2.4 Supercharger pulley size boost calculation

[Unholy707]

I need to give them a call and make sure they port the intake runners that the 18+ superchargers have

 

[Unholy707]

This 18 supercharger has been kind to me

 

[DavidKFla]

Big difference between 9.8 and 9.2

Of course there is. You've thrown a shit load of stuff at your car though. I would expect more than a 9.8. Just saying.

 

[Unholy707]

Of course there is. You've thrown a shit load of stuff at your car though. I would expect more than a 9.8. Just saying.

Not me, I don’t have anything done really. The chiller is to be safer. E85, pulley, wheels and tires.

 

[Demid22]

Not me, I don’t have anything done really. The chiller is to be safer. E85, pulley, wheels and tires.

What coolant pump are you using?

 

[Unholy707]

Stock

What coolant pump are you using?

 

[Unholy707]

Charged with 1234yf, the way it should be

 

[Unholy707]

Also have a 1.25 gallon tank, takes only a minute or 2 more to chill the coolant. Once it’s chilled can have the drag valve off and it stays chilled, no temp creep

 

[hellno]

Charged with 1234yf, the way it should be

i ran 134 in mine never an issue

 

[Unholy707]

Some do, some don’t. The compressor and its seals are made for 1234yf, so that’s what I run. I also get it a lot cooler than a lot of people that use 134

i ran 134 in mine never an issue

 

[Unholy707]

The refrigerants are cross compatible, but the pag oil is not

 

[hellno]

The refrigerants are cross compatible, but the pag oil is not

i used the regualer pag oil as well , i liked going fast on the cheap and lets not believe everything they tell ya

 

[Unholy707]

So do I, but 250 for evac and recharge with extra wasn’t horrible. You sold your car before the compressor failed 🥲

i used the regualer pag oil as well , i liked going fast on the cheap and lets not believe everything they tell ya

 

[Speedy!]

Does anyone have the chart or math that shows how much boost is expected with a 2.57 pulley, or how I can calculate it for a 2.4 supercharger?

Found this in my notes:

 

[Unholy707]

Yeah, I came across that on the other forum but a lot of people were saying the boost numbers were off

Found this in my notes:

View attachment 126239

 

[2ndgen]

The refrigerants are cross compatible, but the pag oil is not

The pag oil shipped with the R-1234yf filled systems is Denso ND-12, which is fully compatible with R-134a coolant.

 

[Octanewide]

Found this in my notes:

View attachment 126239

What's this chart showing then? Rotor rpm is way higher.
Also my 2.86 upper stock lower has shown a 4-5# increase over stock on a 2.4..

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[Speedy!]

@Unholy707 that chart was accurate for my 2.72 pulley, but boost doesn't really matter it's aircharge that counts.

@Octanewide the pulley chart is drive ratio for the supercharger pulley. The chart you posted is male rotor RPM which is a not to exceed critical speed.

 

[Octanewide]

@Unholy707 that chart was accurate for my 2.72 pulley, but boost doesn't really matter it's aircharge that counts.

@Octanewide the pulley chart is drive ratio for the supercharger pulley. The chart you posted is male rotor RPM which is a not to exceed critical speed.

Got ya good info here..

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[2ndgen]

What's this chart showing then? Rotor rpm is way higher.
Also my 2.86 upper stock lower has shown a 4-5# increase over stock on a 2.4..

The male rotor spins 66% faster than the female.
The stock Nachi 6203 bearing holding the rotor in the front bearing plate is only rated for a 12k RPM limiting speed, which is why upgrading that bearing is rather important if you're going to push it to even higher RPM than stock.

Also, there will be a critical speed for the rotor itself--beyond which can be a different set of problems--of a much more exciting variety...