What Procharger Should I Use?
03-10-2018, 09:50 AM
#42
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It looks like whipple has priced the 8.3 too high the quad rotors cost similar and probably perform better with 3.3s and up.
There is a big cost jump from the 4.5 to the 8.3.
Eddie do you ever use the FOAC? Or is it overkill?
There is a big cost jump from the 4.5 to the 8.3.
Eddie do you ever use the FOAC? Or is it overkill?
03-10-2018, 10:13 AM
#43
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That's the FOAC on the engine above. In most cases it is overkill. It has (2) 1 1/4" npt inlets and outlets. We used a 4 stage water pump and fed the intercooler with 2 of the stages with #24 lines.
03-10-2018, 03:19 PM
#44
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the FOAC? I thought it was MOAC?
Yes I know most people are saying whipple charger and the other thing that is good is it mounts on top so I dont have to worry about side mounting things
and the whipple charger is probabaly better for resale also. What is better a 8.3 double rotor or 4 rotor dual pulley in this case ?602 ci
I like the dual pulley more but more $$
Also can you use a multiport injection with this setup or do you have to use throttle body mounted injectors? I prefer multiport
Yes I know most people are saying whipple charger and the other thing that is good is it mounts on top so I dont have to worry about side mounting things
and the whipple charger is probabaly better for resale also. What is better a 8.3 double rotor or 4 rotor dual pulley in this case ?602 ci
I like the dual pulley more but more $$
Also can you use a multiport injection with this setup or do you have to use throttle body mounted injectors? I prefer multiport
03-10-2018, 05:29 PM
#45
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They make both a MOAC and a FOAC. I answered which blower you should use above.
Stick with the injectors in the throttle body in the rear of the blower. At idle, they tend to pitch more air to one side then the other. You can't control it. Since the fuel in already mixed in, it is distributed with the air. With port injection, you end up with one side richer then the other. Even with a sequential injection, it's tough to control it. They work great with the injectors in the throttle body. Also, that fuel goes a long way to cooling the air charge and sealing the blower.
Eddie
Stick with the injectors in the throttle body in the rear of the blower. At idle, they tend to pitch more air to one side then the other. You can't control it. Since the fuel in already mixed in, it is distributed with the air. With port injection, you end up with one side richer then the other. Even with a sequential injection, it's tough to control it. They work great with the injectors in the throttle body. Also, that fuel goes a long way to cooling the air charge and sealing the blower.
Eddie
03-10-2018, 06:13 PM
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Ok so then the MOAC or the FOAC, why do you say the FOAC is a overkill?
I think I need the overkill , ocean water temperatures of 83 or higher
Also why is the quad rotor supercharger not recomended, bigger pump should be better
I think I need the overkill , ocean water temperatures of 83 or higher
Also why is the quad rotor supercharger not recomended, bigger pump should be better
Last edited by turbos230; 03-10-2018 at 06:25 PM.
03-10-2018, 06:36 PM
#48
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Everyone is hoping you buy soon.......
......
......
03-10-2018, 06:52 PM
#49
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I'm just gonna pipe in here one time.
There is NOTHING NEW or WEIRD about your horsepower/longevity goals.
You have access to INCREDIBLY talented MARINE engine builders on this thread. Laz Mesa and Eddie Young have "been there, done that". You have a lot of people giving you opinions, but advice THEY give should count at least 288 times as much as what your buddy next door is telling you.
Information is available everywhere, but information on a manufacturer's website is ALWAYS going to have some tweaking going on - probably not outright lies, but locations of IAT sensors, hose sizes on intercooler plumbing, belt tensions, you name it, they will play with it.
You also have some "rules of thumb" confused with reality.
Here's one:
If you provide 14 psi of boost into an engine, you will double its horsepower.
This is a rule of thumb, and it's wrong. It would be MORE correct to say this: if you take a NA motor and determine its TORQUE PEAK (and RPM) with a manifold vacuum of less than 1.5" Hg (to make sure it isn't starving for intake flow), and an IAT of a given temp (let's say 125 degrees for this example). So you have a torque reading (let's say it is 400 ft lb) at an RPM (let's say 3600), and an IAT of 125 and manifold vacuum of 1.25".
Now, take that same motor - feed it boost from an EXTERNAL SOURCE (not engine-driven, but by some external NASA blower device), along with the proper air/fuel ratio, cool the intake (also by an external source) to result in the same IAT of 125, and up the pressure until you see a manifold pressure of 14.7psi. If the above parameters are exactly as described and the engine is running at the same 3600 rpm with no additional parasitic drag, then THEORY says the following:
If the intake runners and intake ports and intake valve sizes do not present an additional restriction to twice as much flow and...
If the exhaust valves and exhaust runner and exhaust manifold and exhaust system do not present an additional restriction to twice as much exhaust flow...
THEN the engine SHOULD produce DOUBLE the torque that it did in the initial test.
As you can clearly see, all of the "ifs" and all of the "requirements" DO NOT EXIST IN THE REAL WORLD.
First, your exhaust valves, ports, manifolds, and pipes WILL present an additional restriction to the double exhaust flow, thus reducing the theoretical doubling of the torque.
Second, your intake plenum, runners, ports, and valves WILL present an additional restriction to the double exhaust flow, thus reducing the theoretical doubling of the torque.
Third, the compressor/supercharger is NOT driven externally - it is driven by your engine, sucking parasitic power from the equation.
Fourth, the intercooler itself requires additional water flow which comes from a pump or a thru hull fitting. Even a thru hull fitting with no pump presents a restriction to the boat's forward motion, so even if it is not sucking parasitic drag from the motor, it is increasing boat friction. AND the restriction of the air flow thru the intercooler reauires that you spin the blower harder to end up with the same maniufold pressure.
Blah blah blah.... doubling manifold pressure will NEVER actually deliver the doubling that theory says can occur.
Turbos are by far the most efficient form of supercharging, but even THEY present a parasitic restriction in the form of exhaust backpressure. They also generate incredible amounts of heat that must be tackled.
Young has recommended 2 blower options and has given you reasons for them (one for your current goal, one for future expansion). He has also given you an intercooler recommendation and has repeatedly told you that the other choice is overkill, even if you want to go up a touch later.
Mesa has given you the appropriate Procharger recommendation if you want to go that way - although the ONLY reason I can see wanting to switch to a Procharger is if you want to toss out your hatch scoops and go with a smooth low profile hatch... Aside from that, you will be fighting an uphill battle and having custom mount plates fabbed, and you still won't be able to run your nice headers OR climb in there to service your motors.
Roots blowers are also not the Devil Spawn you have been led to believe. You really just need larger blowers in order to keep from spinning them too fast and generating excess heat. Rotor speed is the culprit for heat.
Finally, you seem dead set on port injection.
Blowers LIKE a little wetness going thru the rotors/screws. It provides a better "SEAL" on the rotor interface and also provides a little lubricating effect if you have teflon tipped rotors. Keeps em from eating up the teflon. You can use port injection AND squirt some in front of the blower, too.
But from an observer's point of view, you are rejecting EXCELLENT ADVICE and repeating the same things you started off with.
MC
There is NOTHING NEW or WEIRD about your horsepower/longevity goals.
You have access to INCREDIBLY talented MARINE engine builders on this thread. Laz Mesa and Eddie Young have "been there, done that". You have a lot of people giving you opinions, but advice THEY give should count at least 288 times as much as what your buddy next door is telling you.
Information is available everywhere, but information on a manufacturer's website is ALWAYS going to have some tweaking going on - probably not outright lies, but locations of IAT sensors, hose sizes on intercooler plumbing, belt tensions, you name it, they will play with it.
You also have some "rules of thumb" confused with reality.
Here's one:
If you provide 14 psi of boost into an engine, you will double its horsepower.
This is a rule of thumb, and it's wrong. It would be MORE correct to say this: if you take a NA motor and determine its TORQUE PEAK (and RPM) with a manifold vacuum of less than 1.5" Hg (to make sure it isn't starving for intake flow), and an IAT of a given temp (let's say 125 degrees for this example). So you have a torque reading (let's say it is 400 ft lb) at an RPM (let's say 3600), and an IAT of 125 and manifold vacuum of 1.25".
Now, take that same motor - feed it boost from an EXTERNAL SOURCE (not engine-driven, but by some external NASA blower device), along with the proper air/fuel ratio, cool the intake (also by an external source) to result in the same IAT of 125, and up the pressure until you see a manifold pressure of 14.7psi. If the above parameters are exactly as described and the engine is running at the same 3600 rpm with no additional parasitic drag, then THEORY says the following:
If the intake runners and intake ports and intake valve sizes do not present an additional restriction to twice as much flow and...
If the exhaust valves and exhaust runner and exhaust manifold and exhaust system do not present an additional restriction to twice as much exhaust flow...
THEN the engine SHOULD produce DOUBLE the torque that it did in the initial test.
As you can clearly see, all of the "ifs" and all of the "requirements" DO NOT EXIST IN THE REAL WORLD.
First, your exhaust valves, ports, manifolds, and pipes WILL present an additional restriction to the double exhaust flow, thus reducing the theoretical doubling of the torque.
Second, your intake plenum, runners, ports, and valves WILL present an additional restriction to the double exhaust flow, thus reducing the theoretical doubling of the torque.
Third, the compressor/supercharger is NOT driven externally - it is driven by your engine, sucking parasitic power from the equation.
Fourth, the intercooler itself requires additional water flow which comes from a pump or a thru hull fitting. Even a thru hull fitting with no pump presents a restriction to the boat's forward motion, so even if it is not sucking parasitic drag from the motor, it is increasing boat friction. AND the restriction of the air flow thru the intercooler reauires that you spin the blower harder to end up with the same maniufold pressure.
Blah blah blah.... doubling manifold pressure will NEVER actually deliver the doubling that theory says can occur.
Turbos are by far the most efficient form of supercharging, but even THEY present a parasitic restriction in the form of exhaust backpressure. They also generate incredible amounts of heat that must be tackled.
Young has recommended 2 blower options and has given you reasons for them (one for your current goal, one for future expansion). He has also given you an intercooler recommendation and has repeatedly told you that the other choice is overkill, even if you want to go up a touch later.
Mesa has given you the appropriate Procharger recommendation if you want to go that way - although the ONLY reason I can see wanting to switch to a Procharger is if you want to toss out your hatch scoops and go with a smooth low profile hatch... Aside from that, you will be fighting an uphill battle and having custom mount plates fabbed, and you still won't be able to run your nice headers OR climb in there to service your motors.
Roots blowers are also not the Devil Spawn you have been led to believe. You really just need larger blowers in order to keep from spinning them too fast and generating excess heat. Rotor speed is the culprit for heat.
Finally, you seem dead set on port injection.
Blowers LIKE a little wetness going thru the rotors/screws. It provides a better "SEAL" on the rotor interface and also provides a little lubricating effect if you have teflon tipped rotors. Keeps em from eating up the teflon. You can use port injection AND squirt some in front of the blower, too.
But from an observer's point of view, you are rejecting EXCELLENT ADVICE and repeating the same things you started off with.
MC
03-11-2018, 10:01 AM
#50
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I think we should go back to the original reason for the change
Have you measured your IAT`s? My 900`s without intercoolers are at 150* at WOT , never underestimate fuel vaporization on a carb set up.
Go boating dude , take the $$ you were about to waste and buy your wife something nice
But I have to do it,No you don`t
2 x 800 hp carbureted is nothing like 2 x 1200 fuel injected.You`re right the first one is way more reliable Roots to procharger change- power more efficient, less iat heat, less fuel use and more benefits to go faster and be more reliablenope, nope and nope
2 x 800 hp carbureted is nothing like 2 x 1200 fuel injected.You`re right the first one is way more reliable Roots to procharger change- power more efficient, less iat heat, less fuel use and more benefits to go faster and be more reliablenope, nope and nope
Go boating dude , take the $$ you were about to waste and buy your wife something nice
