Single pulley question: crank out S/C?

[AudiC7Owners]

So it seems that must people on the C7 forums do the S/C pulley for their single pulley tunes, but in the B8 S4 forums, it seems most people recommend doing the crank pulley fit the single pulley tunes.

Why is that?




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[gk1]

Is it a matter of more press-fit s/c pulleys on the B8’s so may be easier to bolt on the crank pulley vs. more bolt on s/c pulleys on the C7?Possibly avoids service position and/or press-fit removal/installation.

[AudiC7Owners]

Is it a matter of more press-fit s/c pulleys on the B8’s so may be easier to bolt on the crank pulley vs. more bolt on s/c pulleys on the C7?Possibly avoids service position and/or press-fit removal/installation.

Both cars have the same pulley setups with the press on S/C pulley. And it's definitely easier to swap the S/C pulley vs the crank pulley.

[Dippy]

I wouldn't say that most B8 owners with single pulley tune choose the crank, in fact the opposite. Most of those who are uprating the crank are going dual pulley. In some respects doing the s/c pulley is easier, however a few people have had problems seating the new one properly because it wasn't hot enough or cooled too quick. However especially for those cars which are older/done more mileage, the crank pulley should perhaps be chosen instead because there have been a worryingly high number of reports of OE crank pulley failure due to the vibration damping polymer degrading. Also its pretty clear that the smallest s/c pulley which can be used is about 57mm giving a drive ratio of about 2.84, whereas the crank pulley can be uprated to give ratios well over 3.0 and are limited only by how much you want to stress the s/c.

[MattyMarkey]

Pretty sure one of the main reasons is, because of the crank pulley failures - the Crank Pulley is notorious for failing in the B8 and causing some gnarly damage.

It's all about ratio's anyway - meaning, put in a larger crank pulley and keep the OEM s/c, you are creating the same ratio (and increasing boost) as if you were swapping out the s/c pulley for a smaller diameter and keeping the OEM crank pulley. With a new Crank and OEM s/c pulley, you are getting the increase in boost, and better reliability! Sounds like a win, win to me!

[pfar54]

Both cars have the same pulley setups with the press on S/C pulley. And it's definitely easier to swap the S/C pulley vs the crank pulley.

Not the facelift models. My car has a bolt on s/c pulley.

[ELaw]

Are the pulleys on the C7 known for failing too? I just got one yesterday and am trying to figure out what I need to keep an eye on.

[Chris@EPL]

In North America the 2016-2018 3.0T A6/A7 cars have the bolt on SC and the earlier cars have the press on SC pulley. The SC pulley is cheaper and easier to hide if you are still under warranty. It looks the same and even takes the same size belt. Larger crank pulleys stand out if they look under the hood and it takes a different sized belts.

You can do either one, but the SC pulley is cheaper and we actually rent out our SC pulley removal tools for EPL customers. Most shops charge the same 3 hours of labor for either set up to install. The OEM crank pulley is failure prone so some people want to get it replaced and kill 2 birds with 1 stone and go Stage 2 that way.

[AudiC7Owners]

I wouldn't say that most B8 owners with single pulley tune choose the crank, in fact the opposite. Most of those who are uprating the crank are going dual pulley. In some respects doing the s/c pulley is easier, however a few people have had problems seating the new one properly because it wasn't hot enough or cooled too quick. However especially for those cars which are older/done more mileage, the crank pulley should perhaps be chosen instead because there have been a worryingly high number of reports of OE crank pulley failure due to the vibration damping polymer degrading. Also its pretty clear that the smallest s/c pulley which can be used is about 57mm giving a drive ratio of about 2.84, whereas the crank pulley can be uprated to give ratios well over 3.0 and are limited only by how much you want to stress the s/c.

I feel like every time I see the roof come up on the b8 s4 Facebook group every single person tells others to change the crank pulley.


Not the facelift models. My car has a bolt on s/c pulley.

Oh yea I'm totally aware of that. I'm only referring to the press on s/c pulley cars.


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[AudiC7Owners]

Pretty sure one of the main reasons is, because of the crank pulley failures - the Crank Pulley is notorious for failing in the B8 and causing some gnarly damage.

It's all about ratio's anyway - meaning, put in a larger crank pulley and keep the OEM s/c, you are creating the same ratio (and increasing boost) as if you were swapping out the s/c pulley for a smaller diameter and keeping the OEM crank pulley. With a new Crank and OEM s/c pulley, you are getting the increase in boost, and better reliability! Sounds like a win, win to me!

That makes a lot of sense. Think I'll do the crank pulley when it's time to go single pulley tune for the same reason.


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[Dippy]

I feel like every time I see the roof come up on the b8 s4 Facebook group every single person tells others to change the crank pulley.
Yes, just like I am doing. But I think if you surveyed B8 owners you'd find that most single-pulley tunes are s/c pulley and most crank pulley tunes are DP.