Usefull for supercharger users.
Usefull for supercharger users.
depends really, the more boost you run, the hotter everything runs and the shorter the life of the charger. If you find the equation for working out pulley sizes in that thread i linked you to.
FIRST CALCULATION (Engine Litres/min @ 0 Psi )
Multiply engine capacity (in litres) times maximum engine Rpm. E.g. 2 litres x 6000 rpm = 12,000 litres/minute. Divide this figure by two as engine only fills every second stroke. (12,000/2 = 6,000 litres/min.
This is the engines air requirements in litres/minute at 0 Psi boost.
SECOND CALCULATION (boost ratio)
Add the boost pressure desired (10 Psi) for the engine to 14.7 Psi (atmospheric pressure).
(10 psi boost desired +14.7 =24.7 psi)
Divide this answer by 14.7 and this gives the boost pressure ratio. (24.7/14.7=1.68) This is the boost pressure ratio above atmospheric pressure.
THIRD CALCULATION (Actual air requirements @ desired boost)
Multiply the boost ratio by the litres/minute obtained for 0 Psi and you get the actual air requirements in Litres/min for the engine at that boost. In our example this is 6000 litres/min X 1.68 = 10,080 litres/min for 10Psi boost.
To decide on the correct size of supercharger you need to know :-
1. The swept volume per revolution of the supercharger. (Eaton M62 1 litre/rev, SC14 from a 1G-GZE 1.5 litres/rev, SC12- 1.2 L/rev)
2. The maximum continuous safe operating speed for the supercharger. (Eaton M62 14000 rpm continuous, Toyota SC14 12000 rpm??)
3. The maximum pressure that can be safely produced by the supercharger continuously. (Eaton M62 12 psi, SC14 10-12Psi??? teflon on rotors melts??)
CALCULATION (Supercharger rotor speed)
Divide the desired air flow (5313.6 L/min) by the swept volume of the supercharger (SC12 from the 4A-GZE is 1.2 litres per revolution). This will tell you the maximum speed the supercharger rotors must be run at to produce the volume required.
10,080/1.2 litres = 8,400 rpm for the SC12.
So, to make your wanted 10psi happen, you need to spin the SC12 up to 8,400rpm while the Engine is doing 6,000rpm.
8,400 is well under 12,000 so youll be safe running that boost.
Its up to you how much boost you wanna run, but remember, the more boost you run, the more heat is created and the harder the charger has to work. SO, the harder you boost it, the shorter the chargers life will be due to heat and wear.
Hi all i found this on the net while searching for more specs relating to which superchargers are best to use for which application, i'm not sure if you guys will find this useful but i did... Any way here goes, they are calculations that allow you to calculate whether or you choice of charger is correct for your choice of engine.
depends really, the more boost you run, the hotter everything runs and the shorter the life of the charger. If you find the equation for working out pulley sizes in that thread i linked you to.
FIRST CALCULATION (Engine Litres/min @ 0 Psi )
Multiply engine capacity (in litres) times maximum engine Rpm. E.g. 2 litres x 6000 rpm = 12,000 litres/minute. Divide this figure by two as engine only fills every second stroke. (12,000/2 = 6,000 litres/min.
This is the engines air requirements in litres/minute at 0 Psi boost.
SECOND CALCULATION (boost ratio)
Add the boost pressure desired (10 Psi) for the engine to 14.7 Psi (atmospheric pressure).
(10 psi boost desired +14.7 =24.7 psi)
Divide this answer by 14.7 and this gives the boost pressure ratio. (24.7/14.7=1.68) This is the boost pressure ratio above atmospheric pressure.
THIRD CALCULATION (Actual air requirements @ desired boost)
Multiply the boost ratio by the litres/minute obtained for 0 Psi and you get the actual air requirements in Litres/min for the engine at that boost. In our example this is 6000 litres/min X 1.68 = 10,080 litres/min for 10Psi boost.
To decide on the correct size of supercharger you need to know :-
1. The swept volume per revolution of the supercharger. (Eaton M62 1 litre/rev, SC14 from a 1G-GZE 1.5 litres/rev, SC12- 1.2 L/rev)
2. The maximum continuous safe operating speed for the supercharger. (Eaton M62 14000 rpm continuous, Toyota SC14 12000 rpm??)
3. The maximum pressure that can be safely produced by the supercharger continuously. (Eaton M62 12 psi, SC14 10-12Psi??? teflon on rotors melts??)
CALCULATION (Supercharger rotor speed)
Divide the desired air flow (5313.6 L/min) by the swept volume of the supercharger (SC12 from the 4A-GZE is 1.2 litres per revolution). This will tell you the maximum speed the supercharger rotors must be run at to produce the volume required.
10,080/1.2 litres = 8,400 rpm for the SC12.
So, to make your wanted 10psi happen, you need to spin the SC12 up to 8,400rpm while the Engine is doing 6,000rpm.
8,400 is well under 12,000 so youll be safe running that boost.
Its up to you how much boost you wanna run, but remember, the more boost you run, the more heat is created and the harder the charger has to work. SO, the harder you boost it, the shorter the chargers life will be due to heat and wear.
![[Image: LexuS-Copy.jpg]](http://i65.photobucket.com/albums/h204/Sparkystav/LexuS-Copy.jpg)
Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
Sparkystav
02-06-2019, 02:27 PM #2Good info that!
Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
ZAIS200 Why thank you sir, thats what we're here for, right?
To share info and help eachother.:wink:
EXACTLY the reason.
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
FirebirdPhil
10-06-2019, 10:02 AM #5ZAIS200 Why thank you sir, thats what we're here for, right?
To share info and help eachother.:wink:
EXACTLY the reason.
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
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