RUNMYTA

I know this is kind of a shot in the dark, but here is what I am trying to accomplish. I have a LT1 383 with Dart Heads that flow roughly 250/170 at .500. I need to pulley my D1SC to make 13-15lbs for my HP goal. Currently I have the stock pulleys that come with the kit and would rather change the pulley now to get me in my target area, instead of putting the stock pulley on, tuning, seeing where I am at then tuning again for the new pulley. Hopefully one of you guys have been through this before. Thanks!!

T/A KID

This is a shot in the dark, try the 3.7bp with the 7.625cp, lol.

joe-96z1le

I agree. 3.70 pulley should get you there. But I think you'll be closer to 13 lbs than 15lbs.

TehFonz

i have the same question but for a vortech v-1 t trim. unless they are the same thanks

mdcaprice

I have a Vortech T-Trim and I use a 10 rib 7" crank and a 2.5" head pulley from ASP Racing makes 15lb boost but this setup does reach the max RPM for the bearings in a t-trim.

Here is the equation:

(Engine Redline or Shift Point) x (Crankshaft Pulley Diameter "A") divided by (Supercharger pulley diameter "B") x 3.5 = Impeller Speed "D"

Maximuim recommended Impeller RPM is 55,000 for a t-trim

TehFonz

im aiming for a bit lower i suppose 10-13 but the information was very useful

T/A KID

The T-trim is a 1200cfm blower while the D1SC is a 1400cfm blower. The equation works for both manufacturers though.

Boost PSI is a bi product of many things, CR, efficiency of the motor, etc. The better the motor is breathing then you'll see lower boost from a given pulley setup.

Privateer454

That isn't true. The D1-SC has a 4.10 step up ratio, not a 3.5. A set up calculated with the 3.5 ratio to 55,000 rpm would be 66,000 with the 4.1. Big difference.

mdcaprice

This is why I posted the formula to caculate with. Just plug in your numbers. The vortech is really 3.45 but 3.5 works well for math and leaves a little safety margin.

Maximum for the d1-sc is 62,000
So the formula should look like this

6500 rpm shift point x 7.625 crank pulley=49562.5 / 3.7 head pulley=13395.27 x 4.1 = 54,920 rpm you still have room to spin.

So with a 3.5 head pulley with the same numbers above you would be at 58,058 near Max I would think

T/A KID

The EQUATION is the same, the numbers in the equation will be different of course

fabgmc4me

Thats what I'm making using a 3.4 and a 7.65

through a front mount, with 195cc Trick flows and a 383

Remember that boost is just the measure of restriction, and a better flowing combo will make less boost with the same pulley combination.

mzgp5x

I agree, flow is everything. Running 190 afr heads on a 97 Camaro 383 with custom exhaust and hard pipe intake and CM cam 231*/240* .550" @ 114lsa. I tend to like the larger gearhead ratios since they spin-up faster (a... D1 w/4.44:1). Running a Large Spearco 24x3.5x12 and seeing approx 14 psi @ 6000+ rpm with a 7.6 --> 3.4 pulley ratio.