CAMARO6 - View Single Post - Question about pulley size/ boost amount on a Magnuson 2300

toohighpsi · 11-07-2018, 02:41 PM

The stock Z06 lower pulley is 8" (203mm), you have a 18% over so 8*1.18=9.44 (240mm).

For simplicity we'll look at the stock blower which I believe has about a 62mm pulley. 240/62=3.87 drive ratio so at 6600 RPM the stock blower is at 6600*3.87=25,550 RPM.

The change in blower size is 1740/2300 which is 25% larger, so to flow essentially the same amount of air you need a 25% larger pulley which would be 77.5mm.

Now this comparison can be a bit tough as the 1740 is pretty much done at 23,000 RPM, so the extra RPM you're spinning it will just pull more power from the crank with less than the usual expected gain in HP.

Since it is a PD SC, the power output is completely dependent on SC speed. There are some differences based off the efficiency of the engine (compression ratio, cam, heads etc) but these are normally pretty small. The SC completely controls the air into the engine so it determines the power the engine will make.

The TVS 2300 for LT4 ships with an 80mm pulley, using your 18% lower will result in a blower speed of about 20,000 at 6700 RPM. I expect that that should get you pretty close to your target of 800RWHP for air.

For Reference:
My stock Z06 with TVS2300 makes 740RWHP with a blower speed of 18,800 RPM.
Our LT1 416ci Camaro made 875RWHP with a TVS2300 blower speed of 20,500 RPM.

Hope that helps!

11-07-2018, 02:41 PM	#10
toohighpsi Drives: 2015 C7 Z06 M7 Join Date: Dec 2012 Location: So-Cal Posts: 665	The stock Z06 lower pulley is 8" (203mm), you have a 18% over so 81.18=9.44 (240mm). For simplicity we'll look at the stock blower which I believe has about a 62mm pulley. 240/62=3.87 drive ratio so at 6600 RPM the stock blower is at 66003.87=25,550 RPM. The change in blower size is 1740/2300 which is 25% larger, so to flow essentially the same amount of air you need a 25% larger pulley which would be 77.5mm. Now this comparison can be a bit tough as the 1740 is pretty much done at 23,000 RPM, so the extra RPM you're spinning it will just pull more power from the crank with less than the usual expected gain in HP. Since it is a PD SC, the power output is completely dependent on SC speed. There are some differences based off the efficiency of the engine (compression ratio, cam, heads etc) but these are normally pretty small. The SC completely controls the air into the engine so it determines the power the engine will make. The TVS 2300 for LT4 ships with an 80mm pulley, using your 18% lower will result in a blower speed of about 20,000 at 6700 RPM. I expect that that should get you pretty close to your target of 800RWHP for air. For Reference: My stock Z06 with TVS2300 makes 740RWHP with a blower speed of 18,800 RPM. Our LT1 416ci Camaro made 875RWHP with a TVS2300 blower speed of 20,500 RPM. Hope that helps!