Flatbottom Prop Questions
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Flatbottom Prop Questions

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    Junior Member Ragerunner's Avatar
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    Default Flatbottom Prop Questions

    The 82 Sanger Flatbottom I just bought came with a 11x15x1 two blade. I'm running a 427 bbc, 11/1 comp, and pushing nearly 600 hp. I'm not sure of the gears but there is a two speed tranny w/rev in it. The boat hits the rpm limiter (5500rpm chip) really quick with speed topping out about 63/4Mph. It also starts pulling to the left pretty hard at about 55 and up. Real hard if I just let off from top speed. I have a three blade prop also, size&pitch unknown, and it tops out at about 68mph also hitting rev limiter but not nearly as fast. It pulls a lot less to the left then the two blade and feels generally smoother. I'm interested in increasing top end as 64 seems too slow for the HP being generated. I'm going to up the rev limiter chip to 6k/6.2k/6.4k rpm, but I'm wondering if I need to look for a larger prop to create more top end? I'm fairly new to all of this so be gentle .
    Last edited by Ragerunner; 11-08-2015 at 06:06 PM.

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    Italian-Rage rich's Avatar
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    Quote Originally Posted by Ragerunner View Post
    The 82 Sanger Flatbottom I just bought came with a 11x15x1 two blade. I'm running a 427 bbc, 11/1 comp, and pushing nearly 600 hp. I'm not sure of the gears but there is a two speed tranny w/rev in it. The boat hits the rpm limiter (5500rpm chip) really quick with speed topping out about 63/4Mph. It also starts pulling to the left pretty hard at about 55 and up. Real hard if I just let off from top speed. I have a three blade prop also, size&pitch unknown, and it tops out at about 68mph also hitting rev limiter but not nearly as fast. It pulls a lot less to the left then the two blade and feels generally smoother. I'm interested in increasing top end as 62 seems too slow for the HP being generated. I'm going to up the rev limiter chip to 6k/6.2k/6.4k rpm, but I'm wondering if I need to look for a larger prop to create more top end? I'm fairly new to all of this so be gentle .
    Before you change the chip find out what your cam tops out at, is it a solid cam or hydraulic,also 3 blades are a smoother prop.
    on steering cables my need to be tighten up.hope this helps

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    Junior Member Ragerunner's Avatar
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    Thanks much for the response Rich. The CAM looks to be hydraulic roller according to receipts that came with the boat and a JEGS lookup (XR296H-R12 @ COMP Cams CL11-456-8, Comp Cams 'Magnum' Hydraulic Roller Camshafts | COMP Cams). Oh, and we spent some time tightening the steering cables after first trip out.
    Last edited by Ragerunner; 11-08-2015 at 06:07 PM.

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    Italian-Rage rich's Avatar
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    Quote Originally Posted by Ragerunner View Post
    Thanks much for the response Rich. The CAM looks to be hydraulic roller according to receipts that came with the boat and a JEGS lookup (XR296H-R12 @ COMP Cams CL11-456-8, Comp Cams 'Magnum' Hydraulic Roller Camshafts | COMP Cams). Oh, and we spent some time tightening the steering cables after first trip out.
    You can get the cam specs it should tell you max rpm's I would guess 6000 or 6500 you don't want to float the valves.

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    Senior Member Bubbletop409's Avatar
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    I would try raising the RPM limiter first of all. Cam specs say good to 6200, I would set the limiter at 6500 and give it another try. You are giving up a small amount of power driving a tranny, but you should be able to pull to 6500 or so safely if the engine is capable of generating that much power.
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    ptc
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    You also need to figure out your v-drive gearing (ratio) hopefully its about 15% or 18% but revving that quick it may be lower. and I assume youre running the tranny (2sp Powerglide?) in "D" gear, not ever in 1st.... also is it a 10 degree or 12 degree drive ? and what is the angle of your prop shaft on that boat?

    Talk to Andy - "BANDIT" on here and he can get you setup... he did mine perfect!
    1975 Sanger True Flat - 496 BBC
    http://v-drivecalifornia.blogspot.com/

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    Find out if you still have a torque converter if you do -it's gotta go

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    Junior Member Ragerunner's Avatar
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    Default Flatbottom Prop Questions

    Thanks all for the responses!

    Bubbletop409 - thanks for checking the CAM specs. I'll try a 6.4k chip and see if it the motor can pull it and report back - hopefully this weekend!

    ptc - just called the previous owner and he has no idea of he gear ratio in the v-drive. It's a Casale so I'm going to pull the serial and give them a call to see if they have record of what was sold in this V-Drive. If they can't tell me, any ideas on how I might determine the gear ration w/o cracking the case? It is indeed a 2sp powerglide and I only used 1st near the docks . Not sure on the 10 or 12 degree drive... Any cheater way to tell? No idea on angle of prop shaft either, ideas on how to check?

    Mdsheppie - not sure on the torque converter, but I'm guessing yes, since I can shift in motion from 1st to drive.

    I feel pretty worthless in the way of answers. Again fellas, really appreciate the feedback.

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    ptc
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    An easy way to check the ratio is to mark both shafts straight up with a sharpie line, then turn the top shaft ONE revolution and look at the bottom shaft and where the mark ended up.Then think of it as a clock and the mark is going to end up most likely between 1'oclock and 3'oclock.

    straight up would be (12:00) or a 1 to 1 ratio..... and if 3 o'clock is 25% then

    1 o'clock is about 8% - very low gears
    2 o'clock is about 16% - medium

    Theres a more exact way to do it, but just for quick info this works. Im sure somebody will post it up

    Heres the Casale lit on model numbers if you can find one on your unit. or just measure the degree angle between the two shafts.



    The way to check your prop shaft angle is to get a mag angle finder, (can find them at any hardware store) set your boat level, and then attach the angle finder to the prop shaft under the boat and read what it says.



    1975 Sanger True Flat - 496 BBC
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    Junior Member Ragerunner's Avatar
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    Great info, thanks again! I'll post back once I've found gear ratio and the angles.

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    Quote Originally Posted by ptc View Post
    An easy way to check the ratio is to mark both shafts straight up with a sharpie line, then turn the top shaft ONE revolution and look at the bottom shaft and where the mark ended up.Then think of it as a clock and the mark is going to end up most likely between 1'oclock and 3'oclock.

    straight up would be (12:00) or a 1 to 1 ratio..... and if 3 o'clock is 25% then

    1 o'clock is about 8% - very low gears
    2 o'clock is about 16% - medium

    Theres a more exact way to do it, but just for quick info this works. Im sure somebody will post it up

    Heres the Casale lit on model numbers if you can find one on your unit. or just measure the degree angle between the two shafts.



    The way to check your prop shaft angle is to get a mag angle finder, (can find them at any hardware store) set your boat level, and then attach the angle finder to the prop shaft under the boat and read what it says.




    Good info on both the gearing and prop shaft angle.

    They way I have always done it for gearing is to rotate the top shaft 10 times. it is easier for me to see exactly the bottom revolutions and get a pretty accurate idea as to what is in there. For split case Casale v-drives you will see 6%, 9%, 12%, 15%, 18% 22% 25% and up. With hitting the limiter I would not be surprised if it is 12% or less. A 6% is a ratio of 1.06 to 1. So 10 revolutions of the top would give you 10.6 revolutions of the bottom shaft.

    (Sorry if it seams as if I was talking down to you, but I just want to make sure it wounds clear).

    Also, not all props are created equal. if you know of any other v-drive guys around, try as many Steel or Stainless Steal props as you can. Stay way from Bronze props as they are not as strong and can break an ear off with decent power. Many times two props with the same diameter and pitch stamp will act completely different. Last but not least, stay safe! Always wear a life jacket, and if you are serious about this stuff look into a race jacket.

    Post up pictures of your ride in the v-drive section. We love seeing new boats and meeting new people.

    Paul

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    Junior Member Ragerunner's Avatar
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    So i was able to discover a few things since last post ...

    - The V-Drive is a Casale 61000 which lists as a 10 percent.
    - One rotation of top shaft brings bottom shaft to about 2 o'clock; so I'm thinking 16 percent.
    - Shaft angle under the boat is 6/7 degrees.
    - The 2 blade is a 11x16 vice the 11x15 that I originally posted.
    - I replaced the 5500 with a 6200 rpm module. Can't wait to see what it does .

    I'll report back once I have some data on the jump up to 6200 chip. 16 pitch seems like a lot. Could that be taking off top end our do I have that backwards?

    Here are a few pics of my work in progress .

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    No beach, just mud .

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    So you can see the Powerglide tranny.

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    Shifter and pedal set up.
    Last edited by Ragerunner; 11-15-2015 at 07:31 PM.

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    Senior Member bville's Avatar
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    I question your 2 blade prop.You said your 3 blade prop was 4mph faster.All things being equal I would think a 2 blade would be faster.You may want to have it checked to see if it is what it says it is.

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    How do you know you are pushing 600 hp ?11to1 comp 427ci single 4barrel.What about the heads?

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