Questions and Discussion on Vortech Supercharging Systems

[ft86me]

Originally Posted by Adeets

Any one know if this is the belt to run the 3.0 pully? Or is that one a different size?

I believe this is the one for the nine psi

[Rick@Vortech]

Originally Posted by Adeets

Any one know if this is the belt to run the 3.0 pully? Or is that one a different size?

That belt will be too big. Since your pulley is .48" smaller than the stock pulley (3.48") you'll need to subtract that difference on the belt length, bringing you down to a belt length of 97.0". If you can find a belt that's just a hair shorter than 97.0", it should be a very snug fit & less likely chance of belt slip.

[DJCarbine]

Originally Posted by Rick@Vortech

That belt will be too big. Since your pulley is .48" smaller than the stock pulley (3.48") you'll need to subtract that difference on the belt length, bringing you down to a belt length of 97.0". If you can find a belt that's just a hair shorter than 97.0", it should be a very snug fit & less likely chance of belt slip.

What PSI will the 2.87 pulley put you at?
Is there perhaps a chart with the different pulley sizes and the respective peak PSI at factory redline?

[Rick@Vortech]

Originally Posted by DJCarbine

What PSI will the 2.87 pulley put you at?
Is there perhaps a chart with the different pulley sizes and the respective peak PSI at factory redline?

Unfortunately there is no chart that can give you estimated peak PSI, mainly because there's a lot of contributing factors that will affect your boost. Supporting mods, type of fuel you run, stock or built motor, etc.

The one thing I can tell you is that every pulley size you go down, it usually equals a 1-2psi increase (I say "usually" because your overall altitude comes into play in certain areas). Again, it all depends on what's done to your car & where you live (altitude comes into play). For example, someone with a 2.87 pulley in Los Angeles (just about sea-level) may make 16psi, but someone in Denver with that exact same pulley on the exact same car may make 11psi (those are just random numbers. strictly for example)

Going from a 3.48" to a 2.87" is one heck of a jump. At that point, I would do the calculations to make sure you don't over spin the blower. Again, that's just me.

[pheoxs]

Originally Posted by DJCarbine

What PSI will the 2.87 pulley put you at?
Is there perhaps a chart with the different pulley sizes and the respective peak PSI at factory redline?

It's right about 14psi on our engines give or take based on elevation

[Adeets]

Originally Posted by DJCarbine

What PSI will the 2.87 pulley put you at?
Is there perhaps a chart with the different pulley sizes and the respective peak PSI at factory redline?

There's a write up about it, under google how to read a compressor flow graph, after doing it to establish the difference between the rotrex and the vortech... After doing all that I'm never gonna ask the psi of xxx again because I realize how violently of a shift the psi you will see based on ambient air and how good your intercooler is doing its job... To sum up my experience with doing all that (you can see it in the kraftworx thread) all I can say is I'm Jon snow and I know nothing.

[nelsmar]

Originally Posted by Adeets

Any one know if this is the belt to run the 3.0 pully? Or is that one a different size?

The 975 will not fit. I have been testing a number of belts (dont ask how many i have snapped... you dont want to know!).

For a 3.00" you will likely need to be running the 962 belt. They do not make a blue belt or even a green belt (drats! this is for a chevy 2500 too!). This should fit nice and snug placing you cold at roughly 1/3 tension on the tensioner.

I have a 3.125" pulley but a passenger side idler with ~ -0.1-.2 (i forget the exact, my stock one got completely obliterated with a 975 belt and a 3.125 pulley within 20 miles on the highway with cruise control on) size difference and the 962 was the only belt that i could run without snapping it within 200 miles.

Just make sure once you put this pulley on you verify your pulleys are lined up as close as possible. There is a lot more "play" in the backplate angle than you may realize which can easily cause issues with your belt.

[v1ru5]

Originally Posted by DJCarbine

Gates 38006 Pulley
Gates K060975RB belt

The pulley is a somewhat common steel pulley to replace the plastic pulley people have issues with (me included), the belt is the blue "racing belt" from gates. Supposed to last longer, and perform better under high stress

I just had a belt snapping incident.... without snapping the belt. That blue belt hopped a groove on the crank and water pump pulley. They weren't kidding about strength. Now I know why my belts where snapping... I just don't know how to fix the problem. Does this sound like the tensioner is bad?

[nelsmar]

Originally Posted by v1ru5

I just had a belt snapping incident.... without snapping the belt. That blue belt hopped a groove on the crank and water pump pulley. They weren't kidding about strength. Now I know why my belts where snapping... I just don't know how to fix the problem. Does this sound like the tensioner is bad?

Check the aligned of your pulleys. You may have your blower pulley shifted 1 tooth forward or back from the motor. This needs to be carefully lines up during install. If not the belt can jump and due to the edging on the idler it can easily damage the belt. It's fairly easy to be an entire tooth off. Stand near a fender and peer from one head to tue other and see where the blowers pulley is placed. I am going to guess you need to loosen the upper bracket attached to the alternator and slide it away from the firewall if the belt was pushed towards the firewall then the supercharger breeds to be pushed away from it. This bracket is slotted for alignment purposes.

[pheoxs]

Originally Posted by Adeets

Anyone have a boost gauge or IAT readings with a 3" pully, occording to our flow map we should be getting around 13psi (50,000 rpm) with that pulley at around 70f ambient temp or 125f IAT temps, just want to verify my maths with reality.

Sounds close but probably 12psi instead. I think the 2.87 makes 14psi

[DJCarbine]

Ordered the FA20club 12psi upgrade as well as injectors/fuel pump.
Going to measure the pulley when I get it to see what size they are using for this.

[charged86]

Originally Posted by DJCarbine

Ordered the FA20club 12psi upgrade as well as injectors/fuel pump.
Going to measure the pulley when I get it to see what size they are using for this.

Maybe 3 inch. 3.125 got me 10psi

[nelsmar]

Originally Posted by charged86

Maybe 3 inch. 3.125 got me 10psi

According to the dynos weather station 3.125 gave me 11.5psi at 7100 rpm. Ecutek logs with checking ambient atmospheric pressure of my 3var showed 11.5 at 7400

Your exhaust flow and can tuning cam affect this boost reading. Unless someone has installed a pre-intercooled iat sensor you may not get the info you want. However my pulley is nearly that size and I have been doing a lot tests including multiple dyno sessions. Maybe if you just tell me what you are aiming to find I can just directly answer it.

[nelsmar]

I tapped 360whp on the dyno today with a 3.125 pulley and e80 fuel. . Plot shows hood open vs hood closed.



Stock exhaust. No snorkel. 3.125 pulley. Fa20club flex fuel and tune. Dw65
Pump 540cc injectors. Berk test pipe.