I did a little experimenting with different size pulley combos this weekend. I wasn't really looking at maximum boost levels, I was more trying to find the most streatable combo.

Since I allready had a JDM 8lbs lower on I started there.

With the 8lbs lower and a 3.5inch upper it was a pritty good street combo.

I next tried the 3" upper, and all I can say is wow, it is very fast, but a little touchy for street use.

I then tried a 2.75" upper with the 8lbs lower. All I can say you better have big ***** to drive that combo on the street.

Today I swapped the 8lbs lower for my JDM 6lbs lower.

With the 6lbs lower and the 3" upper the truck has about the same power as with the 8lower 3" upper combo, but the supercharger spools up quicker.

I then tried the 6lbs lower and the 2.75 upper, It seamed ok, but I have to get a smaller belt to really test that combo. I was getting to much belt slippage to really get a accurate feeling on how it would drive.

So for me the 8 lbs lower and 3inch upper pulley seems to be the best all around street combo.

I have 3 of the New Reichard racing pulleys comming tommorow, I will be doing some testing to see how they work. I am sure they will be a huge improvent, since the KB pulleys suck. I have allready allmost thrown a belt twice with the KB upper pulley.

I have a 2.8" a 3" and a 3.2" pulley to test out. I will let you know how they work.

 

Stock Lower and 2.50 upper = 21 to 22 Lbs of BOOst

 

That sounds right -- Holdener found a 16 rwHP advantage at stock boost levels (with no chip). With the cooler boost from the twin screw, some additional spark advance might uncover a little more.

 

Jusy wondered if you got your reichard pullies yet and how you like them?? How much were they and who did you get them from.
Thanks
Mike

 

guys if your heads arre ported and outflowing the stock setup your going to make allot less boost then, so thats not the reason your maiking more boost. Anything that allows the motor to breath better is going to reduce your PSI. Boost is just a measurement of the amount of pressure going into the motor.

When you shotgun a can of beer, more beer will flow out with a bigger hole right? now imagine if you pressurized that can so it would flow faster. its kinda the same theory, and if you have a bigger exit your going to push more beer out and loose pressure cause its easier to flow. If you make that hole tighter your going to increase the pressure and allow less beer to flow.

So basically the best way to measure your blower would be in CFM.

I'm sure most of you know this, but I just wanted to clear that up.

 

Great analogy

--Joe