S3 Boost Modulation/Flutter

Silky-S3

Silky-S3

Is loving his new 8V S3!
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Hi guys,

My S3 has always had this since going to Revo Stage 1, but now I've just fitted a ITG CAI (See here: http://www.audi-sport.net/vb/new-a3-s3-sportback-8p-chassis/137241-silkys-s3.html) its now much louder (to be expected) and just though I'd check with your guys.

So on WOT or 80%+ (I.e not when letting off the throttle, so its not DV noise (I do get this though, but thats nomal)) I get something that sounds like turbo flutter/modulation. It sounds like the turbo is pulsing on and off very quickly, with a air sounding 'psst' noise. It has no effect of performance and the car pulls strong all the way through it. It seems to happen between 3k to 4k and then stops.

Nomal? I seem to remember Awesome GTI saying this was normal when the car went to S1 due to the higher boost pressures, but now its a bit louder just thought I'd check!

The car pulls well strong so I don't think anything is amiss!

Also - on that note, anything I can log in VCDS to check the boost is ok etc? Requested vs Actual? Any advise?

Thanks :)
 
Think i have the same problem as you. The problem logging boost is that if its a small leak the turbo will over boost to make up for the leak and it still make the requested.

I have done a pressure test to 1.5bar and there are no boost leaks on mine i think my problem is the rocker gasket is leaking letting out blow by gas as there is some oil on the back of the gasket.
 
I don't think my issue is a problem so to speak mate, and I as far as I know I don't have any boost leaks. The car pulls very very strong and its only 9 months old. No oil leak/marks on the block or turbo as well.

Ive been searching round and it seem that this is common on TFSI 2.0 lumps once remapped. It seem to be the ECU modulating the boost and it happens even on the OEM map but as the boost it so low you can't hear it.

Anyone else got an idea?



s3ollie said:
Think i have the same problem as you. The problem logging boost is that if its a small leak the turbo will over boost to make up for the leak and it still make the requested.

I have done a pressure test to 1.5bar and there are no boost leaks on mine i think my problem is the rocker gasket is leaking letting out blow by gas as there is some oil on the back of the gasket.
Click to expand...
 
if its part throttle then the constant change of vaccum then positive boost pressure will make your piston dump valve 'flutter' a little.
is your DV aftermarket? make sure you have the right spring

edit: just re-read you said WOT. it could be surge i suppose? although im not sure how likely that is
 
Cheers mate, cant see the vid but thanks for the info. Puts my mind to rest!

:)
 
Yep, thats the sound mate. Thanks! :)
 
Mine makes it, alot.. constantly.. usually if you tap the accel through gears, or if you are really light on the accel just puttering around.

This audio is taken from a "drive" so you can hear the intake/flutter i guess.

here clicky
 
OK, cool. Sounds like mine :):)
 
I've been pointed to this thread since I questioned the noise on mine after a revo stage 1 map, still not convinced its normal mind you.

Fairly sure it holds back while the boost flutters, running yellow spring, maybe I need the next one up so it holds the valve shut rather than letting out boost?
 
Its totally normal mate been confirmed by loads of people/tuners. It sounds ever better now Im at S2+! I've done tons of logs (and have a boost gauge installed) it does not lose boost pressure when doing it.
 
TimJK said:
I've been pointed to this thread since I questioned the noise on mine after a revo stage 1 map, still not convinced its normal mind you.

Fairly sure it holds back while the boost flutters, running yellow spring, maybe I need the next one up so it holds the valve shut rather than letting out boost?
Click to expand...

Mine too hesitates but only when on full throttle, especially at the start of 4th, I figured it's because of needing fuel pump upgrade. (I'm stage 2)

When I get stage 3 rolling hopefully this will be solved in the new mapping.
 
mjr901 said:
Mine too hesitates but only when on full throttle, especially at the start of 4th, I figured it's because of needing fuel pump upgrade. (I'm stage 2)

When I get stage 3 rolling hopefully this will be solved in the new mapping.
Click to expand...

Be careful with that mate, might be leaning out due to a lack of fuel. Get a HPFP installed ASAP.
 
mjr901 said:
Mine too hesitates but only when on full throttle, especially at the start of 4th, I figured it's because of needing fuel pump upgrade. (I'm stage 2)

When I get stage 3 rolling hopefully this will be solved in the new mapping.
Click to expand...

Yup that's when mine does it full throttle only, you can half throttle though 3500-4000rpm and it won't do it. Mine is from 2nd - 6th gear though
 
Silky-S3 said:
Its totally normal mate been confirmed by loads of people/tuners. It sounds ever better now Im at S2+! I've done tons of logs (and have a boost gauge installed) it does not lose boost pressure when doing it.
Click to expand...

Have you logged your requested Vs actual fuel pressure. On mine the actual was dropping 50 bar when i heard the noise (3-4K). It wasnt running lean as i logged AFR and lambda and all was ok, it was opening the injectors longer to make up for the loss in pressure, however I couldnt live with it and had the map removed.
 
s3ollie said:
Have you logged your requested Vs actual fuel pressure. On mine the actual was dropping 50 bar when i heard the noise (3-4K). It wasnt running lean as i logged AFR and lambda and all was ok, it was opening the injectors longer to make up for the loss in pressure, however I couldnt live with it and had the map removed.
Click to expand...

I have mate, loads of times as setting the map up with SPS. I'll see if I can dig out a graph for you.
 
Silky-S3 said:
Be careful with that mate, might be leaning out due to a lack of fuel. Get a HPFP installed ASAP.
Click to expand...

Yeah I planned to do it this month but for some reason the mrs's Clio needed to be purchased? so I have to wait till next month now! :(

i can't see it being my dv, cars 3 months old. So perhaps all the hesitation issues are fuel pumps not keeping up? I spoke to a Revo dealer a while back and they said some people struggle at stage 1 with their maps with the standard pump. I knows there's plenty that don't, but some maps may do?
 
mjr901 said:
Yeah I planned to do it this month but for some reason the mrs's Clio needed to be purchased? so I have to wait till next month now! :(

i can't see it being my dv, cars 3 months old. So perhaps all the hesitation issues are fuel pumps not keeping up? I spoke to a Revo dealer a while back and they said some people struggle at stage 1 with their maps with the standard pump. I knows there's plenty that don't, but some maps may do?
Click to expand...

I did my HPFP at S1 and it made a big difference at high revs, confirm by logging requested vs actual rail pressure.
 
Silky-S3 said:
I did my HPFP at S1 and it made a big difference at high revs, confirm by logging requested vs actual rail pressure.
Click to expand...

If I were to start again with all this modding, the HPFP would be no 1 purchase, then the maps and bolt-Ons to follow after.

Ill get it read when I go stage 3 and check everything is OK, i dont think it's going to go bang any time soon, it's been stage 2 from new ( now 6.5k miles)and nothing significantly wrong. I don't have VCDS but shark will :) roll on next month...
 
Well the flutter is normal, but any great hesitation is probably due to the mapping/fueling. I think you should get the car read by VCDS and see if fuel requested is being met.

If it is, then no need to jump into fuel pumps unless you want to go further, i.e stage 2 or more.

If the fuel is being met, what else could cause the hesitation? Perhaps change the spark plugs for some cooler ones?
Make sure your using High octane fuel.

Contact revo for some finer tuning, Im sure they can fiddle with it somehow and make it more refined. My friends golf TFSI 2.0 stage 2+ REVO has seemless power. no hesistation, nothing, Just whaaaam. They did have the car for a week or so as they used his car as a test car for new software. So they are capable of producing good maps, probably just need to spend a bit more time with it at a guess.

My shark maps no different. It needs refining, but that will be at tackled stage 3.
 
mjr901 said:
Well the flutter is normal, but any great hesitation is probably due to the mapping/fueling. I think you should get the car read by VCDS and see if fuel requested is being met.

If it is, then no need to jump into fuel pumps unless you want to go further, i.e stage 2 or more.

If the fuel is being met, what else could cause the hesitation? Perhaps change the spark plugs for some cooler ones?
Make sure your using High octane fuel.

Contact revo for some finer tuning, Im sure they can fiddle with it somehow and make it more refined. My friends golf TFSI 2.0 stage 2+ REVO has seemless power. no hesistation, nothing, Just whaaaam. They did have the car for a week or so as they used his car as a test car for new software. So they are capable of producing good maps, probably just need to spend a bit more time with it at a guess.

My shark maps no different. It needs refining, but that will be at tackled stage 3.
Click to expand...
yep, think that map has to be properly tweaked for each car.. mine is going back to garage soon to get it 100% set for my car and crappy fuel that is sold over here..
 
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