David Weaver
Enthusiast
I have been toying with the idea of making a larger crank pulley. Finally did it and the results have been outstanding so far. Sean Roe told me the max RPM for his blower is 21,000 RPM's. By my calculations, the 8 inch diameter pulley I have built puts the blower at that limit with a 2.5 inch pulley.
The test car is a built motor with ported blower manifold, ported heads, custom camshaft, 2.5 inch blower pulley. The VEC2 log was indicating 9 to 9 1/2 lbs of boost. The car was making 680 HP on a conservative, Texas hot climate tune. I bolted on the pulley and made 721 with no other changes. The log indicates 12 lbs of boost at the hit and 11 through the dyno run.
In addition, this larger pulley will allow you to go to a larger blower pulley while maintaining the same boost level. This should make for better belt wrap/adhesion and less belt slip by using the larger diameter blower pulley.
The pulley is made from billet aluminum on a CNC machine. I have not done any "durability" testing. I built this identical to an aftermarket Viper underdrive pulley. The only difference is the diameter so I am confident that the pulley will hold up just fine. There is just enought clearance between the pulley and the water pump to be able to change the belt.
You can see pics of the pulley at the alley under viper discussion. My user name is the same there. I will be heading out of town this evening and will return on Tuesday the 6th. I am offering these pulleys for $249.99 for the initial run. Please PM me for more information.
Thanks, DW
www.americanracingtech.com
The test car is a built motor with ported blower manifold, ported heads, custom camshaft, 2.5 inch blower pulley. The VEC2 log was indicating 9 to 9 1/2 lbs of boost. The car was making 680 HP on a conservative, Texas hot climate tune. I bolted on the pulley and made 721 with no other changes. The log indicates 12 lbs of boost at the hit and 11 through the dyno run.
In addition, this larger pulley will allow you to go to a larger blower pulley while maintaining the same boost level. This should make for better belt wrap/adhesion and less belt slip by using the larger diameter blower pulley.
The pulley is made from billet aluminum on a CNC machine. I have not done any "durability" testing. I built this identical to an aftermarket Viper underdrive pulley. The only difference is the diameter so I am confident that the pulley will hold up just fine. There is just enought clearance between the pulley and the water pump to be able to change the belt.
You can see pics of the pulley at the alley under viper discussion. My user name is the same there. I will be heading out of town this evening and will return on Tuesday the 6th. I am offering these pulleys for $249.99 for the initial run. Please PM me for more information.
Thanks, DW
www.americanracingtech.com