38 donzi ZR mph
#14
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Joined: Oct 2005
Posts: 5,825
Likes: 612
From: Clarkston, Michigan
Next, get your RPMs up so that you bump the rev limiter running light. Near 5,400 RPM is where these engines shine. Also, get any extra weight out of the cabin. You are right; You should be running mid to upper 80s from what I've seen.
lol, three posts when up while I was typing this!
#16
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Joined: Jul 2010
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Here's a link to several magazine articles on the 38ZR. All say the boat topped 90mph. The first article says it was running 32" 5 blade Herings at 91mph. http://www.donzimarine.com/Boats/ZR_38_Extras.html
#17
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Joined: Dec 2005
Posts: 448
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From: Raystown Lake Pa
Not sure about the compairson but my 36 Sunsation is running in the low 90's with 525's and 32" 5 blades. I don't have a ton of seat time yet so I'm still figuring the optimum trim settings but it's turning ~5200 - 5300 RPM.
#19
I had an 05 38zr with 525s, XR sport masters, 32 pitch 6 blade herrings.....it had rear bolsters which added weight over a standard bench back seat.....it was always good for high 80's and routinely ran in low 90's......I do not think it required much trim for this hull to find it's sweet spot.....Also I would be careful over trimming as this will create a condition to break prop shafts
#20
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Joined: Oct 2010
Posts: 92
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From: Long Island N.Y
First check your fuel/water sep filters if theres no water or ethanol separation then You need to have both engines compression tested, spark tested, leak down tested, and checked out on the diagnostic laptop by a reputable high performance shop and then take it from there



