Supercharger and pulley

[W1N]

I've searched everywhere information and gotten some seriously confusing aswers

First of all, what is the size of pulley that comes with Radix SC. I've found like 2 answers 3.30" and 3.40". Which one is it? And what is the boost with this pulley 5 psi or 6 psi?

Then the more "difficult" one. Going for some smaller pulley will give me more boost, but how much? Allen Nelson at Nelsonperformance told me 3.25" would get 7psi +-.5psi and reading the forum (again using the find function succesfully) I found for example CHarris running 3.10" pulley and getting only 6.5-7.0 psi??? Not making a whole lot sense to me

I also found on the Internet the table below:


For Magna Charger Radix Applications, below are the Boost increases over stock 3.30" pulley application:
- 3.20" pulley: expect 1 lbs. more boost over stock pulley.
- 3.10" pulley: expect 2 lbs. more boost over stock pulley.
- 3.00" pulley: expect 3 lbs. more boost over stock pulley.
- 2.90" pulley: expect 4 lbs. more boost over stock pulley.
- 2.80" pulley: expect 5 lbs. more boost over stock pulley.


I'm looking to get like 7-8 psi's and seriously like to know the size of pulley I need. I already have ordered a shift kit and Corvette servo as well as 160 t-stat to make these all work well. I also ordered a personalized tune from Allen Nelson.

Any knowledge regarding this issue is more than welcome.

[W1N]

I've searched everywhere information and gotten some seriously confusing aswers

First of all, what is the size of pulley that comes with Radix SC. I've found like 2 answers 3.30" and 3.40". Which one is it? And what is the boost with this pulley 5 psi or 6 psi?

Then the more "difficult" one. Going for some smaller pulley will give me more boost, but how much? Allen Nelson at Nelsonperformance told me 3.25" would get 7psi +-.5psi and reading the forum (again using the find function succesfully) I found for example CHarris running 3.10" pulley and getting only 6.5-7.0 psi??? Not making a whole lot sense to me

I also found on the Internet the table below:


For Magna Charger Radix Applications, below are the Boost increases over stock 3.30" pulley application:
- 3.20" pulley: expect 1 lbs. more boost over stock pulley.
- 3.10" pulley: expect 2 lbs. more boost over stock pulley.
- 3.00" pulley: expect 3 lbs. more boost over stock pulley.
- 2.90" pulley: expect 4 lbs. more boost over stock pulley.
- 2.80" pulley: expect 5 lbs. more boost over stock pulley.


I'm looking to get like 7-8 psi's and seriously like to know the size of pulley I need. I already have ordered a shift kit and Corvette servo as well as 160 t-stat to make these all work well. I also ordered a personalized tune from Allen Nelson.

Any knowledge regarding this issue is more than welcome.

[Fastest H-Town Realtor]

A-Why not ask the folks who make the blower the answer to the questions posed about pully size/boost with a stock blower. They would know best

2-"Boost" is an artificial measure of back pressure within an intake tract. The same 2 vehicles will exhibit different boost readings according to tolerance and manufacturing differences.What you measure with boost is the resistance of the air charge going thru the intake tract. Hog out(port) the intake tract and the boost read will go down.

I would buy 2 or 3 pullies then test the results according to the boost pressure guage. I would also be careful of overboost that could/will damage stock internal components. According to what I have seen/read/heard, anything over 500 HP becomes a dangerous trek.

[evomind]

i would seriously have ur truck dyno tuned after swapping pulleys....this is the most common way people blow their motors with superchargers. they get smaller pulleys, make more boost, and their engine isnt tuned for it...
fuel and air....

[KenP]

Nelson should be able to answer all those questions since he's doing the tune. He has to know what boost you plan on running to avoid going too lean.