See a lot of different comments on this so wanted to just ask. With having long tubes and full dual 3 inch I have read can lose some boost. Running the stock truck balancer which pulley is best to go with for 10 lbs at minimum. Wanting 10-12 lbs which I feel is still safe and good for a daily driver. Don't think anything else in my setup with affect boost. Stock cam for now too.

 

In this case, less boost does not equal less power.

While your boost is lower on the gauge, you didnt lose anything, the engine is just better at digesting the air that was already there. Lower boost (less stress) and more power. Who can complain?

As for the pulley, you can 2 different crank pullies depending on your drive. If you are 8 rib, the LSA crank pulley and Innovative 10% OD will be upgrades over stock truck.

For the snout pulley 2.38 is the smallest you can go. That being said, the rumor is that a 5.3 with a stock truck crank pulley and stock snout pulley already is making 10lbs.

Boost is a measure of restriction. Which is why your better breathing engine is "losing" boost. Its not really lost, just more efficient.

2.55 snout pulley or lower will get you there.

 

Yea I was going to say I think the stock Pulley will put you right in that ball park. I believe its 3.0".

Do you already have the truck running?

 

No not yet just getting the rest of the stuff together before the install. Just about there deciding on the hx pump still and pulley really. Then have to work out the tune on my e38 ecm which is about the same as the e67 ctsv so looks like might be easier then expected.

 

The snout pulley on a LSA is 2.95
and i have been told the trk crank pulley is 7.24
I don't think you can swap the crank pulley for
lack of room. on my truck there is only about 1/4"
between the crank and water pump pulleys.

 

Did find this too. But still would have to change upper to get 10 lbs I believe.

 

Not sure what truck you have, but I assure you they arent all that close. Swapping crank pulleys to a larger OD is possible

 

Doing the upper is cheaper.

But I want to reiterate that you are getting hung up on a number that doesnt mean a whole lot. Right now, when your truck is tuned, it will be making more power at a lower boost level than a comparable truck without breathing mods.

If you wanted, you could save money and not re-pulley. You are still making better power.

Pick a whp goal, not a boost level goal. There are 4 cyl motors out there with 22psi in them factory that are getting their *** handed to them by built motors and bigger turbos pushing 18. Its just a number.

 

im running a 2.5 upper, with longtubes, and a full exhaust and i see about 10.5lbs of boost on my 5.3.

 

Stock 5.3 lm7 with lsa blower and 2.75 pulley.
Getting 11lbs peak with long tubes and dual 3 inch exhaust.