Procharger performance
02-24-2018 | 10:55 PM
#51
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From: St. Pete Beach, FL
But the science says that wouldn’t really buy you much more cooling. The energy required to raise the temperature is much lower than what it takes to evaporate the fuel once it’s out of the carburetor.
the only good solutions for non intercooled setups would involve alcohol for fuel, extra injection or a water injection setup.
Screw blower’s advantage is the non rotor contact not heating the blower as much. The higher tech automotive roots superchargers are like this as well. But they only recently were made large enough for big blocks. Multiple smaller Eaton superchargers would work better than single GM based x-71 blowers.
the only good solutions for non intercooled setups would involve alcohol for fuel, extra injection or a water injection setup.
Screw blower’s advantage is the non rotor contact not heating the blower as much. The higher tech automotive roots superchargers are like this as well. But they only recently were made large enough for big blocks. Multiple smaller Eaton superchargers would work better than single GM based x-71 blowers.
02-24-2018 | 11:31 PM
#52
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I think it would also be cool to see someone put a 100LL+mtbe octane booster or E85 plus a smaller pulley tune in their boat. Swap the jets and timing or swap a set of carbs plus big props and see what their blower setup would run or as like a shootout setup.
02-25-2018 | 12:27 AM
#53
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Yup pretty common sense post. I'd like to have larger blowers so I wouldn't have to spin as much and reduce heat. But that's not the works currently. Not real cost effective to go through the trouble and expense if going to switch over to whipples a year or so down the road. (May or may not). Seems like MT and joe did some testing on the ambient temps btwn 871/1071 non innercooled and innercooled. I'm limited to hp and torque given my drives and trans so I'm not looking for max on either rather just good foundation for future gains and boat all together.
Guess I'm still going to aim for the static compression as stated and continue my cooling efforts for the time being.
Guess I'm still going to aim for the static compression as stated and continue my cooling efforts for the time being.
02-25-2018 | 07:21 AM
#54
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Yup pretty common sense post. I'd like to have larger blowers so I wouldn't have to spin as much and reduce heat. But that's not the works currently. Not real cost effective to go through the trouble and expense if going to switch over to whipples a year or so down the road. (May or may not). Seems like MT and joe did some testing on the ambient temps btwn 871/1071 non innercooled and innercooled. I'm limited to hp and torque given my drives and trans so I'm not looking for max on either rather just good foundation for future gains and boat all together.
Guess I'm still going to aim for the static compression as stated and continue my cooling efforts for the time being.
Guess I'm still going to aim for the static compression as stated and continue my cooling efforts for the time being.
Whipples have proven to be really good on boats. I still can’t get over how fast Billy boats went with 1150hp 4.0L units. He tested 8-71s and 10-71s as well and couldn’t get them to make much over 1000hp reliably on 588s.
TKO is making 1200hp with 14-71 588s. I think that’s the ticket for roots. 8-71s really hit a wall. That boat goes 118 in a 26* 40’ straight V, so they are definitely working.
i saw either 4.0L or 4.5L whipples were a little cheaper like a year or so ago. I think he was discontinuing one. Anyways, that size seems to outperform it’s displacement, I think due to the length vs. dia of the rotor pack. Plus they are only rear entry, which works better.
02-25-2018 | 07:42 AM
#55
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From: St. Pete Beach, FL
https://imgur.com/gallery/l3Rcs
https://imgur.com/gallery/l3Rcs
if if I was building to turn it up later, go big on the cubes and heads, low on compression.
https://imgur.com/gallery/l3Rcs
if if I was building to turn it up later, go big on the cubes and heads, low on compression.
02-25-2018 | 08:47 AM
#56
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From: Taunton Ma
The load curve of a planing hull boat matches the torque curve of a naturally aspirated engine quite closely. Because positive displacement blowers have a relatively constant boost level, they just amplify this torque curve. An added benefit is they can extend the max rpm as well.
The centrifugal supercharger increases boost with engine speed one to one. 4lbs at 2000, 12lbs at 6000. Like mentioned above, when the boat is propped to use all of the top end power, it won’t have enough torque at planing speeds. Basically the torque curve doesn’t match the load curve of the boat as well anymore.
Ironically, I kind of think a straight bottom boat would be a good fit for a centrifugal supercharger. Because these boats never really free up and fly at high speeds, they need big power on the top end in order to keep going faster.
I think for tuning centrifugal superchargers you should probably keep the compression ratio up, spin the blower fast, and then deal with excess boost on the top end by pulling timing.
these are just my science backed theories, please experiment on your fancy motors
The centrifugal supercharger increases boost with engine speed one to one. 4lbs at 2000, 12lbs at 6000. Like mentioned above, when the boat is propped to use all of the top end power, it won’t have enough torque at planing speeds. Basically the torque curve doesn’t match the load curve of the boat as well anymore.
Ironically, I kind of think a straight bottom boat would be a good fit for a centrifugal supercharger. Because these boats never really free up and fly at high speeds, they need big power on the top end in order to keep going faster.
I think for tuning centrifugal superchargers you should probably keep the compression ratio up, spin the blower fast, and then deal with excess boost on the top end by pulling timing.
these are just my science backed theories, please experiment on your fancy motors
02-25-2018 | 10:50 AM
#59
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From: St. Pete Beach, FL
