V20 with the 4 cylinder I/O
 

What kind of performance can I expect from a V20 with the 4 cylinder I/0 (cuddy cabin model)?

Will it need trim tabs to get on plane quickly? What pitch prop (average loaded) and what kind of cruise/WOT speed?

thanks

Help us out here.. give us a hint ...Which year boat, what model 4 cyl? Yes, it should get you on plane, no you won't need trim tabs.
It's impossible to know what the WOT revs are without knowing what model engine you have. :head:

I/O 4 cylinder perfomance
 

Oops.

1986, 4 cyl. Mercruiser, 170

I have an '83 V20 Cuddy with the same motor. Turning a 15x17 prop and get about 35 mph on GPS @ 4000 rpm WOT with a heavy load on (3 men, full tank of fuel, and 30 gal livewell). I'm going to drop another inch of pitch to get into the 4200-4600 WOT band. Will end up with a top end of 33-35 mph. I installed a Faria fuel flow meter and it looks like the sweet spot for cruising is about 24 mph @ 3000 rpm, getting 3.5 mpg. Trim tabs do help getting on plane faster, and are essential for any rough water / offshore running.

.

I/O 4 cylinder perfomance
 

Okay; that's what I suspected. A 4 cylinder I/O is not going to get 40mph+ in any case, I think.


thanks

I've gotta 77 V cuddy cabin with a 170 Mercruiser I/O but don't know what size stainless steel prop it is. The brand name on the prop is ELITE, but it dosent have any other markings on it inside or out. I've had it up to 42 mph with 5 folks, 2 full 20 gal tanks of fuel, trimmed up and WOT on slick water in the Albemarle sound. It seems to run faster on salty/brackish water, don' know why.

I think your speedo may be off... That's a pretty fast speed to be going with that load with that engine...even assuming that you're getting a full 170HP from it. Is that a GPS number or an indash speedo number?

As to your comment about faster in salt water...Hmmmm... That might be true. For the same reason that, when swimming, you can float in salt water easier than in fresh water. Salt water is denser than fresh, so the boat rides higher. It's a tiny increase, but it is there, so that may be the reason.. You're riding higher so there's less resistance of the water on your hull since there's less hull in the water. I admit that it's a S.W.A.G. (Simple Wild Assed Guess) ...but it sounds logical enough to actually make sense.

My 91 V with the 350 volvo duo prop all I can get according to the GPS is 42mph

I use to 9have the 165 6 cyl in my V and i would get mid to high 20's at curz and top speed mid 30's

Hey, I always thought a SWAG was a SCIENTIFIC wild *** guess. Makes you sound a little smarter that way.