Whipple, Yes or No?
07-25-2005 | 08:05 PM
#11
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Re: Whipple, Yes or No?
Boost vs. power with Rtech on this engine is approx:
3.87 pulley - 4 psi - 650 HP
3.60 pulley - 6 psi - 725 HP
3.47 pulley - 8 psi - 800 HP
We would be happy to help you school your brother-in-law on the advantages of centrifugal supercharging. What Mike said about controlling your throttle hand is true.
3.87 pulley - 4 psi - 650 HP
3.60 pulley - 6 psi - 725 HP
3.47 pulley - 8 psi - 800 HP
We would be happy to help you school your brother-in-law on the advantages of centrifugal supercharging. What Mike said about controlling your throttle hand is true.
07-25-2005 | 08:17 PM
#12
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From: Traverse City, Mi
Re: Whipple, Yes or No?
Tomcat..
Thanks for the numbers. That is huge power @ 4psi boost.. How many hours are the engines holding up at say 4psi of boost? Under normal conditions, not to much WOT and mostly 3500-4000 cruise.
Thanks for the numbers. That is huge power @ 4psi boost.. How many hours are the engines holding up at say 4psi of boost? Under normal conditions, not to much WOT and mostly 3500-4000 cruise.
07-25-2005 | 08:36 PM
#14
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From: Cape Coral, FL or Colonial Beach, VA
Re: Whipple, Yes or No?
Originally Posted by KAAMA
Josh, been around the block on this subject a time or two. Got to admit that they have the marine supercharger stuff down real good now a days. This is just me, but I would keep them naturally aspirated and buy some good aluminum heads---AFR is a good casting 315cc, CNC ported. WithOUT the blowers the torque will be much more forgiving on your drives----especially with your size/weight of boat, and the insurance folks might be a touch easier on you too. Also, less moving parts. Ask "JimV"---he had a B&M 420 supercharger in his boat and really liked it, but kept blowing drives. He went back to a N/A engine and though the boat is slower, he told me he is MUCH happier because he doesn't have the drive issues he once had. He said the torque from the blowers are very hard on the drives. You can pick up some decent power with your engines just from adding a real GOOD set of heads without changing the cubic inches. Whatever you decide to do I wish you the best. 
07-25-2005 | 10:00 PM
#15
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Re: Whipple, Yes or No?
They will last a long time at 4 psi. We did a 35 Lightning last summer with 500MPI engines built up with CMI headers and the HP500EFI cam. Those engines dynoed at just over 500 HP and the boat went 85 mph. With the 3.87 pulley and a prop change we could just reach 5000 RPM and 4.5 psi for 95 mph. With the 3.60 pulley we got 6 psi @ 5000 RPM and the boat went past that to run just over 100 mph. The big intercooler helps to keep out of detonation but the fuel has to be right or even a short blast will hurt the engine.
Customers running this package are typically running XR or aftermarket upgrades like IMCO or Bmax. We recently converted an 8-71 blown 555 to the Rtech carb system. He picked up 7 mph and called in this weekend saying the acceleration is scary and unlike anything he's had in the boat before. His was a built engine with ported Brodix heads, lower compression and a big cam. We put a 3.33 pulley on that one. He is going to break his drive soon.
This drawing shows the clearance required for the supercooler box.
Customers running this package are typically running XR or aftermarket upgrades like IMCO or Bmax. We recently converted an 8-71 blown 555 to the Rtech carb system. He picked up 7 mph and called in this weekend saying the acceleration is scary and unlike anything he's had in the boat before. His was a built engine with ported Brodix heads, lower compression and a big cam. We put a 3.33 pulley on that one. He is going to break his drive soon.
This drawing shows the clearance required for the supercooler box.
07-26-2005 | 06:16 AM
#19
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From: Western Michigan
Re: Whipple, Yes or No?
bobd, What kind of boat do you have and what engines did you end up modifying? A good set of ported heads can do an engine good! That was a nice gain you made on the speed! I have the Crane ignition boxes too, and have had them for 5 years. One got drenched with water the first year and they are still working with no problems---I really like them.
