So far the belt has blew off the pulleys towards the rad 5 times and went back towards the motor 2 times. I did check the tensioner though out the tensioner swing and every pulley I spun while the laser was on it to make sure it was true except the crank pulley but when the truck is running the crank pulley doesn't wobble or anytbing like that. And the alt. Bracket looks good. I didn't touch that at all and same with the p/s. If I flip the blower pulley I can't put the bolts into the pulley cause the raised lip that does around the snout is on the outside then and the bolt head hits that. And I have a 110" belt on it that I have to put the tensioner all the way down against the stop to get the belt on then it comes up and 1" to tight and has a good 5" left of travel to tighten if it needs it. And I can try a different spacer on the tensioner. The washers were the easiest thing I could do at the time. They are 2" round washers so they aren't exactly small. They are about 1/4" away from the dowel pin in the tensioner. I just don't see how the 6 rib could be fine then go to an 8 rib and get them all spaced out correctly and they just blow belts off. It was happening a lot less and now it's getting more frequent. I was at 465hp on the 6 rib and j added meth and more boost and made the 4" intake for it and got it to 598. I'm getting close to calling it quits on this 8 rib and putting the 6 rib back on but then I have $1100 worth of pullies that I wouldn't wanna sell to anyone it they are messed up unless it's something on my truck.

 

Grabbing at things that might cause the "getting worse" clue besides belt getting stretched: with the belt off, does the water pump, altenator, and power steering pump pulleys spin freely including no wobble or rough spot. Is the power steering pump fluid still clear (not dark or burnt). Is the dampner bolt still tight.

Don't give up man, its a PITA but you are going to make this problem your bitch!

 

The p/s, alt and the water pump all spin great and have no wobble or anything. I didn't check the fluid in the p/s and I didn't check the crank bolt but I can check them! I'm not sure how to post a video from my phone on here? But I took a video and sent it to iw and they are sending me a new smooth idler pulley. It has a slight wobble to it. Maybe I missed that and that's been the issue the whole time. You can't notice it unless you look straight down on it you can see a slight wiggle. I don't think it's the damper cause the a/c belt is still on there and looks great. I have to go down to autozone and warranty my belt again haha. I ordered my 2 gates fleetrunner belts online cause it was $25 cheaper than the place by me that sells them so no warranty on them. So got a dayco gold hd belt from autozone with a warranty so I can keep getting a new one when it shreds. My poor engine bay looks trashed and the nice aluminum pulleys covered in rubber and dust. Gunna be a heck of a cleaning when/if I ever fix this! Thanks for all the suggestions!

 

Just to make sure the basics are covered, is your crank pulley pinned (or keyed), and your water pump pulley welded?

 

Well time to do it one by one.

Put the 6 rib belt back on with the 6rib tensioner, make a couple pulls, if everything is fine go to the 6 rib blower pulley then make a couple pulls, then idlers and so on. Eventually you will get down to everything is 6 rib but the crank pulley.

 

The crank is pinned/keyed with the iw kit. And the water pump isn't welded... Wasn't aware of that? And I'm gunna try and do this smooth idler when I get it and if that doesn't work then I'll go down the 6 rib road!

 

I didn't read through all of the replys, but see you are still having trouble. I looked at your laser pics and everything there seems to be in order. That makes me think something is flexing under high load. I'm not real familiar with these kind of blower set ups so I don't know what could be flexing. Is it possible the tensioner itself is moving around?

 

The one smooth idler pulley has a slight wobble to it. If that doesn't fix it I will get a buddies go pro and mount it and see what's going on down there. Everything is solid and tight but I can't really see it under a load... I rev it up in park and the belt doesn't come off at all it's only when it's really under a load. So I have to see what's going on with it with a camera if this new idler doesn't fix it. I took a video of it and sent to it innovators west and they are sending me a whole new pulley and bearing not sure when it'll be here though.

 

Does it come off under load or right when you let off?

 

It comes off under load. Now I'm not sure if it's between shifts or just in high rpms...