Powerdyne BD-11a versus Powerdyne XB-1A dyno numbers - need some input | Page 4 | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Powerdyne BD-11a versus Powerdyne XB-1A dyno numbers - need some input

The fuel was lean on two runs at 3,000rpm. 3,000 is the point at which boost is high enough to need more fuel and less timing. 16.28 is way lean!!! 13.72 is lean! 12.71 sounds a bit lean at 3lbs of boost even with your intercooler. It should get richer as boost builds. It is amazing to see the tuning to me, boost jumps to 2.84lbs and the torque jumped when the fuel got better.
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





Received these observations from a user at corral

IMG_5107.jpeg


IMG_5108.jpeg


IMG_5109.jpeg
 






rhthrth.jpg

We had another dyno session with Big White Ford Explorer and the XB-1a on November 30th. We did a few dyno pulls again with the 2.7" pulley and improved standoff pulley on the bottom side of the SC belt. You can see the last pull as runfile 2 in the sheet above. This time we were datalogging and we saw the MAF counts plateauing when it was expected to see them keep rising. We checked in the previous runs to see if there was any possible restrictions before the blower (airbox/filter) and there was nothing noted. What the MAF counts showed when put with the dyno data from runs 0-2 (only run 2 is shown above) is there was definately some belt slip happening - more so from 4500 rpm and above. On run two we saw a max boost level of 6.01 lbs at 5.64k rpm

The guys at Stage and I then decided to change the 2.7 (2.65 actual?) pulley to the 2.8 (2.86 actual) and try it again. Surprise (see runfile 3 above) - we saw a larger max HP number and boost number (almost 8 lbs) with the larger 2.8 pulley which means that there was alot less belt slip. So it seems pretty clear that belt slip is the main issue. If the 2.7 pulley had not been slipping, I suspect we would have seen probably mid 320's or higher on HP, perhaps 360's on torque and probably more than 9 or 10 lbs of boost. The maf counts in the datalog continued to rise this time as expected too. You can see that at 4700 RPM and above, with the 2.8 pulley, HP continued to rise and the 2.7 pulley, HP was dropping (belt slip)

Unfortunately after that last dyno run, I finally took the truck out on the road for a few miles (about 15 total) of actual driving - shifting at a max of 5400rpm (AWD 4R70W Transmission with stock 2nd Gen Explorer Torque Converter). The blower started making some bad noise and it appeared the the high speed bearing in the XB-1a decided to have some issues.




here is what the blower sounded like before this issue


The blower only had the previous dyno pulls on it and no driving. The blower had never been spun higher than the recommended 50k rpm. It was sent back to the builder and the builder confirmed

"
The inside high speed bearing was damaged a little. Probably overheated or lacked enough lubrication for some reason...
Multiple Dyno runs are some of the harshest conditions any engine parts will see !

We will replace it this time for no charge, tho
"

From my visual inspection prior to sending it back - the impeller and surround area seemed fine with no damage. Seems as if only the high speed bearing is what had a problem.

I spoke to the guys at Stage and we intend to check the oil pressure going into the blower after it comes back. I am asking the builder what the oil pressure spec for the XB-1A should be at if this is what caused the problem. Wondering if the oil pump in the Explorer 302 puts out different pressure from that in the SN95 or Fox Mustang 302?? As far as overheating, again the blower was never spun beyond 50K and not sure what else could have caused the issue. We are still having some discussions about it. I am waiting on photos of the bearing and hope to confirm what the specification of the high speed bearing is installed in this new production XB-1A blower.

Once the blower comes back, we will stay (for now) with the 2.8 pulley and work on increasing the crank pulley from 6.5 to hopefully 8 inches which would allow us to run the 2.8 pulley or larger to further eliminate the belt slip and hopefully see a better result with this blower.
 






More info from the Powerdyne builder on the high speed bearing issue


Actually I assumed wrong ! The bearing felt rough when spin by hand, so I assumed it was bad…

But in reality, turned out when we took it out - just was a few tiny pieces of trash in the bearing - seemed like maybe tiny pieces of aluminum - but cleaned it out and seems fine, but will obviously still replace it !



I really have no idea what it was, or where it can from, but so small it fell out when I popped it apart, and lost it, I figure it was causing the balls to ‘skate’ along, causing the sound, without damaging the race… “
 














Latest Dyno pull after XB-1A was repaired.

I had hoped to hear of success, sorry if your build lost another blower, or if something else is up?
 






Finally have the Powerdyne XB-1a on my 2000 Explorer initially dialed in. Here is a quick comparison short of my initial 0-60 pulls versus those with the BD-11a with the same pulleys. Dyno sheets for current setup are coming soon….


 






So the original Ford OEM Waterpump decided to make these interesting noises and realized it was time to replace it while increasing the crank pulley size, ribs and changing to a different waterpump pulley size (to make it all fit) for the Powerdyne XB-1A Gear Driven Supercharger that is currently installed.

The reality is that the secondary musical like sound it was making has been ongoing since the 1st Powerdyne BD-11A silent drive/belt drive Supercharger was installed. You would always hear it just as you shut off the engine. Interesting to finally know where it was coming from.

Found out that Ford no longer makes the waterpump for the 2nd Generation Ford Explorer V8 5.0 Motor but I was fortunate enough to find an NOS Genuine Ford unit - brand new in the box and never opened.

 






Hoping this gives a bit more for reducing any possible slippage. Coming off of the lower alternator bracket we put an idler pulley that basically puts pressure on the bottom of the supercharger belt (pushing up) and then tensioned it (the belt) to the appropriate tension measured using the Gates KriKit tool
 






Hoping this gives a bit more for reducing any possible slippage. Coming off of the lower alternator bracket we put an idler pulley that basically puts pressure on the bottom of the supercharger belt (pushing up) and then tensioned it (the belt) to the appropriate tension measured using the Gates KriKit tool
It does seem to have helped some. Right now in the middle of building a new crank pulley (going larger), new waterpump pulley and possibly moving all for the supercharger to an 8-rib setup. Its a tight fit. Also moving to a true 200 amp alternator.
 






Go man, Sounds like you got it figured-out and will be pumping better boost soon!
 






So finally took care of alternator and waterpump issues. Figured out new spacing and might be able to fit 8 ribs while making the SC Crank pulley larger. Here are the new XB-1A blower rpm calculations.

Blower builder recommends 50K max RPM for longevity/reliability


So thinking between 48.5 - 50K


Calculations (I think they should all be correct)


8" Crank Pulley and 3.1/2.86/2.65 SC Pulley


  • 5200
    • 46262.58
    • 50036.36
    • 54001.51
  • 5300
    • 47050.32
    • 50998.6
    • 55040
  • 5400
    • 47938.06
    • 51960.84
    • 56078.49
  • 5500
    • 48825.81
    • 52923.08
    • 57116.98
  • 5600
    • 49713.55
    • 53885.31
    • 58155.47

7.5" Crank Pulley and 3.1/2.86/2.65 SC Pulley


  • 5200
    • 43277.42
    • 46909.09
    • 50626.42
  • 5300
    • 44109.68
    • 47811.19
    • 51600
  • 5400
    • 44941.94
    • 48713.29
    • 52573.58
  • 5500
    • 45774.19
    • 49615.38
    • 53547.17
  • 5600
    • 46606.45
    • 50517.48
    • 54520.75

7.0" Crank Pulley and 3.1/2.86/2.65 SC Pulley


  • 5200
    • 40392.26
    • 43781.82
    • 47251.32
  • 5300
    • 41169.03
    • 44623.78
    • 48160.00
  • 5400
    • 41945.81
    • 45465.73
    • 49068.68
  • 5500
    • 42722.58
    • 46307.69
    • 49977.36
  • 5600
    • 43499.35
    • 47149.65
    • 50886.04

6.5 (Current) Crank Pulley and 3.1/2.86/2.65SC Pulley


  • 5200
    • 37507.10
    • 40654.55
    • 43876.23
  • 5300
    • 38228.39
    • 41436.36
    • 44720
  • 5400
    • 38949.68
    • 42218.18
    • 45563.77
  • 5500
    • 39670.97
    • 43000
    • 46407.55
  • 5600
    • 40392.26
    • 43781.82
    • 47251.32
 






So here you can see the difficulty in going with a bigger supercharger crank pulley on the second generation V8 Ford Explorer with the Powerdyne kit

Right now we have an initial test spacer that is pushing out the stock supercharger pulley and now it’s understandable how much room that we have to work with to increase the diameter of the supercharger crank pulley. We have to work around the water pump pulley, and the clearance to the E fan. As it’s been explained to me, we should now be able to go with an eight rib pulley and increase the diameter significantly and fit within the clearance allowed this particular set up.

IMG_2422.jpeg
 






I feel the pain, took me three tries to get my belts/fans/cooling working good and the way I wanted.

I bet it's nice to know it's progressing towards more boost with 8 ribs to eliminate belt slippage!
 






I feel the pain, took me three tries to get my belts/fans/cooling working good and the way I wanted.

I bet it's nice to know it's progressing towards more boost with 8 ribs to eliminate belt slippage!
Yes, I think with the 8 ribs and the increased reliability plus boost of the Powerdyne XB-1A, this thing will end up being quite the package.
 






Prototype crank pulley extension and original
Powerdyne pulley being sent off for fabrication and increase of crank pulley size and ribs count

IMG_2685.jpeg
 






Back
Top