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Thread: Cmi Install On 496

  1. #1
    ULTRA26 # 1
    Has anyone here installed CMI headers on a boat with below swim step exhaust openings? If so were additional parts required such a water jacketed s pipes?
    Thanks

  2. #2
    Raylar
    We,ve set up a few 496's with the new CMI kits. I say kits, because there is a lot more in the install than just boltng on the headers. It will take a good mechanic an honest 8 hours labor depending on the boat. Yes you can run cast s-pipes to below a swimstep, but depending on the fit measure carefully and talk to CMI or Fred at Trick Marine to make sure the tips they supply in the kit are the exact correct length.
    Ray @ Raylar

  3. #3
    ULTRA26 # 1
    We,ve set up a few 496's with the new CMI kits. I say kits, because there is a lot more in the install than just boltng on the headers. It will take a good mechanic an honest 8 hours labor depending on the boat. Yes you can run cast s-pipes to below a swimstep, but depending on the fit measure carefully and talk to CMI or Fred at Trick Marine to make sure the tips they supply in the kit are the exact correct length.
    Ray @ Raylar
    Ray,
    Thanks for your input. It was very helpful
    John M

  4. #4
    Decided Advantage
    We,ve set up a few 496's with the new CMI kits. I say kits, because there is a lot more in the install than just boltng on the headers. It will take a good mechanic an honest 8 hours labor depending on the boat. Yes you can run cast s-pipes to below a swimstep, but depending on the fit measure carefully and talk to CMI or Fred at Trick Marine to make sure the tips they supply in the kit are the exact correct length.
    Ray @ Raylar
    All right! A pro. The next question. What kind of real world improvement was realized. The last time invested was on a 350 MAG/MPI that I upgraded from a lowly thru-prop exhaust. The result sounded great but with all the other variables (people, temp, wind, etc.) the result was no measureable performance difference.
    I think they advertise a 60HP increase on a stock 496HO, which should provide measurable (3-5MPH?) results.
    What is your experience?
    My take was that while the headers look cool, that a Raylar kit leaving the exhaust stock would provide better bang for the buck and maintain better reliability(I hate dealing with water leaks).
    You are the pro with tons of experience, dyno, and testing in this area.
    My insurance company specifies no engine, exhaust mods. These headers would be a bit to visible to ignore. I'd prefer to keep with mods more suttle in appearance.

  5. #5
    ULTRA26 # 1
    All right! A pro. The next question. What kind of real world improvement was realized. The last time invested was on a 350 MAG/MPI that I upgraded from a lowly thru-prop exhaust. The result sounded great but with all the other variables (people, temp, wind, etc.) the result was no measureable performance difference.
    I think they advertise a 60HP increase on a stock 496HO, which should provide measurable (3-5MPH?) results.
    What is your experience?
    My take was that while the headers look cool, that a Raylar kit leaving the exhaust stock would provide better bang for the buck and maintain better reliability(I hate dealing with water leaks).
    You are the pro with tons of experience, dyno, and testing in this area.
    My insurance company specifies no engine, exhaust mods. These headers would be a bit to visible to ignore. I'd prefer to keep with mods more suttle in appearance.
    Sorry to go off topic but I have to ask who you are insured with? No engine or exhaust mods stated in an insurance policy seems a bit stiff. Again, sorry for going off topic.

  6. #6
    ULTRA26 # 1
    We,ve set up a few 496's with the new CMI kits. I say kits, because there is a lot more in the install than just boltng on the headers. It will take a good mechanic an honest 8 hours labor depending on the boat. Yes you can run cast s-pipes to below a swimstep, but depending on the fit measure carefully and talk to CMI or Fred at Trick Marine to make sure the tips they supply in the kit are the exact correct length.
    Ray @ Raylar
    Has anyone who has installed CMI's on their 496 had issues with the front header pipes on both sides running much hotter than the rest? This is happining with mine. No hoses are bindiing or are kinked.
    Thanks

  7. #7
    JB in so cal
    Has anyone who has installed CMI's on their 496 had issues with the front header pipes on both sides running much hotter than the rest? This is happining with mine. No hoses are bindiing or are kinked.
    Thanks
    Minor details... What kind of performance improvements are you seeing? Went from ?? to ??.
    I'm thinking of going w/cmi's this winter.

  8. #8
    ULTRA26 # 1
    Minor details... What kind of performance improvements are you seeing? Went from ?? to ??.
    I'm thinking of going w/cmi's this winter.
    Fairly serious performace increase accoss the board. I had only had it out last Sunday and my headheld GPS batteries were dead. Prior to the headers, maxx spreed shown on the speedo was 76 which was 74 on my GPS. Last Sunday, speedo well past the 80 mark. 4 to 5 MPH increase minimum. Acceleration from 40 to top speed increased dramatically and the boat sounds extremely good. You will be satisfied too

  9. #9
    Cole Trickle
    The CMI headers are really nice and look great.
    I would think realistic gains would be closer to 20-25 HP. and 1-2 MPH
    No way people are seeing 5-6 mph with a header swap in the same conditions......No Way!!
    They are nice and have alot of parts but the price is absurd.

  10. #10
    djunkie
    The CMI headers are really nice and look great.
    I would think realistic gains would be closer to 20-25 HP. and 1-2 MPH
    No way people are seeing 5-6 mph with a header swap in the same conditions......No Way!!
    They are nice and have alot of parts but the price is absurd.
    Damm buzz kill.

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