Go Back  Offshoreonly.com > Technical > General Q & A
need advice on clamp -on mufflers >

need advice on clamp -on mufflers

Notices

need advice on clamp -on mufflers

Thread Tools
 
Old 08-24-2009, 08:56 AM
  #1  
Registered
Thread Starter
iTrader: (1)
 
Join Date: Jul 2007
Location: St. Louis / LOTO
Posts: 476
Received 2 Likes on 2 Posts
Default need advice on clamp -on mufflers

I need to get a couple sets of clamp on mufflers. I pulled off my Big Gibsons with the Gaffrig air pump and lines, I want some full time clamp on mufflers for 4". It honestly isnt too loud for the lake. The WP went by me several times this past weekend and never looked twice at me, a couple times I was really into the throttles.

So, I am not looking for a lot of db reduction, just something that will extend the pipes out a bit - I am concerned about water reversion, and looking to take just a slight bit of the bark the exhaust has out of it.... and something that looks really nice is a big plus.... I have looked at the full time gibsons, HPI's, etc.... any recomendations? again, not looking for big restriction or db reductions, very slight. thanks.
eichhoma is offline  
Old 08-24-2009, 11:02 AM
  #2  
Registered
iTrader: (7)
 
Join Date: Feb 2009
Location: NW Michigan
Posts: 8,302
Received 1,492 Likes on 807 Posts
Default

with the gafrig clamp on style with the pump actuator etc. looks like you need to drill a 11/32 hole through the transom next to the exhaust pipe for the actuator rod. is this correct?

those cmi's look nice. is there a open area on the under side of those?
getrdunn is offline  
Old 08-24-2009, 11:34 AM
  #3  
Registered
Thread Starter
iTrader: (1)
 
Join Date: Jul 2007
Location: St. Louis / LOTO
Posts: 476
Received 2 Likes on 2 Posts
Default

That is what I had was the Gaffrig air pump controlled clamp ons. Spring pressure held them open, but then air pressure would hold them close when you needed it. I want to get away from all that, gel the holes up and put a full time clamp on muffler on... those cmi's do look nice, but am thinking those will quiet it down a lot mroe than I want it.

I would also like somethign a little smaller and cleaner looking... Here is a pic of what I had...
Attached Thumbnails need advice on clamp -on mufflers-p1010001.jpg  

Last edited by eichhoma; 08-24-2009 at 11:38 AM.
eichhoma is offline  
Old 08-24-2009, 12:58 PM
  #4  
Registered
 
Brad Zastrow's Avatar
 
Join Date: Jun 2001
Location: McHenry, Illinois
Posts: 2,287
Received 79 Likes on 23 Posts
Default

No open area below the CMI's. All the exhaust goes out the back. I just put two sets on my Pantera with 502's. They will muffle the exhaust at less than 3000 rpm and then they open to full open exhaust after that.
No flaps, no pumps and nothing to worry about. Back pressure opens the outer ring out to hang open on a cam that springs shut after you slow down. CMI tested to ZERO back pressure at WOT!
Brad Zastrow is offline  
Old 08-24-2009, 01:17 PM
  #5  
Registered
Thread Starter
iTrader: (1)
 
Join Date: Jul 2007
Location: St. Louis / LOTO
Posts: 476
Received 2 Likes on 2 Posts
Default

Thanks Brad.... I really like the concept to them... I sure would like to hear what they sound like at idle though.... I guess thats the draw back here, I need to take a guess and buy something and try it, and most likely stuck with them if I dont like them.... I'm not really liking that
eichhoma is offline  
Old 08-24-2009, 02:28 PM
  #6  
Charter Member # 55
Charter Member
 
Griff's Avatar
 
Join Date: Oct 2000
Location: Omaha/LOTO
Posts: 19,558
Received 1,821 Likes on 907 Posts
Default

I assume you are talking about reversion from wave action since you have basically dry exhaust like mine and no internal flappers. Really the only other alternative foor waht you are loking for is Drew Marine Shotguns. They are a lot less $$ than the CMI's, but don't look nearly as good. They work the same way as the CMI's.
Griff is offline  
Old 08-24-2009, 02:48 PM
  #7  
Registered
 
Gladhe8er's Avatar
 
Join Date: Jan 2006
Location: Fairfield, CT
Posts: 3,692
Likes: 0
Received 2 Likes on 2 Posts
Default

A guy I know has CMI's on HP500's. 90 Db at idle. Probably 98-100 without the mufflers.
Gladhe8er is offline  
Old 08-24-2009, 03:58 PM
  #8  
Registered
Thread Starter
iTrader: (1)
 
Join Date: Jul 2007
Location: St. Louis / LOTO
Posts: 476
Received 2 Likes on 2 Posts
Default

Originally Posted by Griff
I assume you are talking about reversion from wave action since you have basically dry exhaust like mine and no internal flappers. Really the only other alternative foor waht you are loking for is Drew Marine Shotguns. They are a lot less $$ than the CMI's, but don't look nearly as good. They work the same way as the CMI's.
yeah, sorry, I should have clarified.... with nothing on there now it seems easy for water to splash back up in there eassily and go down the risers.... I want to clamp something on that will provide a minimal amount of sound suppression, and also help prevent the possibility of water reversion....

I am basically looking for something like this I think:
http://www.hardin-marine.com/detail~ID~286.aspx

I just dont want to muffle the sound too much.
eichhoma is offline  
Old 08-24-2009, 03:59 PM
  #9  
Registered
Thread Starter
iTrader: (1)
 
Join Date: Jul 2007
Location: St. Louis / LOTO
Posts: 476
Received 2 Likes on 2 Posts
Default

Originally Posted by Gladhe8er
A guy I know has CMI's on HP500's. 90 Db at idle. Probably 98-100 without the mufflers.
Really? Interesting.... I have some mildly mod'd 502's with blowers .... I dont mind the CMI's, but am not too crazy about any moving parts.
eichhoma is offline  
Old 08-24-2009, 05:55 PM
  #10  
Registered
 
Join Date: Nov 2004
Location: wolfeboro nh
Posts: 58
Likes: 0
Received 0 Likes on 0 Posts
Default

imco gattling mufflers worked awesome on my blown 510's
38tg is offline  


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.