With the Vortech after-cooler you loose less than 1/2# of boost and the lower air-charge temperatures do make a difference. I do spray water/meth after the after-cooler and my max air-charge temperatures are with in 10 degrees of ambient on a sustained full boost run. The power adder of after-cooling is in the timing, the less temperature you have the less timing is pulled from border line knock table by the air charge temperature sensor. The computer pulls a lot of timing with higher air charge temperatures. I had a problem with my pump not operating and you could feel the difference when the charge temperatures were up.

 

Looks like I need to get one of those Impellers from 928 motorsports.


I have a BD11A on my 4.6 I want to make some changes to my current set up. I have a little bling under the hood and want to change out my current pulley to a billet one from 928. I just purchased some 42lb injectors and a 90mm MAF to replace the FMU. I would like to upgrade to a 9lb pulley set up, , so which one do I get? The current stock BD11a uses a 6 rib/6lb pulley RIGHT???? So do I contuine to use a 6 rib or go 8 and what size would work best? I'm not looking for a race truck, just some more hp, but still reliable, I drive to shows 2-3 times a month and will be heading up to SC/TN in a few months

Sorry for the stupid questions, I'm still trying to learn about this stuff


Here is a pic from under the hood along with a few of the truck

 

Also, do I need a "Blow Off Valve


What size is the Crank Pulley on a 4.6 ?




Just so you know...I currently have 19lb injectors, stock MAF, 255 LPH Fuel Pump. The BD11A was used, but was rebuilt with the Gates Kevlar Belt and better bearings(not sure which ones). Also running a Innovative Wideband 02 with Gauge, NKG plugs, and a SCT Chip with a very mild tune. Like I said before, I will be installing 42lb injectors and a 90mm MAF


Thanks again

 

I am running a BD-11a and using a 2.62 pulley from 928 motorsports. 6 rib. I am pretty sure the crank pulley is either a 5" or 6" dia. One of the other guys im sure can tell you. I am producing 10 psi of boost at shift points. Check sig below to determine compatibility with what you want to do.

 

I would recommend the 928 impeller as the first upgrade, it will make more boost and CFM improvement than dropping several pulley sizes. Also the balance on that impeller is much better and will help maintain bearing life. At 5400 RPM shift points a 2.7 pulley puts you at the edge of stock impeller and bearing durability. The lower stock Powerdyne pulley is 6.5 inch I would recommend a Good Year Gator back belt to resolve belt slip issues. with my combination, 928 impeller and 2.5 pulley in cold weather I have hit 14# of boost, i just modified and installed 928s boost control valve to limit my top boost to 11# without sacrificing low end boost. I would highly recommend a bypass valve at any boost even at the stock 5 or 6# this relieves compressor issues when the throttle is quickly closed. You will also need some type of inter cooling once you hit 8# of boost or so. I would also recommend the 42# injectors and the 90mm mass air along with a good tune. As long as you are not in a hurry, Mike Troyer can make you an excellent tune and can dial it in if you are willing to do some data logging, you have a wide band and with the Xcal2 that would be all you need to get a good safe tune. I would not trust a stock tune if you are going with extra boost. One problem in many stock tunes is that the computer does not allow open loop operation in a timely manor, some configurations never see open loop. Fell free to email me if you have any questions.

 

^^^ Thanks for the info

 

Are you going to switch to a blow-through MAF setup with that boost controller?

 

No I modified the boost controller to accept a hose on the outlet side and I returned the air to the supercharger side of the intake elbow just as you do with the bypass valve, and it is working just fine. I have limited the boost to 11# and have had no air/fuel or performance issues.

 

Well, looks like I'm going to get a new pulley from 928. I'm thinking of getting a 2.75". Looking for about 9lbs, will that do the trick?


Also, I'm getting an SCT Xcal3 to replace my SCT chip. The truck will be getting tuned by Salvatore Mennella @ PSP on March 1st

 

The rebuild on my Powerdyne has only about 8,000 miles on it, I will be doing the impeller/shaft from 928, later in the year

 

Hey Chuck, I sent you a couple of PM's. Did you get them?

 

Yes i did, I sent you an answer last night, if you did not get it send me an email my address is with the site and I can get back to you directly. That is easier.

 

Did not get them, email sent.


Thanks

 

Chuck, I need to speak with on the Bosch Blow-off Valve, you have mail


I ordered the 2.75 from 928, I wanted the Natural, but they were out, so I got the blue anodized for now. They had the natural in the 2.62, but I thought that would be pushing the impeller.

Using 928's formula for finding the right pulley


(Engine Redline or Shift Point) x (Crankshaft Pulley Diameter "A") divided by (Supercharger pulley diameter "B") x 3 = Impeller Speed "D"


(I used 5,400 based off of your email/post for the shift point, is that correect?)5400*6.25/2.75*3= 36,818(that is with the 2.75" pulley from 928)

5400*6.25/2.62*3= 38,645(2.62" pulley)

So should I stay with the 2.75" or the 2.62"???? I want to keep it around 8-9 lbs????

 

The difference between the two pulleys will be about 1#, you're actual boost will be determined by a lot of things, such as air flow and supercharger clearance, all you can do is try one and see what you get, i would say that you should be right in the area that you desire, give or take 1#.