Procharger? How to determine Boost/Pulley SIze?

[THE GOON]

I'm trying to determine what pulley sizes I need. FOr the sake of keeping this easy let's just use cog/gilmer as the reference point. Is there any way to determine what size crank and blower pulleys to start with to coincide with my intended boost level?? I have this worksheet to use as a reference point if it helps??

I know that the The smaller the crank cog the slower procharger turns and the lower the boost

The smaller the procharger head cog the faster the procharger turns – more boost.

But what size do I start with or is it all trial and error?? I really don't want to have to buy 6 sets of pulleys.

[1BADBET]

Boost is a measure of positive manifold pressure so what manifold and cylinder head you run is going to play a huge part in how much boost it is going to take to make X horsepower or how soon the induction system becomes a restriction thus creating boost/ positive manifold pressure. There's no exact science to it your best bet is to call pro charger, let them know what you have and what you want to run and take their recommendation since they'll have the most experice with their own stuff. Worse case you buy one set of upper and lower pulley and it's off a little from your goal and you just buy one upper OR lower to get it right but they'll be able to get you closer than anyone else from the start.

[THE GOON]

Thanks badbet. I do agree with you and understand that much.

Here's where my head is at,

I believe 8" is the standard rib style crank pulley I have not seen a larger one. With your D1X I would need to run about a 3.4 supercharger pulley to get the boost level up on my engine.3.4 is one of the smallest for my head unit and I will need to put a lot of tension on the belt so it doesn't slip.that should make around 10-12 psi of max boost due to the size of your engine maybe less. I think with my set up having high compression even with less boost you will have good performance

If I can obtain 10 psi of boost, that is a PR of 1.68. My Engine N/A dyno sheet indicates I achieved 526HP @ 4900rpm, so 884 Hp, minus the hp to drive my blower, and other ineffieciency's. The smaller blower could put out a lot of heat and be less effiecient, something I need to be aware of and make sure my water/meth nozzles are sized accordingly

[1BADBET]

I think the d1 style supercharger have a cog pulley, if not I think you can swap it out for one so you don't have to worry about a lot of tension on the belt since the ribs in the pulley will help keep it from slipping. If it were me I would run the pulley set up that gave the most boost then use one of their blow off valves to regulate it on pump gas cruises. Depending what kind of electronics you want to run you could have the blow off valve build more boost as the meth comes in. More power, more street friendly, just cost more money lol. You could also look into the supercharger store they make a crank drive set, up and i think chassis works does also, that makes it easier to mechanically change the impeller speed/ boost level

[THE GOON]

Thanks Jordan,

I already have the serp pulleys but would need to fabricate a good tensioner so I may just change to cog anyways to get the positive contact and not worry about slippage.
Supercharger stores website is the absolute worst and they seem very difficult to deal with if you don't buy the Entire setup from them... at least that's my experience. But thanks for the lead on chassis works I wasn't aware of them.

I do have a BOV and think between the aerosol blowthru, IC and Meth I hope I'm covered



Cheers and thanks for your help!