OK, I'm new at this. I'm getting ready to pickup my pulley/injectors and have a guick question.

Here's what I want to do:
Get a Modular Pulley System
Run a Smaller pulley (2.5") for race days
Run a Larger pulley (maybe 2.7" or 2.8") for normal driving later in time

I know you have to machine the snout for the 2.5" pulley. Can you still slap on the 2.7" or 2.8" pulley with the machined snout/mod pulley system for normal driving days?

I know I'll need a custom tune for each. I'm planning on getting HPTuners so I can just change at the track. I may just go with the 2.5" pulley for now and get the bigger pulley later once I have HPT, but I need to know if i can do that.

So any of you guys running the smaller pulleys, chime in anytime

 

Yeah, I would talk to Dan about that one ... he's got the 2.5 on his redline.

As far as the tune goes... I don't see what would prevent you from doing this, but when you say "modular pullies".... that is where you lost me.

Are these 2 piece pullies that the inner section stays on, and then you unbolt the "outer" section that is the differing size??

If not, I would say that it would be a big hassle to be swapping pullies on a regular basis. THen you have the belt tension issue as well. Once you get the smaller pulley on, and use either the smaller belt or bigger tensioner pulley, what do you do when you go back? Putting the bigger belt on would be easier, but still a pain snaking it thru.

I've never done this either, I'm just going by what I've seen on other cars and just some things that pop into my head for if I would be doing it that I would be curious about.

 

I think I found my answer.... ZZP has a mod pulley system that drops to 2.6" w/o machining. I think this is the way I'm gonna go now.

http://www.zzperformance.com/cobalt_...58d15496171e9f

I don't know...maybe a 2.6" and 2.85" pulley. Shouldnt have any tuning issues with the 2.85" and 60lb injectors

 

The mod pulley system is just a piece that is pressed onto the supercharger shaft with 5 tapped holes to bolt different size pullies on (2 piece like you said above). Move belt from pulley, remove 5 bolts, replace pulley, tighten 5 bolts, put belt back over new pulley, load tune if needed, and drive. I figure if i use the adjustable tensioner, I shouldnt need to replace the belt with a different size everytime I change, just take it off the pulley and replace it when done. Hopefully maybe a 10-15min job all together.

 

Actually now that I think about it, I may go with 3 size pullies and 3 different tunes (yeah, I can see this taking a year or two...) One for street, one for Auto X, and one for the strip. Maybe 3.0", 2.85", and 2.6"

RL Dan - do you see any problems with tuning 60lb injectors with a 3.0" pulley? Can HPT cut them back far enough?