Go Back  Offshoreonly.com > Technical > General Q & A
Turndown exhaust >

Turndown exhaust

Notices

Turndown exhaust

Thread Tools
 
Old 07-06-2007, 04:13 PM
  #1  
Registered
Thread Starter
 
Dude! Sweet!'s Avatar
 
Join Date: Nov 2006
Location: Huntington Beach, CA
Posts: 1,955
Likes: 0
Received 0 Likes on 0 Posts
Default Turndown exhaust

I did a search and didn't find anything useful.

Anyone using the Gibson or CMI turndowns (aka "DonkeyD1cks") and willing to share their experiences with them? I don't really dig the looks but I've got a couple of young children and the noise at idle and low speed seems to be excessive for them with my current exhaust (which I actually quite enjoy!).

Thanks!
Dude! Sweet! is offline  
Old 07-06-2007, 04:33 PM
  #2  
Registered
 
Too Old's Avatar
 
Join Date: Oct 2000
Posts: 2,713
Likes: 0
Received 1 Like on 1 Post
Default

Check with forum members "GLH" or "Old School".

Both of them have some time on sets I've sold them.


Fred
Too Old is offline  
Old 07-06-2007, 04:41 PM
  #3  
Registered
Thread Starter
 
Dude! Sweet!'s Avatar
 
Join Date: Nov 2006
Location: Huntington Beach, CA
Posts: 1,955
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks Fred. Will do.
Dude! Sweet! is offline  
Old 07-06-2007, 10:23 PM
  #4  
Banned
Gold Member
 
Elite Marine's Avatar
 
Join Date: Aug 2002
Location: IL
Posts: 5,660
Likes: 0
Received 0 Likes on 0 Posts
Default

We sell alot of them. I run them on my Pantera and Brad runs them on his MTI - see this months Extreme Boat!!!

They work great, are silent when idling and are open pipes when running.

If we can quote you a set, let me know. Pantera discount in effect!

The CMI Sound Elimination Mufflers are awesome also!!

Kirk
Attached Thumbnails Turndown exhaust-custom-downtube2oso.jpg   Turndown exhaust-custom-downtubeoso1.jpg  
Attached Images  
Elite Marine is offline  
Old 07-06-2007, 10:59 PM
  #5  
Charter Member # 55
Charter Member
 
Griff's Avatar
 
Join Date: Oct 2000
Location: Omaha/LOTO
Posts: 19,668
Received 1,903 Likes on 956 Posts
Default

DS, For a slight reduction you can move the allen screw down one more hole on the Shotguns. It will help a little.
Griff is offline  
Old 07-07-2007, 07:58 AM
  #6  
Platinum Member
Platinum Member
 
RMPRam's Avatar
 
Join Date: Oct 2000
Location: Santa Barbara CA. USA
Posts: 1,026
Received 28 Likes on 7 Posts
Default

I had air activated mufflers on my 38 Cigarette w/1100's for several years and got nothing but a giant hassle from the water patrol.
I removed them and made a complete new exhaust from the transom. It goes underwater 6" at idle, shoots the exhaust down rather than back and at speed is all between the drives, which helps the noise factor from the side. It is now very quiet. I did drill a small hole in the bottom of ea. pipe, near the transom to relieve the pressure for start-up.
I wish that I would have thought of this years ago, it would have saved me a lot of money for noise tickets and mufflers.
Attached Thumbnails Turndown exhaust-38-cigarette-2006-005.jpg   Turndown exhaust-38-cigarette-2006-007.jpg  

Last edited by RMPRam; 07-16-2007 at 07:07 PM.
RMPRam is offline  
Old 07-07-2007, 08:06 AM
  #7  
Charter Member #927
Charter Member
 
Payton's Avatar
 
Join Date: Jan 2001
Location: IN
Posts: 4,834
Received 2 Likes on 2 Posts
Default

RMPRam, that looks very trick. I think it's cool.
Payton is offline  
Old 07-07-2007, 05:14 PM
  #8  
Gold Member
Gold Member
 
CcanDo's Avatar
 
Join Date: May 2002
Location: DFW
Posts: 1,127
Likes: 0
Received 0 Likes on 0 Posts
Default

RMPRam, That is a fancy transom.

Subject to engine size, is there most back pressure on the outside banks ? The outside pipes are longer and have two elbows vs. one on the inside. One could wonder if there would be on imbalance.

Have you compared spark plug color and condition between the Port and Starboard heads ? Or, looked at each head with a temperature gun after a hard run ?
CcanDo is offline  
Old 07-08-2007, 08:38 AM
  #9  
Platinum Member
Platinum Member
 
RMPRam's Avatar
 
Join Date: Oct 2000
Location: Santa Barbara CA. USA
Posts: 1,026
Received 28 Likes on 7 Posts
Default

I have not done any checks on the outside plugs. I realize that the outer pipes are longer and contain one more sweeping right angle bend than the inner pipes but that was necessary to place the pipes between the drives. I'm running EGT probes on #6 cyl of both motors. That would place one probe on an outer bank,(stbd. motor), and the other on the inner bank. The result that I've seen, is the stbd. motor runs @ 1300 degrees @ speed and the port will run @ 1350. Does not seem to be any problem, so far.
RMPRam is offline  
Old 07-08-2007, 09:53 AM
  #10  
Registered
Thread Starter
 
Dude! Sweet!'s Avatar
 
Join Date: Nov 2006
Location: Huntington Beach, CA
Posts: 1,955
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks for all the info! Next step is to see if they'll actually fit on my boat (it looks like there's a potential interference with steering rams).
Dude! Sweet! is offline  


Quick Reply: Turndown exhaust


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.