hey guys im about to buy a 92 formula with a 350 tpi, i want to convert it to carb and put a root style s/c im going to put this s/c on it

http://www.summitracing.com/parts/WND-6502-1/

and i was wndering what size carb to put on i was thinking of this one

http://www.summitracing.com/parts/WND-6502-1/ but im not very good with carbs and if i do this it will by my first carb'd car.

if this carb isnt worthy please let me know what other one to put on, and i know im going to need a fuel regulator and fuel lines but what else would i need to do to convert it to carb.

 

id go with the holley 700 cfm supercharger carb. it is specificly setup for a draw thru roots design.....boost referenced power valve, 50 cc acc pumps etc.....

as for your fuel lines you would need a return style fuel pressure regulator something like the mallory 4309 and ald a fuel pressure guage would be good too.youll want to run 6psi of fuel pressure at idle and have a vacuum line coming off the intake manifold over to the boost referenc eport on the regulator.as boost increases youll need more fuel......

timing you will want to run no more than 30* total...depends also on your compression ratio and what other modifications you have...if you have any other questions let me know thanks

 

I highly recommend talking with Patrick at Pro-System. He will custom calibrate the carb for your application. What this means is that when you bolt this thing on all you have to do is set the idle rpm and it should be right on. He is very good and even has his cell# on the carb bowl for assistance. This is great customer support.

http://www.prosystemsracing.com/custom.html

 

Options?

You can buy a Pro-Systems carb like already mentioned, but get your wallet out and be prepared to spend some scratch.

Buy a Demon blower ready carb, have it tuned on a chassis dyno and most likely get off a little cheaper or the same as above....

Buy a used NA Demon on Ebay and get the blower baseplate which will reference the PV, and tune from there...and most likely get off cheaper than the above...

Buy a NA Holley and reference the PV yourself (I've done it) - cheaper than any of the above.....

Buy an Edelbrock carb and not worry about refrencing any PV, and just tune it.....probably the cheapest route.

In any case, I'd go with a bigger carb - probably an 800 or 850 CFM...

EDIT:
- on any roots blower with a carb on top, you want a constant 7-8 PSI fuel pressure (it doesn't need to go up with boost, that's only for blow thru)

-The general rule is to back off 2 degrees of timing per pound of boost, but that depends on your cam, compression, type of gas, etc..like Badass355ciz28 said.
-I can run 32 degrees of mechanical at 5 pounds of boost without detonation...

-You may or may not need 50cc Acc pumps (I didn't)....

 

I know it has been awhile since anybody has posted in this topic,but I recommend giving John at JDR Performance here in Marshfield,MO a call.. We just had him build us,a new carb for my dads 383 with the magnuson 122 supercharger,and all I can say is,WOW!! I had Quick Fuel supposedly set me up a custom 750 for my combo and it never worked right,always sluggish feeling at part throttle and had no choke...I later found out that everybodys blower carbs from Quick Fuel all have the same specs as mine....so that leads me to believe it was just an off the shelf carb. That's what you'll also get with a Holley "out of the box" supercharger carb also,they will have a generic tuneup in them for a supercharged engine. John at JDR Performance will set the carb up for your specific combibation with a manifold referenced power valve,we also went with a manual choke for better cold weather starts for a daily driver. The drivability and response of this new carb is unbelievable,its approaching fuel injection quality...and I am being very honest...I was amazed myself how smooth and responsive it was compared to the Quick Fuel I had on it...The carb he set up for our 383 with the magnuson 122 has a,1.400" venturi and the bigger 1.750" butterfly billet throttle body,he said this combo will flow around 840 cfm and is still very reponsive...it seems he was right!!

Anyway just a suggestion for a guy that can build you a carb that will work excellent...trust me...we have been through this...it took us about $1300 worth of carbs to get a good one...your better off to buy the good one the first time and be done with it....here is his website if you want to check him out... WWW.jdrperformance.com

Brian