Thanks for the info and comments. The truck was made at the ft wayne indiana truck and bus plant and its the same color as the highway dept. trucks. I just changed the blower pulley from the 3.5" to a 5" and it definetly helped I can definetly push the pedal further ! I still have the overdriven balance on it- its easier and cheaper to have blower pulleys made then to change back to 6 ribs.

 

What's the blower putting out with the 5" pulley?

 

I dont know yet but remember the balancer is much bigger. 3.5" was 13.5lbs

 

WOW, incredible truck!! And like Kyle said 4wd to boot!!!
I'm wondering if he can put all his power down to the ground if he can break into the 9's like Jarrett did! 20lbs of boost on a 4wd 408...it's gotta be low 10's high 9's!!
Awesome work man! Get the bugs worked out already!!

 

honestly wouldnt worry to much bout the turbo being small. the way your compounding is the correct way. small turbo to feed the supercharger, which then compresses the air futher. i know its not quite the same but diesels do it that way - small turbo to get up quick feeding a larger turbo to keep up on top. get the wastegate situation settled and you should be fine. looks like a blast to drive.

 

So, could the small turbo's exhaust housing be causing a restriction in the exhaust path? I understand the intake path theory, it sounds like exhaust restriction causing exhaust gas reversion back up the intake tract, subsequently increasing boost but doing nothing for HP/TQ. Am I thinking correctly on the exhaust side theory?

 

Nice looking set up. Do you know the EGT and drive pressure numbers?

 

Reversion won't increase boost. Think of what is happening is 60k people in the ballpark stadium are all trying to exit through one set of revolving front doors, the doors are going to spin uncontrollably fast until you open up some alternate routes(larger/additional wastegates) or increase the size of the doors(larger turbo/exhaust housing).

 

I was kinda hoping you'd chime in henry!!

 

I guess I just don't under stand your thinking here... A small turbo in this setup is like having a big supercharged motor sucking though a small straw and then trying to blow out that same small straw...