I have a 3.25 pulley on a 5.3l. When the truck is floored it 2nd gear, from 2500-5500 rpm, I'm only seeing around 7 lbs of boost, does that sound right? Right at 6000rpm I may see 8-8.5 lbs, I dont think Im seeing enough boost.

 

...when it comes to the Radix but I think it is about right. There are many factors to consider. It's summer and very hot out. I have heard terms of "Wash Through" with high flowing heads and exhausts. Again I am a beginner so...

From what I read here 8.0 - 8.5 is alot of boost without spraying? You may want to verify your gauge.

 

I would still consentrate on less boost and more tuning. Better for the heat.

Rick

 

That does sound right to me. I have the 3.4" pulley on my 5.3 and see about 6 pounds on top. I have a 3.25" that is going on the Radix when I get my dyno tune in a few weeks, I am hoping to see 9 pounds on top. When people say that size X pulley equals X pounds of boost, they mean at the very top end, around 6000 rpm. 8.5 @ 6000 rpm sounds correct for a 3.25" pulley

 

I saw 8-9 with 3.25 until cam install. Now only see 6.

 

I lost a lb after headers and exhaust. On my LQ9 with a 3.3 pully I saw about 5 lbs. Now that I have the 3.0 I am seeing 7 - 7.5 lbs when the belt isnt slipping.

 

my 4.8 had a 3.7 stock and would pull 7 and peak @ 7.5. I now have a 3.25 and it peaks @11.5 with stock motor and no exhaust mods.