Supercharger belt shredded while driving

[P1Racer]

I was driving calmly for about 30 minutes and felt my power steering go out. Pulled over and saw the belt of my supercharger shredded.

I have seen this happen a few times here on the forum. My question is what belt should I replace this with? I have a CTS pulley kit. It's been on the car for 1000 miles.


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[14S4GWM]

Stock

[P1Racer]

Stock

Would the stock pulley work well the with the aftermarket smaller pulley? I didn't think it would fit since it's a smaller diameter.


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[Sudz]

Tell us about your car, year, mileage, is it stock, etc.?
Otherwise we are really guerssing here.

[plat]

What's your car's mileage? When you installed the CTS pulley kit, did you change the belt or use the original belt?

[P1Racer]

80k miles, pulley and belt are CTS and has been on for 1k miles. Cars a dsg and is stock tune.


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[Sudz]

My guess is the belt was loose or miss alligned. I would look for misaligned pulleys that really bend the belt.
If this is the case, the belt is getting stressed during each revolution of the pulleys, this is a crazy guess.

I once told our quality manager I do car repair over the phone, this almost qualifies, I am the ME manager.

[P1Racer]

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[plat]

+1. I agree with Sudz's guess/hunch/theory that the pulleys are not properly aligned with each other. A belt just does not get shredded like that unless the pulleys are misaligned with each other which means that the grooves in the belt are not seating properly on the grooves of one of the pulleys. Or, the replacement belt was a poor quality part which I somewhat doubt but who knows?

[P1Racer]

+1. I agree with Sudz's guess/hunch/theory that the pulleys are not properly aligned with each other. A belt just does not get shredded like that unless the pulleys are misaligned with each other which means that the grooves in the belt are not seating properly on the grooves of one of the pulleys. Or, the replacement belt was a poor quality part which I somewhat doubt but who knows?

I'm kind of thinking it's the quality of the belt. I'm going to try and find another brand belt that works with the 57 size pulley.


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[jmaddr]

80k miles, pulley and belt are CTS and has been on for 1k miles. Cars a dsg and is stock tune.

Why would you have a stock tune with an undersized pulley? And if it’s not undersized why was the stock pulley replaced?

[P1Racer]

I have a date to get tuned at the end of the month. I don't drive the car often and was told it's fine to have it on. The pulley was replaced to allow for more psi when tuned


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[xpoweruk]

A similar case recently was down to the charger pulley not being on the shaft far enough.

[whiped]

Since no one really answered you. 7pk1270

[gdawg'05a4]

A similar case recently was down to the charger pulley not being on the shaft far enough.

Yep. The pulley should be flush on the shaft like this:

[P1Racer]

Since no one really answered you. 7pk1270

Thank you whiled! This is the exact answer I was looking for


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[P1Racer]

Since no one really answered you. 7pk1270

That's the appropriate size for my aftermarket pulley?


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[infinkc]

If your powersteering went out, it's your crank pulley that failed, not the supercharger pulley like everyone is saying. When the crank pulley fails it can shift the belts causing the shred also.

[xpoweruk]

Good spot

[LINDW4LL]

If your powersteering went out, it's your crank pulley that failed, not the supercharger pulley like everyone is saying. When the crank pulley fails it can shift the belts causing the shred also.

This

That's the appropriate size for my aftermarket pulley?

Correct. The smaller SC pulley does not require a change in belt size. The belt tensioner takes up any slack.

[P1Racer]

After getting the car home and looking more into it, the accessory belt shredded and the supercharger belt just popped off. At 80k Miles, is it possible my tensioners are already worn out?

[Dippy]

As already noted - your priority should be to check if the OE crank pulley has failed

[whiped]

Sorry, the 7pk1270 is for the supercharger side of things. I am not sure what the accessory belt size is.

ECS has kits though you can reference: https://www.ecstuning.com/Audi-B8_S4...ccessory_Belt/

FWIW, check your crank as noted above.

[P1Racer]

Sorry, the 7pk1270 is for the supercharger side of things. I am not sure what the accessory belt size is.

ECS has kits though you can reference: https://www.ecstuning.com/Audi-B8_S4...ccessory_Belt/

FWIW, check your crank as noted above.

Thanks I'll be checking those out today. If so I guess it's a good time to go DP


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[whiped]

Even if you don't go DP grabbing a fluidampr pulley is wise as you can easily add the larger sleeve on later

[P1Racer]

Even if you don't go DP grabbing a fluidampr pulley is wise as you can easily add the larger sleeve on later

Alright, so crank pulley is sliding like that on my car so that must be the cause. If so I'd like to go with the 187mm is the fluidamp better than apr? Which is easier to install myself?


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[whiped]

APR bolts on over the OEM pulley. So if you go APR you will need to buy an OEM pulley and the APR extender thing.

If you go Fluidampr you buy the crank pulley and a sleeve that bolts to it.

The Fluidampr is a better solution IMO. Both will require the same amount of work to install.

If you don't mind running undampened JHM/KI also offer solid pulleys.

[P1Racer]

With this failure, JHM Also sells a 187mm Crank pulley that looks like it includes the inner pulley section.
https://jhmotorsports.com/shop/catal...html?cPath=0_1

Also, Would it be safe to drive the car with both pulleys for a few weeks?

[whiped]

Yeah no problem, you'll just bleed off the extra boost.

[F40LM]

I have a stock belt and pulley for sale under 15k miles on it btw


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[P1Racer]

Just ordered my JHM 187mm crank pulley. That kit comes with a new supercharger pulley I assume. Which means I also will be ordering a new accessory belt. Since I'll be doing this, is there another moving part around there that I should service or upgrade?


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[xpoweruk]

Looking at the JHM site it doesn't come with a charger pulley
https://jhmotorsports.com/shop/catal...si-p-4227.html
PARTS INCLUDED:
- 1x JHM "HD" Overdrive Lightweight Crank Pulley (187mm)
- 8x 8mm x 1.25 Allen Bolts
- 1x High-Quality Belt, Longer for Use with Larger Pulley

It will still give a good ratio though & is what MRC use in the UK for stage 2

[P1Racer]

Looking at the JHM site it doesn't come with a charger pulley
https://jhmotorsports.com/shop/catal...si-p-4227.html
PARTS INCLUDED:
- 1x JHM "HD" Overdrive Lightweight Crank Pulley (187mm)
- 8x 8mm x 1.25 Allen Bolts
- 1x High-Quality Belt, Longer for Use with Larger Pulley

It will still give a good ratio though & is what MRC use in the UK for stage 2

Awesome! Well after digging around a little a 1320 supercharger belt seems to be the sweet spot with my new ratio. Is anybody running something similar?


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[whiped]

Depends on the brand of belt. I'd go gates rpm 7pk1310 personally. Or a 1320HD

[xpoweruk]

JHM provide the belt by the look of it

[P1Racer]

Thanks for the info, I'll be installing tonight and hopefully the S4 is back up and running!


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[P1Racer]

JHM Sent me a Bando 1300, hopefully that works.

[whiped]

Might be tight but should be fine. Belt sizing is inconsistent so you'll have to test it

[bhvrdr]

JHM Sent me a Bando 1300, hopefully that works.

Bando belts are complete junk. I'd rather run a gates 6 rib.

https://www.amazon.com/Gates-K060516.../dp/B001R5W4EC

[P1Racer]

I got it together successfully! Thanks for everyone's help


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