smaller supercharger at high boost vs larger supercharger at low boost - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

880 · 07-12-2013, 10:49 AM

Just curious about these setups. Let's say 2 superchargers create the same power, but do it differently.

One is smaller displacement at high boost vs another is larger displacement at low boost.

I'm thinking that the smaller displacement is creating more stress for the engine and the supercharger itself and also adding more pressure and heat? The larger one is more efficient?

Anything wrong? Any other thoughts?

Rcfiddy1 · 07-12-2013, 10:57 AM

I think the only stress factor is amount of boost. The engine doesn't know how it's created, only that 10 psi is 10 psi in the cylinders. The extra boost created in the cylinder on the compression stroke is the stress factor. All superchargers are just air pumps. Larger pumps mean more boost so you can create more boost if needed. But 2 superchargers at 10 psi will create the same power. Unless you take into account heat and power it takes to spin the s/c. So I would think it takes a little more power to spin a bigger blower. Also, PD blowers are prone to heat soak while centris are less prone. I'm no expert and could be wrong.

east TX Muscle cars · 07-16-2013, 05:58 PM

your pretty much dead on. but the bigger, lets say 2300 over a 1900, will make more power at same psi cause it will be working less to make that psi. So less heat is created.

600 hp is 600 HP the motor doesn't know the difference. what it does know is PRESSURE on the pistons, heat on them, and RPM to make the power, and those things are harder on the motor.

old motorhead · 07-16-2013, 07:07 PM

If you're wanting more boost than a small blower is capable of making, sure, the bigger one will be better. If you're wanting a tiny amount of boost that a small blower will easily make, a bigger one won't be quite as efficient. But, probably hard to measure. At a boost level that both blowers are comfortable with, there isn't enough difference to even argue about.

The old "you need to go with a smaller TVS at under 8 (or pick your number) psi is BS. 8 or 7 or 6 psi takes very similar power from either blower to produce the boost. If you only want mild boost, you can save a few bucks with the smaller blower. That's about the only advantage I can see. If you know you'll eventually want more, the smaller blower makes little sense.

Regarding the OP's first post....boost is boost. 8psi from a big blower will make similar power vs 8psi from a smaller one. As long as you're not talking about an enormous blower spinning way too slow vs a tiny blower spinning way too fast.

07-12-2013, 10:49 AM	#1
880 Drives: 2011 Z06, 2004 Cobra, 1991 MR2Turbo Join Date: Dec 2011 Location: Delaware Posts: 472	smaller supercharger at high boost vs larger supercharger at low boost Just curious about these setups. Let's say 2 superchargers create the same power, but do it differently. One is smaller displacement at high boost vs another is larger displacement at low boost. I'm thinking that the smaller displacement is creating more stress for the engine and the supercharger itself and also adding more pressure and heat? The larger one is more efficient? Anything wrong? Any other thoughts? __________________

07-12-2013, 10:57 AM	#2
Rcfiddy1 Sold car... Drives: 2010 Rally Yellow 2SS/RS #37115 Join Date: Oct 2009 Location: Manalapan, New Jersey Posts: 2,019 View My Garage	I think the only stress factor is amount of boost. The engine doesn't know how it's created, only that 10 psi is 10 psi in the cylinders. The extra boost created in the cylinder on the compression stroke is the stress factor. All superchargers are just air pumps. Larger pumps mean more boost so you can create more boost if needed. But 2 superchargers at 10 psi will create the same power. Unless you take into account heat and power it takes to spin the s/c. So I would think it takes a little more power to spin a bigger blower. Also, PD blowers are prone to heat soak while centris are less prone. I'm no expert and could be wrong. __________________ Build Thread ECS Novi 1500 Supercharged, LS3 conversion, Small blower cam, Alky Meth injection, 3:45 rear, BMR Suspension parts, 1LE Sways, Billy Boat ZL1 dual mode exhaust.

07-16-2013, 05:58 PM	#3
east TX Muscle cars Drives: 2x 05 Vettes/65'AC cobra/68 camaro Join Date: Apr 2009 Location: LONGVIEW, TEXAS Posts: 845	your pretty much dead on. but the bigger, lets say 2300 over a 1900, will make more power at same psi cause it will be working less to make that psi. So less heat is created. 600 hp is 600 HP the motor doesn't know the difference. what it does know is PRESSURE on the pistons, heat on them, and RPM to make the power, and those things are harder on the motor.

07-16-2013, 07:07 PM	#4
old motorhead Drives: Maggie blown LS3 vette Join Date: Aug 2009 Location: SE TX Posts: 1,490	If you're wanting more boost than a small blower is capable of making, sure, the bigger one will be better. If you're wanting a tiny amount of boost that a small blower will easily make, a bigger one won't be quite as efficient. But, probably hard to measure. At a boost level that both blowers are comfortable with, there isn't enough difference to even argue about. The old "you need to go with a smaller TVS at under 8 (or pick your number) psi is BS. 8 or 7 or 6 psi takes very similar power from either blower to produce the boost. If you only want mild boost, you can save a few bucks with the smaller blower. That's about the only advantage I can see. If you know you'll eventually want more, the smaller blower makes little sense. Regarding the OP's first post....boost is boost. 8psi from a big blower will make similar power vs 8psi from a smaller one. As long as you're not talking about an enormous blower spinning way too slow vs a tiny blower spinning way too fast.