A little roots blower info.
08-30-2014, 08:58 AM
#1
A little roots blower info.
Thought I would share this with my roots blower friends. I've always preached about how you shouldnt under carb a roots blower setup.
Last weekend, I was running my boat. I noticed my starboard engine, was only hitting 5lbs. (always at 6lbs). I starting thinking the blower was tired or hurt. I got back to the dock, and started looking around. Turned out while I changed jets prior to the weekend, I had pinched the secondary accelerator pump linkage on one carb, and it was keeping the secondarys on ONE carb from opening (twin 850's per engine). So, my one engine, was really working of 6 barrels instead of all 8, or lets say instead of 1700CFM, I had 1275cfm of airflow. That was enough to make my engine down on power from 3500-5500RPM. These are 468 engines, not 598's either. 420 blowers 7% underdriven.
I'd like to think, IF my engines had single 1050 carbs atop, I would have to spin the blower much harder (pulley down), to get to 6lbs of boost. Which in turn, would heat up the air charge. Something to think about if you're running that single carb atop of your roots blown big block. I think many look at twin carbs, like twin fuel dumpers. But, twin carbs, doesnt always equal more fuel consumption, but it does mean double the airflow capability.
Last weekend, I was running my boat. I noticed my starboard engine, was only hitting 5lbs. (always at 6lbs). I starting thinking the blower was tired or hurt. I got back to the dock, and started looking around. Turned out while I changed jets prior to the weekend, I had pinched the secondary accelerator pump linkage on one carb, and it was keeping the secondarys on ONE carb from opening (twin 850's per engine). So, my one engine, was really working of 6 barrels instead of all 8, or lets say instead of 1700CFM, I had 1275cfm of airflow. That was enough to make my engine down on power from 3500-5500RPM. These are 468 engines, not 598's either. 420 blowers 7% underdriven.
I'd like to think, IF my engines had single 1050 carbs atop, I would have to spin the blower much harder (pulley down), to get to 6lbs of boost. Which in turn, would heat up the air charge. Something to think about if you're running that single carb atop of your roots blown big block. I think many look at twin carbs, like twin fuel dumpers. But, twin carbs, doesnt always equal more fuel consumption, but it does mean double the airflow capability.
08-31-2014, 07:47 AM
#3
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08-31-2014, 07:59 AM
#4
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iTrader: (1)
Most single engine single carb N/A boats won't plane if the secondaries don't open. I've shown many people this that didn't agree when talking about it.
VIP Member
09-03-2014, 11:21 PM
#7
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09-03-2014, 11:53 PM
#8
Thanks Bill,Naw just got it running,5 miles, POS Magno at Nutech fuzked me on a NEW snout, seal had lip missing,puking oil out front,miss matched bearings,one seized,and shaft looks used,harwood hood came in busted,to much boost,never ending bs,Im calling it ZoomZoomBoom
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The Only Time You Have To Much Ammo Is When Your Swimming Or On Fire.
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The Only Time You Have To Much Ammo Is When Your Swimming Or On Fire.
09-04-2014, 08:28 AM
#9
Registered
Thanks Bill,Naw just got it running,5 miles, POS Magno at Nutech fuzked me on a NEW snout, seal had lip missing,puking oil out front,miss matched bearings,one seized,and shaft looks used,harwood hood came in busted,to much boost,never ending bs,Im calling it ZoomZoomBoom
