Originally Posted by Boog View Post
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
__________________
Leon

Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles

(My Dually Pickup Project Thread)

http://67-72chevytrucks.com/vboard/s...d.php?t=829820

-
LockDoc is offline   Reply With Quote
Old 09-27-2020, 08:48 PM   #29
HO455
Post Whore
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,757
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,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 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
HO455 is offline   Reply With Quote
Old 09-28-2020, 09:49 AM   #30
Sheepdip
Senior Member
 
Sheepdip's Avatar
 
Join Date: Nov 2018
Location: Waterford California
Posts: 2,334
Re: Exhaust Drone Question

Quote:
Originally Posted by Steeveedee View Post
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.
Sheepdip is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 04:14 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com