Anyone that says the 2 lb uppers only add 1LB, I say BULL****INGSCHITT. I just took my 2lb upper off and went back to the stock size Upper. I left my 4 LB Lower on and the difference in boost is out right depressing. I agree with the mfg. of this product "that it's every bit of 2 to 3 LBS".

Before when I just ""touched the pedal"" I Buried the gauge, and at WOT I had every bit of 16-18 LBS. Now I immediately noticed that you can go dam near 1/4 to 1/2 throttle before getting 10 LB'S. Yes at WOT I still have at least 13-15 Lb's but the difference of HOW QUICK IT BOOST UP IS NIGHT AND DAY.

It's gonna rain all weekend so I cant see the difference at the track YET, but when I do, I'll post the difference.

The good news is, it took less than 3 minutes to do, with the Dial-Ur-Boost Upper Hub, so I can UN-DO it just as fast. I'm SURE I WILL...

 

I think you have something here. Don't have a upper myself but think that changing the lower will give you more boost. But changing both the lower and the upper will give you more. Someone let me know if I am wrong. You get 1 - 2 lbs from the upper with the stock lower but change the lower and the upper and the blower will spin harder than just changing one.

 

That's exactly right. Its the ratio of the pullies that matters. They call it a 2 lb. pully becuase when stock, it will give you around 2 lb. If you put a 2 pounder on the top, and then a bigger pully on the bottom, the top acts like more than a 2 pounder.

 

Rob,
I've got two questions for ya if you don't mind; do you have an aftermarket boost gauge and have you done the boost bypass adjustment? Thanks.
Steve

 

You can do the math here thanks to andy

http://www.svtlightnings.com/svt/how-to/blowerrpm.htm

See what the total blower RPMs are based on various size pulleys..

 

Rob,
The reason I asked the previous question is that the referenced blower pulley spreadsheet shows a 2.8 upper (2lb.) combined with an 8.5 lower (4lb.) producing less than 6lb. of increased boost. Besides trying to understand the cause of your fried plugs, I'm trying to understand why you'd notice a change in how fast the boost came up after you changed the upper.
Steve

 

Steve,

I originally did it in steps and here's how it went.
1st mod was 12" Hi Flow JDM Cool Air Induction. Stock I had @ 9lb's of Boost. With ONLY the Filter I immediatly pinned the guage and it would go a little more, I'd say 11 Lb. My next Mod was the Chip and that seemed to add even a little more Boost along with the usual Chip HP + Torque. Then I added ONLY the Top 2lb Pulley, the first thing you immediatly notice is "HOW MUCH FASTER IT WILL BOOST UP" beside the added boost, which now went totally off the scale, Pulling out of a Driveway can get you 10 LBS of Boost. The slightest touch of the peddal will immediatly give you guage pinning boost. Then I did a chip re-burn and put the 4lb lower on. I NOTICED NO FASTER BOOST UP AT ALL, but immediatly saw that at WOT the STOCK Boost guage would now go all the way around and into the Tach Area of the Dash Board. I then did the JDM Boost by-pass mod, oil seperator, Breather, and TR-6's.

So to answer your question no I do not have an aftermarket guage but the stock one ""CLEARLY"" showed the difference of each Mod. By taken the 2 lb off yesterday and keeping the 4, I immediatly saw a major major difference in HOW FAST IT BOOST UP. In my opinion, and I stess MY OPINION, the Upper not only adds boost but it clearly makes it boost up quicker. Where as the lower did add boost, but at WOT, and DOES NOT make it Boost Up Quicker.

It actually makes sence if you think about it. By making the top Pulley smaller it clearly turns faster AT ALL RPM, hence making more boost quicker. By adding a LARGER lower Pulley you are ALLOWING IT TO TURN MORE, BUT NOT FASTER.
There's a difference between turning it FASTER, and turning it MORE. "THINK ABOUT THAT" ?????????

Thanks for the Link Doug, I already have that one but unfortunatly it doesn't show a 2.8 Upper. Hope your feeling better.

 

Rob_02Lightning,
Nice thought but I don't believe that it works that way. All that your doing in either scenario is turning the upper pulley faster. It doesn't matter at all if you use a larger lower or a smaller upper, the ratio is the bottom line. Think about it. The blower is either turning faster, or it's not. And it doesn't spool up at all. It is completely linear.

 

This is enough to drive anyone crazy. All I can tell you, is there is a MAJOR DIFFERENCE IN HOW FAST IT BOOST'S UP, with the Upper Pulley on, and the second I took it off, that went away.
MAYBE I WOULD HAVE THE SAME RESULTS WITH A 6 LB ON THE BOTTOM ???

Does everyone running a 6 get instant guage pinning boost at feather peddal ???

 

You can plug in any size upper and lower in the last column "other"

4# upper and 2.8 lower yeilds net lower numbers than the JL 6# column

I still feel like crap - thanks for asking. 802.11 wireless is a wonderful thing

Doug

 

WOW,
I've had that sheet soooooo long and never knew that, THANKS DOUG. I guess I can't argue with the numbers. BUT MAN WHAT A DIFFERENCE IN BOOST UP TIME. As soon as I figure out why it happen, BACK IT GOES

 

I posted something about this about 2 years ago and no one ever really knew the answer. It would seem that a smaller upper would linearly increase the speed of the blower as the bottom pulley increased.

Therefore, if you have a stock lower, each revolution of the lower pulley would turn the top pulley x amount of times. However, if you install a larger lower, the upper pulley would turn more times per revolution of the bottom pulley because it's larger. At least that's how it works with gearing and other pulley designs. I'm not sure if the gearing in the blower or something makes a differnece or not.

 

Couldn't have said it better myself.Its exactly like the sprockets on a motorcycle. The total ratio is predicated on the size of BOTH pullies.The smaller will spin faster if the larger one is bigger and the larger pulley will spin the blower faster if the upper pulley is smaller.

 

Thank You Modo and SVT Lightning.

Here is the answer straight form the Experts that Make the Upper And Lower Pulley.

AND I QUOTE:

One word for your Rob, that is Less Rotational Masses , give you not only instant boost, but spooling the supercharger up allot quicker, over any lower crank pulley installed. I have preached this for years. You just recognized it as well. Exactly Rob, why do you think I would take Upper Pulleys on a Lightning, along with the Lower Pulley in all my Recommended Performance Packages my customers buy from me. But still nothing will ever spool up quicker than an Upper Pulley on any Supercharger. This is why other vehicles, I offer different sized pulleys, dependant upon their wants and needs of performance. Hope this helps.

Regards, XXXXX
Owner: XXXXX XXXXXXX Pulley XX

No need to start a war

 

Here is the more of the same from my Friend and Tuner:

http://www.nloc.net/forum/showthread...038#post222038