MK6 Fluttering after Tune

[mk6r20]

Hi guys,

Ever since I got my car tuned the car seems to flutter (dose), usually in the higher RPM range. Occasionally, if I'm at half throttle the car will hesitate then flutter.

No CEL's or codes.

Cheers

[tigger73]

Have you checked for pigeons and installed under the bonnet?

Have you checked with your tuner?

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[mk6r20]

Definitely no pigeons 😂

Tuner thinks it may be the DV, however the DV that I have is a REV D

[tigger73]

Yeah I was going to say DV is possibly the cause.

If you’re going to upgrade I’d recommend a “proper” DV like Forge rather than DV+ which I’ve heard good and bad.


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[Lucas_R]

Has it still got the factory intake on it or did you put an aftermarket intake on it? My Mk6 R was stock-like quiet with the factory intake and a stage 1 tune, but once I fitted an aftermarket intake there was a lot more noise (which is what i wanted - turbo spool and sutututu air recirculation when you let off the throttle).

If your DV is the stock one as fitted by VW then in theory it should be ok as they generally dont fail, but with these cars being up to 8-9 years old you never know. GFB make this product GFB T9351 DV+ Blow Off Valve (VAG/EURO) which retains the top part of the factory DV and simply replaces the moving parts on the bottom which is where they fail.

[mk6r20]

I have a CTS air intake, before the tune I didn’t get any flutter. After being tuned At high rpms then letting off will make it flutter quite loud

[tigger73]

I’d say it’s normal. If you don’t like it maybe go back to stock intake or go for a more closed style intake.


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[Lucas_R]

I have a CTS air intake, before the tune I didn’t get any flutter. After being tuned At high rpms then letting off will make it flutter quite loud

It will be the increased boost after the tune and the aftermarket intake. The aftermarket intake on the stock tune probably wasn't very noticeable. The aluminium pipe used in the aftermarket intake really amplifies the flutter.

If you dont like the noise then your only option really is to put the stock intake back on, but its a terrible design and will cost you some power.

[mk6r20]

It will be the increased boost after the tune and the aftermarket intake. The aftermarket intake on the stock tune probably wasn't very noticeable. The aluminium pipe used in the aftermarket intake really amplifies the flutter.

If you dont like the noise then your only option really is to put the stock intake back on, but its a terrible design and will cost you some power.

I'm not bothered by the noise at all, I was just worried that I was leaking some boost from the DV.

As mentioned before, when I occasionally drive the car at half throttle it jerks and the DV flutters then goes back to driving normally

[Lucas_R]

I'm not bothered by the noise at all, I was just worried that I was leaking some boost from the DV.

As mentioned before, when I occasionally drive the car at half throttle it jerks and the DV flutters then goes back to driving normally

Hmm the half throttle hesitation and DV sound doesn't sound right. Might be misfiring which is very common on the Mk6 R and GTI as the ignition coils go bad, and usually present themselves after the car has been tuned as you are asking more of them. Luckily they are relatively cheap and you can get a full set for around $250 (blame the crap exchange rate, they used to be under $200 a few years back).

The other thing that comes to mind is fuel pressure and/or the fuel pump cam follower. The stock high pressure fuel pump (HPFP) design struggles most at around 3-4,000rpm. If your tune is wanting more fuel than the HPFP can provide this could be causing the hesitation. The other thing to put on your to-do list is replacing the HPFP cam follower. The cam follower is a sacrificial part which looks a bit like a thimble your grandma would have used when sewing, and is designed to wear out over time. Most specialists VW mechanics will recommend changing it every 30-50,000km's as its cheap and if it wears through it causes significant damage to the inlet cam and the HPFP. If this part is worn then it affects fuel pressure.

Even better is that the cam follower is not listed as a maintenance item every X amount of km's by VW, so unless its been changed previously due to wearing out, there's a good chance your cam follower is just as old as your car.

Audi R8 Ignition Coil Pack Set 4 - 06E905115– V-tech Australia | European Performance

Genuine VW Fuel Pump Cam Follower Kit – 06D109309C – AutoInstruct


Have you got any way of logging the car to check for misfires?

Can I ask who tuned it and how many km's are on the car?