Do not overspin your Powerdyne Ford Motorsport SVO Supercharger

[MuscleJunkie]

Received some early info back regarding the reinstallation of the Ford Motorsport SVO Powerdyne supercharger on my AWD 2000 5.0L Explorer. I decided to go from the 2.7 inch pulley from 928 motorsports (which was actually 2.65) back to the 2.8 pulley from 928 motorsports (actual 2.86) and I had little to no horsepower loss (from what it was dynoing with the 2.65 before the rebuild by Jon Bond Performance ) even through the blower is spinning much slower. Seems as if the upgraded impeller from Jon Bond Performance is doing what is advertised.

So before with the 2.65 - the blower was spinning at 38,812.11 rpm at a 5200 RPM shift point. The Explorer was dynoing just over 300hp (at the rear wheels). Now going back to the 2.86" pulley the blower is spinning at 35,962.27 rpm at the 5200 rpm shift point and they've told me Big White is dynoing just about the same HP (+- 3hp). I haven't heard myself yet but they also told me the blower has a "beefier" sound now than it did before the rebuild.

 

[MuscleJunkie]

Just an interesting information note. Found some obsure period marketing material for Powerdyne Superchargers. It appears that they had a trademarked name for their impeller that was installed inside the supercharger head unit.. Powerdyne called their impeller the Hyperdyne Impeller.

Here is a blurb

One of the key reasons why the POWERDYNE Supercharger provides substantial power increases is due to the unique design of the impeller. The exclusive curved blade inducer type impeller (compressor wheel) grabs air at low speeds to provide POWERDYNE's unmatched low RPM boost. The impeller's airfoil design and computer-matched scroll combination provides more pressure and flow than any other centrifugal supercharger at comparable RPMs.

 

[410Fortune]

I’m still in awe that you were shifting at 5800-6000!!!!

 

[MuscleJunkie]

I’m still in awe that you were shifting at 5800-6000!!!!

Live and learn. Seems now I’ll be safe with a max 5400 shift. Tune is currently set to 5200.

What’s interesting is the original pulley for the Ford Motorsport SVO Powerdyne supercharger was sized for the blower to only reach the 38,000 blower rpm at at 5800 + rpm shift point.

I think this explains Saleen’s choice (besides cutting costs) to not install a boost gauge on the XP8 as the Explorer with the Powerdyne blower installed would normal be shifting around 5000 rpm which probably means only around 3lbs or so of boost versus the 6lbs that was written about back in those days. Under those circumstances probably wasn’t a hard sell for Ford to warranty at such a low boost level.

 

[C420sailor]

Assuming your impeller is 6” in diameter, at 41,000rpm the edge of the impeller was moving at 731mph, or 95% the speed of sound at sea level.

This is in the transonic region, where any low pressure area created (by the vanes, for example) will cause localized supersonic flow, and the creation of shock waves.

That can actually cause a massive increase in drag, a corresponding reduction in compressor efficiency, increase in heat, and possibly vibration/resonance/blah blah blah nerdy ****.

This may have contributed to the bearing failure, and may also explain why you’re seeing similar performance at lower blower RPM.

Most people don’t know this, but once you’ve achieved supersonic flow, a converging nozzle (which normally accelerates a fluid) actually causes it to slow down. A divergent nozzle accelerates supersonic flow. It’s upside down world once you hit Mach 1.

Turbochargers tend to self limit their RPM as rotor speed approaches critical mach number, and the drag created equalizes against the force provided by the exhaust gases. A centrifugal supercharger is direct driven, and doesn’t have a choice—the engine wastes HP forcing it supersonic.

 

[MuscleJunkie]

Assuming your impeller is 6” in diameter, at 41,000rpm the edge of the impeller was moving at 731mph, or 95% the speed of sound at sea level.

This is in the transonic region, where any low pressure area created (by the vanes, for example) will cause localized supersonic flow, and the creation of shock waves.

That can actually cause a massive increase in drag, a corresponding reduction in compressor efficiency, increase in heat, and possibly vibration/resonance/blah blah blah nerdy shi*.

This may have contributed to the bearing failure, and may also explain why you’re seeing similar performance at lower blower RPM.

Most people don’t know this, but once you’ve achieved supersonic flow, a converging nozzle (which normally accelerates a fluid) actually causes it to slow down. A divergent nozzle accelerates supersonic flow. It’s upside down world once you hit Mach 1.

Turbochargers tend to self limit their RPM as rotor speed approaches critical mach number, and the drag created equalizes against the force provided by the exhaust gases. A centrifugal supercharger is direct driven, and doesn’t have a choice—the engine wastes HP forcing it supersonic.

Thank You very much for the time of this response. Very interesting information that helps clarify alot. I appreciate it!

 

[MuscleJunkie]

Here is another example from some period literature (a chevy or truck focused magazine) that talks about the Powerdyne used in our trucks (they also made kits for the Chevy S-10 using the same head unit) while they are promoting the smaller BD-550. Here they refer to the BD -1X series as having 1000-cfm while other places (then and now) state that that that it only has 700 to ~ 800 cfm.
Alot of inconsistent information was put out back in the day...

 

[MuscleJunkie]

Received some early info back regarding the reinstallation of the Ford Motorsport SVO Powerdyne supercharger on my AWD 2000 5.0L Explorer. I decided to go from the 2.7 inch pulley from 928 motorsports (which was actually 2.65) back to the 2.8 pulley from 928 motorsports (actual 2.86) and I had little to no horsepower loss (from what it was dynoing with the 2.65 before the rebuild by Jon Bond Performance ) even through the blower is spinning much slower. Seems as if the upgraded impeller from Jon Bond Performance is doing what is advertised.

So before with the 2.65 - the blower was spinning at 38,812.11 rpm at a 5200 RPM shift point. The Explorer was dynoing just over 300hp (at the rear wheels). Now going back to the 2.86" pulley the blower is spinning at 35,962.27 rpm at the 5200 rpm shift point and they've told me Big White is dynoing just about the same HP (+- 3hp). I haven't heard myself yet but they also told me the blower has a "beefier" sound now than it did before the rebuild.

So some more info regarding the differences with the new impeller. Seems the guy's at stage weren't 100% forthcoming about the quick dyno pull results (or maybe I didn't understand correctly) But they finally coughed up the dyno sheets. Here is the comparison

• Before Dyno pull (with stock impeller)
• • 2.65 Supercharger Pulley and 6.485 Crank Pulley
  • 303.07 HP - 336.51 Torque
  • 5000 RPM cutoff
  • I think we saw about 6 pounds of boost
  • Supercharger RPM approx 37319.34 rpm at 5000 Engine RPM
• After Dyno pull (with Jon Bond Impeller)
• • 2.86 Supercharger Pulley and 6.485 Crank Pulley
  • 287.50 HP and 337.08 Torque (-15.57HP +0.57 Torque)
  • 5000 RPM cutoff
  • On this we saw in the 5 pounds boost range
  • Supercharger RPM approx 34579.11 rpm at 5000 Engine RPM

Also noticed on the graph that even with the larger pulley, the HP and Torque numbers were a bit higher through the pull until the HP at the very end (belt slip maybe?)

Before and after dyno sheets attached

 

[MuscleJunkie]

So, you are going to love this. The other day - another issue has come up and now I have to take off the blower and send it back to Jon Bond Performance. Hopefully they can tell me what went wrong. For some reason, the significant difference in sound after the rebuild didn't seem right to me. Maybe I'm wrong, but it could be related to what happened. Any ideas. To explain, I'll just show you the email that I sent to them.

Hi again guys,


So I spoke to Nick the other day there about my FMS Powerdyne that you rebuilt for me. I explained that my unit that you rebuilt was received and installed by my shop (Stage Fabrication). They put everything back together (and moved me back to the 2.8 pulley from the too small 2.7) and let my shift point at 5200 rpm. I have a 6.5" (6.485 as measured by Stage) blower crankshaft pulley. Currently my truck is set to shift at no higher than 5200 rpm on the 1 to 2 and the 2 to 3 shifts and I think in the 4000s rpm on the 4 to overdrive shift per the tune from Stage.

One of the things that the guys at Stage told me right away is the blower had a very different sound than it was before and they assumed that it was because of the different impeller that was installed during the rebuild by Jon Bond Performance. When I picked up my truck, I noticed the same thing. I immediately contacted Nick and let me know about this and just wanted to confirm that the significant difference in noise was normal. He asked me to send the videos over which I did. I still haven't heard anything from him other than he received them.





The guys at Stage also told me that everything seemed to be working fine and confirmed on the dyno with data. I or they can supply the dyno sheet for this if needed. The only difference was the noise the blower was making (much louder heard at idle as you can see in the above videos)

I drove it around yesterday and everything seemed to be fine with the blower. Today, I went to drive my truck. I started it and let it warm up. Blower sounded the same at idle as it did the day before while waiting for the truck to come to temperature. When I left my neighborhood, I noticed on my boost gauge that I was no longer seeing any boost during driving conditions that I would normally observe boost. I also was not hearing the blower any longer. I didn't hear any strange noises or feel anything strange during this. I pulled over and saw that the blower belt and blower pulley was turning normal but the blower was no longer making any noise. I immediately went home and shut the truck down. The truck was driving normal other than there was no boost.

I checked from under the truck and the belt to the supercharger looking to be fine with no issues. I started the truck again and the belt and supercharger pulley was turning but absolutely no noise from the blower. The blower was also not warm to touch. I then shut everything down and came to write this email. If needed I can make another video showing the the belt and supercharger pulley is spinning but the blower is not making any noise at all.

Please advise

 

[Fix4Dirt]

So, you are going to love this. The other day - another issue has come up and now I have to take off the blower and send it back to Jon Bond Performance. Hopefully they can tell me what went wrong. For some reason, the significant difference in sound after the rebuild didn't seem right to me. Maybe I'm wrong, but it could be related to what happened. Any ideas. To explain, I'll just show you the email that I sent to them.

Hi again guys,


So I spoke to Nick the other day there about my FMS Powerdyne that you rebuilt for me. I explained that my unit that you rebuilt was received and installed by my shop (Stage Fabrication). They put everything back together (and moved me back to the 2.8 pulley from the too small 2.7) and let my shift point at 5200 rpm. I have a 6.5" (6.485 as measured by Stage) blower crankshaft pulley. Currently my truck is set to shift at no higher than 5200 rpm on the 1 to 2 and the 2 to 3 shifts and I think in the 4000s rpm on the 4 to overdrive shift per the tune from Stage.

One of the things that the guys at Stage told me right away is the blower had a very different sound than it was before and they assumed that it was because of the different impeller that was installed during the rebuild by Jon Bond Performance. When I picked up my truck, I noticed the same thing. I immediately contacted Nick and let me know about this and just wanted to confirm that the significant difference in noise was normal. He asked me to send the videos over which I did. I still haven't heard anything from him other than he received them.





The guys at Stage also told me that everything seemed to be working fine and confirmed on the dyno with data. I or they can supply the dyno sheet for this if needed. The only difference was the noise the blower was making (much louder heard at idle as you can see in the above videos)

I drove it around yesterday and everything seemed to be fine with the blower. Today, I went to drive my truck. I started it and let it warm up. Blower sounded the same at idle as it did the day before while waiting for the truck to come to temperature. When I left my neighborhood, I noticed on my boost gauge that I was no longer seeing any boost during driving conditions that I would normally observe boost. I also was not hearing the blower any longer. I didn't hear any strange noises or feel anything strange during this. I pulled over and saw that the blower belt and blower pulley was turning normal but the blower was no longer making any noise. I immediately went home and shut the truck down. The truck was driving normal other than there was no boost.

I checked from under the truck and the belt to the supercharger looking to be fine with no issues. I started the truck again and the belt and supercharger pulley was turning but absolutely no noise from the blower. The blower was also not warm to touch. I then shut everything down and came to write this email. If needed I can make another video showing the the belt and supercharger pulley is spinning but the blower is not making any noise at all.

Please advise

sounds like an alien spaceship!

 

[Blown]

It's like the impeller is not connected if there is no boost. No worries about getting anymore vids, something obvious is wrong with the supercharger. I hope they get it strait for you!

I got 8lbs in a 351W bronco, huge heads, big exhaust, but mild cam with that blower.

 

[MuscleJunkie]

It's like the impeller is not connected if there is no boost. No worries about getting anymore vids, something obvious is wrong with the supercharger. I hope they get it strait for you!

I got 8lbs in a 351W bronco, huge heads, big exhaust, but mild cam with that blower.

Initial thought until they inspect it is the internal belt broke in the blower. Before that incident as you can see from the Dyno numbers, it was functioning, but just had a different sound and was much louder after the rebuilt.
As I mentioned in the email now, even though the pulley and external belt are turning - the blower makes absolutely no noise so this must mean that the internal belt is broken or something else?

 

[Blown]

Yes, must be the belt. The only other thing would be the impeller being loose which I think would would make noises as it slipped on the shaft.

 

[MuscleJunkie]

Yes, must be the belt. The only other thing would be the impeller being loose which I think would would make noises as it slipped on the shaft.

Blower is 100% silent It will be coming off and sent at the beginning of the week.

Honestly can't seem to understand why the "new" gates HTD belt internal belt would have broken. The stock belt they removed was in perfect condition from what I can tell looking at it. Blower was ran in the same exact conditions less than 100 miles. Also, wasn't shifted more than 5200 rpm and blower RPM was way below the 38,000 limit they claim for the BD-11a I am going to send the Bosch plastic bypass valve with it to have that checked in case that has something to do with it.

 

[Blown]

I wouldn't give them anything to blame it on by sending in the bypass. It is easily tested. It should open, partially, with vacuum applied by mouth or at least you would know if the diaphram in the vacuum actuated bypass is leaking. It would be like pulling on a broken straw if bad or if good would produce vacuum to try to activate the diaphram.

 

[MuscleJunkie]

I wouldn't give them anything to blame it on by sending in the bypass. It is easily tested. It should open, partially, with vacuum applied by mouth or at least you would know if the diaphram in the vacuum actuated bypass is leaking. It would be like pulling on a broken straw if bad or if good would produce vacuum to try to activate the diaphram.

Thanks - I will try that when we take the blower off and see what we find.

Since this thread is long, here is a summary (with some additional informative goodies) regarding this Ford Motorsport SVO Powerdyne Supercharger so far

• I bought one of the last "sold new" Ford Motorsport SVO Powerdyne supercharger kits that was available for sale in the general marketplace
  • The kit then say on my shelf more many years along with a simple Bosch bypass valve that bought at the same time
  • The kit was the one made for the 2nd Generation Ford Explorer 5.0
  • Originally came with a 3.1" Supercharger Pulley and 6.5" Supercharger crank pulley (actually measures out at 6.485")
• Finally got around to installing the kit in 2021
  • Big White - Ford Racing Powerdyne Installation Thread is where I documented the initial build
  • When the kit was installed, immediately switched the 3.1" supercharger pulley that was installed to a 2.8" (actually measures 2.86") pulley from 928 Motorsports
    • After driving it for a few months, I decided to switch to a 2.7" (actually measures 2.65") pulley from 928 motorsports
      • My decision was then based off some misunderstood (by me - totally my fault) information on how fast the BD-11a could spun without issues
      • I read many different reports of anywhere from 38,000 rpm to 42,000 rpm
      • The shift point on my truck was set (via tune) to 5200 rpm and the 3rd to overdrive shift even lower than that (higher 4000's)
        • With the original installed (but never used 3.1") pulley - the blower rpm's would be
          • 33254.84 rpm at 5200 rpm shift
        • With the 2.8" pulley (actual 2.86") from 928 Motorsports
          • 36045.45 rpm at 5200 rpm shift
        • With the 2.7" pulley (actual 2.65") from 928 Motorsports
          • 38901.89 rpm at 5200 rpm shift
            • When I had this pulley on, I apparently (totally my fault) was overspinning the blower which most likely led to a bearing failure (and destruction of the OEM impeller) as I talked about in this thread
              • Do not overspin your Powerdyne Ford Motorsport SVO Supercharger
      • At this point, I sent the blower off to Jon Bond Performance for a rebuild.
        • Jon told me that the output shaft bearings failed (due to being overspun - again totally my fault)
          • I had them do a full rebuild of the blower and also install their billet impeller
          • The bearings and belt, etc that Jon removed from the blower during the rebuild (these what were what was installed by Powerdyne new)
            • Koyo 3NC6202-3Z Japan (2x) (Output shaft bearings)
            • Koyo 6205Z Japan (2x) (Input shaft bearings)
            • H80147-375 belt (only other markings on belt beside this are 282mc written 4 times next to number 45, 46, 47, 48)
            • Impeller (markings handwritten on bottom in sharpie are letters X Y A K and 28 )
          • Jon Bond wrote they installed
            • SKF SB C1 Bearings for the (output shaft) side (replaced the stock
              koyo bearings)
            • SKF SB 11 bearings for the (input shaft) side (replaced the stock
              koyo bearings)
            • Gates HTD Belt (said something about it being 3mm wider than
              stock.
            • output shaft belt retainer
            • Jon Bond Performance Powerdyne Billet impeller
            • seals, etc
      • I received the rebuilt blower back from Jon Bond Performance and both the installing shop and I noticed that it had a very different sound than it did from when it was stock. Here are two audio clips of how it sounded at idle after the rebuild. The assumption was the different sound was due to the new billet impeller that was installed by Jon Bond
      • After driving it for a few days, apparently something has failed in the blower. Here are pieces of the email that was sent to Jon Bond that describes the issue
        • "I drove it around yesterday and everything seemed to be fine with the blower. Today, I went to drive my truck. I started it and let it warm up. Blower sounded the same at idle as it did the day before while waiting for the truck to come to temperature. When I left my neighborhood, I noticed on my boost gauge that I was no longer seeing any boost during driving conditions that I would normally observe boost. I also was not hearing the blower any longer. I didn't hear any strange noises or feel anything strange during this. I pulled over and saw that the blower belt and blower pulley was turning normal but the blower was no longer making any noise. I immediately went home and shut the truck down. The truck was driving normal other than there was no boost.
          
          I checked from under the truck and the belt to the supercharger looking to be fine with no issues. I started the truck again and the belt and supercharger pulley was turning but absolutely no noise from the blower. The blower was also not warm to touch. I then shut everything down and came to write this email."

 

[MuscleJunkie]

Informational - here are a couple photos of the original bearings (1 of each) that were originally installed in the Ford Motorsport SVO Powerdyne BD-11A supercharger