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headers/exhaust

ross

ross

Well-known member
wondering what headers/exhaust you guys are using on your boats. what motor are you running it on and whats your setup? what kind of hp increase did you see? wet or dry exhaust?
 
yours are good leave em alone lol just kidding im running 4.5 inch sportubes dry i couldnt tell you how much better it runs with em thats how i bought it rule of thumb stock then manifold style with stainless collectors then true tube headers and of course the dry versions usually work better but they get a little obnoxious although arent yours dry you should know
 
yea mine are dry, and very loud. i am wondering what the hp gain is on the average set of headers? i cant seem to find what the rating is on mine(cmi big tube) dry off course....and also curious what else has worked good for the other members on here:cheers:
 
ross said:
yea mine are dry, and very loud. i am wondering what the hp gain is on the average set of headers? i cant seem to find what the rating is on mine(cmi big tube) dry off course....and also curious what else has worked good for the other members on here:cheers:
Click to expand...
Sounds like you are getting worried about YF88!!!!!:poke:
 
lcboater said:
Sounds like you are getting worried about YF88!!!!!:poke:
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nope just an honest question.....i get him out in the bay here(lake michigan) in some 3-4 footers and i have no worries:D in calm water i will just refuse to start my boat, nope i will sit here and drink beer:cheers::bigthumb:
 
yellowfiero88 said:
You think that will slow me down in the new one :shakehead: :lol:
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whats the new one? hey ross if you go to lightnings website they compare their headers to a bunch of other manufacturers on a 500 hp motor i havent looked at it in a while but something was weird about how the chart reads i think the numbers are above and beyond what gils do or something like that
 
  • just gotta remember to take any manufacturers numbers with a grain of salt
  • HEADER PERFORMANCE
Performance figures on headers very considerably. As a rule, the higher horsepower engines benefit more than lower horsepower engines. For example the 330 horsepower Mercury engine will gain approximately 75 to 100 RPM, where as the 365 horsepower Mercury engine will gain approximately 300 to 400 RPM (45 HP). Blown engines gain up to 800 RPM (80 to 100 HP).

When comparing our headers against other performance exhaust systems recent dynamometer test have shown the following using a 460 CI big block Chevrolet, 9 to 1 compression ratio, solid roller camshaft ( 255 @ .050 duration, 110 lobe separation angle, 680 lift), dual plane intake manifold and 850 Holley carburetor. Results taken at 5500 RPM.
  • Gill manifold Lightning increase 20 HP
  • PFM manifold Lightning increase 16 HP
  • IMCO manifold Lightning increase 22 HP
  • CMI Elbow Top Lightning increase 12 HP
  • Stainless Marine manifold Lightning increase 21 HP
  • Eddie Marine manifold Lightning increase 20 HP
  • Mercury Marine manifold Lightning increase 51 HP
  • Stellings Header Lightning increase None
from lightnings website
 
I have EMI thunder manifolds with the long tube stainles risers that are dry until the very end so I am running a custom cam for a dry exhaust. They came with the boat so I have no idea on the difference they made......the previous owner sid that he didn't notice much but he didn't re-tune the ecm to handle the extra flow either. They have pretty big runners and sound nice though.......
 
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