Offshoreonly.com - Does prop slip increase or decrease with speed? Top speed less than expected.

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- - Does prop slip increase or decrease with speed? Top speed less than expected. (https://www.offshoreonly.com/forums/general-q/319588-does-prop-slip-increase-decrease-speed-top-speed-less-than-expected.html)

Quote:

Originally Posted by onesickpantera (Post 4211515)

Wouldn't the "blade tip speed" be similar for a 1.36 drive with an engine turning 5200 rpm as a 1.50 drive with an engine turning 5700 rpm? Plenty of engines out there turning that rpm with 1.50 ratios.

Not necessarily because other factors come into play. First you would not be running the same prop between those two combinations.

I think the general rule of thumb is that you would step up 2 inches of prop pitch going from a 1.36 to a 1.5, and I pretty much verified that with my testing a few years ago.

I'm thinking more and more that I have a fuel delivery or less likely an ignition issue keeping me from realizing the full potential of this engine. Now that I think about it, I do recall hearing a subtle, dull pop on occasion - sounded like it was coming from the exhaust, but it was so hard to pick up I figured I was being neurotic again and hearing things. :eek: Going to borrow my kid's GoPro and aim it at the pressure gauge. I can have someone monitor it remotely with my smart phone. That should be a little easier than raising the hatch and sticking my noggin under there.

Hey SB, what filters did you end up running. Did you pull inserts out......

Is there a anti siphon fitting on the fuel pick up? If so remove it and put a shut off valve in ..

Quote:

Originally Posted by 01scarab29 (Post 4212587)

Hey SB, what filters did you end up running. Did you pull inserts out......

Edited: I rambled a little too much. LOL.

The exhaust inserts are bolt in screw type. They bolt in - really easy to take out.

We have one of the stiffest Db's laws in the country. I leave them in until it's the season the cops are off the lake and we can go have fun speed wize.

negative on the filter. The boat just got an Alpha SS to hang on the back, so I will probably get too changing Flame Arrestors as the SS will probably get me back into the clawing for every mph mode again.

Until that time (Ie in public and the forums), it's just a 38mph turd with a 350 rocket motor, Harley carb, RV cam, with a Corvette tune in it....boat.

Quote:

Originally Posted by Budman II (Post 4212141)

Budman, I'm thinking of coming down and kicking you a couple times square in the nuts. :evilb::kiss:

The info you gave us below is why:

Quote:

Originally Posted by Budman II (Post 4211242)

In regards to the drive ratio / prop issue, I feel like I pretty much covered that one years ago with my 454. I swapped to a 1.5 drive with a 23 M+, and saw no difference in speed. I really don't think that's the problem here.

For comparison, my buddy is running the identical hull with an HP500 clone with Lightning headers, 800 Holley, Dart intake, etc. He is running a 1.5 Bravo 1 with a 25 Mirage Plus, and is seeing around 71 MPH. That is the range that I was expecting this combo to run in.

Quote:

Originally Posted by SB (Post 4212639)

Budman, I'm thinking of coming down and kicking you a couple times square in the nuts. :evilb::kiss:

The info you gave us below is why:

Um, why hath that offended thee? :party-smiley-004:

I was trying to show I was saying that friendly...with the emoticans.

The answers to all your performance issues are in your buddies boat.

You can't get any better than that.

The answers are right there. You just got to find them.

I figured I shouldn't take you literally - beside, I'm pretty good at kicking myself in the nuts. :p

The thing is, Tim (my buddy with the same Baja) is running the exact same Carter black fuel pump, carb, etc., as I am. Or at least he says he is - maybe he is lying to me and trying to sabotage me so I don't pass him up. :evilb: