Go Back  Offshoreonly.com > Technical > General Q & A
Different CMI header types >

Different CMI header types

Notices

Different CMI header types

Old 04-29-2006, 07:45 PM
  #1  
Registered
Thread Starter
 
Rebel_Heart's Avatar
 
Join Date: Feb 2004
Location: LOTO
Posts: 1,173
Likes: 0
Received 0 Likes on 0 Posts
Default Different CMI header types

I posed this question on the end of another post and it didn't get too much of a response.

I plan on using my e-tops on my new powerplant, 540 cu in @ 700 hp. What am I leaving on the table? CMI's are very expensive, so I would like to use what I have. They are 4" headers with a 4 1/2" tube exiting the boat. What are other doing with NA power?
Rebel_Heart is offline  
Old 04-29-2006, 07:59 PM
  #2  
Registered
 
Join Date: Feb 2002
Location: Honeoye, NY
Posts: 763
Likes: 0
Received 0 Likes on 0 Posts
Default Re: Different CMI header types

You will probably get lots of different answers on this, but; Generally speaking, unless you want to run over 6000 rpm, it would be my opinion that there would not be much to gain by going to the long tubes over your e-tops. --- Jer
jpclear is offline  
Old 04-29-2006, 08:14 PM
  #3  
Registered
Thread Starter
 
Rebel_Heart's Avatar
 
Join Date: Feb 2004
Location: LOTO
Posts: 1,173
Likes: 0
Received 0 Likes on 0 Posts
Default Re: Different CMI header types

Thanks for the reply. I would imagine max hp would be around 5,800. I'm certainly not looking to spend money if it isn't going to do me any good! The engine builder didn't seem to think that the gain would offset the price of new headers. Just wanted to get what other views are.
Rebel_Heart is offline  
Old 04-29-2006, 09:21 PM
  #4  
Registered
Thread Starter
 
Rebel_Heart's Avatar
 
Join Date: Feb 2004
Location: LOTO
Posts: 1,173
Likes: 0
Received 0 Likes on 0 Posts
Default Re: Different CMI header types

I appreciate the honesty. I would like to have 750 hp or more, but know that I won't be close. Thank you.
Rebel_Heart is offline  
Old 04-29-2006, 10:22 PM
  #5  
Registered
 
Too Old's Avatar
 
Join Date: Oct 2000
Posts: 2,713
Likes: 0
Received 1 Like on 1 Post
Default Re: Different CMI header types

There's also a small matrix on the CMI website to help you with your decision.


http://www.custommarine.com/headerap...erAppChart.php

Last edited by TRICK; 04-29-2006 at 10:26 PM.
Too Old is offline  
Old 04-30-2006, 12:14 AM
  #6  
Registered
Thread Starter
 
Rebel_Heart's Avatar
 
Join Date: Feb 2004
Location: LOTO
Posts: 1,173
Likes: 0
Received 0 Likes on 0 Posts
Default Re: Different CMI header types

TRICK - great explanation of header types and hp limits. Looks as though I will stay with what I have. I may need some clamp-on mufflers as the tailpipes should go through the transom about 7 inches. I'll know more once I water test the boat and my wife adds her 2 cents!
Rebel_Heart is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Outdrive1
Wanted
2
06-12-2008 07:22 PM
custom29scarab
General Q & A
0
08-01-2007 08:26 PM
Rrice
General Boating Discussion
1
05-14-2007 08:12 PM
34scarab
General Q & A
4
04-27-2005 01:15 AM
Punk Rocket
General Q & A
21
08-07-2002 08:33 AM

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
Trackbacks are On
Pingbacks are On
Refbacks are On


Quick Reply: Different CMI header types


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.