S3 8V "bludder from exhaust" on full throttle

[Lovric Nikola Martin]

Suddenly (past month) my S3 8V -16 has begun to make a "bludder" sound from the exhaust when going full throttle. Only in this specific scenario (full throttle). Its not a continuous sound, there are about 2 or 3 quick bludders when accelerating hard, and then everything goes back to normal. Never had this happen before. I thought maybe bad gas, but I've had a few tank refills from different pumps and issue is the same. I have step1 software and the transmission software update on this car since a few years back without any issues. Car is at 89000kms. Any ideas what could be causing this, and if it possibly could cause damage?

Thanks for any tips

 

[JohnM100]

Can you post a recording of it, either outside or from inside with the windows down?

Any hesitation from the car when it does this?

Since you are stage 1 and TCU tune then that open a lot of other possibilities compared to a car with a stock map.

 

[Lovric Nikola Martin]

Can you post a recording of it, either outside or from inside with the windows down?

Any hesitation from the car when it does this?

Since you are stage 1 and TCU tune then that open a lot of other possibilities compared to a car with a stock map.

Thanks for your reply. I think that will be very hard to record without setting up an outside recording device. Yes there seem to be a tiny hesitation in effect when the bludder occurs, but its extremely tiny. Also what I forgot to mention, it doesnt occur every time I accelerate like this. Maybe every other three times. And there are maybe 2-3 "bludders" (dont know how to describe it, like a very faint farting noise) that presents itself very quick, not even a seconds time. Usually there are like two or three of these every time this occurs.

The car is up for an oil change, spark plugs and some filters, so I will see what happens after this. Maybe I will ask the shop to troubleshoot the issue.

 

[JohnM100]

DSG farts (like someone ‘blowing a raspberry’) are normal on fast acceleration high rev upshifts - try googling and see if it is your noise. If not then audio recording would really help to try to identify it.

Do you know which company did your stage 1 remap? It could be programmed to make noises that a standard car wouldn’t.

 

[Lovric Nikola Martin]

DSG farts (like someone ‘blowing a raspberry’) are normal on fast acceleration high rev upshifts - try googling and see if it is your noise. If not then audio recording would really help to try to identify it.

Do you know which company did your stage 1 remap?

Yeah, that's not the sound. This sound does not come from shifts. However I keep reading that bad spark plugs can cause this issue, so I am hoping for that. These plugs have not been replaced for many years. According to the dealer they are also scheduled to be replaced, or should have already been replaced. So I will await the replacement and see what happens. Regarding the remap I dont know the make, but I know its a reputable company. And during the 3-4 years I had the map I never had any issues, so I am hoping for the spark plugs.

 

[Harvey]

At your mileage I'd be also considering replacing the coil packs as well as the spark plugs. The coil packs can break down over time and with you having a Stage 1 they will have a higher stress with workload and heat. Just something else to consider

 

[blodwen715]

When I had my old Octavia vRS running on stage 1 remap, I had the occasional 'splutter' on full throttle. I removed the map and it never happened. I changed the spark plugs, but still the same. I did get error codes on 1 pot, it was in the end a single coilpack causing the issue..

 

[Potterswheel]

Not exactly on topic but I think it's interesting all the same, did you know there was a hole in the back box on the S3?
I was under my car yesterday with the engine running, looking for leaks etc. after changing the Haldex oils and could hear a strange noise (can't even begin to describe it!) eventually found a pressed hole about 4 mm in diameter in the bottom of the back box, presumably it is a condensate drain as it has a darkened trail blowing backwards from it, but all the same it does make a slight noise.
So if you do hear a small unusual noise from the back it could be this.

 

[Lovric Nikola Martin]

I had the car back from service for a few days. There was an inspection service done, change of haldex oil, motor oil, spark plugs etc. And I have not been able to re-create the stutter/sound, so it seems to have been solved. Im guessing spark plugs. The coils were replaced maybe 3 years ago for RS3 coils.

Thanks all for your input, much appreciated