bovien

I have a growing and unnerving sound from my front end at track only. 997.2 GT3. Its a metallic noise when I turn. Both ways, but more pronounced turning right. It sounds like if the dust covers are touching the discs or the likes. They are not.

Symptoms:

• Only when car is warmed up on track. Only heard it once on the street after a long drive, turning in a tight bend onto motorway
• Its been growing in volumen over 2-3 seasons, each with 5-7 trackdays
• It comes on at lower degree of turn in now than it used to
• Very easily heard from the outside. People actually turned to watch when I turned in the pits today after a few testing laps
• Is not affected by braking in turn.
• Noise is speed and rotational dependant. Not tied to loos objects, bumps or handling except the turning of steering/wheel/bodyroll itself.

To remedy/diagnose, I've done

• Renovate brakes
• replace discs + pads (cup discs + PFC pads)
• Thoroughly inspected wheel wells, inner fenders, dust shields, brakes, wheels discs, hats, hub for markings that would result from this metallic sound. Nothing at all.
• Switched wheels
• Cleaned down center locks and re applied paste
• replaced bearings
• Checked for any play
• Full alignment

I've had a gold certified (or whatever they are called) OPC GT3 technician diagnose. He came up with replace bearings. Didn't help anything but their own pockets. Next step is to drive the car 500 miles to the Nordschleife and get Manthey or some of the other teams to figure it out. But that would be a pain.

So you geniuses in here, SHOOT!

audipwr1

Yeah screams of wheel bearings

CRex

If the noise is rotational and metallic there HAS TO BE A TELL somewhere along the inside of the wheel barrel and on your suspension members or calipers...

I'd suggest checking the LCA thoroughly for wear/rub to the (rubber) base of the outboard trunnion. Then toe links. Then thrust arms.

997_rich

take a close look at the rotor-to-hat hardware. Sometimes the pad backs can touch those depending upon brand of pads.. the interference gets worse as the pads wear. I saw that on a Gt3 i test drove one time.

DJN

Double check torque on the CL's (when was your wrench last calibrated?)....also insure that your CL's are properly lubed with fresh OEM Optimoly grease (not too much, not too little), and that your drive pins are secure.

I had a slight metallic ticking when turning left with G's.....

facelvega

If the noise is consistent and reproducible, after you are warmed up and can count on the noise being there:

• Go to the closest empty parking lot
• open the frunk and have a friend get in with a 4 foot length of garden hose
• Put the steering at full right lock, and let the car go in a tight circle at low speed
• Frunk man with hose to his ear should be able to direct the other end of the hose to tell if the noise is coming from the hub, disc / brake, tire to liner area
• Should be able to see if just one side or both, and which side is louder
• If not any of these, I would vote for issue with the steering rack.

You might also have someone hang out the window, and use a hose to make sure the sound is coming from the front, not the rear. When low on power steering fluid, or when the PS pump is going out, it moans loudly when you turn. Moaning typically does not start until the car/pump/fluid is hot. Did you isolate it to wheel speed versus engine speed? While holding the tight loop at medium RPM, put in the clutch and let the RPM drop to idle - does the sound drop with the RPM, or stay steady with speed? If it is not RPM dependent, then never mind about the PS pump...
Good Luck!

RAudi Driver

frunkman

bovien

Thanks for all the input all! There is some good thoughts in there

Agree, which is why they were replaced this winter, based on my own thoughts + OPC GT3 tech guy. Didn't change anything at all in regards to the sound. One of the bearings were a bit worn and grumbly though. So good they were replaced

I agree 100%.It is so god damned weird. There is nothing, nothing at all to see on any of the suspension arms, links or bars. I've had it all aport on both sides due to damper and bearing replacement. + spend several hours looking at them on the lift. The sound is proportional to speed and rotational, getting louder and louder. Seems metallic, but could be some REALLY sturdy plastic.
ou say: "...(rubber) base of the outboard trunnion". Do you mean the bushing on suspension arm? All looks very nice. No racking or anything to notice there. Seems soft and more or less new, even though the car as been trough 3-4000 track miles. When doing the bearing replacement, I was not able to separate the lower ball joint from the hub carrier. But there were no play. Was it a bushing/joint issue, I would assume a knocking sound on bound/rebound movement.
This sound like a little man sitting on the suspension member with metallic or thick plastic zip tie, holding it against the spokes of the wheel or brake disc.

This is something I thought as well. I have taken it apart and looked for any points that could catch. Nothing visible. I've had the little red conically shaped "wheel guides" off and re mounted. Also, would this make a difference hot vs cold?

How about the pad itself. I see it being a bit wider than the disc. Is that an issue? I've mentioned, that the sound does not change if I apply brakes in a corned, but could this pad (and maybe the endless before them) with its wider "base" result in this? Or is it normal, that the pad is a few millimeters wider?

They are good. Each time I go in track, I switch wheels and re-torque them. Also check the paste, and I have replace the Optimoly twice. Once with 3rd party, and then again with OEM Optimoly according to Porsches instructions. This does not affect the sound sadly. I did read that others has had strange sounds due to this, but not even a change in the sound after doing this.

I just continuously get more and more pronounced

This is a good idea. We did something like that in the pits at the trackday this saturday. We are sure its up front (100%. Its also easily sourced to front when taking the helmet off). Inside it sounds more centered. Outside it sounds like right wheel. Driving with helmet, I can hear its more pronounced turning left than right, and definitely not from the same side/place.

I'm also moving towards steering rack, but I have never really seen that, but trom a general steering rack, I would not see how this would make that sound.

Trouble with your idea is, that its not making a sound without having been on track, and it disappears after an hour or so, car cooling down. Also, it would not be heard ad the speed you are able to do with a frunkman installed ;-)

• So, question: Would it make any sense (and is it doable), to lift out the frunk and see if there is ANYTHING in there able to make a sound? Maybe the previous owner installer a hamster wheel with a paper clip on it to **** me off..

Fisher

Mount a Go-Pro type camera with good audio and drive around with it in different places inside the wheel well. Compare location sound levels at different frequencies if you have the equipment.

Auto_Werks 3.6

Mine makes all kinds of low volume noises after warmed up, and at limit handling. This weekend's first autocross brought them to my attention. My car is new to me, so I need to clean and re grease all the center lock hardware, and it's probably ready for brakes. There are a frustrating amount of these threads in the rennlist archives. Most people are pointing at wheel bearings, but like you, they didn't effect the noise. Mine very much sounds like a fender liner vs tire, but I can't find the witness marks. I'll be watching to see what resolution you come to.

Turbo Racer

Subscribed

noro78

If you have one of those digital thermometers handy might be worth pointing to a bunch of components and compare left to right. Sounds typically = friction = heat.

bovien

Thats a good thought. I'm hesitant to it working on this one, especially if sound is from something already hot from track work, and the freakin'wheel/disc is in the way, but I'll give it a go next time around

CRex

Just because you said this, try removing the front brake ducts and see if the sound persists?

By "trunnion" I was referring to the outboard tip of your LCA which protrudes into the base of the wheel carrier. The case of that tip (viewed from underneath the car) is a sealed rubbery plastic. I gather from your comments that it looks AOK?

bovien

I have thought about the brake ducts, but at next track test it could be worth removing then to see.

In regards to the tip, are you referring to the ball joint the hub/wheel carrier is resting on?
As seen here?


That seems to be in good order for both wheels. Having had bad ball joints in other cars, this usually shows itself with play in the wheel and a deep cluncking noise in turns/bumps.

Your inputs are much appreciated!