I have recently purchased a M3/4 with the Powerdyne BD-11 supercharger. It has NOT taken me long to hate this unit. I first learned I bought the car with the internal belt broken, and now, less than 1k after an expensive rebuild, it is broken again. I do NOT even intend to put it back on the car. I would love to just purchase another brand's system, but I cant afford it. So I think my best option at this point is to upgrade to the XB1A. But I can't find one. All I hear about Powerdyne is bad bad bad. I am open for suggestions on where to possibly find one.

I will TRY to talk to someone at Powerdyne tomorrow, but after 3 unsuccessful tries, why will tomorrow be any different:confused , otherwise a dealer I have talked to said he is at the 80 day mark waiting on some.

I have bought an M3 with a BD-11 and an auto............... I think I started out on the wrong foot with my 1st BMW experience.:D

Powerdyne reportedly got bought out. They have relocated. They seem to be hard to find and hard to communicate with if you do find them. Apparently, there will be a delay before any XB1a are shipped. Contact markesq from the forum for more information. I think he has one on order.

The BD11 works great if rebuilt and run at a maximum of about 9 psi. www.superchargerrebuilds.com rebuilt mine with ceramic bearings. I also used a 10% wider kevlar belt from stattama.

If you do not have a decent and working bypass valve and you raise the boost, the internal belt will have trouble. If you overspeed the impeller, the belt will let go. You can run an absolute maximum pulley ratio of 2.0:1 (i.e., 6.00 inch crank and 3.00 inch blower) if you use a stock rpm limit, but a little more is safer. Stock Dinan was 5.25/3.125.

Philip Bradley

Thank you Philip for the info. I am actually communicating with markesq via PM's.

I think I have contacted at least 10 different dealers, all of which are saying the same thing you are. Based on what markesq is saying, the chances of someone having one in stock are 0, because of the XB being a special order unit.

You might consider staying with your BD11 if you were happy with it when it was working or if it was reasonably close to what you want -- markesq can tell you that they can give your car about 300 rwhp. To get anymore out of the XB1a than you have now, you should use new, larger injectors, new software, probably a bigger HFM, probably a bigger crank pulley and possibly a different blower pulley. Water injection would be a good idea even with what you have now. An aftercooler would be a good idea if you go significantly further.

If you add up the cost of all those parts, you might want to look for a new kit like the AA C38 on sale or the VFE Vortech kit or a new or used RMS Vortech kit. I am just not sure you will pay $1,750 for the XB1a and be done.

Philip Bradley

Your Powerdyne should not have failed. Either the rebuild missed something or the boost was too much for this unit. Markesq is the only one I know running 10 psi on a Powerdyne. I have had zero issues with mine at 5 psi which is what it is designed for.
I thought the guys in Texas were pretty good at doing a rebuild. What boost were you running and you should have a blow off valve too if running more then 5 psi boost.
I have heard of of Powerdyne's breaking running higher boost but Markesq has a lot of miles on his so something else is up with yours.
I do think a previous poster was right that the internal belt will break if shocked by boost, no boost conditions.

I cant say if I was happy when it was working, because I dont know if it WAS working. I have just recently installed a boost gauge, and then found 0 boost. So I dont know if I have felt the car with boost at all.

Within a week of getting the car, I had a local BMW fanatic(bbaz on BF.c) check my car out, that is when we discovered the belt broke the first time. But, when the car was sitting, I did several things like: plugs, fuel filter, fix a few vacuum lines. When I put the PD back on, I may have been feeling the improvement from the tune up and not a fresh PD. I could have possibly shredded the belt the second I started her up. I dont know:embarrasm

I am sorry to say that I dont know where it was sent by bbaz for the rebuild. Infact, I talked to bbaz yesterday, and he said that the belt already
shredding is absolutely unacceptable, and he would send it back for me and make them do it again.:)

I also agree and admit that I wont be done after $1750, I have already purchased a 3.5 hfm, planned on getting injectors, and pulleys for 9 to 11psi. But I can sneak up on it financially without dropping 5K + . Maybe I am impatient and want boost now, and am willing to make improvements over time.

Oh, btw...... I would love 300rwhp. I could possibly be happy with that, if I knew what it was like to have it.:D

I dont have any valve for releiving boost, so I may need to look into that.

If it is a proper Dinan kit, it has a small bypass valve, an odd three way valve, integrated into the cyclone air/oil separator and the valve cover and the blower intake, with a probably old and failed cannister style fuel filter check valve plumbed in somewhere.

You can run a good DB11 with a 3.5 HFM, 42 lb injectors, and pulleys for 9 psi. I have a 6 inch six rib RMS crank pulley for sale for $250 if you are interested. Interchangeable with the Dinan Powerdyne, although you may also have to change the blower pulley to obtain the desired pulley ratio. I ran my Powerdyne with a 6 inch crank pulley. It is the smarter way to get more boost; with a small crank pulley and a small blower pulley, there is a greater likelihood of belt slippage.

Philip Bradley

Philip, No it is not a Dinan kit. The kit came from ESS, which I dont hear much about, so they may be belly up. All I can confirm is the PD head unit, and the brackets to hold it. I have no clue about the tuning, or the injectors, or the desired boost. I really feel ignorant not knowing, but that is what I get from trusting the seller on a long distance sale.

I could possibly be interested in your crank pulley. I need to measure my current crank pulley to get an idea of desired boost. I am pretty sure I measured the blower pulley at 2.7 inch. I will let you know something within the next few days.

I think I have read where I would definitely need a bigger blower pulley if I were to go with the 6 inch crank pulley.

Could someone possible show me a rundown of intended boost with matching pulleys??

for example 6in crank w/3.2in blower = 6psi
5.75 crank w/ 3.2in blower = 5psi
6in crank w/3.0in blower=9psi.......................you get the picture

Yes, if you go to a 6 inch crank pulley, you would use a bigger blower pulley to go back to where you were in terms of boost. Think in terms of impeller speed. You calculate that by multiplying the pulley ratio by the blower internal step up ratio by the maximum engine rpm. The pulley ratio is the big pulley size divided by the little pulley size. Do't count the shoulders -- just the rib diameter. The blower step up ratio is 3.05 for a BD11. ((6.00/3.00) x 3.05) x 6750 = impeller speed at stock rpm limit of an E36 M3 with 6 inch crank and 3 inch blower pulley and BD11 blower.

The 6/3 combo should make 9-10 psi on an otherwise stock E36 M3. The 5.25/3.125 should make 6-7 psi on an otherwise stock E36 M3. Calculate some impeller speeds and you should be able to estimate boost for other combinations with inbetween pulley ratios.

A 6 inch crank and 3 inch blower is the absolute most you would want to run, and that you should run that only on a BD11 that is rebuilt with ceramic bearings and a kevlar internal belt -- preferably the 10% wider one sold by Stattama, preferably one that is vented like the Dinan to help reduce bearing heat, and with a good compressor bypass valve. You should get 9-10 psi on an otherwise stock motor. If you do not have a BD11, you should upgrade. If you do not have a BD11 that is vented, don't try to run 9 psi -- be happy with 6-7 psi or upgrade.

Philip

I have a xb1a less then 500 miles on it. i upgraded for the same reason. but i think im going to part out my car. if your interested email me at kurt_landin@yahoo.com Im not sure if i wana part out or not i need a week to decide but id give ya a deal on it if i decide to sell.

I have an ESS PD systemon my m50 , they have a website.. Asbjorn seems to be the contact if you email them from their website. The crank pulley on mine is 4.7 inches and the sc pulley is 2.67 inches.. gives me 6 psi. Have over 10k (mostly previous owner) miles w/out hardware issues. Software on the other hand is another story. They told me a bpv wasn't necessary for only 6psi.
By the way, pbonsalb , where did you buy the 1 inch bungs for your bpv? I think I'll take my piping to a muffler shop to weld them for my bpv.

I use some metal tubing. Small engine exhaust pipe would work. I don't think you need anything specialized -- you just have to find metal pipe that can be welded (i.e., not galvanized unless you grind off the galvanization). A BPV is not necessary for low boost, but helps blowers live longer. I think the Powerdyne is particularly susceptible to damage from surve due to the weaker design of the internal cog belt compared to a gear drive.

Philip Bradley

How has your search been coming along DADx2?

Hard shifts will put lots of strain on the PD's internal belt. I've found smooth shifting to be imperative when trying to get the most out of your internal belt. Especially at higher RPM's.

Todd Maness at Superchargerrebuilds.com is a stand up guy. The last time I was there he'd just opened a new shop out in the middle of nowhere and had, of all things, a Conquest (ti? Whatever the turbo ones are called.) parked in the back.

IIRC Todd said the venting on the Dinan blowers didn't really seem to help much. I have 2 head units now - one having been modified by Dinan and the other a standard PD unit without venting (on the car now). If/when I get the dinan one rebuilt since it needs some machine shop work (one of the bearing races got warped) I'll see about comparing the temps between the two.

The very expensive 928 Motorsports shop that installs Powerdynes on Porsche 928s, thinks venting is really important. It uses different style vents than Dinan, though. That is two high end shops using venting. Theoretically, it should help cool the bearings.

Could the hard shifting be related to the bypass valve? Shifting is one of the most common opportunities for surge.

Philip Bradley

I wouldn't be surprised if the venting did help but I'm not holding my breath until I do the temp readings myself or blow the non-vented one up at 10 psi or something. Is 928 or Dinan willing to release their temperature readings between the two units?

I'd assume the broken belts could be related to the bypass valve. But I've been told it can also be from missing a down shift and shocking the s/c belt or shifting hard to the point of chirping the tires going into second. The latter is how I broke my first internal belt after I bought the car.

Shifting hard should not harm the Powerdyne if everything else is right. Dinan used to let the magazines drag test them at the strip. I think twin bypass valves, ceramic bearings, venting, and a 35 mm (3mm wider) kevlar belt, and observing the 43,000 rpm absolute maximum is the way to go. Many people are running well used Powerdynes that have standard low speed bearings, fiberglass 32 mm belts, no venting, and no bypass valve.

Philip Bradley

I've always been told that a hard 1st to 2nd shift that chirps the tires can snap the internal belt. Especially an older belt. I know I've popped one that way.

How has your search been coming along DADx2?

Hard shifts will put lots of strain on the PD's internal belt. I've found smooth shifting to be imperative when trying to get the most out of your internal belt. Especially at higher RPM's.

Todd Maness at Superchargerrebuilds.com is a stand up guy. The last time I was there he'd just opened a new shop out in the middle of nowhere and had, of all things, a Conquest (ti? Whatever the turbo ones are called.) parked in the back.



I have stopped looking for an XB-1A. I bought a used RMS Vortech kit several weeks back and am currently collecting the few remaining pieces to install it. I would have started by now, but I am waiting until after 2/10/07 to attend a local BMW event. I did not want to start, and NOT be able to take my car because of not being finished.

Hard shifts are not a problem for me. I am the best and smoothest shifter ever........... just kidding.... I have an automatic.:D Maybe that is helping the 2nd rebuild w/o a BPV stay together. I am at about 10k now.

Yes, Todd Maness is a good guy. I dealt with him personnally when I needed parts to do the 2nd rebuild myself.


Hey @bgynite@, Thank you for offering up your XB-1A, Since I am going a different route, I am not interested, but I am sure someone else on BF.c would be. I have not tried to talk to Powerdyne in several months, but I would speculate that they are still behind on XB-1A orders. It should sell fast if you decide too.