Ok guys(BlownChevy and friends) I have a good radix question for you. I have two trucks at the shop that have 3.4 pulleyed radix kits that appear to be the same. One is a 2003 suburban with 6.0L w/ETC stock tbody and K&N coldair kit and this truck makes 5psi all the time and has since day one and the kit now has about 60,000 miles on it with no trouble at all. THe other truck is the Regency with the 5.7L LS6 unaltered, with stock ETC tbody and same K&N cold air kit. All pulleys are the same size and the setups appear to be the same but the regency makes 8psi always and doesn't fall off even at 7000 rpm. It made the same boost on the 2002 Silverado it was on with this same motor. My question is what is the actual diffence, is it ported inside or something? We special order the setup for the truck with the car motor and the level of boost. How was it done? Can you guys tell me what the difference is? They even sound totally different to drive down the road. The one making 8psi sounds like you put the blender on a higher speed. Is the a difference in crank pulley size between the 6.0L and the 5.7L and if it was the flow differences between cams and the heads I would think the 6.0l would have a higher psi due to it only being around 300-320hp stock and the LS6 is a 405hp motor stock. The Z06 motor flows way better so it should make less boost from the same setup. What do you guys think?

 

combustion chamber volume is what comes to my mind

 

You think the LS6 has a smaller chamber due to it's 10.5:1 comp and that is the cause? Makes since to me, thanks moregrip! Anybody else?

 

I know the CC volume for the truck heads are approx 72cc, not sure about the 5.7 but I think they are in the low to mid 60's.

 

6.0 5psi
5.7 8psi
both with 3.4 pulley......Sounds about right to me.
The radix is a positive displacement pump and is pumping the same amount of air with the same pulleys. You are going to have higher pressure on the smaller volume that it is forcing the air into. The radix probably wines more becuse there is more load on it compressing the air on the LS6.
Does that answer your question?

 

Yeah, makes since to me. The 5.7 makes way more power and flows way more air as it pegs the maf and the 6.oL doesn't even come close to pegging it. Thanks guy for the feed back.