575's w/ intercoolers by whipple
12-02-2006, 11:09 AM
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Re: 575's w/ intercoolers by whipple
Sounds to me like issues with the water flow to the drives being disturbed for some reason. The planing ability of the boat should not have changed at all with the intercooler install. I would look very carefully at the water pickup. I always use a transom mount pickup for the intercoolers. I've done quite a few I/C additions on 575s and they have always worked well. 2-4 mph gains are the norm.
12-02-2006, 11:38 PM
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Re: 575's w/ intercoolers by whipple
Originally Posted by doubletake
Hoping to get some feed back! I have a 03 38 t/s with 575's. I recently put intercoolers on (whipple) and was told that in addition to helping with longevity of motors and helping to prevent detonation, i would see a minimum of 50-75 horsepower increase.
The pulley system was modified and the boost will go to 7lbs and rev limiters are set at 5600rpm per dustin at whipple who modified the computers.
I was running a 4 blade 33 lab finished prop and the boat would do a solid 89mph @ 5100rpms. After the install ($10,000 later) i could no longer get the boat on plane with ease (sometimes have to start and stop a few times). Props wash out when coming out of hole. But when boat is up and running im not seeing anything over the same 89mph but now at 5300rpms. So then i was advised to go spend an additional $3000 and buy a set of 28 pitch 5 blade maximus props to fix my planning problem. Well it fixed the problem and now im running 86 mph@ port5250rpms,star5450rpms with all the same conditions (water, air, fuel, weight). My frustration is that i spent good money and haven't seen any differences in the boats performance. I've had to change props to get boat on plane and have lost 3mph after all the work done and am running the boat at higher rpms to get the speed. Any advice would be greatly appreciated!
The pulley system was modified and the boost will go to 7lbs and rev limiters are set at 5600rpm per dustin at whipple who modified the computers.
I was running a 4 blade 33 lab finished prop and the boat would do a solid 89mph @ 5100rpms. After the install ($10,000 later) i could no longer get the boat on plane with ease (sometimes have to start and stop a few times). Props wash out when coming out of hole. But when boat is up and running im not seeing anything over the same 89mph but now at 5300rpms. So then i was advised to go spend an additional $3000 and buy a set of 28 pitch 5 blade maximus props to fix my planning problem. Well it fixed the problem and now im running 86 mph@ port5250rpms,star5450rpms with all the same conditions (water, air, fuel, weight). My frustration is that i spent good money and haven't seen any differences in the boats performance. I've had to change props to get boat on plane and have lost 3mph after all the work done and am running the boat at higher rpms to get the speed. Any advice would be greatly appreciated!
TO START WITH I AM COMING UP WITH AROUND 19% PROP SLIP BEFORE THE INTERCOOLERS WHICH TELLS ME YOUR BOAT HAD MORE SPEED IN IT BEFORE THE INTERCOOLERS WERE EVEN ADDED. BY JUST THE RIGHT SETUP. I AM PRETTY SURE IT IS A V HULL ACCORDING TO YOUR SPEED NUMBERS. WHERE YOUR PROPS ORIGINALLY 32 BRAVO 4 BLADES THAT SOMEONE RE-WORKED THEM TO SUPPOSEDLY 33'S? I KNOW THAT MOST 32 BRAVO 4 BLADES PETER OUT AT AROUND 90 MPH ALSO. DOES THE BOAT NEED MORE BOW LIFT OR STERN LIFT? YOU ARE ALSO AT THE SPEED WHERE A NOSE CONE IS GOING TO MAKE A DIFFERENCE ALSO AS FAR AS GEAR CASE BLOW OUT. SOUNDS LIKE SOME 30 PITCH 5 BLADES MAY BE BETTER.
NOW ON TOO THE MOTORS YOU HAVE INCREASED THE POWER FOR SURE. YOU HAVE ALSO INCREASED YOUR PROP SLIPPAGE PROBLEM BY ADDING MORE POWER. THEREFORE YOUR INTERCOOLER PICKUP ONLY A HALF INCH DOWN COULD EFFECT THE PROPS AND DRIVES IF IT IS MOUNTED IN FRONT OF THEM. A PICKUP LIKE THAT CAN EVEN EFFECT THE NOSE OF THE BOAT. DOES IT FEEL AS IF THE NOSE IS DOWN MORE THEN BEFORE.
575SCI'S DO NOT MAKE ANY POWER PAST 5100 RPM'S PERIOD. EVEN WITH 7 LBS OF BOOST IN WHICH IS TO MUCH FOR THE WIEAND BLOWER THERE IS NO EFFICIANCY WITH THAT BLOWER AT THOSE LEVELS.
TRYING TO SPIN THIS MOTOR PAST THAT RPM YOU ARE USUALLY JUST SWAPPING RPM FOR SPEED AND NOT GOING ANY WHERE. YOU COULD HAVE A TUNE UP ISSUE AS FAR AS A/F RATIO OR TIMING IN WHICH IS IMPORTANT. HOWEVER NOT USUALLY AN ISSUE WITH DUSTIN. HAVE FOUND THE BEST RESULTS ON MODIFIYING THE 575SCI IS WITH A NEW HYDRAULIC ROLLER CAMSHAFT AND A 3300 WHIPPLE AND SOME GOOOOD ALLUMINUM HEADS AND 9LBS OF BOOST AND YOU WILL SEE THAT MOTOR REALLY WAKE UP,(ABOUT 15 MPH ON A 38 FOUNTAIN.) OR JUST A CAM CHANGE AND YOU WILL SEE SOME GOOD RESULTS ALSO.
THANKS FOR YOUR TIME, I DID NOT MEAN TO WRITE A BOOK HOWEVER, WHEN YOU OR SOMEONE DOES THESE KIND OF JOBS EVERYTHING NEEDS TO BE TAKEN INTO CONSIDERATION. JUST MAKING MORE POWER IS NOT ALWAYS THE ANSWER YOU NEED TO BE ABLE TO GET THE POWER TO THE GROUND OR WATER.
THANKS, CAM-SHAFT
Last edited by Cam-shaft; 12-02-2006 at 11:41 PM.
12-04-2006, 03:46 PM
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Re: 575's w/ intercoolers by whipple
Originally Posted by bobl
Sounds to me like issues with the water flow to the drives being disturbed for some reason. The planing ability of the boat should not have changed at all with the intercooler install. I would look very carefully at the water pickup. I always use a transom mount pickup for the intercoolers. I've done quite a few I/C additions on 575s and they have always worked well. 2-4 mph gains are the norm.
12-04-2006, 04:05 PM
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Re: 575's w/ intercoolers by whipple
Originally Posted by tomcat
Adding 50 HP per side would be good for about 3.5 mph and that's exactly what your RPM increase says you got. I don't know why your speed readings don't agree with this.
With a pulley change and the intercooler you are making more torque down low. If your drives were high from the factory and on the verge of blowing out before, the extra torque down low is blowing out the props.
Sure the five blades fixed this and I'll bet the boat accelerates better but it's rare for five blades to be faster than four. Maximus blades are big, P5X is the next smaller blade area, P5 the smallest. More blade in the water, more than you alsolutely need to absorb all shaft HP, is usually slower but you have to balance this with driveability at lower speeds.
Borrow some P5X props and try them. I would also try your original props with drive spacers (to lower the props into the water a bit more) to solve the planing problem. I'm sure someone here knows a good rigger in your area with a selection of spacers and props to help you sort this out.
I'm also wondering if a bigger cam wouldn't help by taking away some of the low end torque and adding it up top? Next time you're in the engines you could consider this.
Finally if you have access to a wide band Air/Fuel ratio (ask your rigger) check it at WOT. Maybe you're running really rich. Wouldn't be the first time that a reprogrammed ECU needed adjustment.
With a pulley change and the intercooler you are making more torque down low. If your drives were high from the factory and on the verge of blowing out before, the extra torque down low is blowing out the props.
Sure the five blades fixed this and I'll bet the boat accelerates better but it's rare for five blades to be faster than four. Maximus blades are big, P5X is the next smaller blade area, P5 the smallest. More blade in the water, more than you alsolutely need to absorb all shaft HP, is usually slower but you have to balance this with driveability at lower speeds.
Borrow some P5X props and try them. I would also try your original props with drive spacers (to lower the props into the water a bit more) to solve the planing problem. I'm sure someone here knows a good rigger in your area with a selection of spacers and props to help you sort this out.
I'm also wondering if a bigger cam wouldn't help by taking away some of the low end torque and adding it up top? Next time you're in the engines you could consider this.
Finally if you have access to a wide band Air/Fuel ratio (ask your rigger) check it at WOT. Maybe you're running really rich. Wouldn't be the first time that a reprogrammed ECU needed adjustment.
12-04-2006, 04:33 PM
#25
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Re: 575's w/ intercoolers by whipple
The P5s are made by Hydromotive and they used to have a prop testing program. I don't know if you can modify the Maximus props, maybe reduce the diameter, talk to the prop guys. Try the Hydromotive first. If the boat likes them you can always sell the Maximus props, especially if they aren't modified.
12-04-2006, 07:14 PM
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Re: 575's w/ intercoolers by whipple
Originally Posted by doubletake
Tomcat, i appreciate your input and would like to talk to you more on the phone if possible. Also, my drives are xr w/sportmaster lowers and i do have a 1inch spacer on them! Is the prop your talking about made by hydromotive? also, would it be smarter for me to send out my 5 blade maximus to have them reworked? they are brand new and i hate to waste them if not needed. Thanks again!
Thanks, Cam-shaft.
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12-04-2006, 09:21 PM
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Re: 575's w/ intercoolers by whipple
Originally Posted by THEJOKER
Zuckerman:
What size boat do you have? Weight? Top speed? Thanks!
What size boat do you have? Weight? Top speed? Thanks!
It has a lightly modified Merc575 (est. 700HP) and runs 85GPS more or less depending on load and weather.
Why do you ask?
Steve
