Just had Revo Stage 1 Remap on my S3

[Ginger Prince]

That does sound a bit similar, but, I pretty much pestered the tuner about this & they 100% guaranteed me that it isn't compressor surge, the guy that installed the exhaust & CAI even drove it himself with me in it so he could see....

I haven't changed the DV valve, as far as I was aware the stock S3 (8P) one is sufficient?

 

[veeeight]

Revision D = Yes
Earlier revisions = No.

See post #19 earlier in this thread.

 

[Ginger Prince]

I wouldn't have a clue mate, can only say I've got a 57 plate (2008) S3 so what ever that comes with?

Anyway, deffo don't want my turbo to blow up since I do enjoy my S3's power/performance so is there anything I can do (other than obviously driving slow), purchase to avoid any issues. Ive been told I don't need a BOV cos it does damage & not required as the S3 has a DV. Presumably I'm gonna end up having to look at an uprated turbo which is big cash right?

 

[S3Alex]

Like I've said many times before, the squealing noise on throttle lift is compressor stall and opinion is divided on how detrimental if it all,it is.

I can say that the K04 on mine had no problems with 20 000 miles doing this.

It's inevitable with a relatively small compressor run to the ragged edge of its map and at very high rpm.

What Revo and all of the other major tuners have said about testing and reliability is correct as not only would they all be out of business but the forums would also be full of complaints about S3's with blown K04s on these remaps.

And yes....a big turbo will cost a lot if done properly and a lot more if done on the cheap.

 

[Ginger Prince]

Nice one Alex, I know you've helped numerous times.

Im disheartened now as I thought I had found a reliable tuner but it seems extremely rare to find....

Unless there's something that can be done to take the pressure off the turbo I'll have to keep my fingers crossed that the K04 doesn't blow !!

 

[Kelza]

Statlers in sheffield is who i use,there a very reliable tuner hi alex do you still have the picture of the standard oem turbo and the gt3701r ..

 

[veeeight]

I wouldn't have a clue mate, can only say I've got a 57 plate (2008) S3 so what ever that comes with?

2008 S3 8P won't have a Revision D Diverter Valve as standard, so unless the previous owner has fitted one, you need to update your DV.

Like I've said many times before, the squealing noise on throttle lift is compressor stall and opinion is divided on how detrimental if it all,it is.

I can say that the K04 on mine had no problems with 20 000 miles doing this.

The KKK's are tough, and yep, there are a few documented cases of shaft bearings failing, but again, there are many factors involved in failure, so difficult to read.

In my line of work, we deal with compressors on a much larger scale, and any surging in undesirable for many reasons, it's not something that is "designed into" a compressor flow system. In fact, we take great pains to ensure balanced airflow for maximum performance, minimum air disruption, so, in my books, I'd never want to own a system that had inherent airflow issues!

I'm not familiar with the design envelope of Revo's Stage 1, but I doubt it's anywhere near the limits of the KKK K04, and surely on a Stage 1 you shouldn't be experiencing any compressor surge. Stage 3 maybe, but probably not Stage 1, which is a "mild" upgrade. In the case above I'd initially suspect something else, like a knackered DV.

Edit: Just a pedant, but it's not stall, it's surge (the noise is the sound of the blades chopping turbulent back-flow of air from a closed throttle plate). Stall is when the turbine shaft (in this case) actually comes to a stop (it never actually does this), but it only surges, which itself sets up increased mechanical strain on the shaft/spindle bearings, plus it disrupts the airflow and speed of the turbo such that it may, in some instances, affect the spool up time, and could lead to increase in "turbo lag".

Here's a case of compressor surge in a larger system:
ThomsonFly 757 bird strike & flames captured on video - YouTube

 

[Ginger Prince]

Its only done 31,000 miles.

Im surprised garages/stalls at car events & also the tuner who took the car out for a drive all didn't have a clue?!

I live in Manchester, anyone know where I can purchase this Rev D from, price & preferably someone who's good that fits them. I do have a 'well known' VAG specialist local, however, they were one of the people who didn't diagnose compressor stall....

 

[S.]

get it from audi, or ebay i think price is 50-60€. you can replace it yourself. it's pretty much easy job. there is a good tutorial by warren_s3 here...

 

[Ginger Prince]

get it from audi, or ebay i think price is 50-60€. you can replace it yourself. it's pretty much easy job. there is a good tutorial by warren_s3 here...

Jesus, I don’t think I’m that brave....

Question, when I have this done does the map need adjusting as the guy that fitted all the upgrades on my car said he needed to adjust the map after the Neuspeed P-Flow/or intake (not sure which I have) was fitted.

Awesome GTI seem to sell the Rev DV valve but they don’t do Revo anymore after they went back to APR.

Mike

 

[warren_S5]

Honestly Mike, the hardest part of doing DV switch is taking the engine cover off! If your running a CAI then its likely this is already off.

The next hardest part is taking the DV clip off without breaking the awful VAG clips. You need to put a thin flat head screwdriver in the clip and release the catch before pulling it apart. I tried to push it with my thumb once and snapped it,and i then had to buy a Laser VAG connector tool remover (£11), and a new connector (£12) so be warned as that tool is hard to use!

I only noticed the compressor surge once I was running ITG CAI, not when I was running Carbonio intake / panel filter. I'd always assumed that it was one of a few things causing the surge:

1. The increase in the diameter of the pipes ahead of the MAF (100'ish mm down to 67mm) without any mesh air screen in front of the MAF was causing air turbulence ahead of the turbo
2. The complex twists and turns in the CAI (lots of 90 degree angles) were causing massive air turbulence
3. the CAI metal pipes were possibly amplifying something that may to some extent already be there

The OEM engine cover has always struck me as very restrictive, and whilst it's design at the intake duct may help ensure water is not taken into the system, it's still dumping a significant dose of air at the engine with its open design (and not force feeding turbo). I've always wondered whether this design is engineered in conjunction with the plastic cramped intake to suppress any surge tendencies. I know space is tight under there, but I was amazed they didn't do a battery relocation into the spare tyre well and put a proper airbox intake in rather than the halfarsed cover. Having cut one to pieces really it's not an optimised system.

I rany my last S3 8P2 mapped for 60k with no issues and she did Combe a couple of times, the Ring, and was warmed up / cooled down / serviced considerately throughout her life. Only issues other than rear diff were plugs and MAFs, and last dyno at 56k showed 348bhp so it's hard to quantify if it is damaging car or not as mine felt pretty good. If it went now......Lobatime!

 

[Ginger Prince]

Warren - Move to Manchester

I'd like to have a go myself so we'll see & like you, I got the problem as soon as the map, exhaust & 'CAI' were installed.

P.S You're right again, engine cover now lives in my garage as it was taken off during the CAI install.

Thanks very much pal!!

 

[S3Alex]

Veeight....

I'm not going to quote your post as yours and mine would run off the page !

I'm sure your terminology is correct as mine is only colloquial and put as simply as possible.

In any case,I can confirm that mine made the same noises from Stg1,but obviously much more apparent at Stg2+ and with a bigger less restrictive intake.

Perhaps you can answer one for me though....even if a bit off topic.
A bigger turbo,such as a 3071 or 3076 ...this presumably flows the same or more gas at a presumably lower shaft rpm and also the value of a ported shroud compared to non ported.

 

[veeeight]

Oh gosh, this is getting geeky, isn't it!!

Very briefly: Important to distinguish between the 2 different types of compressor surge - on boost surge, and off boost surge. Ginger Prince (Mike) above has off boost surge, where the throttle plate is snapped shut and the turbocharged air in the compressor has no where to go except to the diverter valve, and if this isn't up to the job, will surge the compressor. On boost surge is where you get compressor surge because the compressor stage is trying to shove more air into the engine (throttle plate open), but the engine can't ingest this volume at these revs, so the turbo is operating to the left of the "surge line" on the compressor map. In this instance, a ported shroud can alleviate compressor surge, as it is effectively widening the surge line of the compressor, by "bypassing" or "leaking" some of the unwanted charge. So a ported shroud is only of value if you suffer from these specific circumstances.

Bigger turbo & higher flow rates at lower rpm - I'd have to study the compressor maps to definitely answer the question, but briefly - in a steady state condition (fixed rpm) yes, a larger turbo can yield a higher flow rate compared to a smaller turbo, however, in a non steady-state condition (like in a car), other factors come into play that may outweigh that advantage (such as longer spool times, increased inertia, the efficiency line with respect to rpm will change etc.) So we start getting into twin-turbos, and quad-turbos to overcome these issues

But one of the most important factors is the overall gas flow velocity throughput - much like boy racers that put on 4" exhaust pipes in the belief that this will improve the breathing of their car - quite the opposite, because of the larger diameter, in most cases, they will have reduced the overall gas flow velocity, and set up all sorts of problems with engine breathing (urban myth = exhaust backpressure is good).


/geek

 

[warren_S5]

So to get my head round this, we have off boost chatter / surge, so either the DV isn't up to the job, or (question?) are the DV hoses too small in diameter to 'manage' the backlog of air when the throttle plate shuts?

As the DV is electronic (e.g.open/shut switch), I'd expect it to be OK unless it can't hold increased boost pressures without cracking. I run OEM type G valve (not a Forge with updated spring), so would switching the DV make it better?

As your knowledge is so extensive it would be really handy to now whether you have any views as to how we could manage this siutuation (e.g. Change DV/reduce boost/change hose diameters/something else) if you believe it will cause long term damage.

Really appreciate you taking the time to explain it in detail as not many can. And thanks in advance for any advise you can offer to the question above.

 

[Ginger Prince]

And also if I need the software adjusting once the new DV valve has been fitted please.

 

[S3Alex]

Oh gosh, this is getting geeky, isn't it!!

Very briefly: Important to distinguish between the 2 different types of compressor surge - on boost surge, and off boost surge. Ginger Prince (Mike) above has off boost surge, where the throttle plate is snapped shut and the turbocharged air in the compressor has no where to go except to the diverter valve, and if this isn't up to the job, will surge the compressor. On boost surge is where you get compressor surge because the compressor stage is trying to shove more air into the engine (throttle plate open), but the engine can't ingest this volume at these revs, so the turbo is operating to the left of the "surge line" on the compressor map. In this instance, a ported shroud can alleviate compressor surge, as it is effectively widening the surge line of the compressor, by "bypassing" or "leaking" some of the unwanted charge. So a ported shroud is only of value if you suffer from these specific circumstances.

Bigger turbo & higher flow rates at lower rpm - I'd have to study the compressor maps to definitely answer the question, but briefly - in a steady state condition (fixed rpm) yes, a larger turbo can yield a higher flow rate compared to a smaller turbo, however, in a non steady-state condition (like in a car), other factors come into play that may outweigh that advantage (such as longer spool times, increased inertia, the efficiency line with respect to rpm will change etc.) So we start getting into twin-turbos, and quad-turbos to overcome these issues

But one of the most important factors is the overall gas flow velocity throughput - much like boy racers that put on 4" exhaust pipes in the belief that this will improve the breathing of their car - quite the opposite, because of the larger diameter, in most cases, they will have reduced the overall gas flow velocity, and set up all sorts of problems with engine breathing (urban myth = exhaust backpressure is good).


/geek

Guess it does get geeky at that level doesn't it!

The thing is,if someone with better technical knowledge comes along,you're going to get tapped for it all the time.

The reason I asked,aside from my misunderstanding of the surge/stall naming,is this.....

Later in the year,I'll be fitting a bigger turbo to mine,as the 3071 is again pretty well wrung out on the car's current settings,and I'd value any information I can get about things like ported shrouds,and aspect ratios and so on.

If you'd either like to post it here or maybe on my thread here......

http://www.audi-sport.net/vb/a3-s3-sportback-8p-chassis/106134-time-build-thread-big-turbo.html


I'd be very grateful.

I can give you the current turbo's spec over there if you wish.

Thanks.

 

[veeeight]

Hi Warren

My automotive application theory is fairly rusty, so won't be able to answer in specifics, less so because I've not taken the time to study the S3 system, but as initial thoughts off the top of my head, I wonder why the DV is so far away from the turbo itself, maybe engine bay packaging issues? Also, maybe the tuner hasn't spent enough time with the DV opening duration, or the start time of the DV opening? Also - I'd want to see the interaction of the boost controller vs rpm vs throttle position, and how this affects airflow.

I've not spent enough time with the S3 to understand the implications of base map vs. remap to fully understand what parameters they've changed, and which they've ignored! Most aftermarket tuners I've spoken are software whizzes, but not so hot on thermodynamics, thus sometimes leading to some iffy remaps. Each component has to work well in the whole system to get maximum volumetric efficiency, and sometimes just altering a map and changing the intake & exhaust doesn't achieve that. Sorry not to be of more help.

Alex: I'll ready your other thread!!

Mike: Change your DV first, and then see how it goes. As the others here have said, unless your driving balls out 100% of the time, and as long as you look after all the other factors (frequent good quality oil changes, a warm-down regime, letting it idle for a couple of minutes after thrashing it etc.) then you may wish to trade off a little boost plus compressor surge, against the risk of reduced longevity of your turbo bearings! But change your DV. That's a first good relatively cheap step.

 

[S3Alex]

Hi Warren

My automotive application theory is fairly rusty, so won't be able to answer in specifics, less so because I've not taken the time to study the S3 system, but as initial thoughts off the top of my head, I wonder why the DV is so far away from the turbo itself, maybe engine bay packaging issues? Also, maybe the tuner hasn't spent enough time with the DV opening duration, or the start time of the DV opening? Also - I'd want to see the interaction of the boost controller vs rpm vs throttle position, and how this affects airflow.

I've not spent enough time with the S3 to understand the implications of base map vs. remap to fully understand what parameters they've changed, and which they've ignored! Most aftermarket tuners I've spoken are software whizzes, but not so hot on thermodynamics, thus sometimes leading to some iffy remaps. Each component has to work well in the whole system to get maximum volumetric efficiency, and sometimes just altering a map and changing the intake & exhaust doesn't achieve that. Sorry not to be of more help.

Alex: I'll ready your other thread!!
.

Much appreciated.

It'll be a lengthy read now ,but most of the info is in there.

The relevant bits have been both reliable and powerful,plus driveable,but with the next step coming,any extra knowledge is always useful!

 

[warren_S5]

Interesting stuff.

On the S3 the intake tract is long, complex and full of 90 degree bends (if you run an ITG or similar the air has to negotiate three 90 degree bends before reaching the turbo housing, and the whole intake piping is probably in excess of a metre in length even from shortest point to point.

On the KO3 the DV was mounted to the turbo housing but it suffered quite a bit with the heat, so when VW upped the boost on the S3 to about 16psi from memory, they elected to relocate the DV cold side on the front of the engine (directly opposing corner to the turbo housing). This means the DV hose is around a metre in length, but I'd never considered this an issue as I ran my DV on my 1.8T Leon Cupra R 225 (at stage 2 pushing 21psi), and had none of these issues.

I'd heard from one tuner, and it could be wrong, that TFSi engines that VAG were recycling exhaust gases back into the system (caveat - I could have horribly misinterpretted this as it seemed strange to me), and I was wondering whether if this was the case was causing further issues when the boost was ramped up?. There was certainly something different going on, but I can't be certain that's how it was explained so sorry if it's a red herring. It just seemed strange it never happened running similar spec / boost on 1.8T.

Geeky this may be, but it makes a change from the usual! Too much plug, play and accept these days!

Many thanks again for any light you can shed.

 

[Ginger Prince]

Hi Warren

My automotive application theory is fairly rusty, so won't be able to answer in specifics, less so because I've not taken the time to study the S3 system, but as initial thoughts off the top of my head, I wonder why the DV is so far away from the turbo itself, maybe engine bay packaging issues? Also, maybe the tuner hasn't spent enough time with the DV opening duration, or the start time of the DV opening? Also - I'd want to see the interaction of the boost controller vs rpm vs throttle position, and how this affects airflow.

I've not spent enough time with the S3 to understand the implications of base map vs. remap to fully understand what parameters they've changed, and which they've ignored! Most aftermarket tuners I've spoken are software whizzes, but not so hot on thermodynamics, thus sometimes leading to some iffy remaps. Each component has to work well in the whole system to get maximum volumetric efficiency, and sometimes just altering a map and changing the intake & exhaust doesn't achieve that. Sorry not to be of more help.

Alex: I'll ready your other thread!!

Mike: Change your DV first, and then see how it goes. As the others here have said, unless your driving balls out 100% of the time, and as long as you look after all the other factors (frequent good quality oil changes, a warm-down regime, letting it idle for a couple of minutes after thrashing it etc.) then you may wish to trade off a little boost plus compressor surge, against the risk of reduced longevity of your turbo bearings! But change your DV. That's a first good relatively cheap step.

I shall do just that!

Many thanks

 

[Kelza]

Always loved this video of keiths (s3decked) car...
Audi S3 Revo stage 2+ - YouTube

 

[Ginger Prince]

Thats the same video I put up earlier in this thread. That too has surge!

 

[Kelza]

Hi mate , this is normal running a cai with revo software...

 

[Ginger Prince]

Hi mate , this is normal running a cai with revo software...

Hi Kel (Working nights if anyone thinks I'm a vampire....)

Bad news brother, it would seem it isn't normal, my car sounds exactly the same as Keith's & is "surge" so beware to anyone else who's also sounds like this!

Have a read back through this thread & you'll see the Master/s comments.

Cheers,
Mike

 

[Kelza]

Hi mike,Just watching fifth gear on sky,lol

 

[Ginger Prince]

Hi mike,Just watching fifth gear on sky,lol

Good lad

 

[warren_S5]

And hopefully we might soon come up with some possible ideas for a fix!

I'm going to be speaking to some industry folk this week to get their take on it, but there doesn't seem to be a definitive view, so will need to be careful with how we interpret the data!

 

[Acheron]

I've yet to hear a K04 2.0TFSI with an intake that doesn't have that sound

 

[S.]

had 2 different maps on my car and 2 different CAI's, 3 DV's and always sounded like that, as Acheron said i think that there is no K04 with remap and CAI that doesn't sound like that. eventualy some CAI's are quiet (like twintake or so).

 

[S3Alex]

Statlers in sheffield is who i use,there a very reliable tuner hi alex do you still have the picture of the standard oem turbo and the gt3701r ..

Yes...here it is....don't forget the smaller K04 comes with an integrated exhaust manifold and turbine housing,so that does make it look bigger than it really is in effect.

This one shows the sizes of the compressor and turbine areas better....

 

[Kelza]

I want ..,thanks alex

 

[S3Alex]

I want ..,thanks alex

Thanks!
What it does illustrate is how small the sections of the K04 actually are,especially the hot side,and by comparison the 3071 is MUCH bigger,but actually does not suffer from greatly increased lag,or a much higher rpm band within which it will operate.
I find that the 3071 hits its best about 500rpm higher than the old stock turbo did,and with minimally increased lag,unless you are well below the operating band.

 

[downtothebone]

Chaps,

Where exactly is the DV valve on the A3? I want to check my revision ... I can get the engine cover off easily as I've just fitted some Denso Iridium plugs ...

 

[Ginger Prince]

I shall do just that!

Many thanks

I did it, today I went to Awesome GTI here in Manchester & had the DV changed. I also had the S3 put on the rolling road which gave me a bit of a shock....


The readings came back as:

Run 1

Max Power = 278.32
Max Clutch Torque = 319.35

Run 2

Max Power = 285.67
Max Clutch Torque = 313.35

The lad from the workshop handed me the print out & said "nice car, 286 BHP." I was like, huh, is that it...?!

 

[-Ju-]

Nothing wrong with those figures mate, as said tuners always quote flywheel figures. At the wheels figures on a 4 wheel drive car can easily be 40+bhp less.
In any case I would not rely too much on "dyno lottery" figures as there only really comparable against other cars on the same dyno on the same day. To get a true horsepower figure at the flywheel you would have to mount the engine on dyno!

 

[Ginger Prince]

Nothing wrong with those figures mate, as said tuners always quote flywheel figures. At the wheels figures on a 4 wheel drive car can easily be 40+bhp less.
In any case I would not rely too much on "dyno lottery" figures as there only really comparable against other cars on the same dyno on the same day. To get a true horsepower figure at the flywheel you would have to mount the engine on dyno!

Nice one, thumbs up 3.2Ju

 

[-Ju-]

Everyone knows Red S3's are quicker anyway

 

[S.]

I did it, today I went to Awesome GTI here in Manchester & had the DV changed. I also had the S3 put on the rolling road which gave me a bit of a shock....

Revo say stage 1 on the S3 (8P) should take you to 300 BHP. I also have a Neuspeed CAI & Milltek cat back non-res exhaust which I was told gives a few extra BHP.

The readings came back as:

Run 1

Max Power = 278.32
Max Clutch Torque = 319.35

Run 2

Max Power = 285.67
Max Clutch Torque = 313.35

The lad from the workshop handed me the print out & said "nice car, 286 BHP." I was like, huh, is that it...?!

When I queried it saying Revo publish 300 BHP (the tuner who did the work on mine said he estimated mine to be at approx 310 BHP with the exhaust & CAI) they said that the figures they publish are fly wheel figures and not power at the wheels.

Is this right? I was expecting to get a figure of at least 300 BHP at the wheels & feel a bit cheated now

i think they gave you at the wheels figures! if so, those figures are great!
with 15% loses that's 320bhp

 

[warren_S5]

Chaps,

Where exactly is the DV valve on the A3? I want to check my revision ... I can get the engine cover off easily as I've just fitted some Denso Iridium plugs ...

On the turbo housing for the A3, on the front RHS of engine S3.

Decent figures GingerPrince. Did DV make any difference to feel of car?