I put on the modified A/C pulley the other day and made many hard pulls. So far so good, belt is still on. I guess time will tell. Hope that aluminum pulley works for you!

 

Who is the manufacturer and what is the part number please?

 

that’s a question for double06

but I did find this and it looks promising doesn’t say “no supercharger” either



This with the billet pulley 👍🏻

 

Just checked, and both my upper and lower pulleys are the OEM plastic ones with side supports to begin with.



So not sure how you ended up with a metal pulley that did not come with the side supports on the A/C, but plastic pulley like you have posted to replace the metal one, and just lathing off the grooves to make the side support higher from the surface, may be the solution to the problem. If not and belt is still jumping off, then just pull the adjuster apart to install a stronger tension spring and double check the alignment of the HB and A/C pulley instead.

Once last thing does come to mind and that is to check the clutch bearing on the A/c compressor to make sure it not binding,and even to add in a switch on the A/C connector wiring so the A/C clutch does not engage during the runs. Hence A/C will kick in even in the dead of winter and summer time when you start the car, since it's use to pull the humidity out of the air to keep the windows from fogging up from the inside with the heater on (even when you have A/C off at the a/c controller.

 

did this ended up helping, Do you have PN for the pulley?

 

Ughh, so much random info crosses my mind with this issue. I encountered this recently so I'll add a bit of info as I try to figure the issue out/remedy the issue over the coming months. There are several things going on when doing "spirited driving" that can exacerbate an A/C belt throwing issue. I do all the work on my father's 700 rwhp Magnuson 2005 and recently I went over to his house to take the car for a ride and record a few logs when I realized very quickly that the IAT was going up after cold start rather than decreasing (Interchiller). I found the A/C belt thrown. I'd say this car is more susceptible to a thrown A/C belt that almost all other C6s for a few reasons.
1. The car has a bunch of power and is traction limited on the street.
2. The rev limiter is raised to 7,200 rpm. Probably a double edged sword, higher rpm....higher belt speed thus higher load on the belt plus factory disables the A/C clutch at something like 7,083 RPM so the engine actually crosses that threshold.
3. The car has an Interchiller on it so it's putting a larger load on the compressor, or at least it's putting a load more often than normal cars.
4. Can't forget it's a manual transmission, that tensioner is swinging as the rpms move.....and then will have very abrupt swings during shifts.

Let's set aside the obvious in that improper belt alignment can cause problems, that goes without saying and on a C6, there really shouldn't be much possibility of this assuming the balancer is of a reputable brand, installed correctly, the compressor bolts in a positive location and so does the tensioner. It's rather idiot proof. Once we get beyond alignment there are 2 big factors that I'd guess cause most of the problems, 1.hitting the rev limiter, 2. traction control being activated. Now if you get into a scenario where you're engaged in both a rev limiting AND traction control scenario...that's very hard on the belt train making that tensioner swing around erratically. Now add a gear change on a manual to that......even worse. In my case I can probably add the A/C clutch disengaging at 7,083 RPM which is right in the RPM window of a gear change and the rev limiter.
Mileage-wise the A/C tensioner was replaced recently along with a new Gates A/C belt. The tensioner used was a Genuine GM.....which according to what I see is a Litens tensioner that has a GM part # engraved. Seems Litens (made in Canada) makes tensioners for a good portion of the automotive industry across many manufacturers. There seems to be subtle differences here and there......like a Gates tensioner won't say LITENS on it like the GM one, but the Litens logo (Globe) is still on it, or Continental tensioner will have the Litens logo but the hardware like the pulley bolt is black oxide finish looking versus silver colored (zinc?) anodized/plated etc. They may use their own pulley.....but most of the tensioners are LITENS. I'm going to take one apart when I get my hands on the car next time. I will say I came across the Dayco tensioner which isn't a LITENS and they claim it uses a flat spring which lessens variations in tension. Dayco's belt tensioner features a patented "flat spring" design that's engineered to provide less operating range variations in tension. This reduces the risk of premature failure due to high tension when a new belt is installed. It also lessens the risk of belt squeal and slippage, or poor accessory performance caused by low tension after the belt begins to stretch and wear.
Features & Benefits:

• Patented flat spring provides less operating range variations in tension for longer life and quieter performance
• Heavy-duty cast aluminum offers additional strength and less fatigue or distortion
• Steel locator pin and pivot tube (where the application demands) provide additional support for critical torque requirements
• Thermoplastic rubber "spring slot plug" keeps out harmful contaminants
• Zinc coated mounting bolt (where included) resists rust, and is concentric for a more even degree of constant tension

I bought one, but the car is hundreds of miles from me so I won't be able to test it until I get the car back.
I'd assume this problem doesn't really happen on the dyno.....roll into the throttle to redline, push in clutch and coast to zero tire speed/idle. I'd also assume with proper traction and proper shifting (ie staying out of the lev limiter) this doesn't happen too much at the track. I'd expect it's on the street, traction limited, flirting with things like rev limiter, traction control, and shifting.
I'm going to play with the A/C disable RPM next time I get the car too.....rather than disable at the factory 7,083.....where the compressor is a load on the belt to that RPM and then suddenly disengages which I'd assume suddenly allows the belt to contract (gets shorter/less length/less stretch) and then almost at the same time a gear change happens.....while at the same time if the gear change doesn't happen, the rev limiter is doing it's thing. If I set A/C disengage to say 5,000 rpm, that lessens the load on the A/C belt at 5k....so by the time I get up to a 7,000 rpm shift point.......the belt is less stretched, so when I grab the next gear......the change in belt length will be less severe.....and when I go WOT the belt is happier to accelerate a freewheeling A/C compressor pulley. I imagine most of the time I shift near redline, I'm not quite satisfying/meeting the ECu's 7,083 rpm requirement so the belt stays loaded. Hope all this rambling makes sense. As far as different parts, aside from the Dayco tensioner which is a different design from all the other LITENS stuff, it looks like we are stuck (stock belt length wise) with a plain Gates micro v or Dayco belt. I don't see a Gates Fleetrunner (suffix HD) color green belt available. What I have found that I'd entertain trying to make work is a Gates RPM belt which is aramid cord which is supposed to have much less stretch. Although I've had issues in 2 different RPM belt applications in the past, I feel like this A/C issue may be a good candidate for a fix. The RPM belt that is available is about a 0.5" longer......so I'd try to find a larger diameter pulley for the tensioner to help make that difference up.
Any and all info/experience with the A/C belt issue is welcome. Sorry for my long blah blah. I figure if we help someone down the road with this issue, it's worth it.

 

Do anyone have a simple way on how to replace AC tensioner on a LS2 engine… I know the bolt is a 13mm but trying to get it off from the top is a hassle.. I’m using a 13mm deep socket

 

"simple" certainly entails accessing the tensioner from below.

 

can I please have the part buy for this pulley? I am have the same issue with my AC belt.

 

On a customer car I ended up installing an rpm activated switch, programmed it for anything above 4500 rpm to open the ground circuit to the A/C compressor clutch to disable it. This kills 2 birds with 1 stone.
1.) no more thrown belt.
2.) protect the compressor from high rpm

 

old thread but just for info, I fought with throwing the ac belt for almost a year.

​​ here's a video of it not completely rolling off, but close. it doesn't matter if the ac is on or off.



in the end it's belt alignment, it's not anything else. the rest are all bandaids. if the tensioner is weak, the belt would slip with the ac on. not roll the belt off. few shims under the back of the ac compressor to align it to the crank and alls good. no clue why it changed. went 100k without throwing a belt once. end of it's first track day it threw a belt. couldn't keep one on since then. c6 had no bracket to bent, the ac compressor works fine, no leaks. I've heard ls engines do have core shift, maybe that's what happened? don't know.. but aligning the belt is what fixed it after many other "fixes" and money spent.