Highest pressure the mapwill readis with the motor off. It will be whatever the atmospheric pressure is that day- 28 inhg( bad bad bad storm) to 31 inhg (good day for the beach). When you start the motor it will read whatever this pressure is minus the vacuum pulled by the motor at idle. At wot, as the motors vacuum decreases, the reading will re-approach the atmospheric pressure. Under deccel, as the engines vacuum increases, the reading will shoot down below where it was at idle.

I don't think those guys had any idea how much boost they were running. The diode was probably to stop the map reading from going higher than the initial start-up reading. The pcm was definately shutting the fuel off. You can tell if that is your problem by observing the map reading on a scanner when the problem occurs.

 

Ok here we go. I have a Powerdyne BD11 on my 2001 Ram 1500, 5.9. You can down load the installation manual from Powerdynes website. Don't expect much support from Powerdyne's tech support. The whole company is kind of cheezy at best. There should be a MSD 6A unit in you system as well. There is a white plug in rev limiter chip on the side of the MSD ignition box. See what you have. A word of caution. Do not over rev your super charger. It kills the bearings very very quickly. If you do not know it's history I suggest you get it overhauled or bench tested. The blue FCU it a unit that redirect higher fuel presure to you injectors if and when the supercharger is boosting. Your stock fuel pressure should be around 50 psi. I beleive the pump istalled as part of the Powerdyne kit raises the pressure to 100-130 psi. I'm no expert and still setting mine up but, I'll try and help you as best I can. I think the Powerdyne is a good "design" & "idea" but it lacks big time in the factory support department. Your more or less on your own with a Powerdayne. The sights above have lots of good info too. I modified my belt routing too so I could use the stock tensioner. It would slip. The plastic tubing is cheap at best and you should have a blow off valve in the system.

[IMG]local://upfiles/41527/7D1D6E153E9149CCB0A0AD689CFE08A3.jpg[/IMG]

 

You might find this interesting. I cut & pasted it from a Supercharger forum.


I thought it might prove useful for readers to understand what causes the belt-driven Powerdyne units to fail. This applies to all Powerdyne BD-series blowers.

They are very reliable superchargers when applied correctly, and they typically fail when over-tasked by the un-informed. Maybe I can help.

I make a living rebuilding and upgrading Powerdyne blowers - so believe me - the more you guys blow them up the better it is for us. We have no association with Powerdyne.

Two main reasons I see Powerdyne's fail:

1) Over-spooling the bearings
2) Use of the wrong Blow-off Valve

1) Overspooling - The most common reason for a Belt-driven Powerdyne's failure. One of their attributes is that the bearings are permanently lubricated and you do not have to run oil lines to and from the motor when you install a Powerdyne BD-series blower.

But - the lubrication (like all oils) has its limits. The engineers I worked with at SDK tell me that the oil within the bearing will break down at 272 degrees Fahrenheit. Then it looses its ability to lubricate the bearings.

Here is the sequence of events: usually the bearings are over-spooled by use of the wrong pulleys. The heat within the bearing spikes, and goes above 272 deg. The oil fails. The bearing becomes hard to turn. The belt fails trying to turn the dragging bearing.

I often get calls at www.powerdynerebuilds.com for "just the belt - the bearings are fine" No.... the bearings have cooled down again and the oil has re-congealed, and they FEEL fine, but they are not fine. The belts do not fail without a reason, and the bearing failing is the reason.

Solutions to this: Measure (do not guess) your crankshaft pulley. Measure (do not guess) your blower pulley. Several sites including ours have posted the simple calculations needed to find out how fast your impeller is spinning (and as a result, the bearings). Adjust your pulley sizes to run the BD-11 series to 36,000 rpm at the impeller with occasional spikes to 40,000 rpm on their standard bearings and you should be fine.

Other solutions: Ceramic bearings like we offer run cooler, and we also specified a lubricant with our bearing manufacturer that will withstand up to 312 deg Fahrenheit before failing. We also vent the case of the Powerdyne to run cool air through it to help the bearings cool. This service is available from us here:
http://www.928motorsports.com/services/rebuild.html

2. Use of the wrong type of blow off valve. I rarely see this discussed - but I often see this mistake. Pop off valves for Turbo applications and Blow-Off valves for Superchargers are NOT the same thing, and not interchangeable.

Think of this: you are shifting at or near redline. The blower, at redline, is making maximum boost. Now you lift suddenly off the throttle (to shift, to brake for the corner, whatever) and you slam the throttle body shut. All that boost has no where to go, all that force runs backwards through the system looking for an escape. The blow-off valve is supposed to take care of that.

A valve for a turbo system will "flutter" - you can hear it if you listen - as it is designed to NOT loose all the back-pressure and keep the turbo spooled-up if it can. This open-shut-open-shut action in a turbo-type valve pushes the belt-driven Powerdyne sprockets forward-and-back several times a second and the belt takes a beating. These same valves when applied to a gear-driven blower seem to work OK - but its just because the gears can take that kind of abuse where a belt cannot.

A blow-off for a Supercharger is designed differently and will open ONCE and dump the boost like it should on a supercharged system. It is much kinder on belts.

Over years of trial and error and a LOT of money spent on blow-off valves, I still have not found a better blow-off valve than the one the Bosch engineers designed for boosted applications. It is readily available, and can be found for about $75 if you look.

It is Bosch part number 034 145 710B later superseded to Bosch number 0 280 142 108. Your parts guy may say that it is listed as "Turbo cut off valve" - don't let that scare you. The guys that write parts books don't know the difference between a Turbo valve and a SC valve either.

Finally - I have made some Powerdyne units last longer just by damping the flow out of the Blow-off valve. If your blow-off valve is uncovered, then when the pressure in the system goes from, say 9 psi to zero in 1 second - thats really hard on the belt. I have installed a breather vent on the blow-off-valve to slow the exit of the boost a little bit, and found that the belts in the supercharger last a little longer.

Hope this helps your Powerdyne's last longer - Happy Motoring

Carl


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Carl
928 Motorsports, LLC
www.928motorsports.com/services/rebuild.html


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Edited by - Carl Fausett on 12/21/2006 14:57:34