28 w/280s
 

Guys,

Looking for some setup advice...

Current setup = 28 with twin 280s. Mids are 15" and powerheads are stock. Preferred props are currently 14.5 x 32 four blades, spinning out, with motors toed in (prop shafts closer than nosecone). Speeds are unimpressive at 105-106mph. Tried spinning in but lost speed and only ran 103 (with the 14.5 x 32 props and motors mounted straight). Have tried a set of three blades that are faster but the boat blows-out and the rear end starts to get real loose...!

Based on what I have read on here a lot of people prefer 15 x 34 four blades (but with 300 motors). Most also spin their props in. My setup question is this: with a pair of 280s are these props something to try? And would toeing the motor out whilst spinning in be something to reconsider? Also, why do most of you run 15" vs 14.5" dia. props?

Feel free to share any 28 + 280 setups you run or know have run in the past... I'll take any info I can get!

What's you prop shaft height?
You can usually run the props higher with a bigger diameter and not blow out.

BTW... prop shafts closer than the nose cone is toed out.
Think of it like your feet, if your toes are closer together than your heels you are toed in.

also, watch your trim angle as most outboard cats run best with neutral or very little positive trim
What rpm are your turning when running the 14.5 x 32s @ 105-106?

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Running at 8,000 rpm and prop shafts about an inch above the bottom of the hull. Tried 30p props but the motors wouldn't turn them.

What gear ratio? 8000rpm turning 32's does not add up unless the ratio is high like 2 to 1

I thought they were 1.87s. What doesn't add up? The props have been re-worked...so maybe the #s I was told are off?

Seems like your engines should be higher, if you can keep water pressure. My guess would be 1 3/4 - 2 inches above the bottom.

I assume these are the race ecu's? They have 8200 rev limit. the sport ecu's are 7500 I think?

supercat, correct.