I have a vortech supercharged s2000 with the following engine mods:

AEM ems.
650 injectors.
Toda header.
Amuse R1000 exhaust.
Exedy hyper single clutch / flywheel.

Soon to have:

Rick's 4.57 gears.
Cusco RS 1.5 way LSD.
Comptech reinforced diff housing.
Lower compression pistons.
Stronger rods.
Sleeved block.
Crank girdle.

I want to run higher boost with my Vortech. I just got off the phone with Vortech and they said the blower will support up to 20 psi. I'm sure the motor will handle all the boost after it's built. Here's what I know and need to know to get the job done.

Per vortech's website: The SC comes with a 6.0" crank pulley and a 5.0" SC pulley. This translates into an impeller speed of 38,880rpm. (http://www.vortechsuperchargers.com/...pspeedv-2.html) They say this is around 8psi. How fast does the impeller have to spin to create 20 psi of boost. If I know this, I will be able to figure out what size pulleys to use. Vortech will not help me. I don't think the impeller speed increases linearly with crank RPM. I know there are some of you that are running an 11psi. pulley. If I know the size of your pulleys, I may be able to make a model to determine the size of pulleys I need. Any help would be much appreciated.

These links may help:
http://www.vortechsuperchargers.com/...pspeedv-2.html
http://www.vortechsuperchargers.com/suppor...rim_v2_map.html

Thank you,
-Dave

 

just curious, what comp ratio are u dropping ur car to?

 

You need to find out from vortech what the gear ratio is in the unit.

impeller speed DOES increase linearly with crank RPM. That ratio is based on gearing in the unit, and the ratio of the belt pullies.

I don't think you will have enough thread to be able to put that small of a pully on the stock bracing. You will have to tighten down the bolt too far to keep the belt on the pully... unless you find an approperiately smaller pully belt... but if you are going to have custom stuff made, if you make a larger crank pully, that will give you more boost too. b/c it will increase that ratio.

 

I'm not 100% certain yet. I was thinking around 8.8:1. I need to do some research to see what the highest compression I can run with 20psi of boost. I'm not sure yet either, but I would like to run 93 octane gas too.

Lots of research to go

 

Well.....

I do know that at 9000 crank rpm with a 6" crank pulley and a 5" SC pulley the impeller spins at 38880 rpm. With that information I should be able to determine the gear ration is in the unit. I'm not sure that helps me that much though.

I think what I should have said earlier is: Does boost increase linearly with rpm? If it does, I have enough information to figure out the correct pulley sizes. I really only need to know is how fast does the impeller need to spin to create 20 psi of boost.

 

Looks like 3.6:1.

Can you change the gears in the Vortech? If not you are going to need a 3:1 ratio between the crank and sc pulley to get near your boost target.

 

I calculated on my car the Vortech would max out the impeller speed (53,000) with a 3.8 inch pulley going 9500 rpm. It would only reach 15.X lbs of boost and that equates to 450 or so rwhp (Dynopack.) To see 500 hp with a Vortech may require finding a bigger blower unit to get the job done.

 

So, with the 3.8" pulley you got 15lbs of boost. Did you try this, or was it all on paper? Acording to Vortech, the blower should make 20lbs of boost.

 

Are you assuming that boost increases linearly with RPM? I'm not sure if it does or not.

 

Ask vortech for a compressor map. It will tell you the amount of airflow produced at what impeller rpm and much more. Hope your good at math or know someone who is. Superchargers don't actually produce boost. They move a volume of air over a span of time. This air flowing into a restriction is what produces boost. Every application will be different. If you set up your car for 11psi of boost then you port the intake and thus have less restriction, your boost will drop but the amount of air flowed into the engine will stay the same and possibly even increase. In other words, more power with less boost.
-Brian