Crazy idea for powerdyne guys (P&P)

[97rs4life]

I was looking at the bd11a headunit we just got and was wondering if anything could be gained from porting the scroll casing where the air is pushed out of the charger. Like make the innerdiameter bigger of the discharge part of the housing. I guess I see those gtp guys porting their blowers and just wondered if this would help take some pressure off the blower by opening that up bigger. Maybe would work better for guys with smaller pullies so it doesn't heat the blower up as much.

Let me here your thoughts.

[Mighty Thor]

Re: Crazy idea for powerdyne guys (P&P)

I was looking at the bd11a headunit we just got and was wondering if anything could be gained from porting the scroll casing where the air is pushed out of the charger. Like make the innerdiameter bigger of the discharge part of the housing. I guess I see those gtp guys porting their blowers and just wondered if this would help take some pressure off the blower by opening that up bigger. Maybe would work better for guys with smaller pullies so it doesn't heat the blower up as much.

Let me here your thoughts.

The head unit doesn't heat up much. Only the heat from the engine and headers gets to the blower. If you have a BOV it's even better.

When it comes to Centrifugal what you're after is airflow and how that flow shows in the graph. The BD-11a is rated at 850 cfm and it shows really good at the graph. 928motorsports has a graph of this but they don't have it anymore in their site.

I think porting and polishing would mess it up. Centrifugal is very different from Root or Screws that's why you don't hear guys P&P their blower. There's a calculation of how big the intake, impellers and discharge should be in order to get that desired cfm and to show well in a graph. Hope this helps.

[97rs4life]

Re: Crazy idea for powerdyne guys (P&P)

yup makes sense, thanks. I am just trying to figure this whole powerdyne world out.

[usd2sing]

Re: Crazy idea for powerdyne guys (P&P)

good idea/concept. but most likely will have a negative effect. they designed the scroll to specific specs for a reason.

BUT!.

if u really want to be creative....
reduce the tubing in steps to the tb from the output port from the s/c.
creating more velocity/boost.

i took part in a c4 (vette) project that had a procharger on it, the idea worked.
8lb pulley ended up producing 13lbs of boost.
only bad part was the motor blew on the dyno. (non forged).
after the 11th pull ran out of meth, didnt check it...KABOOM!!
it was nasty. shook the entire building...
after he went with a forged ls1 he upgraded to a D1 (procharger) kit.
he runs low 9's in the 1/4 now. (15lbs, meth, and 100 dry nitrous to get out of the whole)

FWIW

[grayman]

Re: Crazy idea for powerdyne guys (P&P)

p and p on the scroll might help. it is not as if the makers would do it themselves even if it did work better. stuff like porting and polishing is left to aftermarket techs. as mentioned above a good discharge route works positively as well. the least amount of bends, no resrictions, etc, all help the intake system.
if you do it make sure you get a rag soaked in petroleum jelly stuffed down the scroll so as to not get crap down there. better yet, rmove the scroll and work on it seperatly.

pwerdyne discharge inner diameter is 2.25" but the TB has a 3.5" outer diameter. kinda hard to 'step that down'. the shortest length is most likely the best for the powerdyne.


i wouldn't take too much material out, though. i think durability and strength of the blower unit might be more important than a little gain in output efficiency....but that scroll is rather thick...about 1/4" thick walls.