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When did MRC start doing that? My stage 2 was done in Feb 2017 and the clutch is not locked. The car is an early 2015 and also has the AT supercharger - rev N clutch. No slip at ratio 2.99, although I do have a Fluidampr crank pulley. Audi did state for the original engine that the "rubber buffer" improves resonance damping which "significantly" reduces load on the drive belt. Maybe since Audi then had to increase the belt tensioning force by 32% for the CREC engine the reduced dampening from single piece crank pulleys is contributing to the problem?
 

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I too am at around 2.98 ratio with a single piece crank pulley. I haven't noticed any slippage, but whether this would only be identifiable on a rolling road graph or possibly a EPC/MIL light, I'm not sure.

I don't know whether mine is locked or not. I don't think so as every now and then I hear a chirp when initially pressing the throttle. My FIS control however shows the SC speed consistently increasing with engine revs even on a cruise. So not sure if the SC will spin 'freely' in speed with the engine but needs the clutch to lock when engine is loaded.

What sort of speeds does yours show Dippy?
 

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I have a Fluidampr/ vDamper with a 189mm crank pulley too. I had contact with Issam from vDamper about this issue and he recommends me to go down to a lower pulley ratio (or have someone weld the clutch, but that solution is also prone to failure + this solution may also destroy the supercharger bearings in a short time + no-one in my area has that expertise).

Note, I don’t have an EPC or CEL but I can clearly hear (with the radio off) and feel the supercharger clutch slipping for half a second when quickly pressing 100% throttle. With normal driving in D, I don’t think a lot of drivers would notice the slipping clutch (although it is faintly audible after the transmission has changed gears). In S with sporty driving and with the transmission constantly shifting, it is pretty obvious it is slipping. In M, if I gradually increase throttle to 100%, I can get it to accelerate as if there is no slipping clutch.

The tuner (European dealer MRC) thought it may be a slipping supercharger belt, but the belt doesn’t show any signs of slipping in over 2000km; plus I am still hitting 1.3 bar of boost (2.3 bar MAP reading from VCDS) in 4th gear so I don’t think the belt is slipping. Issam also said it is unlikely a slipping supercharger belt.

As a new supercharger clutch is more expensive and replacing it more labour intensive than getting another (used) supercharger, I got another supercharger with 1/4th of the mileage mine currently has (<7500 miles). Getting it installed in spring next year as the car is not being used in the winter, possibly in addition with a smaller crank pulley. Might even get the used supercharger ported and serviced, to make up for some of the boost I will lose because of the smaller crank pulley, as stepping down in power is never ideal.
 

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I heard of SC clutch slipping in recent times, more so when the CREC engine was first being pushed in stage 2+ tuning and even then I'm not sure if it was proven it was clutch or belt slippage.

What are your symptoms of clutch slippage, how can you tell?

The boost pressure is controlled by the bypass valve and increasing the ratio affects boost lower down in the revs rather than outright pressure.

Mine seems to be consistently maxing out at 1.15/1.2 bar using the FIS control.
 

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This is how it started (around 0:02 you can hear the noise, currently it is slipping worse). This video is also before the TCU tune, so the transmission isn't really happy; but you get the idea.


On logs I can also see the supercharger rpm is fluctuating after shifts and on initial throttle input, indicating either clutch slip or belt slip:
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Sorry, I don't see or hear it. :)
I can hear the SC whine, normal, I can see some 'glitches' in the rev counter, but this is the gearbox or engine. Your graph above shows the SC speed drop each time with the engine speed.

I'm not being obtuse, just don't see the evidence of any drive slip to the SC?

If there was any drive slip like belt or SC clutch, then the green line would dip where there is slip away from the engine speed. Same as gearbox clutch slip, the engine revs will be higher than the output from the gearbox.

Also during shifts, the SC should bleed boost, fuelling cut and maybe some timing, hence DSG farts.

I have noticed on mine shifts can 'drag' to seem like a clutch slip, more so on the gearbox. This is the TCU slipping the clutch slightly to give either a smoother change or protect the gears whilst changing. I have also noticed when I've been on a long drive and drive spiritedly the shifts can be more punchy. I think this is due to the gearbox oil being hot and the mechatronic valves operating quicker, sharper? That's my logic anyway. But this is the TCU. That's why you find the shifts different in an R8 V10 and Huracan, same drivetrain, different TCU/ECU mapping and the Huracan gives sharper shifts than the R8.

Honestly, I think this is the gearbox, not SC clutch. It is always best to have the TCU mapped with an ECU map as the gearbox is expecting a certain level of power and torque, so when the ECU is remapped it is putting more power through and the gearbox doesn't expect it and can give that fluffy shift as the TCU is trying to 'protect' the box. A TCU remap also gives depending on the map a faster shift and slightly less DSG farts. Not sure if you have tried, but in a launch, you don't hear DSG farts as much. You can also have no auto upshift.

Above is my opinion based on some knowledge and experience, I'm no specialist tuner. :D
 

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So not sure if the SC will spin 'freely' in speed with the engine but needs the clutch to lock when engine is loaded.
What sort of speeds does yours show Dippy?
As you might expect since the clutch is magnetic, the rotors do keep turning when it is open, but at a much lower speed. Unfortunately since I don't daily drive (or even weekly these days) my memory of details is a bit faded but I think that when the clutch is open and the engine is in the idle/low load range, the rotors will be in the 100-300rpm range. Whereas at high load I think they could go above 1000rpm. Since I have FIS-Control MMI I have often looked at the revs whilst driving and when it is closed the ratio does always look around 1:3 as expected.

So it is totally clear that my clutch is not locked as in held closed under all conditions. It does get held closed in ADS dynamic .I can't remember if that's true for gearbox S and M modes when ADS is not dynamic. Based on my observation of the data on FIS-Control MMI I can't see any slip, however I always thought that clutch slip would be flagged by the ECU - and that's what Doug @ MRC thought too when I discussed it with him. But maybe a short slip is not detected as a fault if the revs differential doesn't cross a certain threshold.

I have a Fluidampr/ vDamper with a 189mm crank pulley too. I had contact with Issam from vDamper about this issue and he recommends me to go down to a lower pulley ratio (or have someone weld the clutch, but that solution is also prone to failure + this solution may also destroy the supercharger bearings in a short time + no-one in my area has that expertise).

Note, I don’t have an EPC or CEL but I can clearly hear (with the radio off) and feel the supercharger clutch slipping for half a second when quickly pressing 100% throttle. With normal driving in D, I don’t think a lot of drivers would notice the slipping clutch (although it is faintly audible after the transmission has changed gears). In S with sporty driving and with the transmission constantly shifting, it is pretty obvious it is slipping. In M, if I gradually increase throttle to 100%, I can get it to accelerate as if there is no slipping clutch.

The tuner (European dealer MRC) thought it may be a slipping supercharger belt, but the belt doesn’t show any signs of slipping in over 2000km; plus I am still hitting 1.3 bar of boost (2.3 bar MAP reading from VCDS) in 4th gear so I don’t think the belt is slipping. Issam also said it is unlikely a slipping supercharger belt.

As a new supercharger clutch is more expensive and replacing it more labour intensive than getting another (used) supercharger, I got another supercharger with 1/4th of the mileage mine currently has (<7500 miles). Getting it installed in spring next year as the car is not being used in the winter, possibly in addition with a smaller crank pulley. Might even get the used supercharger ported and serviced, to make up for some of the boost I will lose because of the smaller crank pulley, as stepping down in power is never ideal.
The other thing we haven't compared yet is the drive belt. Mine is a Gates Micro-V Horizon 7PK1325.
When the topic of clutch failure arose years back it was when someone I knew was allowing his car to be used by APR UK to test the ultracharger. His clutch failed twice, but in that case not only was the ultracharger fitted but some of the tests were with 102RON race fuel. Maybe the stresses were too high. I also read of a case of failure on a car tuned by MRC but IIR that was down to a faulty supercharger. Nevertheless I spent some time trying to find out if there were other cases of failure mainly on Audizine which is strongly US-based. Although the CREx engine is only fitted to A6/A7 and a few other models there were enough owners posting that I did find a few cases of owners having clutches replaced under warranty. Backed by the fact that the clutch has been revised a few times by Audi this suggests that unfortunately there is a failure rate for this component.

Remember that a smaller clutch pulley reduces the surface area of contact with the drive belt. In my mind a larger crank pulley is the safest way of increasing drive ratio.

Mine seems to be consistently maxing out at 1.15/1.2 bar using the FIS control.
FYI mine peaks at around 1.25 bar

Sorry, I don't see or hear it. :)
I also struggle to notice anything.

I have also noticed when I've been on a long drive and drive spiritedly the shifts can be more punchy. I think this is due to the gearbox oil being hot and the mechatronic valves operating quicker, sharper?
Me too. Since I don't use the car much I often feel that it is initially sluggish until it is warm and I give it some beans to wake it up.
 

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I shall have to check the FIS tables for a more accurate boost reading! But it does sound similar.

I have a Bando 7PK1310 on mine, but I do have a very slightly smaller pulley at 187mm, but it is damn tight getting it on, even with the tensioner fully retracted!
 

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In IE's response, they are referring mainly to a beta tester that they're working with that I'm in regular talks with. They're correct, his weld did fail but it's a work in progress and they've identified a second weak link in the clutch and now have welds in two different areas of the clutch. To my knowledge, it has not slipped since the second weld was implemented. The guy who performed the welds, also intimately involved in the IE beta testing has produced an alternative to the welding method in which he's using a coupler to keep the clutch engaged at all times. This requires no welds and eliminates the possibility of weight imbalances due to the welds. He has one person beta testing the coupler now but the tester is only stage 1. He's had zero issues with the coupler but wanted a second beta tester who's running a more aggresive tune/mods. He just mailed one to me to beta test for him and I should have it installed in the next week. For reference, I'll list my mods below and keep this group updated on my journey. FYI, I'm on a 2016 A7 US Spec.

Stage 2 Dual Pulley 190/57.7
TCU Tune
Ported Blower
larger Porsche throttle body
Intake
full custom exhaust
Custom down pipes
Merc Racing HX
Iightweight 2 piece rotors
lightweight forged wheels
misc add ons for stabilization
 

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Thanks for that. That is interesting. What I have wondered, is the actual drive unit replaceable with the fixed no clutch unit? I know this part is bolted to the front of the supercharger, but whether it all lines up, I don't know. I'm sure the clutch unit could be removed and replaced by a solid drive unit?

So with all those engine mods, what power are you running? I'm always interested to know with the extra mods, and being quite expensive, how much extra power is achieved. :)
 

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Thanks for that. That is interesting. What I have wondered, is the actual drive unit replaceable with the fixed no clutch unit? I know this part is bolted to the front of the supercharger, but whether it all lines up, I don't know. I'm sure the clutch unit could be removed and replaced by a solid drive unit?

So with all those engine mods, what power are you running? I'm always interested to know with the extra mods, and being quite expensive, how much extra power is achieved. :)
You're welcome, I've been banging my head against the wall for over a year now trying to find a solution or beg the US tuners to find a solution. Just now have the tuners started putting some effort into the SIMOS 16 here in the states. I can't really tell you what the power level is because I was running all of the above except I was at 183/57.7 pulleys for about 2 years with no issues. I decided to go 190/57.7 and within 3 pulls, my clutch failed and from there on, even half throttle would give me a EPC and go into limp with no boost. I've been stock tune and stock pulleys ever since. I'm really hoping this clutch will let me reflash to stage 2 and run my pulleys again without issues.

As for your theory/question regarding the CTUB drive unit. A few of us have tried it without success. Our CREC blowers have a speed sensor plug which the CTUB units do not. Because the ECU doesn't register a speed for the blower rotors, it just doesn't drive right and throws additional codes.
 

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It may be an Eaton supercharger but AFAIK its a custom design for Audi/VAG. There are significant differences between the designs for the CREx and previous engines that it appears that using the snout from the old one is not an option. Whether a whole old style supercharger could be fitted instead I have no idea.

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There are plenty of stage 2 CREC engined cars in the UK with larger crank pulleys, mine is 187 and Dippy's is 189mm with no issues. We do have the std SC pulley though.

I can't get my head round why they fail though as no more power or torque goes through the SC, just an increased speed, but maybe if the increased speed demands more load on the clutch? But the increase in speed is only 3-5krpm.

When I put my larger crank pulley on, I did this a week before my remap and as you say Gid, any more that 1/4 throttle and the EPC and limp mode comes on. This was because the SC speed sensor was picking up 'extra' speed. After the remap, that speed sensor was either recalculated with the new pulley ratio or turned off, I don't know, I didn't ask my mapper. So I think there maybe an issue with your tune? The clutch is separate and I think you should be able to run the pulleys and tune.

I'm sure the SC clutch could be 'gutted' and a solid fixed drive input inserted, created? :)
 

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When I want to "use" my stage 2 I nearly always switch to ADS dynamic which holds the clutch closed. So even at the redline the only difference is that the supercharger is spinning a bit faster.

Unless some of the clutches have manufacturing defects (which is possible and one of the reason why parts are up-revved) then it could be the times when the clutch is actually subjected to extra torque. It's been a few decades since I studied physics, but if the drive belt generates a given force from the crank pulley then the actual torque on the axle of the supercharger increases if a smaller pulley is fitted? Then there's the question of when the clutch opens and closes. If there's a sudden increase in engine speed before the ECU manages to close the clutch then won't that give it a bit of extra torque "shock"?
 

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Has there been any movement on the IE fixed / welded clutch on the CREC? I'm in the US with a 3.0T A6 and I've just burnt up my 3rd clutch in 2 years, running APR Stage 2+ with DP. When it fails I get the EPC light and no boost. I've done some experimenting with welding the previously worn out clutches (and they really are worn out, burnt up, pitted and FUBAR), and I'll fit one of them to the car this week without the silly shroud on the back so I can put it on and take it off without removing the supercharger. I take it I'll need to get the codes tuned out by APR, otherwise the car's going to complain about the clutch being closed when it expects it to be open, etc., but I'll suck it and see, and then report back.
 

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I have read somewhere that someone drives around with a CREC blower and Gen1 rotor pack with press on pulley..
 

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I have read somewhere that someone drives around with a CREC blower and Gen1 rotor pack with press on pulley..
I don't think that will fit. There's a lot different between the mag clutch coupler and the original straight shaft with the torsion spring.
I'd rather have the setup like the Jag/Landrover where the coupling can be serviced.
 

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I think someone on Audizine already tried fitting a fixed supercharger snout from a previous gen, although it did fit, it didn't work:
"We tried retrofitting a CTUB snout and rotor pack in the blower with the goal of reliability, but while it fit, we couldn't get the ecu happy and it kept making boost at idle."

By the way, I also had contact with Powerhouse Automotive regarding the supercharger porting, but I didn't go with them as I am from mainland Europe which makes the import/export process cumbersome and expensive (although I would go for them if I would live in the UK).

In the end I got my spare supercharger ported by Startline Motors, they removed quite a bit of material from the supercharger and also checked the state of the supercharger bearings (said they were fine). I will get it installed in the spring, to combine it with some regular maintenance.
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Do you have any power runs before to see the affect of your porting? Then power runs when you have fitted it. :)
 

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Has there been any movement on the IE fixed / welded clutch on the CREC? I'm in the US with a 3.0T A6 and I've just burnt up my 3rd clutch in 2 years, running APR Stage 2+ with DP. When it fails I get the EPC light and no boost. I've done some experimenting with welding the previously worn out clutches (and they really are worn out, burnt up, pitted and FUBAR), and I'll fit one of them to the car this week without the silly shroud on the back so I can put it on and take it off without removing the supercharger. I take it I'll need to get the codes tuned out by APR, otherwise the car's going to complain about the clutch being closed when it expects it to be open, etc., but I'll suck it and see, and then report back.
It would be interesting to know if this affects crank pulley only tuned cars the same as DP cars. Using a smaller snout pulley must put more stress on the clutch.
 
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