Hey merchant if you are going to add boost levels to your first post you really need to add what size crank pulley they are running. People who don't know the Vortech kit might be mislead because Vortech sends a 6" crank pulley with their kits when they made them. Not sure if SOS or Comptech does that. Also FYI it would be good to know if the people you are listing is running a FMIC or Air to water as this plays into the approximate boost levels you are trying to list. All of this matters plus some such as what exhaust setup? Release of back pressure will also drop boost levels........As others have said many variables that need to be factored into your goal here.

Min requirements should be

Blower Kit name and blower size
Blower pulley size
Crank Pulley size
FMIC or Air to Water?
Exhaust setup
AP1 or AP2 and\or Modified

 

I'll measure my SOS pulley and see where it stands compared to the Vortech and add the info if they are different. Different crank pulley sizes definitely will make a difference. As for exhaust changes affecting boost levels; this thread was intended to get a "rule of thumb" for PSI levels. I expect a certain S/C pulley size to have close to a 3 PSI difference on similar cars. Small differences will have to be expected. I have noticed that most people are getting higher numbers than what SOS advertises on their website, so I wanted some clarity on the subject. The aftercooler/intercooler would be a good add too. Thanks!

 

I'm running the Comptech Novi 1000 kit on a 2006 AP2 (aftercooled, SOS Racing Heat Exchanger) with a 3.4" SOS pulley and get max 7psi. SOS says it should be good for 9psi, but I've never seen that much, even in winter with colder/denser air.

 

You guys pulling out tables and graphs and all kinds of s**t in here! LOL. I was told that there existed somewhere on this site an "updated" pulley chart for the SOS pulleys since the chart on the SOS site seemed to be off in the smaller pulley range, but I've never been able to find it. Anyone know who created that chart and what basis they used for their numbers? It was probably Junky or Arax or one of the OG's.

 

So similar but kind of different question. If your on a stock AP2 engine and want to run the 3.2" pulley on a Novi 1200, considering this will probably be upwards of 16-18psi, does anyone run this much on a stock engine w/o meth injection? Is that too much for the stock engine on 93 pump?

 

Nahhhhh you'll be fine man. You would be able to make MORE power with meth or E85, but as long as your tuner has your knock sensor stuff working right and has your ignition tables set properly, you'd be fine. I ran the 16-18 PSI level on 93 octane for a summer, autocrossing regularly, before going to flex fuel.

 

"A larger crank pulley will spin the blower pulley faster and give you better belt wrap (less slip potential)."

Yes when ratio between the pulleys increase the blower pulley will turn faster but where out of your butt did you pull that you will have better belt wrap??? That was the point of my last post that went totally over your head. Again whether you increase the big pulley or decrease the little pulley you effect belt wrap and slip potential in the same way. Increasing the bigger pulley still decrease belt wrap of the smaller pulley which gives you more slip potential. To put it another way, if you increase the larger pulley you increase belt wrap on the larger pulley but decrease it on the smaller one.

 

A 6.5 crank pulley with 4.1 blower pulley makes right at the same boost(blower speed) with better wrap than a 6.0cp \ 3.8 blower pulley combo. As you can see you can use a bigger crank and blower pulley combo to spin the blower faster and have better belt wrap.

 

Something is off. My 3.4" on NOVI1000 that I ran for 12 months would hit 9psi right on the nose each time.

That's with BERK Test pipe & HS exhaust.

 

In my experience at sea level, with a stock rev F22 with a Novi 1000, you guys are both not seeing the boost you should be. You guys should be 10 – 10.5psi. Obviously Kenny Stang is well bellow normal and would make me want to start troubleshooting right away, as his boost loss is what I find to be on the low end for someone running an FMIC on that pulley. 9 psi is off the average mark as well, but several factors can cause a 1+ psi variance. I would expect this much to fluctuate just in temp and or elevation above sea level. Slight boost leak at couplers, BOV or some belt slip could be part of the equation. I found that if the belt started to slip, I would notice 1st or 2nd gear would show a lower peak boost then in 3rd or higher gears, this is due to the spin up rate of the motor in the lower gears, asking more from the SC belt to grab the SC pulley and provide grip. Make sure your boost gauge is reading properly, and or that you have a good boost recall feature rather then just eye balling it in 3rd gear redline wile ripping down the street!

As for belt wrap, obviously the bigger the pulleys you run (and that goes for the sc pulley as well as the crank) the more surface area the belt has to grip. I never had big slippage issues on my 5.45/3.2" combo, so I didn’t feel the need to up the crank and sc pulleys. But that would be the appropriate thing to do if you did, to maintain previous boost and increase belt traction.