'96 252 454 Magnum performance benchmark

Big Block Power · Post by **Big Block Power** » Thu May 30, 2019 12:55 pm

akorcovelos wrote: Thu May 30, 2019 8:48 am Whats the going rate on a Blackhawk drive? She might no notice that, looks kinda like a B3, lol.

Its black right

akorcovelos · Post by **akorcovelos** » Mon Jun 03, 2019 2:28 pm

Props are back at the shop getting the cupping removed, lakes are still no wake...That is all.

akorcovelos · Post by **akorcovelos** » Sat Jun 08, 2019 5:18 pm

Props are back on the boat, now the lakes just need to open up. Sounding like early next week, so hoping to get to the boat races on Thursday. Fingers crossed these get me another 300 RPM.

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Big Block Power · Post by **Big Block Power** » Sat Jun 08, 2019 5:26 pm

Nice. Did he Make the edges sharp and thin?

NautiGirl · Post by **NautiGirl** » Sat Jun 08, 2019 8:40 pm

Looks good!! Good luck!!

akorcovelos · Post by **akorcovelos** » Sat Jun 08, 2019 8:47 pm

Big Block Power wrote: Sat Jun 08, 2019 5:26 pm Nice. Did he Make the edges sharp and thin?

No, he wants me to try it with the cupping removed. He had them aggressively cupped on both props, he thinks I’ll get the RPM I need without labbing. I get it, I can get them labbed if this doesn’t work, but can’t un-lab them.

Thanks Nauti, 64 here I come!

akorcovelos · Post by **akorcovelos** » Fri Jun 14, 2019 1:10 am

made one top speed run on the way to the races, the boat planes faster now, I guess the extra prop slip is letting the engine rev faster. Still not getting the extra RPM, topped out at 60mph, same as before. I did have more fuel and gear on board, but not enough to make much of a difference. Not sure why she won’t spin faster.

cmattj · Post by **cmattj** » Fri Jun 14, 2019 7:31 am

You mentioned it feels free in bite so that’s a plus! . Ahhhh but there is going to be the battle of the deep outdrive and hate to say but... way too many blades.

I have the same sensation as the 282 is a rocket to 68mph.. then hits a wall.

One thing I noticed on Duo props is they don’t like a lot of trim in normal cruising or they porpoise. ( Nuetral to the hull line )
But the other thing I notice is that when flying at 60mph she will take a ton of trim. Then I go full throttle and trim even more. ( I technically trim 3 different settings for a wot run )
Run her light in weight, and trim it to where your almost nervous about it.
Or like me ponder pulling everything not bolted down and on fumes trying for 70mph

akorcovelos · Post by **akorcovelos** » Fri Jun 14, 2019 8:12 am

cmattj wrote: Fri Jun 14, 2019 7:31 am You mentioned it feels free in bite so that’s a plus! . Ahhhh but there is going to be the battle of the deep outdrive and hate to say but... way too many blades.

I have the same sensation as the 282 is a rocket to 68mph.. then hits a wall.

One thing I noticed on Duo props is they don’t like a lot of trim in normal cruising or they porpoise. ( Nuetral to the hull line )
But the other thing I notice is that when flying at 60mph she will take a ton of trim. Then I go full throttle and trim even more. ( I technically trim 3 different settings for a wot run )
Run her light in weight, and trim it to where your almost nervous about it.
Or like me ponder pulling everything not bolted down and on fumes trying for 70mph

Yeah, I didn’t have a long run to really dial it in, but it feels like at around 50% trim up is starts blowing out, and if I keep trimming up it start to lose speed, throws a cool rooster tail though.

I’ll run it down on fuel again, and try with less gear, but it definitely won’t hit 64, maybe 61-62 if I’m lucky. Seems like I need more bow lift. Trim on this boat doesn’t have as dramatic an effect as on my smaller boats. I never really feel like I’m getting it up on the pad like the other boats.

I also noticed my swim platform is water logged, and really heavy. Getting that done over winter, should shed at least 50-60lbs.

shrfdeputy · Post by **shrfdeputy** » Fri Jun 14, 2019 11:35 am

My 252 isn't as fast as yours by any means, but GPS confirms it is faster on a decent (1'-2') chop. I guess it makes sense because less of the boat is contacting the water (less drag). What were the water conditions when you made this last run?

You are definitely starting to approach the limits of what a dual prop setup is ever going to let you do I think, but those props sure look pretty if nothing else. My buddy has a 226 with the 8.1 GXI (420 hp) and he hits a wall right at 64-65, and I think it is because of the duoprop. There's just something about the mechanics of it that won't let it push any harder. Even though I know I could get a little more top end out of a single prop, I would never give up the extra control I have around the dock etc.

BTW, what do you mean about your swim platform being water logged? It's all fiberglass isn't it?

akorcovelos · Post by **akorcovelos** » Fri Jun 14, 2019 5:58 pm

shrfdeputy wrote: Fri Jun 14, 2019 11:35 am My 252 isn't as fast as yours by any means, but GPS confirms it is faster on a decent (1'-2') chop. I guess it makes sense because less of the boat is contacting the water (less drag). What were the water conditions when you made this last run?

You are definitely starting to approach the limits of what a dual prop setup is ever going to let you do I think, but those props sure look pretty if nothing else. My buddy has a 226 with the 8.1 GXI (420 hp) and he hits a wall right at 64-65, and I think it is because of the duoprop. There's just something about the mechanics of it that won't let it push any harder. Even though I know I could get a little more top end out of a single prop, I would never give up the extra control I have around the dock etc.

BTW, what do you mean about your swim platform being water logged? It's all fiberglass isn't it?

Water was smooth, no chop, dead calm. I may pick up 1mph running down wind in some chop.

I mean the swim pad/bilge hatch. It’s wood and I can tell the foam is waterlogged. The vinyl isn’t bad, which is why we haven’t done it yet, but I think it will be done off season.

I may call BBlades and see what he thinks, my prop guy said there isn’t much more he can do to free up the duo props. You may be right, without throwing another 100+HP at it I may be at the ceiling with the B3...

shrfdeputy · Post by **shrfdeputy** » Fri Jun 14, 2019 6:00 pm

Still very respectable.

akorcovelos · Post by **akorcovelos** » Fri Jun 14, 2019 6:03 pm

It’ll do for the summer. Time to start making the list for Santa.

Big Block Power · Post by **Big Block Power** » Sun Jul 07, 2019 9:00 am

So I cracked mine up yesterday. It got to 57 pretty quickly. And 4800 rpms no issues. 4 adults half tank of gas and I backed off as I was coming into the rougher part of the lake. She will hit 60 now no issues. I had the fuel cut raised to 5200rpm and I think these props will get me there. I run 40 mph now at 3500rpm about 400rom less then before. These props hold like glue and perform very well. Ecu so far so good. Idle is so lower than I would like but that's the way these things are. I get a little clunk in rev sometimes I don't like. No stalling and performance is now. All in all very happy.

cmattj · Post by **cmattj** » Sun Jul 07, 2019 9:08 am

Nice report pal... I loce the faster cruise speed !!

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