I am going to be going to San Antonio this Wednesday and I am going to try to get the truck to Nelson's to get it tuned, and I figured while I am at it I might as well throw on a smaller pully.

The question is what size pully to go to, and how much boost can I safely run on the stock LQ9 bottom end.

The Radix currently has a 3.30 pully on it. I lost some boost about 1/2 - 1 lb after the headers and exhaust. I am planning on doing heads and cam on it in the near future as well which will also drop the boost.

 

congrats dude...allens got diffrent size pulleys...just run em till you find 1 you want....take a smaller belt with ya thou....

 

I am running the Radix on my SS Silverado with the 2.9 seeing around 8psi. I have the 2.75 standing by though. I doubt you will challenge the bottom strength of the LQ9 with a Radix with any size pulley. I am well modded in the 12's and haven't had an issue.

 

by the book it is 500 hp with the stock rod bolts replaced, but as we know with the right tuning it can go up and over 600 hp, as far as a safe limit on boost with Allen tuning it,
I know he will give you as much as your fuel system and injectors can deliver on 91 or 93 Oct, without causing damage to the engine. your final result could be some where around 8 to 11 psi when he is finished.
be sure to post the numbers everybody would like to see.

 

Will do. I can't wait to feel the difference.

 

You picked the right guy to tune it. Keep us posted. I can't wait to get back over there and redyno my truck.