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  1. #1

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    does it matter what motor i start with for a turbo?

    what are the main differences between a 155 and a 185/215/255 motor? i'm thinking of building a turbo seadoo motor for another project and am looking for wrecked/drowned/etc skis to use as donors. if i go the turbo route, does it matter what motor i start with? it's going to need custom tuning regardless, the flywheel won't matter, what else is there that could throw a wrench in getting a 155 instead of a SC'd motor?


  2. #2
    83.0 @ 8400 jhill19's Avatar
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    Quote Originally Posted by got wake? View Post
    what are the main differences between a 155 and a 185/215/255 motor? i'm thinking of building a turbo seadoo motor for another project and am looking for wrecked/drowned/etc skis to use as donors. if i go the turbo route, does it matter what motor i start with? it's going to need custom tuning regardless, the flywheel won't matter, what else is there that could throw a wrench in getting a 155 instead of a SC'd motor?
    internals are different

  3. #3

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    pistons, rods, valves, valve springs, ???

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    83.0 @ 8400 jhill19's Avatar
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    yepp crank etc..

  5. #5
    b_dolla44's Avatar
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    Crank is same.
    rods, pistons are the big ones...

  6. #6

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    well since i'm looking at salvaged skis, i'd probably have to replace some of the internals anyways. i'm contemplating putting a big turbo on it, so a piston upgrade might be needed anyways. there will be nearly no load on the motor until it reaches near peak power, so low end power is not a concern. and since it's not going in a ski, i'll have more room to work with for a turbo.

  7. #7
    b_dolla44's Avatar
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    You putting it into a boat?

  8. #8

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    an airboat with a 3:1 gear reduction and CVT. that should net around a 10:1 gear reduction until shift out starts. so if the motor spools to 9k rpm, the prop will only be spinning 900 rpm at the start of shift out. i would effectively be transferring peak HP just a little higher than some other motors idle! and using a CVT, i can control how fast the prop spools up to it's highest rpm of about 2700-2800, once shift out starts. it may work great or suck horribly. i've never seen it done, so i figured go big or go home. if it doesn't work with the CVT, i'll just use the 3:1 gear reduction for it without the CVT. but i'm really hoping the CVT works because it'll allow me to idle the motor without any prop spin and it should work great for with a turbo due to nearly no load on the motor until high rpm's are achieved.

  9. #9

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    i just kinda went the same route changing a 2004 gtx 185 to a 2005 rxp 215 internally i used the block pistons counter balance fly wheel and a couple other things out for the 215 and found the 185 uses a strange cam shaft so swap it to a 29 they seem to be good for turbo builds also the cam shaft gear on my 185 was heavier less holes and bigger trigger dowel so i changed that also the oil pumps seem to change from an 04 to 05 block same mounting just 04 uses a gasket and the 05 uses a rubber push in seal the 05 215 oil pump is a taller set up and watch out for the new oem seadoo chains they have had a couple issues

  10. #10

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    the 185 is still a stock FI motor, so i would imagine the rods and pistons are the same as the 215. thanks for the cam and oil pump info. i'd like to start with a 215 or 255 if i can find one for a decent price so i can test the setup before investing in a turbo, but still having a decent amount of power. but if a 155 comes along at the right price, i'd just like to know what i have to put in it to make it turbo ready.

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