Underdrive Pulley + Blitz

[47_MasoN_47]

It just occurred to me to ask.. Since I have one of the old NST 10% underdrive pulleys installed, am I also underdriving my Blitz? Would I be better off getting one of the MI OEM sized pulleys to swap in?

[CTScott]

Do you have a boost gauge, as that would let you see any effect from the underdrive. The Blitz seems to be internally limited to 6 psi, so the only effect you would see is the boost being developed 10% later.

[47_MasoN_47]

Boost gauge usually shows about .7kpa

So it would just delay the boost slightly rather than giving me 10% less boost? That makes sense actually.

[cali yaris]

You are getting less boost, and later. You're S/C pulley is now turning more slowly at all times than it would with an OEM sized pulley. 10% is the diameter. You'd probably have to do some wicked math to convert that to the difference in rpm's.

You should get the MI pulley and enjoy full on-demand boost AND lighter weight with your s/c.

Scott, how is the blitz blower limited to 6psi? I'm unfamiliar with the inner workings I have to admit. We know of at least one user who had a fixed underdrive pulley made for the Blitz, and another had an overdrive crank made for it. Both increased horsepower.

[CTScott]

You are getting less boost, and later. You're S/C pulley is now turning more slowly at all times than it would with an OEM sized pulley. 10% is the diameter. You'd probably have to do some wicked math to convert that to the difference in rpm's.

You should get the MI pulley and enjoy full on-demand boost AND lighter weight with your s/c.

Scott, how is the blitz blower limited to 6psi? I'm unfamiliar with the inner workings I have to admit. We know of at least one user who had a fixed underdrive pulley made for the Blitz, and another had an overdrive crank made for it. Both increased horsepower.

I have no idea as to how it is limited, but once it gets to 6 psi the boost gauge never climbs any further. It may be some type of internal wastegate or it may just be something to do with how the paddles work.

[47_MasoN_47]

I'll have to snag one of those MI pulleys. Ugh at having to redo those freaking belts again, lol.