Low Acceleration Rattle

[Melbourne_Tiggy]

Had the car on a hoist yesterday and checked everything related to the downpipe and the rattle. Plenty of clearance to the heatshield and all brackets tight. I had to trim the ends of the front hangers near the subframe when first installed the downpipe as the hangers were too long and were constantly hitting the subframe.

Dub Addition checked and came for a ride with me to try figure where the noise is coming from. Noise is only at 1500rpm in 4th to 7th, in low throttle, up shifts always put the car at 1500pm so can hear it. Off throttle at 1500rpm is no problem. Sound is like a thin piece of metal vibrating and is coming from the engine bay or at the front of the dash.

I have the 034 Motorsport dog bone insert installed which will not help with small vibrations... The search continues.

Is there a chance that the downpipe is defective and there is something lose within the flex joint or downpipe ?

[INASNT]

Is there a chance that the downpipe is defective and there is something lose within the flex joint or downpipe ?

Part of the work I do is inspecting newly manufactured components, vessels, NDT testing etc. I checked it thoroughly as I had it for a week before I installed it. The noise at 1500rpm is coming more from the front left of the dash away from the downpipe... I think the dog bone insert might be making something that usually does not vibrate now vibrate, but its only a 1500rpm on load. Arghhhhh

[Lucas_R]

Why are rattles always at low rpm so you hear it all the time. If it was at 6000rpm you probably wouldnt care because you are so rarely doing those rpm.

[INASNT]

People always tell me that rattles are normal for a VW, but I didn't have any in my MK6 R.....f a r k i n...

[INASNT]

Looking at some other golf forums and topics about rattles said to check windshield plastic in engine bay and abs lines in engine bay... no rattle.

Put my hand behind the turbo and onto the actuator arm and it rattles like crazy like the MK6 GTI YouTube videos..

Anyone else's rattling if you put their hand on their actuator arm and tap it??

[Dose Pipe Sutututu]

Is it a rattle or engine knock?

As these cars make so much torque at such low RPM, and with these so called flash tunes (most likely just add boost and raise limits to stop CELs and limp modes) you could be exceeding MBT at those load points.

Not sure if VAG ECUs log and actively display the knock channel but worth a look if you have the interface.

Perhaps try running a tank of BP Ultimate mixed with a bottle of octane booster to suppress knock. At least you can rule that out.

If the tune is rich enough, you could splash in 5L of E85 into your tank of BP Ultimate with octane booster to increase knock resistance - just to rule things out.

[Lucas_R]

^ unfortunately the only way to fix that issue is an IS38 turbo

[INASNT]

Is it a rattle or engine knock?

As these cars make so much torque at such low RPM, and with these so called flash tunes (most likely just add boost and raise limits to stop CELs and limp modes) you could be exceeding MBT at those load points.

Not sure if VAG ECUs log and actively display the knock channel but worth a look if you have the interface.

Perhaps try running a tank of BP Ultimate mixed with a bottle of octane booster to suppress knock. At least you can rule that out.

If the tune is rich enough, you could splash in 5L of E85 into your tank of BP Ultimate with octane booster to increase knock resistance - just to rule things out.

Doing a bit of previous work with vibration analysis on large hydro turbines, the noise is small pieces of metal vibrating. The actuator arm when you tap it makes a similar sound.

I can check the logs with Gordie tomorrow.

Lucas_R the wife was asking what the noise was, I said it was the turbo, could be an excuse to upgrade to IS38 or larger and tell her the noise will go away......

[Dose Pipe Sutututu]

if you're upgrading might as well slap on a BW EFR lol...

Since you're in VIC, might be worth talking to Tao from Hypergear Turbos. He could potentially high flow your existing turbo into something better than the IS38 using ceramic ball bearings, and a billet compressor wheel.

I've bought multiple turbos from him, mild -> wild (however for JDM cars). Latest one I'm going to use is the ATR45SAT, should make a healthy 420~440kW at the wheels hehe

[Melbourne_Tiggy]

Doing a bit of previous work with vibration analysis on large hydro turbines, the noise is small pieces of metal vibrating. The actuator arm when you tap it makes a similar sound.

I can check the logs with Gordie tomorrow.

Lucas_R the wife was asking what the noise was, I said it was the turbo, could be an excuse to upgrade to IS38 or larger and tell her the noise will go away......

If the car is on a hoist tomorrow check for loose exhaust clamps and whether the heat shield could be rubbing the exhaust. The other thing I thought it could be is a broken pendulum mount, there are some instances where people who have installed the 034 dog bone mount have experienced broken OEM pendulum mounts.

Fingers crossed he finds it tomorrow.