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-   -   imco or sportmaster lower unit vs xr lower unit (https://www.offshoreonly.com/forums/general-racing-discussion/258825-imco-sportmaster-lower-unit-vs-xr-lower-unit.html)

mannyd292 07-25-2011 12:47 PM

imco or sportmaster lower unit vs xr lower unit
 
Hey guys

I am looking to replace my XR lower units for an imco or sportmaster lower units my question is will changing to either one of them make me lose top end speed i have twin 525's on a cigarette i have heard of some people complain that they are loosing top end speed my fear is to invest the money and lose top end speed. any suggestions or opinions would be greatly appreciated

Roger 07-25-2011 05:29 PM

In our testing several years ago the Imco's were faster than the Mercury units. The skeg is longer on the Mercs, thus more drag. Both should be faster than XR's with all other things the same. There are other factors though. Is your boat a newer one with the big steps. If so you may want the Mercs for more stability from spin outs.

TYPHOON 07-25-2011 06:32 PM

Whats more important to you? Turning or 1-2 MPH tops. Imco also makes a 3" shorty that has a longer skeg that you can put a 1" spacer in. If you look at the 3 differant cases Sportsmaster,Imco -2 and Imco -3 they are all differant in shape. In the end I dont think you will see much differance in a pleasure application. They are all good pcs. If you try the Imco -3 it gives you more range in trying differant X dim. Beware that if you are running the XR upper you will need to trim the upper housing tail stock or the prop will hit due to lack of clearance. You will need aprox 1" clearance due to the prop flexing and making it bigger under high RPM. I learned the hard way.:lolhit:
MD


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