Boost

[BSouders80]

With the 6.6L paired with whipple - There is a problem with the pulley/belt setup from Livernois, when running the 10%OD crank pulley. Whipple pulley is 2.875"

The problem, per Livernois - The angle of the belt when engaging the pullies due to the large crank pulley allows the belt to fly off with a quick hit.
Say you just smash the throttle when taking off at a stoplight - 50/50 on if the belt will fly off.

Livernois solution - go to factor crank pulley and change a couple of pullies to be walled pullies. Some might call them lipped pullies.

I know a guy who bought the "fix" from Livernois. Hasn't had his belt fly off in 3 months of beating on it pretty good.


Here's my problem with the "fix" kit. I upgraded my fuel system to be able to run E85 with high boost for more HP. Injectors, fuel pump and went with their 8 rib pulley setup. I would lose boost going with their fix by changing from 10% OD crank to factory.

I found a site that has whipple 8 rib pullies all of the way down to 2.50"

Can anyone tell me approximately which pulley size to go with to make up for the boost loss from 10% OD crank pulley to factory crank? I would think maybe a 2.75 pulley.

I believe I should be running 18-20 PSI boost with my current setup. But I may be wrong. I do not have a boost gauge.

 

[Gumby]

This is what I use.

Pulley Calculator

Make lifting a breeze with the Pulley Calculator! Calculate mechanical advantage and choose the right pulley for your needs.

calculator.dev

I believe I should be running 18-20 PSI boost with my current setup. But I may be wrong. I do not have a boost gauge

How did you set the waste gate? The gate determines the boost if it is set for 18- 20 then you are making 18-20.

 

[BSouders80]

That calculator is more for figuring pulley sizes related to mechanical force. Like using pullies to lift an object but using different ratios to increase mechanical advantage. In my mind, that's like using a 2:1 ratio to get a 2X mechanical advantage. So a 100 pound load would require 50 lb of force to lift. How could I apply this to belt speed? Pulley 1 could be the crank pull, and the SC pulley be the driven. If my crank pulley is 2X the size of the driven SC pulley, my ration would be 2:1 and the SC pulley would run twice as fast as drive pulley?

 

[BSouders80]

Anyone have any other ideas? I guess I could install a boost gauge, then just start pullying down until I hit the same #'s? Or in Forscan, do a log and look at peak manifold air pressure, then subtract the 14.79?

 

[Gumby]

Ya... boost gauge for sure. math is hard. I know. lol