89 Top Gun straight bottom
 

Ok so after two seasons with the boat I finally have the injection pretty much dial in with a lot of help from the guys at Kinsler and KE, so here is it, 572 tall deck Chev's dart 320 heads, Kinsler/Lucas large throttle body mechanical injections aka, Mercury Racing late 80's early 90's, 720 lift, 2.3 intake 1.9 exhaust jesel solid roller, 9 to 1, dry sump, running 1.5 to 1 SSM #4's inch below bottom, B blades worked merc 16 5/8 29 4 blades, boat is good and dry, never left in the water its entire life, so far turned 5600, easy, what do you guys figure she ran with 1/4 tank and two people and what do ya think she is making for HP.

Would love to see some pictures!

No idea! But interesting recipe!

Speed?

88mph - making 800hp.

Must have missed that somehow lol

that boat was a time capsul. very very cool

My Guess is 750HP and I say 84GPS. I believe that the 89 guns did not have a transom notch.

89's are notched...........not that its going to make a huge difference speed wise.

My calculations and radar show 91 at 5600 RPM which by my and my friends calculation is 11-12% slip and it should require about 800-825 HP to move a big heavy flat bottom to 90 plus mph, and the 89 is a notched transom which in theory allows for higher X dimensions, now the props are actually 28 4 blades that Brett at B blades tells me measure 29 inches of pitch hence the post, not sure if his work added any pitch to the props, so there you have it pretty happy with the results, Engines should spin easily to 6K so gonna keep working on the injection to see where that leads.

Some pretty good guess's

Moxy

https://www.facebook.com/photo.php?fbid=10155612594318228&set=rpd.830033227&type=3&theater

I'd say, you have it pretty well dialed in,

No sh!t, that's a great result for that boat. You should dial mine in, something's not right with my rig, based on your results.

That is dialed in. I had 900's. Really high x Dimension. 3As and I could run 97.4. That was just before I sold it. It was a 1993 Gun. Never played with many props to get the last few ticks. I also could have cheated and just changed blower pulleys.....lol

had 0 tabs, drives at 3.5, me and 110 girl, 1/4 tank, may have run a tad over 5600, these 4 blades from b blades are the secret if you ask me, boat is way better behaved with four blades, mine are spinning out, don't know if there is any speed left spinning in, I am curious what others see for slip, example is my buddys revolution with triple 650's runs 92 with bravo 32's at 5400 witch equate to 16 or 17 % slip, now he has significantly less diameter but I'm curious about prop slip, I am also hesitant to go at higher on x as I have spacers on #4's the boat planes so well know I don't want to go back to planing problems I had with three blades

Moxy

Mine spinning in were good for 3mph. Made no difference in planing. Good luck with your project.

I would try a little more diameter in your props we have found that the big V bottoms like more diameter than what you are running. we start with 18 in diameter and go from there and end up around 17.5 to 17.25 and we get our slip numbers down under 10% Regards Dan

I agree I had 17.75" 4 blades

Yup, I have a set of 18" dia 4 blades x 32pitch, drives even with bottom and cannot get on plane. HOWEVER, when it does run, showing pretty good slip numbers, 10-12%?

I need to space drives down 1-2" for usability.

have you got the nose to settle down yet.....

what are you seeing for speed, I plane at 3000 with 20-30 seconds of cavitation when over half tank and almost no cavitation with quarter tank or less, drives at 0 tabs at 2 or 3, running with 2 in spacer which nets about 1 in below bottom which ny the sounds of it is good considering my wheel's are 16 5/8 dia

Moxy

Justin does burnout for a mile until it hooks up, then it's on lol

Yes, if you bury the tabs, which limit your top end considerably! So no, not really, but plan to install spacers over the winter months, see if that helps the attitude of the boat.

Correct, burnout city. Planes like sh!t, even with 18" dia props, then takes off like a rocket.

I would say your setup is dialed in almost perfect on this hull. Don't change a thing.

Not sure yet on my top end. I think it went 92-93,mph @ 5100-5200 rpm w/30" pitch props? I've never had it WOT, in fact, the blades on the carbs aren't even opening all the way. It's like I have throttle stops, need to adjust linkage. Limiters are set @ 6,200RPM, but never had it over 5,100RPM if I can recall. Trying to run 32s but it will not get up on plane without holding it to the wood for a half mile, which I prefer not to do. So, just going to run the 30p props for now until I can install spacers and do more dialing in next season, on the setup.

I am guesstimating that I have 1.4:1 drives (was told 1.5:1), which puts me around a 12% slip at above numbers? HP is at 1,080 per side.

Or, if they are 1.35:1 drives, would be a 14% slip, which seems more realistic....

What's it do at 3500? That's where most of us run the boats. It's as fast, and for as long, as your wallet can stand. Then it's back to 3500:poopoo:

i'd swear there was a 38 thread where the last maybe 12-18 inches of the outer strakes where angled down side to side. (not hooked, no speed loss, plane/porpoise correction)
the way the guys were talking about it, calling the guy by name, seemed like he was a glass guy at cigarette and he figured it out.
i just can't find it yet, had to be 5-6 years ago.

well as I said about 1 inch below bottom, 16 5/8 4 blades, cupped for sure, not sure if that has impact but boat would not plane with 3 blade mercs, some tab but not much, my motors I'm told are built to turn 6-7000, but ill never even try it, I feel ill likely get to 6K with tuning on the injection, I would love to get to the mid 90's, also it makes huge difference how much fuel I carry as to how quickly she planes out and if she cavitates a lot or not

Moxy

Yes, with high X dim, I noticed fuel level plays a major role in plane-ability and top end. Must really affect the COG, a lot.

Damn, wish I would have just built huge CI fuel injected NA engines as opposed to blowers. Seems like not much payoff for all the extra HP & equipment. These boats are slugs.....

It actually does really well cruising with the 32s, and hence why I want to run them as opposed to the 30s.

I can't remember exactly what it does at 3500, I would say 65-67mph from memory and comparing to my upper end number? Seems about right.

put those in a twin step and go have some fun.....she'd be a rocket

wow that's fast, I run little under 60 at 3500 maybe I should try some bigger props

Moxy

ya but everyone does that lol, I'm sure I could run in low trip digits with my stuff in stepped or padded hull, but it not a classic TG lol

Moxy

where do you boat ^^^^^^

St Lawrence River and Lake Ontario, 1000 Islands :ernaehrung004:

fryckstyle not sure how you get on plane but I`ve found my boat doesn`t like a lot of tab.. 2-3 more than that the boat loses speed, prop slip goes up.. planing is over.
Once I find where a particular prop will plane I don`t waste anytime under that RPM.
The props I lost had a lot of cup and I could get on plane at 3500 easily My current ones don`t have nearly as much cup (same diameter) and require 4300 . Under that and I`m just burning holes in water ..

Also depends on whether you are in fresh or salt water, i had a set on my tiger that would pop up quick in the lower bay, but the further north and the fresher the water it struggled a bit to get up on plane...

exactly,hit the nail on the head

I tried everything, not much change in tab position with the 32s. I get what you're saying, I just think it's too heavy for such a high drive setting. I really want 1" spacers, but have a pair of 2" spacers sitting in the box. Will probably install over the winter and try it out this Spring.

I've experimented with, and purchased:
30pitch props - stock as far as I can tell
32pitch props - stock as far as I can tell
32pitch props - sent to bblades to add "cup"

All merc 18" 4 blades (some measure 17.75", but sold to me as 18" props) The 30s seems most usable, with the 32s showing a faster cruise and more efficiency. The 30s feel to accelerate faster. Boat comes out of the water pretty easy too. (meaning getting airtime, still hesitates getting on plane)

Frick, your engines running good lately? Good to see you on here not having engine troubles....hopefully that holds true.

Dan, do you have any 29 pitch 18" dia 4 blade props? From playing around with the prop slip calculator, I think my drives are 1.4:1.

Anyone think 1.4:1 is causing slight planing issues?