S54 harmonic damper thoughts

[CrookedCommie]

Although I did not measure it, I believe the problem isn't the spacing, but lack of inner lip on the pulley which eats the belt. Essentially you will need a pulley with an inner lip, and a damper that can fit the pulley in line with the rest of the belt system including the tensioner, water pump and alternator.

[F1Dryvr]

Ok does anyone see a problem with spacing the pulley out 1-2mm? or perhaps using the stock pulley and spacing out the tensioner(not sure if thats possible)

[AXDB]

This is a guess. ATi was working on the guidance from VAC. Then VAC wanted to stay cost competitive so they tried to make it work. This is an attempt to make an exclusive product.

This wouldn't be an issue if ATi developed the damper themselves.

This imo compounds the issue. Every ATI damper everywhere is sub $500. Yet the s54 is over double that.

[bigjae46]

This is a guess. ATi was working on the guidance from VAC. Then VAC wanted to stay cost competitive so they tried to make it work. This is an attempt to make an exclusive product.

This wouldn't be an issue if ATi developed the damper themselves.

[CrookedCommie]

so your belt was rubbing the damper like mine?

it just needs like 1mm or less to clear i would guess but easier said than done

Yes. My guess is that to make this damper fit, VAC did not machine an inner lip on the pulley, and it rubs directly on the damper. Typical VAC bullshit. Maybe this was common knowledge, but news to me. Tore up the old belt in one weekend, and a new belt with brand new tensioner and idler pulley in two weekends.

[F1Dryvr]

I would not use the VAC ATI setup. Just blew a brand new belt. I'm guessing it's not aligned correctly. Reached out to Morehead and they had the same issue. I'm switching back to stock. This is the last VAC part out of my car, and will never be using anything they make again.

so your belt was rubbing the damper like mine?

it just needs like 1mm or less to clear i would guess but easier said than done

[CrookedCommie]

I would not use the VAC ATI setup. Just blew a brand new belt. I'm guessing it's not aligned correctly. Reached out to Morehead and they had the same issue. I'm switching back to stock. This is the last VAC part out of my car, and will never be using anything they make again.

[Randall921]

Anyone have experience with the Ross damper?


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[F1Dryvr]

I have the vac pully that shipped with the ati damper and swapped back to the stock pulley due to this concern but that didnt work as mentioned above.

Pic of stock pulley on ati damper causing shift of belt on tensioner(the belt does not rub the damper this way but.......):



Compared to stock there is no "damper side/inbaord" flange to protect the belt like most other pulleys, and while i dont think its a tight rub, the white sticker on the ati damper has marks suggesting a rub. No signs on the belt of wear from relatively short but spirited use.

Wear marks on damper(custom vac pulley), i need to get a pic of belt on pulley but when u look at it it looks to be touching.

[CrookedCommie]

Good to know, mine came with the VAC pulley, so maybe the belt failure was unrelated.

For OP - I have the dual clutch Clutchmasters setup similar to the Tilton, and the engine did the typical idle hunt, with the new damper it seems a bit better. Noticed no other differences. The stock one I pulled off the car at 135k miles seemed fine, no cracks.

[elbert]

It's the damper. You need to use a special VAC pulley to use the ATI.

https://www.bimmerforums.com/forum/showthread.php?2109437-S54-ATI-crank-damper-pulley-misalignment-problem

[CrookedCommie]

So i have recently installed the ati damper in conjunction with the tilton twin disc/steel sm flywheel. My damper had 160k miles on it and 10000 track miles estimated on it so i went ahead w/ the ati for peace of mind(ive fully rebuilt my engine and the time and $$ spent i want it as bulletproof as i can have). Ive done one weekend with this setup and the benefits of the lighter flywheel are quite noticeable. I think my clutch setup saves about 16lb overall rotating mass. The ati damper adds back 4lb to the front since its heavier than stock damper so a 12lb net loss.

The ati damper did come with a crank pulley though and the install has the belt actually rubbing the damper. I tried swapping back the stock pulley and that offsets the belt to where its not fully seated on the tension pulley. I dont know what to do about this, i thought about putting spacer behind the pulley, 0.5mm would probably be all it needs but thats a complex modification and damn near impossible trying to use washers!!!

For now, since the belt lasted the weekend with no signs of wear (4 plus hours of track time), im going to leave it with every session inspection.

Can you take a picture of this? I also have the ATI damper, did not notice anything wrong with it, but after a weekend the belt had developed a rip and had to be replaced before it fully let go. I thought it may be unrelated and just due to the age of the belt, but now I'm worried it maybe the ATI damper?

[F1Dryvr]

So i have recently installed the ati damper in conjunction with the tilton twin disc/steel sm flywheel. My damper had 160k miles on it and 10000 track miles estimated on it so i went ahead w/ the ati for peace of mind(ive fully rebuilt my engine and the time and $$ spent i want it as bulletproof as i can have). Ive done one weekend with this setup and the benefits of the lighter flywheel are quite noticeable. I think my clutch setup saves about 16lb overall rotating mass. The ati damper adds back 4lb to the front since its heavier than stock damper so a 12lb net loss.

The ati damper did come with a crank pulley though and the install has the belt actually rubbing the damper. I tried swapping back the stock pulley and that offsets the belt to where its not fully seated on the tension pulley. I dont know what to do about this, i thought about putting spacer behind the pulley, 0.5mm would probably be all it needs but thats a complex modification and damn near impossible trying to use washers!!!

For now, since the belt lasted the weekend with no signs of wear (4 plus hours of track time), im going to leave it with every session inspection.

[BeardedRyno828]

Typically a lighter single mass flywheel would be the performance choice, but I read there are a number of track driven S54’s that have front crank damper failure and often in association with light weight single mass flywheel.
One can assume the dual mass stock flywheel may play a significant role in mitigating harmful crankshaft harmonics.

Have the single mass flywheel and clutch setup balanced together, toss on ATi vibration damper, send it.

Edit: The steel single mass and M5 clutch kit I did wasn't much lighter than the stock dual mass setup on my s50. I would just avoid a super light aluminum setup.

[Acetech]

Typically a lighter single mass flywheel would be the performance choice, but I read there are a number of track driven S54’s that have front crank damper failure and often in association with light weight single mass flywheel.
One can assume the dual mass stock flywheel may play a significant role in mitigating harmful crankshaft harmonics.