Setting up Supercharger
08-23-2002, 04:31 PM
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Setting up Supercharger
I have been toying with putting a supercharger on my 502ci motor. The motor is freshly rebuilt, just about 9:0to1 compression, 226/234 with 112 lobe seperation on the roller cam.
My question is what modifications will I have to make to my carb if I put it on top of a Holley 250 supercharger. I am planning to set it up with a conservative boost level of around 4lbs.
This will be my first supercharger. Any help from others experience will be helpful.
My question is what modifications will I have to make to my carb if I put it on top of a Holley 250 supercharger. I am planning to set it up with a conservative boost level of around 4lbs.
This will be my first supercharger. Any help from others experience will be helpful.
08-23-2002, 04:39 PM
#2
speel chekk this fokker!
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it will need to be jetted richer. I wish i had more technical info than that. I am sure somebody will chime in with the actual #s
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08-23-2002, 04:59 PM
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Sorry about the lack of info, I'm at work and got interupted, the nerve of these people to bother me when i am on OSO!
Anyway, the carb I have is a Holley #9381 a 830cfm chokless race carb with four corner idle and two powervalves.
The cam as I mentioned is a Comp Cams custom grind 226/[email protected] with 112 lsa and installed at 110 ILS roller.
The motor has full roller rockers in it as well.
I have the D.U.I high energy ignition with about 20 degrees in the distributor.
The other question I have is would the smaller 174 unit be enough or should i spend the xtra for the 250, there is several hundred dollars diff.
Anyway, the carb I have is a Holley #9381 a 830cfm chokless race carb with four corner idle and two powervalves.
The cam as I mentioned is a Comp Cams custom grind 226/[email protected] with 112 lsa and installed at 110 ILS roller.
The motor has full roller rockers in it as well.
I have the D.U.I high energy ignition with about 20 degrees in the distributor.
The other question I have is would the smaller 174 unit be enough or should i spend the xtra for the 250, there is several hundred dollars diff.
Last edited by TomR; 08-23-2002 at 05:01 PM.
08-23-2002, 09:00 PM
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speel chekk this fokker!
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merc use dthe 174 on the 525sc engine but ath wa s 454. I keep hearing for a 502 youshodul go with the 250. I think that a 174 would work you just might have to spin it faster to make more boost. If your going with new i would go with the 250.
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08-23-2002, 09:52 PM
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You're going to need to have your carburetor set up to work on top of the blower, or better yet buy one built, & designed to go on top of the blower. The fuel curve is different, Boost ref. PV along with other changes. As for the blower Go with a 250 from The Blower Shop. It blows anything Holley can make away (no pun intended) talk to Marv out there. www.theblowershop.com great guys, and great products.
08-24-2002, 05:37 PM
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THE 250 WILL MAKE LESS HEAT AND HAVE A DENSER CHARGE AT THE SAME BOOST LEVEL SO BE SURE TO GO WIT THE 250 OR BIGGER ,,ALSO BOOST REFERENCE THE POWER VALVE AND ADD A 2.5 PAIR OF VALVES AND START WITH 4 SIZES LARGER JET AND MAKE A SHORT RUN WITH NEW PLUGS THEN READ THEM AND ADJUST THEM FROM THERE !
HEY THE GUYS AT POWER MARINE ,IN CHARLOTTE N.C. DID MY CARB WORK AND THERE OLD NASCAR GUYS AND GAVE ME A GREAT DEAL AND HAVE BEEN THERE FOR ME EVERY TIME I CALL !
THE GUYS NAME WAS ROBERT AND PHONE 704-889-3777,OR 704-574-4020,
THIS INFO ,I HOPE HELPS :
HEY THE GUYS AT POWER MARINE ,IN CHARLOTTE N.C. DID MY CARB WORK AND THERE OLD NASCAR GUYS AND GAVE ME A GREAT DEAL AND HAVE BEEN THERE FOR ME EVERY TIME I CALL !
THE GUYS NAME WAS ROBERT AND PHONE 704-889-3777,OR 704-574-4020,
THIS INFO ,I HOPE HELPS :
08-26-2002, 07:53 PM
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If you haven't bought the blower yet, I'd consider a 420. The 250 was designed for a high horse 454. They started making the 420 for the bigger motors like the 502. The air/fuel charge will be cooler with the 420 as well. I ran a 250 w/two 750's on a 454. 697 horsepower with 7# boost, blower cam, ignition and fuel delivery mods. The down side was the 250 is real noisy at speed!
Built a 509 with a 420. Used the same carbs, added an intercooler. 878 horsepower. Nothing like blown power
Last weekend marks a year it's been running without a hiccup! Hopefully I didn't jinx the next weekend
Don't scrimp on the ancillaries like ignition and fuel supply!
Craig
Built a 509 with a 420. Used the same carbs, added an intercooler. 878 horsepower. Nothing like blown power
Last weekend marks a year it's been running without a hiccup! Hopefully I didn't jinx the next weekend Don't scrimp on the ancillaries like ignition and fuel supply!
Craig
08-26-2002, 07:57 PM
#8
Ginger or Mary Ann?
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I'm running a 1050 dominator with my 250 on my 502 @ 5lbs boost. It has been boost referenced and built for a blower. Is a single 830 large enough? If it is not right, it will be a night mare! Or worse........costly.
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08-26-2002, 10:51 PM
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Talk to somebody who knows! Shops have been mentioned in this post who may be able to help you. I would use Dean Nickerson at Nickerson performance because I know he has alot of experience with 250 b@M's on various applications. He also is a recognized carb guru. They advertise that something like 95% of their carbs don't require jet changes when they set them up for your application. Some of the others mentioned may be good too. I am currently installing a B@M 250 EFI blower with a Superchiller on a 454. I am about to order my Superchiller from Dean.
