Supercharged belt rubbing against coolant pipe?

[acarr6]

Hi all - see attached pic. I taped it to confirm exactly when the belt was rubbing the pipe, it doesn't rub during idle or normal driving, but at boost 6+ psi, the belt deflects and rubs against the coolant pipe. Never had this issue before, wondering if the tensioner would cause this, or the belt wearing? Chime in your thoughts. Was planning to replace the belt, tensioner, and the coolant pipe - I don't have confidence in the pipe with it being notched.

[DrFerry]

Blower drive belt is either too tight or too lose. Just like a guitar string, the belt vibrates and causes standing waves at specific frequencies of excitation (RPMs). Check the tension on the belt by checking the deflection by hand i.e. does the belt seem lose? Replacing the belt tensioner and the belt should cure the issue.

[acarr6]

Originally Posted by DrFerry

Blower drive belt is either too tight or too lose. Just like a guitar string, the belt vibrates and causes standing waves at specific frequencies of excitation (RPMs). Check the tension on the belt by checking the deflection by hand i.e. does the belt seem lose? Replacing the belt tensioner and the belt should cure the issue.

It seems fine, however it's definitely not haha. I think I'll just replace both like you mentioned to avoid any future issues. I'm going to swap the belt for the HD green gates version

[DrFerry]

Originally Posted by acarr6

It seems fine, however it's definitely not haha. I think I'll just replace both like you mentioned to avoid any future issues. I'm going to swap the belt for the HD green gates version

You might also consider the gatorback Continental Elite belt IF Conti offers an equivalent length gatorback belt.
.

[roastbeef]

Another thought is engine mounts. If the engine is rocking more with hard use, it could be causing contact.

[acarr6]

Originally Posted by roastbeef

Another thought is engine mounts. If the engine is rocking more with hard use, it could be causing contact.

They are brand new

[amrazM]

I installed a used gintani kit last year and I remember one of the idlers being bad and causing the belt to start shredding. I can post pics if you want to see, its def what youre experiencing with the deflection.

[amrazM]

i remember this being a pain in the ass. all of the idlers were custom machined by gintani but they were servicable. it was a weird double bearing setup on the idler with a bmw type belt tensioner. you need to take it apart and really find out whats going on.

[acarr6]

Originally Posted by amrazM

I installed a used gintani kit last year and I remember one of the idlers being bad and causing the belt to start shredding. I can post pics if you want to see, its def what youre experiencing with the deflection.

Interesting, thanks for this. Once I remove the belt I'll check each one out

[acarr6]

So, took the belts off. The deflection pulley is rattling pretty loud, but that wouldn't cause the deflection. I think the belt is just stretched (used a NON HD belt, which I shouldn't be using), will replace the tensioner as well because why not.

[acarr6]

Well, this greasy bastard is still doing it’s rubbing. Even after new belt, coolant pipe, and tensioner lol.

[DrFerry]

Is the radiator properly seated? There are some pegs (ears) on the bottom corner of the radiator that align the radiator correctly. If the radiator has shifted then the top hose will too.

[acarr6]

Originally Posted by DrFerry

Is the radiator properly seated? There are some pegs (ears) on the bottom corner of the radiator that align the radiator correctly. If the radiator has shifted then the top hose will too.

This is actually what I was just thinking tonight. I’m thinking if I remove the screws that hold it, I can lift it enough to try and giggle it back (if it’s off a bit). Without needing to remove the entire thing, because that’s a nightmare lol

[DrFerry]

Originally Posted by acarr6

This is actually what I was just thinking tonight. I’m thinking if I remove the screws that hold it, I can lift it enough to try and giggle it back (if it’s off a bit). Without needing to remove the entire thing, because that’s a nightmare lol

If you remove the felt under tray you'll see there are some rubber bushings the radiator locating pegs slip into. If I recall correctly. So suppose one of those has collapsed or just flaked away from heat cycling and some slop exists then perhaps the radiator could move. Just a thought. But perhaps it could also tilt slightly as well. Thus causing the belt rubbing issue.

[acarr6]

Originally Posted by DrFerry

If you remove the felt under tray you'll see there are some rubber bushings the radiator locating pegs slip into. If I recall correctly. So suppose one of those has collapsed or just flaked away from heat cycling and some slop exists then perhaps the radiator could move. Just a thought. But perhaps it could also tilt slightly as well. Thus causing the belt rubbing issue.

What a dumb issue to contend with. Let me play around with it tomorrow and see if there is a simple solution. I assume all I need is a few MM’s.

[acarr6]

Update : there’s no screws holding the fan housing lol. So it’s probably just bouncing around and banging into the belt. Woops.

[acarr6]

Update 2: no change with securing tbe fan housing.

I’m now wondering if the belt is perhaps a few MM to large allowing it to deflect more than needed. Tensioner feels strong still so I can’t imagine that’s it.

[DrFerry]

Originally Posted by acarr6

Update 2: no change with securing tbe fan housing.

I’m now wondering if the belt is perhaps a few MM to large allowing it to deflect more than needed. Tensioner feels strong still so I can’t imagine that’s it.

The belt will act like a guitar string i.e. at certain RPMs standing waves will appear with amplitude and duration (wave length). This is the modal response of the vibrating belt. A shorter belt, and/pr narrower belt is worth trying - though may put more load on the compressor bearing(s) but less load on the tensioner. With someone in the drivers seat working the throttle, watch the belt at various RPMs and see if the belt's standing waves amplitude are large enough to sometimes rub the top hose. IF so, perhaps there's some adjustability in the compressor mounting assembly which might allow some movement (adjustment) away from the top hose in addition to the shorter belt approach. Good luck. Keep us updated. Maybe shoot a quick vid with your phone and post it here...

[acarr6]

Originally Posted by DrFerry

The belt will act like a guitar string i.e. at certain RPMs standing waves will appear with amplitude and duration (wave length). This is the modal response of the vibrating belt. A shorter belt, and/pr narrower belt is worth trying - though may put more load on the compressor bearing(s) but less load on the tensioner. With someone in the drivers seat working the throttle, watch the belt at various RPMs and see if the belt's standing waves amplitude are large enough to sometimes rub the top hose. IF so, perhaps there's some adjustability in the compressor mounting assembly which might allow some movement (adjustment) away from the top hose in addition to the shorter belt approach. Good luck. Keep us updated. Maybe shoot a quick vid with your phone and post it here...

Good call. I’ll set up a tripod and take a video, and we’ll see what happens. It’s interesting that it just started happening as well. Makes me think it COULD be a case of the belt being slightly too long. I didn’t have this issue before but the belt was worn out so I replaced it - potentially with one slightly too long. The current size is 58.46” (effectively 59”). For now I’m going to put a metal coupler over the pipe to at least shield it from further damage so it doesn’t explode on me.