80 mph + 24' Superboat (continued from Pantera Forum)
 

Continued:

Pat I don't know what the deal was with the 24P Bravo 1 prop. Maybe it was too small? It was quite a ride! This was before we installed the hydraulic steering, and the gimbal is worn pretty bad. That is being replaced now as well.

We ran up to around 70, and then as I pulled the throttle back, not quickly just evenly, the boat pulled HARD right. We did a complete U and no amount of steering input did anything to correct it. I paid more attention to the steering the rest of the day and noticed that it was very unpredictable and wanted to go right as we gained speed. I took it off after that day and didn't run it again. We put the 25P Mirage Plus back on after getting it back form Bblades, and it didn't do that anymore. The steering was still a little sketchy at speed because we hadn't added the full hydraulic yet, but it didn't do the crazy dangerous stuff it did with the B1. After installing the steering, she drives like a dream at speed!

I'm sure with the new engine, we will need to try some other props. I'm not looking forward to the chine walk over 80. That could get a little scary!

I'm betting that your handling issues were related to the steering and worn gimble. I'm not a big fan of the single piston steering, I think it wears the gimble bushings and pins prematurely. Even if a "add on" steering system is install, I'd go with twin piston so the drive is held from both sides.

Please tell us a little more about this engine you built. It's going to make 525-550 HP at what rpm? Tyler Crockett is great to work with.

As for props:
I love my BBlades modified B1. I was not crazy about it stock; it took a lot of trim to loosen the boat up and the sweet spot was vary small.
I did run a Mirage + a lot of the time when I had less power. My boat certainly does handle better with the B1 vs. the M+ but I have not experienced real bad chine walk like you and Dave M. have with your step bottom boats. I think your boats get up on top a little more with the semi pad and larger strakes.
Dave M. and T-island both run 28p B1 props on their boats so I'm thinking that you would want to try one again now that your steering has been upgraded and gimble repaired.
Another prop to try is the Merc Revolution 4. The Rev4 has more rake and less diameter than the B1. More rake should give better bow lift and less dia should work better with how deep the props run on our boats. I'm planning to try a Rev4 soon but unfortunately the largest is 25p.

Hey Guys,

I saw the other thread on the Pantera section.

Before I replaced my gimbal ring, my boat would pull hard to the right when I trimmed it up. GET THAT TAKEN CARE OF! VERY dangerous.

I'm pretty sure my boat would run 80+ any day of the week with a HP500 (470 HP). I think anything over 75 in a 24 is just for bragging rights. I can run 70 or so in some pretty choppy water but any faster I think you are taking a chance.

This is interesting about the gimbal. I might take a look at this. I had it checked last year when I pulled the drive last winter and it was fine but I am going to start getting the parts together for the full Hydraulic conversion from the add one and when I put that on I will take a look at the gimbal. 70+ in a 24 is MOVING! Takes me a solid 2ft chop to really get her running the way I like. I am more about the cruising at 55mph and not the 80 mph top end so I haven't really tuned for top end at all....yet:D

The gimbal ring is being replaced along with a stainless steering shaft and U-Bolt from JR Marine. It will be all new inside the transom assembly with the new power.

The engine is my 454 MAG MPI that is .030 over with 9.5 - 9.7:1 compression. I'm using Tyler Crockett's cam and tuning set up. The heads are RHS Aluminum with 2.25/1.88 valves. There is some port work on the heads. Springs and the like are from Crockett. It will have full roller rockers. We are looking at hitting the dyno next week some time. We are guessing in the 525 range right now at around 5300 rpm. Crockett says more, but the engine builder is a little skeptical. Brad Smith, the guy who does all the engines for the E-Dock crew, is doing this up for me. We are supposed to have it back in and running for the trip to LOTO for the OSS race.

If I can do over 80, it won't happen very often. My wife would divorce me if I did that to her! Whoever buys it now is going to get one HELL of a deal with the new engine and speeds.

JayHawk,

I am currently running around just under 500hp with an out of the box 26 bravo. Haven't done much prop testing other than switching from the 25-3blade that came with the boat. I would think you would want to start with a 26 and go from there. What rpm's are you looking to turn. With my 454 it is reving pretty high which is why I running the 26 instead of the 28.

I'm looking at around 5300 or so. All of this is theoretical of course until we get it on the dyno next week. Then we'll have some real numbers to talk about!

I am very interested in your progress. I would agree with Dave M too. If you can get 525 out of that motor and are still turning lower revs than start with a 28 and see where you are at and then maybe jump up to a 30 if you can spin it. Your boat should DEFINATELY break 80 if you are able to get a true 500hp out of your motor.

Yup, I agree for the most part.
Above 70 in the rough gets a little nutty. If I had a set of those thick sit down racing bolster, I'd probably push her a little harder though. I stand in the rough at this point, I'm short enough...:rolleyes:
On calm water, my boat handles great even at 75mph and if she had more, I'd use it...:D

Cup, you have the same straight V boat that I do.
You may want to consider sending that 26p B1 to Brett at BBlades and have him do the same mods he did to my B1.
From what I've experienced, it requires too much trim to get our boats to loosen up with a stock B1. The sweet spot is small to run fast without modifying the B1 for more bow lift.
You may want to test a Revolution 4 also...

Pat,
I totally agree....takes me a while just to dial her into a decent cruise. I know that in my boat, cruising along at like 55-60 and then bringing up the throttle and trim, you have really pay attention. Lots of times I just don't have the open water to get her dialed in just right before having to back off the throttle for waves/boats/etc. I know that the 3-blade will always be faster on my setup but then you really have to drive the boat. What tweaking to BBlades do to your prop Pat?

Well, my boat is only about 1mph slower with the modified 28p B1 vs. a stock 27p M+. We'll see soon how she runs with a labbed M+.
BBlades modified the tips and trailing edges of my B1. There is a little more cup is some areas. The idea was to create the effect of having more rake. I did not have a full lab job but the blades are thinner than stock. The mods were to give more bow lift without having to trim way high.
My boat handles so much better than with the prop stock and I gained 1-2mph. I have tried lots of props and none give the performance of the modified B1.
If I were in your shoes, I'd test a 25p Rev 4. It is a higher rake prop than a B1 and should give more bow lift out of the box. Then decide if you should buy one of those or have the B1 modified.
IMO, the 3 blade is only good for all out speed in calm water.

I played around on Desktop Dyno some last night. I have a 454 in my basement that needs a rebuild. All of the combinations I plug in had a 460 cube making 500+HP at 5500-5600rpm.
This 460 cube engine your putting together must be a torque monster. Crockett must have developed a real nice cam to have a 454/460 cube produce the same basic peak power as the Merc 525EFI.
You should be real excited to run that beast on the dyno and even more once it's in the boat...:D

Pat, i was told i should have tried a shorty on my boat to get more outta it. Possibly another 3-4?
But i was pretty happy w/ 75, and didnt run it that high that much... as you've already noted.
Speed cost $, and i had enough speed and no more $. :)

I hope it turns out well. Tyler said that this cam in a stock compression .030 454 turned 485hp on his dyno about 2 weeks before I ordered it. He was telling me that with my added compression I should see close to 500 with the factory heads & valve size with some bowl work and port matching.

My engine guy is a bit skeptical of that. He said he would put my setup with the Crockett cam in the 445 - 450 hp range with the stock heads & the port work. My engine guy also says that every time he bolts a set of these RHS heads with his port work on an engine, he's seeing roughly an 80 hp gain.

So if we go with my engine guy's conservative estimate, we should see around 510 - 530 hp? If you go with Tyler's numbers, this thing will be a fire breathing monster. I'm not sure how Tyler achieves the numbers he does, but I'm not discounting them yet.

As I said, it's all fish stories until the real numbers come out. I should know by Wednesday next week what it really does!:ernaehrung004:

My goal is to break 500hp. If we hit 510 or even 525, I'll be ecstatic! Any of those will make the little Super a runin machine.

T-Mone and I have talked about trying a shorter drive. He knows a fellow running a higher X on a 24' Pantera. With a 5 blade prop it would help get more speed for sure.
I'm not sure how far below the V the prop shaft was on your boat, mine is about 5" below.
Running 3 blade props, it could not be set higher on my boat; with 4 blade props, maybe?
Do you remember Condor24 here on OSO? Anyway, when he went from an Alpha to a Bravo he set the prop about 1-1/2" higher than it was on my 24' Pantera. Long story short, it was too high for the Condor.
I would love to try bolting up an extension box and a -2 shorty on my boat. I think there is something to be gain with both speed and rough water handling. But with two kids in daycare, my boating budget has been reduced to keeping what I've got going and playing with different props.

It sounds like your engine should have no problem making over 500HP. The aluminum heads and higher CR will help.
Any idea of the specs on that cam and flow of those heads? I could run the numbers on Desk top dyno for you.

When I get to do my 454 buildup I'll be going with about 9.2CR and GM iron rec port heads. I have the cam from a 500EFI but I'm not sure if that is what I'll use. My goal will be to build an engine that has more power than my 502mag. With the 500EFI cam my guess would be about 470HP @ 5500.

What's your e-mail Pat? I will e-mail the info to you. I'm not sure if Tyler wants me publishing his cam specs or not.

Run it and let me know what it says.

I won't let the cat out of the bag.
[email protected]

Ran the numbers.
Check your e-mail.
She's going to run over 80...:D

Got it Pat. Thanks for the help! Now I just need to find someone as nuts as me to buy it!:D

We are building a 588 Merlin block motor for the avanti. Going to run the stacks. Going for somehwere in the 650-700 HP range with out a high strung motor at all. Hopefully 80 is in our sights!:D

Shorty??????

I have two test report brochures from 1996, so it was the non-step hull.

Test one was with a 502 MPI with a blackhawk drive. 76 MPH, 27P props@4900.

Test two, 502 MPI, bravo drive, 79 MPH, 27P Mirage@4850 rpms.

I'm not sure if these two tests where with the exact same hull and motor. It looks like a bravo might be faster. But, who knows how much time was spent dialing in either setup.

I believe that the X dim on my straight V boat is set perfectly for 3 and 4 blade props. A -1" short drive would probably work with a 5 blade prop. Like I said in an earlier post, I'd love to try a box and shorty.
Dave,
What do you think about a -1 shorty on your boat? I do remember that the prop shaft is about 1" farther below on your boat with the semi pad.
By the way, my boat ran 76 with a stock 27p M+@4850 and 77+ with a Throttle Up labbed 27p M+@5000. We shall see how she runs with the 27p M+ BBlade is labbing for me.:cool-smiley-027:

Hey question for you all.
Anyone know of a 24' step bottom Super cracking 80?
Superbash and Dave M. have both run real close.
We heard of lots of older 24s with big power turning big numbers.

We might have an answer for you in 2 weeks :D:party-smiley-048:

If you are looking for a 26 B1 I have one for sale.

Hi guys,
I had been having an idle surging problem so I replaced the IAC and ECT of the fuel injection today.
Fueled her up and snuck out for a test ride. I ran solo down to Old Saybrook to meet up with a bud.
My gps read 77.2mph @ 4950rpm running south with a tail wind. Running north with 2 on board 74.8mph @ 4850rpm.
I think I've got an outside shot at 80 running solo, spinning a labbed 3 blade, and running on fumes.

Had a 96 that would hit over 80mph.
Man I sure miss that boat. The wife hatted it and if I had been able to keep from pulling that throttle back it might still be in the garage.
I will say that when you got over 70mph you had to "drive" the boat and give it all of your attention.

I will always be a fan of the 24 Superboat!

Cordell

all this crap for 80?????? Jayhawk isnt welcome back to A Dock with less than 90 :rolleyes:

So instead of a hose down at Ketchum Cove I will have to wait an extra 100 yards? :rolleyes: :Whatever:

Henry pushed the throttle harder than mom wanted to ride today. Speedo read 82 the GPS needs new batteries...:cool-smiley-011:

Great shot Pat !!!!! Teach em young !!!!!:D

Listen here Slim Lady! I just want to have enough power that I won't be too scared to run WOT regularly!:D How many times have you hammered it to top speed?:drink:

Pat, that's a great pic!

Dyno party this week in Joplin:ernaehrung004:

B-Rad bet me I couldnt get a 454 to turn 7500..... I love dynoing other peoples engines

Oh noooooo dyno time for the Masher! I'll be there to supervise and make sure none of the A-Dock nare-do-wells get a hand on the throttle! You can watch though, if you pay me $100.00. :D

I only pay for motors with 540+hp.

I know someone here on LI selling a 2" ext spacer for a Bravo anyone interested.

updates? 450hp?

No update yet. There was some trouble with the program running rich. We talked to Crockett and we may send the computer back to him for some tweaking. I'm waiting for a call backfrom Brad right now. He has it on the dyno, and is checking a few things to see if it something that can be corrected without sending the computer back.