When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Last year, we installed a full package of UPD pulleys from Shardul including the 77mm SC pulley, belt wrap kit, and all available idler pulleys from UPD. After much research on these forums, it looked like UPD was the way to go for quality aftermarket parts that would last and be reliable.
FWIW, wrapped Kleeman headers, K&N air filters, new plugs, bigger heat exchanger, new IC pump, and an accompanying Eurocharged tune were the other changes made at the time. After all work was completed, the performance increase was surely felt and the accompanying Dyno showed healthy gains. The gap tolerance was checked and rechecked with feeler gages and was Dead on within spec.
After maybe less than a thousand miles or so, the SC belt shredded into spaghetti and made a mess. I wondered if I just got a bad belt or what, so I cleaned it all up, installed a new belt and went on my way. A couple hundred miles and it shredded again. Now I know something is wrong. My local performance shop that completed the work and I thought maybe pulleys were somehow misaligned or a bearing wasn't free enough, but after inspection I thought no way. I cleaned up all the pulleys again of the powdered belt debris left behind, checked for any burrs that may have been missed, installed a belt without the belt wrap kit to take that out of the equation to find out if that is what was giving it issues. After a few hundred miles, I've determined that the belt wrap kit is not the culprit, as I see plenty of belt dust on the pulley assembly and it's clearly not going to last very much longer. After trying to do a run to check temps and boost level to see if it was engaging correctly which was suspect, I noticed how doggy it was and boost had a difficult time reaching over 5 or 6 Psi. After inspection after the run, the SC pulley had generated so much heat that there is like a black plastic compound melted around the pins between the spring pins of the pulley. Either Some composite material from the pulley or perhaps its hard melted rubber material from the belt dust but it's feels like hard plastic that has melted and coated the pins of the SC pulley. The pulley was so hot that melted materials is like fused around the pins. I pulled the SC pulley off and exactly as i was afraid of, the friction pads of the bell housing and SC pulley are completely sheared off and its smooth on both surfaces now. FML. How could this possibly happen? I've already contacted UPD before I discovered this searching for help to troubleshoot and diagnose the problem. They were of little help. Now I'm ready to send them another email because the only possibility I see here is a faulty pulley that wasn't manufactured correctly at the UPD factory. I had zero problems with the stock pulley, and the friction pads on the bell housing were in fantastic condition before the UPD was installed. Maybe there was a material defect in the friction pad material UPD uses when manufacturing the pulley. I'm not trying to trash UPD here, and until this issue reared its ugly head, I was quite happy with the apparent quality of their products. But Now I find myself searching for a solution to my problem as well as an explanation as to what caused it. After discussing this issue in detail with several highly qualified mechanics and a whole community of guys well acclimated with tuning high performance cars, the only explanation is a faulty manufactured clutch in the UPD clutched SC pulley. I'm beside myself and feeling defeated at the moment. Looking for some perspective here. I don't want to write an email to UPD while I'm angry and upset, and I don't want to point fingers until I've consulted you guys so what do you think? Also, is it even possible to replace the friction material on the bell housing to be able to still run a clutched pulley? Or is the best fix at this point to move onto a fixed pulley and a new tune to accompany it? I eagerly wait your suggestions and feedback. Thanks fellas
Last edited by WannaBeeAMG; 10-07-2018 at 05:58 PM.
Friction pads have been sheared smooth on the bell housing. Also Notice the belt dust debris layered on the belt wrap pulley Serious heat generated to get that melted on so hard Serious Heat! Friction pads on SC pulley sheared smooth
Haven't seen this particular issue before. Obviously heaps of heat is being generated by the pulley slipping against the magnetic clutch surface. Either incorrect gap or the surface was on the way out- not saying anything was done wrong, I just can't see any other scenario. Of course this doesn't explain why you were losing belts unless the gap was too small causing a huge increase in friction off boost.
I lost a belt after the beltwrap kit and upd pulley also. I found that the idler pulley from the kit is Not symmetrical, it's offset to one side by like a cm. If you install it the wrong direction a fraction of the belt hangs off the edge and causes it to shred after a short amount of use. Flip it. You probably have that idler on wrong shredding the belts and a shredded belt some how causing the SC pulley damage.
Haven't seen this particular issue before. Obviously heaps of heat is being generated by the pulley slipping against the magnetic clutch surface. Either incorrect gap or the surface was on the way out- not saying anything was done wrong, I just can't see any other scenario. Of course this doesn't explain why you were losing belts unless the gap was too small causing a huge increase in friction off boost.
As I said before, the gap was checked and rechecked after installation, and the friction pads on bell housing were in great shape only having 102,000 miles on it.. It was perfectly within spec when installed with shims and bell housing spun free. I had at least 500 trouble free miles before problems began and friction pads started to erode before they were sheared off completely.
I lost a belt after the beltwrap kit and upd pulley also. I found that the idler pulley from the kit is Not symmetrical, it's offset to one side by like a cm. If you install it the wrong direction a fraction of the belt hangs off the edge and causes it to shred after a short amount of use. Flip it. You probably have that idler on wrong shredding the belts and a shredded belt some how causing the SC pulley damage.
I will look into that but my shop assured me that that is not the case... naturally they wouldn’t want to accept blame, but I will personally look into this. Would you be able to tell me with good pictures posted if it is indeed installed correctly?
I have no idea how to test this, but if the electromagnet was weak from a short, or low input voltage, that would cause the clutch to slip and build up tons of heat. Maybe change the relay and try a run.
Thought about it a minute, you can test the magnet with an ohm meter.
I honestly don't see any visible problem with either side of the friction interface. First of all, I don't think the pulley has ANY friction material on it; it's just steel. And on the hub side, every one I've ever seen has the friction material flush with the steel (I've never understood why though).
The melted plastic is weird, for sure, but I don't know where that plastic would have come from. I'm with StarvingArtist on this one; it seems like you might have a weak electromagnet that isn't providing enough clamping force.
I honestly don't see any visible problem with either side of the friction interface. First of all, I don't think the pulley has ANY friction material on it; it's just steel. And on the hub side, every one I've ever seen has the friction material flush with the steel (I've never understood why though).
The melted plastic is weird, for sure, but I don't know where that plastic would have come from. I'm with StarvingArtist on this one; it seems like you might have a weak electromagnet that isn't providing enough clamping force.
There were definitely friction rings, or as I called them pads in the earlier posts, in the bell housing and in the pulley itself that were raised slightly higher and had a coarse texture to enforce the bite when engaged. Now My question is, is this a repairable or replaceable piece as far as the traction ribs or friction pads, or whatever you want to call them, in the bell housing? Or should I just go with a fixed pulley so as to bypass this newfound problem altogether? It seems like no one here thinks it's plausible that I simply got a bad pulley that possibly had a manufacturing defect and was the point of failure to cause this issue, so that makes me think it was a good idea to post this here before I wrote UPD a less than polite email pointing fingers. I'd still like to contact UPD and see if they can assist, but just don't know how to word the letter yet. Still trying to sort it out and have it all make sense. I should have time soon to check out the electromagnet, any more thorough instructions on how to properly do this would be appreciated. Thanks for your input so far all..
I had two UPD BWK bearing failures within 10k miles, so I threw my BWK in the trash. You should remove yours and check that bearing; I wouldn't be surprised if that is your culprit.
I would also email UPD a picture of the SC pulley and ask them what's up with the melted plastic. That definitely seems weird. However, I still maintain that both sides of the friction interface look normal. Or at least they look just like mine and I don't seem to have a problem.
Stick the stock pulley back on if you want to rule out the UPD pulley being the problem. There are inherent downsides to fixed pulleys. You can buy new electromagnet but no one has successfully replaced the friction material.
Stick the stock pulley back on if you want to rule out the UPD pulley being the problem. There are inherent downsides to fixed pulleys. You can buy new electromagnet but no one has successfully replaced the friction material.
+1 put the stock pulley back on and see if the problem resolves.
I will look into that but my shop assured me that that is not the case... naturally they wouldn’t want to accept blame, but I will personally look into this. Would you be able to tell me with good pictures posted if it is indeed installed correctly?
I might be able to, I'm away from my car but I'll take a look when I get home Friday and let you know. Basically the center section of the pulley is offset slightly, not dead center, which actually shifts the pulley towards or away from the motor depending on which way it's facing when bolted on. The pulley needs to be mounted the direction that pushes the pulley towards the front, slightly further away from the motor.
When I installed my BWK a year or so ago I noticed a small lip of belt hanging off the edge of that idler. I E-Mail Shardul and was told it was fine. Maybe a thousand miles later the belt shredded. While I had the pulley off to change the belt is when I found the offset. Installed it the other direction gave it just enough movement away from the motor for the belt to be fully on the pulley, have not had a belt issue since. I am guessing UPD sources these kits from some one else and had/has no idea about them other wise when I asked about the small amount of belt hanging off the kit who knows why the **** they wouldn't have said the pulley is probably on the wrong way.
Is the upd pulley flat if you put a straight edge across the friction surface? The magnet drum on mine looks just like that, maybe a little groovier. Same with the pulley, all metal on metal contact. Maybe that friction material is really lubricating material to keep the steel from galling. I've had 2 55's and 1 spare supercharger, and never seen it look any different.
I have no idea how to test this, but if the electromagnet was weak from a short, or low input voltage, that would cause the clutch to slip and build up tons of heat. Maybe change the relay and try a run.
Thought about it a minute, you can test the magnet with an ohm meter.
A little more specific maybe? Anyone have a more detailed instruction as to how to go about this. Where's the contact point I can read and what should it read?
Is the upd pulley flat if you put a straight edge across the friction surface? The magnet drum on mine looks just like that, maybe a little groovier. Same with the pulley, all metal on metal contact. Maybe that friction material is really lubricating material to keep the steel from galling. I've had 2 55's and 1 spare supercharger, and never seen it look any different.
On the UPD SC pulley it is indeed perfectly flat laying a straight edge across it. The Stock SC pulley has slight grooves in it with a different texture in parts of the surface that I was referring to as the friction rings. As I look closer at it, you are right, the "friction rings" or pads or whatever that I was referring to aren't really there. It's a difference in the metal surface with high and low spots on the stock SC pulley that match the high and low spots on the bell housing. closeup of the "grooves" in the Stock SC Left is UPD pulley, right is the stock pulley with slightly over 100k miles UPD left, Stock Right
I honestly don't see any visible problem with either side of the friction interface. First of all, I don't think the pulley has ANY friction material on it; it's just steel. And on the hub side, every one I've ever seen has the friction material flush with the steel (I've never understood why though).
The melted plastic is weird, for sure, but I don't know where that plastic would have come from. I'm with StarvingArtist on this one; it seems like you might have a weak electromagnet that isn't providing enough clamping force.
As I compare the two pulleys, I believe those 3 "pins" are made of a composite plastic material and act as spacers between the clutch surface of the pulley and the actual pulley. Maybe the spacers act as a safety stop so the spring doesn't bang the two pieces together upon engagement/disengagement
All pulleys look nice and aligned to my eyes I can't imagine that this is the culprit. It spins free. stock pulley on left feels abrasive like it would catch and grip. UPD pulley feels super smooth like it'd have a harder time gripping After cleaning it up with some brake cleaner, it looks more like I remember now that its clean you can really see the channels quite well that mesh with the stock pulleys wear pattern
A little more specific maybe? Anyone have a more detailed instruction as to how to go about this. Where's the contact point I can read and what should it read?
There is a connector on the right side of the engine going into the back side of the magnet, you can check voltage there 12v+ . You will have to use Star to power that circuit. You need to back probe the connector with it plugged into the magnet to see if there is voltage drop.
10-07-2018, 05:44 PM
