New SC Pulley from Magnum Powers

Magnum Powers

Registered User
Gentlemen,

David Dalke asked me to provide larger diameter 10 rib supercharger pulleys to decrease overdrive ratio as this would help with a some of his engine builds. So I am providing these for those who may need them. I plan to offer them as a 10% JS/SC pulley kit or you can purchase them separately if you already have our 15% JS/SC pulley kit.

Charles
 
The site doesn't list just a JS pulley.

My point in originally suggesting a different sized blower pulley stems from the fact that for people with a 3.8L engine, the 25% OD combined with the new MP coated rotors results in too much boost for pump gas (19-20psi on a well built motor). Dropping the OD down by 5% will reinstate some pump gas drivability and will also improve belt tension situations for a lot of people which we know is an ongoing issue for anyone running 25% or more.
 
The purpose of this post is getting muddied up with confusing information. This post isn't about a JS pulley at all, it's about a blower pulley. But to understand the blower pulley post, you may need to know a couple things about the MP JS pulley.

The MP JS pulley is 10%. That is not part of this discussion nor is it being considered for alteration. If you want one without a blower pulley, talk to Charles about buying one by itself. That discussion has nothing to do with this post.

This post is about the 10 rib blower pulley.

The 10 rib blower pulley that is included in the 15% MP kit is a 5% OD (which is then coupled with the 10% JS pulley). Stay with me here. So the JS kit is 15%. The MP crank pulley kit is also 10% and this gives you the 25% kit. Many people already have the 10% crank pulley. In fact if you have a built motor and a neutral balance pulley, most likely you HAVE this pulley already. There is also a pretty good chance you have the JS kit, particularly if you have an MPX blower. The next natural upgrade if ALREADY have the 10% crank and 15% JS AND the MPX blower, is to get the MP improved bearing plate and abraidable coating rotor pack. If you don't have all of these things already, then this whole thing may not be of any interest to you. But if you DO have these things, continue to follow along.

If you have 25% OD and an MPX (with the new rotor pack installed) on a built 3.8, then most likely you are experiencing the 2 following problems: 1) belt slip, and 2) too much boost for pump gas!! So what to do now? You have all the best stuff and it doesn't work! Well, in that case it might be a smart move to drop the blower OD back from 5% to STOCK (or 20% overall). This will accomplish 2 things, 1) it will lower boost slightly making the package more pump gas friendly, and 2) it will reduce or eliminate belt slip due to the fact the larger diameter blower pulley will give more belt traction AND it will take up some of the slack on the ONLY belt available in 10rib (40" long) which is a tad too long for a 5% 10 rib pulley.

If you have all of these parts you are aware of these issues. If not, well then you still have some things to learn and experience possibly.

Anyway, that is why the pulley is offered, it has nothing to do with JS pulleys other than being offered for sale in that package. If you don't feel the need for a 10rib blower pulley, then this post isn't for you.
 
Thanks for the clarification David!

The larger diameter pulley is $150 plus shipping. It is not on the website yet as I did not know if anyone would be interested. If you want one drop me an email with your PayPal email address and I will send you a PayPal invoice. If there is significant interest I will have the item added to the MP website.

Cheers,
Charles
 
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