Anyone here rebuilt their own Powerdyne blower?

I have mine in bits at the moment after a belt failure. They are quite simple inside. I'm just waiting for some final parts to arrive before I piece it back together.

If there's any interest I may post up some pics of how I went about it and what i'm doing in an attempt to prevent it happening again.

Jason

post up some pics..
interested in how the internal belt is set up on the powerdyne..
tim@ raptor does internal belt and pulley upgrades for the powerdyne, if you didnt already know???

the belt usually breaks because of compresser surge putting to much load on the impeller and belt..
1 or 2 larger blow off valves usually do the trick..
im running 2x32mm s type bov's with the heavy spring removed so at idle and light throttle the bov's are open.(but i am overdriving my blower with a 12 psi pulley)

no more surge now....

Jason, I'd be interested in seeing a write up.

I've had mine rebuilt twice - first time with standard belt/bearings (lasted maybe 25000kms), second time with raptor internal belt/bearings (a lot noisier but has covered around 50000kms no problems). Haven't built myself though, so would like to follow your progress.

Joe

Cheers for the interest.

The kit has a 38mm Turbosmart BOV on it with a cut spring (it's open at idle and on cruise). Still the blower only managed to last around 5000km behind my Automatic. Carl at 928 says the BOV might be too big??? I doubt this.

I've had a few issues with this particular blower kit, and on disassembly of the blower I am wondering whether the casing may be throw away due to some of the modifications that have been done to it. I'm going to give it another chance by throwing a complete kit through it myself, and see how it goes. The last two rebuilds were done on behalf of the previous owner (not going to name the rebuilders) and despite being sold to me as a comp rebuild I found out it only had a fibreglass 'optibelt' brand belt in it, two mismatched low speed input bearings (one cactus), and two cactus output bearings.

The casing is the most interesting part as it appears to me and a couple of precision fitters i've spoken to that it would have been weakened by both the holes drilled around the bearing races and the "machining" done under the output shaft inner bearing. At the moment the bearings are no longer an interference fit in their bores. Here are some pics of the casing and SOME of the belt material I removed on disassembly.

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The depth of the bearing bores with the current shims is also about 2mm deeper than the shaft/bearing unit, allowing 2mm end float (which is not taken up by the wave washer). I plan on shimming up these bearings so there is no end float before reassembling it, just waiting on some 52mm shim washers now. I've also deburred both sprockets as they both had considerable burrs which I am sure didn't help with belt life. This plus fitting a whole set of matching high quality bearings and ensuring they are a tight fit will hopefully lead to some problem free life. I've read of units in the US doing over 50k miles without a rebuild.

I might start trying to collect some data about powerdyne users, to learn what is working and what isnt. Cut and paste this one fellas, and add your line on the end.

Engine, Transmission, BOV, Pulley size (in), KM since rebuild, Camshaft, Power
EF I6, Automatic, Turbosmart 38mm w/ cut spring, 2.84", 5000km, Wade 1521a, Unknown

Jason

Jason, any idea why the holes were drilled? I know Carl vents some of the powerdynes, and both Carl and Tim use the air assist thing....but I don't see the purpose of drilling around the bearing races?

I don't see a problem with the larger BOV either, though I'm sure Carl would have a reason with their experience. I'm running the common bosch plumb back BOV.

I think you'll find that with quality bearings and belt (I assume from 928?) plus shimming up/deburring, etc, you'll get a reliable blower that will go for some time. That's been my experience.

I'll add to the last line data once I've checked a few details.

Joe

I think the holes were possibly made to help get stuck bearings out? There are smaller holes in the output bearing holes that go into the other side of the casing, behind the impeller. I guess this would help with airflow.

See what happens when I get it back together.

that case looks butchered!!! i'd be thinking about machining up a steel cup and pressing it in.
could even use some of the existing butcher holes for grub screws to make sure it doesn't spin

you sourcing the bearings from the states or getting them here?
do the powerdynes use angular contact bearings on the high speed shaft??

Yeah, it's been 'customised' eh?

I cleaned up the bottom of the output shaft bore a little such that a shim washer would sit flat in there (previously the outer race was true but that mess of alloy in the bore would touch the bearing seal). I now have to shim the impeller to compensate, but at least it's got a little more support under the bearing. I will shim the input bearing in the same way to prevent the end float that I measured, keeping it all tight. I also plan on using a bonding agent recommended to me by a fitter when reinstalling the bearings, to prevent them from spinning in the bore given the fit. I think it'd be very difficult to machine up a cup and get it all true, better off turfing the casing.

As part of cleaning the whole lot up, I cleaned all of the grease/belt material out of each one of the vent holes so they arent blocked.

The output bearings are just ball bearings, albeit precision high tolerance ceramic ones, with grease to suit the application. These supposedly exceed the manufacturers spec. I sourced them from the US in a kit along with the kevlar belt.

Hopefully get it back together soon and see how long it takes me to mine this thread :/

Hey guys,

Well, it's been back on the car to run in the belt and so far no issues. I must say the new belt is noisier than the previous one, even after running it in for a few hundred kms.

I am looking to shim up the impeller at the moment. Is anyone able to tell me the impeller shaft OD so that I can source some shims?

Cheers,
Jason

The stiffer belts are definately louder, but will last heaps longer.



Jason, here are some details on my powerdyne for future record. I added in a section - 'upgrades':

Engine - AUIII I6 (VCT)
Transmission - T5 Manual
BOV - Bosch (standard plastic one fitted to heaps of OEM turbo vehicles)
Pulley Size - 9psi from CAPA (sorry, not sure in inches),
Km since rebuild - 42000kms (rebuilt on 8/5/08 - driven daily since)
Blower Upgrades - 928 motorsort impeller, raptor ceramic bearing and high strength belt.
Camshaft - Standard VCT
Power - Unknown (Last tune couldn't be completed properly due to a pinging issue, suspected to be caused by impeller increasing boost. Before blower uprade engine was making approx 250rwhp@5600rpm, after upgrade it was making over 200rwhp@4200rpm/5psi (tuning stopped at this point). Low end after upgrade is significantly improved...engine begins making boost around 2000rpm, and generates around 7psi @4500rpm at which point it stops accelerating (problem yet to be worked out).

Cheers,
Joe

Might as well add my own!

Engine - EF (w/ ported head, XR6 exhaust valves)
Transmission - Automatic with 3000rpm histall
BOV - Turbosmart plumb back with cut Supercharger spring, venting to atmosphere
Pulley Size - 6psi on 2.84" pulley
Km since rebuild - ~2000km
Blower Upgrades - Kevlar belt, high speed ceramic bearings, shimmed bores, ventilated casing
Camshaft - Wade 1521a
Power - 207.8rwkw w/ 17 deg timing (conservative). http://www.tiperformance.com.au/owners_gallery.php?id=1

That's great power out of a 6psi powerdyne! You must be pleased with the driving result.

is that 17 deg timing at max boost/ max rpm??

Jason, do you know what boost the 2.84" pulley is supposed to make? Is it 6psi or would capa, for example, rate it at more psi?

I wonder if the psi rating that capa suggests for a given pulley size is accurate or not? They sell 3.15, 2.9, 2.7 and 2.5 inch (use with caution) pulleys for the powerdynes. They listed their powerdyne kit with water injection (my kit) as 9psi, which I'm guessing is a 2.7inch pulley, though I've never measured it. People often seem to develop less boost than what the setup is rated at though....

Yup, it's pretty fun to drive

The difference in boost levels has been explained to me like this. Unlike a Turbo, which regulates turbine speed to achieve a desired boost level, a blower produces a fixed amount of air for the input shaft speed. Depending on how well an engine breathes (i.e. exhaust, head/camshaft, intake), it will take a different amount of air to present the same restriction at the intake. This is why you will find a modified engine with a supercharger will produce a lower boost level with the same sized pulley compared to a stock engine but make more power.

I think the pulley I have would be good for 7-ish psi on a stock engine.