Post ECU upgrade boost leak???

[sduktv]

Hey guys,

I got the GIAC stage 1 tune done to my Scirocco R and lately Ive been noticing a slight stutter/boost leak on acceleration under boost.... Some friends tell me it sound like a compression surge.... any thoughts or anyone noticing a similar problem?
When you put your foot down and hit about 3,500rpm + you can hear a stutter in the boost.... hard to explain... at first I thought it was an exhaust leak but now my mates have told me different so Im not sure...
Is it caused due to the tune? Is it normal? Can anything be done to resolve the problem??

Cheers guys

[h100vw]

Hey guys,

I got the GIAC stage 1 tune done to my Scirocco R and lately Ive been noticing a slight stutter/boost leak on acceleration under boost.... Some friends tell me it sound like a compression surge.... any thoughts or anyone noticing a similar problem?
When you put your foot down and hit about 3,500rpm + you can hear a stutter in the boost.... hard to explain... at first I thought it was an exhaust leak but now my mates have told me different so Im not sure...
Is it caused due to the tune? Is it normal? Can anything be done to resolve the problem??

Cheers guys

You should be talking to your GIAC supplier, I would expect them to datalog it.

It wouldn't be unusual to have a boost leak but logging is the quickest way to see.

A quick check of the PCV system involves, undoing the oil filler cap. If you can lift it off easily, the PCV is probably ok. If it is a bit harder to remove and runs badly with it off, the PCV system needs looking at.

Gavin

[sduktv]

Thanks Gavin I shall do that!
Appreciate the help.... Its only got 6000km on the clock... Scared the hell out of me!!! It would be a real shame for things to start giving out already... Thanks for the advice!

[h100vw]

Thanks Gavin I shall do that!
Appreciate the help.... Its only got 6000km on the clock... Scared the hell out of me!!! It would be a real shame for things to start giving out already... Thanks for the advice!

Honestly the PCV system is pretty weak. A customer of mine had one replaced at Audi 2 months ago and it's gone already. Just plain rubbish. I'd get a delete plate/block off.

Gavin

[Tim]

If it was compressor surge you would have driveability problems.
The sound if its what im thinking is pretty normal and nothing to worry about. The stock tune does it sometimes too if you listen closely. Nowhere near as apparent though.

[Rev 555]

Worth checking your diverter valve as well, although they are the upgraded piston type they are not 100% once boost levels increase post standard.

[shimee]

Not sure if its the same thing, I'd also like to get some views on something that happens with my car - it has only been noticed since the TBE was fitted. Occasionally, when I plant the foot hard in 2nd or 3rd, instead of getting power down I get a lot of exhaust spluttering noise and the power doesnt come on properly,. It all happens very fast and I basically let off the accelerator and then re-accelerate and its ok. The sound is loud - from the exahust, sounds like a massive, spluttering expulsion of air.

I've emailed the mechanic over the holiday break and will take the car in next Monday when they re-open...unless it seems normal. The worst thing is it generally happens at times when I am expecting the maximum performance - like competing against another car or lane changes with a fine margin for error.

[BoschAutoShop]

Hey guys,

I got the GIAC stage 1 tune done to my Scirocco R and lately Ive been noticing a slight stutter/boost leak on acceleration under boost.... Some friends tell me it sound like a compression surge.... any thoughts or anyone noticing a similar problem?
When you put your foot down and hit about 3,500rpm + you can hear a stutter in the boost.... hard to explain... at first I thought it was an exhaust leak but now my mates have told me different so Im not sure...
Is it caused due to the tune? Is it normal? Can anything be done to resolve the problem??

Cheers guys

Not an uncommon occurrence, but more likely in colder weather. There are a number of potential causes; none of any major concern. Is there a noticeable reduction in engine output when you're hearing the sound?

Not sure if its the same thing, I'd also like to get some views on something that happens with my car - it has only been noticed since the TBE was fitted. Occasionally, when I plant the foot hard in 2nd or 3rd, instead of getting power down I get a lot of exhaust spluttering noise and the power doesnt come on properly,. It all happens very fast and I basically let off the accelerator and then re-accelerate and its ok. The sound is loud - from the exahust, sounds like a massive, spluttering expulsion of air.

I've emailed the mechanic over the holiday break and will take the car in next Monday when they re-open...unless it seems normal. The worst thing is it generally happens at times when I am expecting the maximum performance - like competing against another car or lane changes with a fine margin for error.

This is merely the ESP system cutting in. The exhaust flutter is more noticeable, though, because you're now using a louder system. Try switching off the ESP and the sound should go away, meaning you'll wheelspin/axle tramp with flaring revs instead. It's still apparent on a standard car, but far quieter.

[Bug_racer]

You should be talking to your GIAC supplier, I would expect them to datalog it.

It wouldn't be unusual to have a boost leak but logging is the quickest way to see.

A quick check of the PCV system involves, undoing the oil filler cap. If you can lift it off easily, the PCV is probably ok. If it is a bit harder to remove and runs badly with it off, the PCV system needs looking at.

Gavin

Thats not how the PCV works on TFSI engines , its the other way around ..

[Tim]

The issue isnt a boost leak or faulty PCV anyways.
As mentioned if the driveability of the car is fine then I wouldnt stress. The noise is normal on most tuned Rs ive been in (including other vendors) and also possible to replicate on a stock R if you hit the throttle at low RPM in a high gear

[shimee]

Thanks for the reply. If it is the case then its an unusual system - I can spin up the wheels without intervention 90% of the time, its just this drastic power drop on occasion. Not just the sound is new, the power drop is new. Could be due to the increased power of the car I guess....
If its ESP its kicking in way too prematurely and interfering with, ahem, normal driving.

Will switch off and test it out tonight...should be fun.

This is merely the ESP system cutting in. The exhaust flutter is more noticeable, though, because you're now using a louder system. Try switching off the ESP and the sound should go away, meaning you'll wheelspin/axle tramp with flaring revs instead. It's still apparent on a standard car, but far quieter.

[BLAKROC]

Mine does exactly the same when giving it WOT, it's ESP kicking in. Makes some fun pops/farts when it does it though, like a machine gun? Turning ESP off will almost certainly solve this but you'll get the subsequent wheel spin as previously mentioned.

Thanks for the reply. If it is the case then its an unusual system - I can spin up the wheels without intervention 90% of the time, its just this drastic power drop on occasion. Not just the sound is new, the power drop is new. Could be due to the increased power of the car I guess....
If its ESP its kicking in way too prematurely and interfering with, ahem, normal driving.

Will switch off and test it out tonight...should be fun.

[BLAKROC]

In response to the OP I'd guess it's the diverter valve too. I've had no trouble with mine so far, but had the exact same situation when I put stage 1 on the old Polo 1.8T. Solved it with the R1 Diverter valve from APR instantly (plus a larger diameter air intake to let it all breath better - seat pd160 for the polo), as it would hold the increased boost compared to the stock one.

There should be quite a few DV options out there for the Roc R.

[h100vw]

Thats not how the PCV works on TFSI engines , its the other way around ..

Must have misread it then. Apologies if I have lead anyone astray.

Gavin

[BoschAutoShop]

Thanks for the reply. If it is the case then its an unusual system - I can spin up the wheels without intervention 90% of the time, its just this drastic power drop on occasion. Not just the sound is new, the power drop is new. Could be due to the increased power of the car I guess....
If its ESP its kicking in way too prematurely and interfering with, ahem, normal driving.

Will switch off and test it out tonight...should be fun.

There are literally thousands of input condition variations that will directly influence the Bosch ESP system, so it will always intervene differently and with varying severity, just as the nature of your engine output will change, based on the way the ECU interprets the conditions. There are so many different factors measured in micro-seconds that it's impossible to identify a standard reaction.