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Cat C18 1015 vs 1150 hp

Discussion in 'Engines' started by bayoubud, Jan 18, 2018.

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  1. bayoubud, Jan 18, 2018
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    bayoubud

    bayoubud Senior Member

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    Interested in a SF that is powered with Cat C18 1015 hp. The C18's have a higher rated model of 1150 hp and curious what is involved to get that additional 135 hp to bump the cruise speed up. Is it doable without degrading the reliability of the engines or major mechanical work?
  2. Capt Ralph, Jan 18, 2018
    #2
    Capt Ralph

    Capt Ralph Senior Member

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    Any time you extract more power from an engine, life span is cut.
    More HP consumes more fuel. One of Cat's guide to engine life is the amount of fuel consumed between service points (vs hours).

    When special tunes like this get modified to get the HP up, The torque curve may also get modified, some better, some curves not.
    IMO, the top of the torque curve is where you want to run or close to.
    That said, keeping your foot off the gas may not save fuel in a higher HP rated engine. You will need to compare all the curves to determine best cruise speed / HP / torque / fuel flow VS fuel consumption to find your real engine life.

    After the math, IMO; engine life is shortened.
  3. bayoubud, Jan 18, 2018
    #3
    bayoubud

    bayoubud Senior Member

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    Thanks rc, i agree more horsepower out of the same block would likely shorten life some. Have heard nothing but good comments about both versions of C18's and thinking it would not be big negative if it is an easy conversion to bump the HP it could be worth it and pickup a few kts. Will know speed and fuel burn this weekend.
  4. Capt Ralph, Jan 18, 2018
    #4
    Capt Ralph

    Capt Ralph Senior Member

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    Ah, going for a ride(s).
    Fill us in on what you find out.
    I let my subscription to the other diesel site expire (got boring). Please fill us in on what you find and comparing graphs if you can.
    I am a C18 fan. Just a few up here.
  5. Capt J, Jan 18, 2018
    #5
    Capt J

    Capt J Senior Member

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    The 1015 HP is bullet proof. I've run a lot of the 1150hp also and they don't seem to add much performance or speed, even in the same boat and they burn about 10 gph more (for both). What boat are you looking at? I think there are a lot of physical differences in the 1150hp and it's not a simple reprogramming.
  6. bayoubud, Jan 18, 2018
    #6
    bayoubud

    bayoubud Senior Member

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    Yep, I do have some numbers for the 1150 hp version in a later model for comparison.
  7. bayoubud, Jan 18, 2018
    #7
    bayoubud

    bayoubud Senior Member

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    Capt J, looking at a 2004 Hatteras GT 54. Have looked at another 04 with C30's,very clean, but like to see the C18 setup for a roomier er and easier maintenance, if performance is ok.
  8. Capt J, Jan 18, 2018
    #8
    Capt J

    Capt J Senior Member

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    The 2004 54 GT was a very very good running boat. The one I ran quite a bit had c30's that cruised at 32-33 knots with a tuna tower at 112 gph and a far superior ride to the 50' of the same era. The c18's would burn 76 GPH and honestly your speed will be somewhere around 28 knots or so and a great running boat as they're quite a bit lighter. They built very few C18 boats, but they're fast enough and a heck of a lot cheaper to operate. They didn't build 1150HP c18's back then and quite frankly you'd only gain 1-1.5 knots for 10 gph more fuel burn.
  9. Capt Ralph, Jan 18, 2018
    #9
    Capt Ralph

    Capt Ralph Senior Member

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    Josie & I delivered a GT54 From Jax to Ft Pierce one weekend a couple of years ago.
    We still talk about her.
    What a blast. With the C18s I could not imagine a faster, smoother, sweeter ride or running setup.
    Just wish that customer would call us back to bring her back north, south, east,, heck anywhere.
  10. Capt J, Jan 18, 2018
    #10
    Capt J

    Capt J Senior Member

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    It's fun to go fast, when you're not the one paying for the fuel!!!!!!! hehehee.
  11. Bill106, Jan 19, 2018
    #11
    Bill106

    Bill106 Senior Member

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    While they share the same footprint the 1150MHP ACCERT C18 is a very different block internally. Main bearing races, webbing, crank, rods and aftercooling are all much beefier (highly technical term I know!). Both have an excellent reputation and no "quirks" that I've ever heard of. From what I've seen the 1015 versions are averaging 5000 hours between majors and have heard the 1150's are averaging slightly higher hours.
  12. bayoubud, Jan 19, 2018
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    bayoubud

    bayoubud Senior Member

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    Thanks for the feedback, great to get info from hands on experienced Captains. This one has a tower and rib on the bow and does 25.4 kt @ 1850 rpm... 73% load...35 gph per side...in a picture of displays and gps...right where we would normally cruise at. All sounds good.
  13. Capt Ralph, Jan 19, 2018
    #13
    Capt Ralph

    Capt Ralph Senior Member

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    Now this is interesting; a Beefed up block and crank before squeezing out more hp. Sorry bayoubud, I believed it was the same block. Maybe have to re-subscribe back on that other diesel web site.
  14. bayoubud, Jan 19, 2018
    #14
    bayoubud

    bayoubud Senior Member

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    Early on it was the same block( 3406), but later Cat came used a new block to increase hp. Read somewhere they were thinking of increasing C18 to 1300 hp tp fill a void. Now, that would be a sweet package!
  15. Capt Ralph, Jan 19, 2018
    #15
    Capt Ralph

    Capt Ralph Senior Member

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    Once again; I am the happy student.
  16. Capt Ralph, Jan 19, 2018
    #16
    Capt Ralph

    Capt Ralph Senior Member

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    Of interest, Torque curve in your data? Any changes?
  17. Capt J, Jan 19, 2018
    #17
    Capt J

    Capt J Senior Member

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    Yes 1300 HP out of a C18 footprint and weight would be a very good thing. I ran the 1000HP C12.9's and in a 62' MY they REALLY lacked the torque of the C18's and the RPM's swung all over the place in a following sea. They do very well in the Hatteras 45' EXs though (light boat/fast). I've been running the new 1950HP C32's quite a bit lately in a big motoryacht and they perform and run very well. Cat also needs to step up it's game in the HP department and come out with a 16 cylinder diesel a bit above 2000 HP.
  18. bayoubud, Jan 19, 2018
    #18
    bayoubud

    bayoubud Senior Member

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    I can't compare the earlier 1015hp version to the later 1150hp because of new block. It is a different engine. The 1150 hp specs I have are on a 2012 54GT. We will see how the 1015's perform in the GT...appears cruise will be ok at 1850/1950 if they are turning the minimum 2300 rpm with fully loaded...which is the way she is kept.
  19. captholli, Jan 19, 2018
    #19
    captholli

    captholli Senior Member

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    Cats been on their game for quite some time now, fifteen yrs ago I had a engine room with 3516 -C @ 2,131 bhp.
    Cat 3516 -C (HD) rated 3,000 - 3,300bhp
    Cat 3516 -E 2,501 - 3,386bhp.

    I believe that some of the old 16v-399 motors 40 yrs back were a tick over 2,000 bhp. They would scare the hell out of you once the pre lube pump would drop out and the motor fired. Sounded like someone had thrown a bag of loose bolts into the cylinder's.
  20. Capt J, Jan 19, 2018
    #20
    Capt J

    Capt J Senior Member

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    Yes, but the 3512's/3516's were low speed motors. The trend now with the big SF and planning motoryachts in the 100'-150' range are higher rpm (2300 +/-), E rated, high output/low weight. The sections the 16v2000's are currently filling. I know one manufacturer that built some with the MTU's and will steer clear of them as much as possible due to too many issues with alarms and sensors and just issues.
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