supercharger

[bob58o]

Sneaks

HOTRODDING THE PREDATOR

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[bob58o]

What about with boost?

I’ll look for that laptop.
Meanwhile just take comfort in knowing that with Boost, these green numbers in the 60% - 80% range will grow to bigger numbers.
100%? Maybe
110% Plausible
120% Feasible
130% Atainable
150% The little engine who could.
200% 5.7L power from 2.0L displacement?

30lbs of boost is like pumping 6L of air through a 2L engine… I think … (2L@45 psi vs 6L@15 psi)

PV = nRT
Is you incorrectly assume temperature stays constant…
If Pressure is tripled (15 psi to 45 psi) in a constant volume (say 212cc) and assume temp stays constant … Then n (number of air particles) has to triple. As you can see as “T” temps go up the “n” has to go down to stay at a given pressure “P”

As physicists, we choose to ignore most things.

 

[John Roger]

I’ll look for that laptop.
Meanwhile just take comfort in knowing that with Boost, these green numbers in the 60% - 80% range will grow to bigger numbers.
100%? Maybe
110% Plausible
120% Feasible
130% Atainable
150% The little engine who could.
200% 5.7L power from 2.0L displacement?

30lbs of boost is like pumping 6L of air through a 2L engine… I think … (2L@45 psi vs 6L@15 psi)

PV = nRT
Is you incorrectly assume temperature stays constant…
If Pressure is tripled (15 psi to 45 psi) in a constant volume (say 212cc) and assume temp stays constant … Then n (number of air particles) has to triple. As you can see as “T” temps go up the “n” has to go down to stay at a given pressure “P”

As physicists, we choose to ignore most things.

View attachment 146292

question how much bosst can a predator 212 stock engine can take before it blows up

 

[Thepartsguy]

question how much bosst can a predator 212 stock engine can take before it blows up

the flywheel can’t take much of anything past stock 3,600rpms because the magnet on the flywheel is held on with a screw and glue... (China)

If you intend to run boost seriously your gonna need at least a flywheel.

 

[John Roger]

question would it be possible to make a 2 setter dingo I think they used to make them but idk

 

[Thepartsguy]

the rpm should not increase much just the hp rises

I’m trying to work this out in my head.. So let’s say 4 pounds of boost.

All before 3,800 rmps that the governor limits the engine to?

What pulleys would you run to spin/overdrive the pump up enough while the engine is only spinning 3,800rpm’s? And if you remove the governor to get more engine speed that makes spinning the pump up easier but the magnet is held on by glue!

I’m just pointing out (I can’t find The post) someone was saying something about a 2” pump pulley and a 32” crank pulley?

 

[John Roger]

I’m trying to work this out in my head.. So let’s say 4 pounds of boost.

All before 3,800 rmps that the governor limits the engine to?

What pulleys would you run to spin/overdrive the pump up enough while the engine is only spinning 3,800rpm’s? And if you remove the governor to get more engine speed that makes spinning the pump up easier but the magnet is held on by glue!

I’m just pointing out (I can’t find The post) someone was saying something about a 2” pump pulley and a 32” crank pulley?

remove the governor

 

[Thepartsguy]

remove the governor

The stock flywheel has a good chance of exploding if you remove the governor and add boost. So just get a good flywheel..The magnet on the flywheel is held on by glue and a screw.

 

[John Roger]

The stock flywheel has a good chance of exploding if you remove the governor and add boost. So just get a good flywheel..The magnet on the flywheel is held on by glue and a screw.

agreeable

 

[bob58o]

Positive displacement pumps make same amount of boost at 2500 RPM as they make at 6500 RPM. It’s a positive displacement pump (roots blower). It’s not a turbo; not a centrifugal supercharger. It pumps a set amount of air per revolution based on pump displacement and pulley ratio. The boost is based on engine displacement, pulley ratio, and pump displacement. RPM falls out of the equation.

 

[John Roger]

Positive displacement pumps make same amount of boost at 2500 RPM as they make at 6500 RPM. It’s a positive displacement pump (roots blower). It’s not a turbo; not a centrifugal supercharger. It pumps a set amount of air per revolution based on pump displacement and pulley ratio. The boost is based on engine displacement, pulley ratio, and pump displacement. RPM falls out of the equation.

but to much rpm and to big of a pulley is to much boost and it will blow up the engine rpm is part of the equation because there is perfect balance between rpm and pulley size to get the right amount of boost I plan on testing and experimenting this theory because to little and the engine will bog down and to much and you know what happens

 

[John Roger]

question you know the leaf blowers that are battery powered and look like centrifugal superchargers

<----- like this one

well I wonder if you put that on the intake and turn it on and a drops of more fuel into the engine will it either
A-blow up
B-BLOW up
C-BLOW UP
D-HP increase

 

[Denny]

E-horsepower will decrease unless you use a blow through carburetor which they don’t make for small engines.

 

[bob58o]

but to much rpm and to big of a pulley is to much boost and it will blow up the engine rpm is part of the equation because there is perfect balance between rpm and pulley size to get the right amount of boost.

No.
Maybe you misunderstood.
I said RPM falls out of the equation.
You added it back in.

212cc per 2 revolution of crankshaft.
106cc per revolution of crankshaft.

300 cc per 1 revolution blower.

300cc / 106cc = 2.83
2.83 * 14.7psi = 41.6psi
41.6 - 14.7 = 26.9 psi boost (if 1:1 pulley ratio)

Volumetric efficiency doesn’t matter as much when forcing induction.

And as you can see, the amount of air pumped by the roots blower per revolution stuffed into a fixed displacement engine doesn’t change with rpm.

One turn of the crankshaft will always pump the same amount from the blower (depending on pulley ratio). Boost won’t increase with rpm. 212cc eats 106cc of air per crank revolution at 100% volumetric efficiency. It eats the same amount of air 2500 as it does at 6500 RPM… 106cc per revolution.

maybe you can explain why it is that you added rpm back in? How does the amount of air pumped by the blower per revolution change. It is literally named 300 because it pumps 300cc per revolution. How does the rpm change the displacement of the engine? Engine displacement is constant, blower displacement is constant, pulley ratio is constant, boost is constant, rpm can be anything. It falls out of the maths.

A engine with More rpm requires more air per minute, not more air per revolution.
A blower with more rpm pumps more air per minute, not more air per revolution.

 

[John Roger]

No.
Maybe you misunderstood.
I said RPM falls out of the equation.
You added it back in.

212cc per 2 revolution of crankshaft.
106cc per revolution of crankshaft.

300 cc per 1 revolution blower.

300cc / 106cc = 2.83
2.83 * 14.7psi = 41.6psi
41.6 - 14.7 = 26.9 psi boost (if 1:1 pulley ratio)

Volumetric efficiency doesn’t matter as much when forcing induction.

And as you can see, the amount of air pumped by the roots blower per revolution stuffed into a fixed displacement engine doesn’t change with rpm.

One turn of the crankshaft will always pump the same amount from the blower (depending on pulley ratio). Boost won’t increase with rpm. 212cc eats 106cc of air per crank revolution at 100% volumetric efficiency. It eats the same amount of air 2500 as it does at 6500 RPM… 106cc per revolution.

maybe you can explain why it is that you added rpm back in? How does the amount of air pumped by the blower per revolution change. It is literally named 300 because it pumps 300cc per revolution. How does the rpm change the displacement of the engine? Engine displacement is constant, blower displacement is constant, pulley ratio is constant, boost is constant, rpm can be anything. It falls out of the maths.

A engine with More rpm requires more air per minute, not more air per revolution.
A blower with more rpm pumps more air per minute, not more air per revolution.

K

 

[Thepartsguy]

So mike clements did not build this. It was built by Justin W youtube channel.. You can see a whole slideshow on his channel along with a short run of the engine before he sold it to the mike clements museum.

EXTREMELY easy to copy.. Instead of that intricate Tilly bracket why not just Slip the pwk boot on the inlet of the pump and tighten the clamp. Then put the pwk carburetor in the boot and tighten the clamp. Run a tube from the outlet to the pump to the engine intake port like shown.

I know exactly the model of pump he used and where to get 3 of them.. I will at one point be making a cheap copy with my own flare to it..

 

[John Roger]

question would it be better for the supercharger pulley to mount to the fly wheel or the torque converter? i am buying the parts i am getting the carburetor you recommended and a AMR 300 supercharger and some other small things

 

[John Roger]

here are some pictures

i will post pictures of the parts hopefully next week that´s when I could go and get them

 

[Denny]

Which ever way is easier to keep it spinning in the correct direction. No sharp corners in the tubing to the engine or from the carb?

 

[John Roger]

Which ever way is easier to keep it spinning in the correct direction. No sharp corners in the tubing to the engine or from the carb?

i know i would just use thick rubber piping there is no piping mode in tinkercad it would be more roundish not like 90 degree angles