ATI LT1 boost equation

Who has the ATI boost equation for an LT1 motor with a stock harmonic balancer????? I need to make sure I dont overspin my new D1 blower!!!:alert:

Take your crank pulley size, divide it by your blower pulley size, multiply by max RPM and then multiply by the step-up ratio. A D1's setup is 4.44 : 1 .. Max impeller speed is 65000.

is the d1sc 4.44 or 4.10?

Chris

http://www.procharger.com/models.shtml

cool.. so the D1 is 4.44 and the D1SC is 4.10.. if it is the same blower in his signature it is a D1SC and he needs to use the 4.10 step up in the equation to get the correct impellar rpm. his post was tricky stating D1 but sig says D1SC.. gotta watch that when posting whonxt?..lol liable to do the wrong math spend the money on the wrong pulley and leave some blower rpm on the table!

Chris

cool.. so the D1 is 4.44 and the D1SC is 4.10.. if it is the same blower in his signature it is a D1SC and he needs to use the 4.10 step up in the equation to get the correct impellar rpm. his post was tricky stating D1 but sig says D1SC.. gotta watch that when posting whonxt?..lol liable to do the wrong math spend the money on the wrong pulley and leave some blower rpm on the table!

Chris

YA, left out that "minor" detail!!! HAHA, well, it is the D1sc so I will do the equation several times just to be safe!! Thanks for the help.

check my math here:
6.75 crank dia./3.4pulley*7,000*4.10=
1.99*7,000*4.10=56,977

So if this is correct, 56,977/62,000=92% max blower rpm usage.
That is cool If I am correct because my blower will not be maxed out even with this new pulley. Anybody see any errors on my part here?

Looks right to me ...

I didn't know ATI made that small of a crank pulley. I thought they only made 7" and 7.6". If so, you could increase your crank pulley size and increase your supercharger pulley size and that will help you with belt slippage. (more surface area for the belt)

or over spin the blower with a 7.5" balancer and the 3.4 pulley to 63140 for max air movement.. :D

mo powa :p

Maybe I am wrong. I measured 6.75 outside diameter on my crank pulley. It is the regular one that came with my D1SC kit. 6.75 or 7.0, I will be fine. My car shifts at 6,500 rpm max, so I have a 500 rpm cushion in the event of a tranny dumping out. This has been good info for me though!! Thanks.