Whipple question.

[SoChrisB]

So, I made the move to a 416 stroker and obviously lost some boost. I heard you can't overspin the whipple to more than 18k rpm. I currently have a 3.5 upper and a 6% OD lower. Any idea how low of a pulley I can go?

Appreciate the help all.

[Brad7294]

I had the same question on here. I have stock block with Whipple on 11 lbs boost it's at 750 rwhp. I was going with 416 and either the 3.25 or 3.0 pulley and 6%od lower 10 rib. I was curious on the boost numbers. 17,18 psi?

[Batmanntexas]

Originally Posted by SoChrisB

So, I made the move to a 416 stroker and obviously lost some boost. I heard you can't overspin the whipple to more than 18k rpm. I currently have a 3.5 upper and a 6% OD lower. Any idea how low of a pulley I can go?

Appreciate the help all.

Assuming Google is correct about the diameter of a stock Camaro LS3/L99 harmonic damper (7.75"), then below is the way to figure out your max pulley size:

(stock diameter * OD%) / (SC pulley size) = blower speed/engine speed ratio

blower/engine ratio * engine RPM = Blower speed

Example: (7.75 x 1.06) / 3.5 = 2.35 (rounded)
2.35 x 6000rpm = 14,100 blower RPM, at 7000rpm = 16,450 blower RPM

To get an accurate answer, you need to pick a MAX engine RPM and then calculate from there.

Originally Posted by Brad7294

I had the same question on here. I have stock block with Whipple on 11 lbs boost it's at 750 rwhp. I was going with 416 and either the 3.25 or 3.0 pulley and 6%od lower 10 rib. I was curious on the boost numbers. 17,18 psi?

Your boost number is actually a resistance to airflow and not tied directly to blower RPM. If you dropped your current combination onto a 416 motor, your boost number would probably drop 3-4psi just from the additional cubic inches, even though the blower is still spinning the same speed. Additionally, Whipple claims about 1psi for each 1/8" decrease in pulley diameter (blower pulley).

-Scott

[SoChrisB]

Originally Posted by Batmanntexas

Assuming Google is correct about the diameter of a stock Camaro LS3/L99 harmonic damper (7.75"), then below is the way to figure out your max pulley size:

(stock diameter * OD%) / (SC pulley size) = blower speed/engine speed ratio

blower/engine ratio * engine RPM = Blower speed

Example: (7.75 x 1.06) / 3.5 = 2.35 (rounded)
2.35 x 6000rpm = 14,100 blower RPM, at 7000rpm = 16,450 blower RPM

To get an accurate answer, you need to pick a MAX engine RPM and then calculate from there.



Your boost number is actually a resistance to airflow and not tied directly to blower RPM. If you dropped your current combination onto a 416 motor, your boost number would probably drop 3-4psi just from the additional cubic inches, even though the blower is still spinning the same speed. Additionally, Whipple claims about 1psi for each 1/8" decrease in pulley diameter (blower pulley).

-Scott

Thanks, Scott. I did the math already. I guess I'm wondering if anyone is overspinning the Whipple.

[Batmanntexas]

I'm not overspinning it, but am close, at 17,600rpm @ 6500...

10%OD with 3" upper....

-Scott