Bolt on Mods/Upgrades for SB/BB -- Dyno results from CHP Magazine
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Bolt on Mods/Upgrades for SB/BB -- Dyno results from CHP Magazine
For those curious about simple bolt ons for your engine, there is a good article in CHP about various bolt on upgrades for BB & SB chevys, here are some dyno results they posted.....
Electric Water Recirc Pump: +23hp, 335hp to 358hp on a 383ci.
Underdrive pulleys & serp belt: +25hp, 335 to 360hp on a 383ci
Exhaust Headers: +8hp, 473hp to 481hp on a stock LS7
Roller Rocker upgrade: +22hp, 344 to 366 hp on a 350ci
K&N air filter: -1hp, 583hp to 582hp on a 406ci
Nitrous kit: +211hp, 602 to 813hp on a 588ci
Blower: +116hp, 390 to 506 hp on a 355ci.
So the smallest, simplest things like electric water pump, pulleys, and roller rockers added decent gains, 20+hp each, while exhaust did very little. I am sure exhaust would add more in a marine setup. The K&N did nothing of course. Blowers and nitrous for big time gains. Others that did little; carb swap +10hp, intake change +11, mass airflow sensor +12, new chip +2. They did heads too, factory iron to Holley aluminum, with +68hp (307 to 375hp on a 355ci) but that would vary so much between apps. Nitrous +211hp!! Wow, (but for how long until the meltdown) Great article.
Electric Water Recirc Pump: +23hp, 335hp to 358hp on a 383ci.
Underdrive pulleys & serp belt: +25hp, 335 to 360hp on a 383ci
Exhaust Headers: +8hp, 473hp to 481hp on a stock LS7
Roller Rocker upgrade: +22hp, 344 to 366 hp on a 350ci
K&N air filter: -1hp, 583hp to 582hp on a 406ci
Nitrous kit: +211hp, 602 to 813hp on a 588ci
Blower: +116hp, 390 to 506 hp on a 355ci.
So the smallest, simplest things like electric water pump, pulleys, and roller rockers added decent gains, 20+hp each, while exhaust did very little. I am sure exhaust would add more in a marine setup. The K&N did nothing of course. Blowers and nitrous for big time gains. Others that did little; carb swap +10hp, intake change +11, mass airflow sensor +12, new chip +2. They did heads too, factory iron to Holley aluminum, with +68hp (307 to 375hp on a 355ci) but that would vary so much between apps. Nitrous +211hp!! Wow, (but for how long until the meltdown) Great article.
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Several years ago while we were dyno testing one of my 540's we were doing dyno pulls with an open carb (no spark arrestor/air filter, etc) then added a K&N air filter and picked up 3+hp------that's not much, but I actually was expecting that we would LOSE at least 5hp!!! I really thought nothing could/would flow better than an open carb and was surprised to find out the opposite.
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Anyone ever tried an electric water recirc pump?? Lots on bolt ons talked about here often but not electric water recirculators. Small pulleys??Never heard of those here either.
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Lots of auto-related stuff not talked about in the marine world.
That exhaust data is from a LS7; probably one of the best "OEM production" exhaust manifolds as stock.
The water pump issue gets fixed with a crossover. What would be more intersting is to consider an electric power steering pump. Get it off the engine and run it at a constant 1500-2000rpm.
"underdrive" pulleys are typically a smaller crank pulley, and/or larger alt/h2o pump pullies. Probably not a good thing for idle-speed zones.
Seeing as how most of these results are on small blocks, I'd expect less improvement on a big block because of engine torque.
That exhaust data is from a LS7; probably one of the best "OEM production" exhaust manifolds as stock.
The water pump issue gets fixed with a crossover. What would be more intersting is to consider an electric power steering pump. Get it off the engine and run it at a constant 1500-2000rpm.
"underdrive" pulleys are typically a smaller crank pulley, and/or larger alt/h2o pump pullies. Probably not a good thing for idle-speed zones.
Seeing as how most of these results are on small blocks, I'd expect less improvement on a big block because of engine torque.
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Have seen this many times...yes, the filter adds resistance, but a well designed air filter base will reduce the entry loss of the bare carb (or centrifugal compressor inlet) so no net loss and sometimes a gain depending on how bad the entry loss was to begin with.
Have seen this many times...yes, the filter adds resistance, but a well designed air filter base will reduce the entry loss of the bare carb (or centrifugal compressor inlet) so no net loss and sometimes a gain depending on how bad the entry loss was to begin with.
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Lots of auto-related stuff not talked about in the marine world.
That exhaust data is from a LS7; probably one of the best "OEM production" exhaust manifolds as stock.
The water pump issue gets fixed with a crossover. What would be more intersting is to consider an electric power steering pump. Get it off the engine and run it at a constant 1500-2000rpm.
"underdrive" pulleys are typically a smaller crank pulley, and/or larger alt/h2o pump pullies. Probably not a good thing for idle-speed zones.
Seeing as how most of these results are on small blocks, I'd expect less improvement on a big block because of engine torque.
That exhaust data is from a LS7; probably one of the best "OEM production" exhaust manifolds as stock.
The water pump issue gets fixed with a crossover. What would be more intersting is to consider an electric power steering pump. Get it off the engine and run it at a constant 1500-2000rpm.
"underdrive" pulleys are typically a smaller crank pulley, and/or larger alt/h2o pump pullies. Probably not a good thing for idle-speed zones.
Seeing as how most of these results are on small blocks, I'd expect less improvement on a big block because of engine torque.
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The numbers don't lie, but keep in mind that the roller rockers really make their living (gains) at high RPM's, 6-7K and up and on real big cams. The gains won't be as big in a 5-6K motor. If I had to guess, those figures were from a higher RPM than we will see. I still like' em though.
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The numbers don't lie, but keep in mind that the roller rockers really make their living (gains) at high RPM's, 6-7K and up and on real big cams. The gains won't be as big in a 5-6K motor. If I had to guess, those figures were from a higher RPM than we will see. I still like' em though.
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My understanding is that while the friction reduction itself gains some power, the "real" benefit of a good full roller is the accuracy/response of the valve action due to both the precision and reduction in friction.