tramping sound under hard acceleration

[Vanne]

Hi, just got back from a rather spirited run through the mountains of Hatta with my buddy also in a coupe. On the way home i notice that under hard acceleration from 1 to 2nd the front right is making a tramping sound, with the associated vibration.. anyone have a clue what this could be?

waiting for the car to cool down so i can jack her up and remove the wheel to have a good look. It kinda sounds like the suspension strut is loose.. is that even possible? anything else you guys can think of?

cheers for the assist guys.

V.

[XMetal]

Engine mount?

[Arsonism]

It's time for some nice vibra technics.

If the sound is while the car is under load it would seem weird that it would be coming from the suspension. I would think that this would be a result of something pertaining to the support of the engine or the transmission. Unless you're hearing this noise when going over bumps/varying road conditions.

[jdoublehcubed]

What does tramping mean? Like stomping? Sort of dull impacts?

[Vanne]

Yep JD, that's exactly what it sounds like. Kinda like shuddering with associated thump thump thumps.. I first though i was taking off over a bunch of little stones on the road...I thought of engine mounts/trans mounts, but they are spankers in there, replaced them 1500 miles ago with oem..
The front under heavy acceleration isn't under load? As it would be very light at that stage possibly?
I can't seem to reproduce the effect in any other setting, just under really hard accell from 1rst to second..

[Finnegan]

Could it be the Guibo?

http://www.turnermotorsport.com/p-41...1995-2006.aspx

[jdoublehcubed]

Originally Posted by Finnegan

Could it be the Guibo?

http://www.turnermotorsport.com/p-41...1995-2006.aspx

Since its under acceleration and its a repetitive sound, I would say it has to be something rotating, so Guibo is a good choice.

You're accelerating smoothly, and you get multiple thumps, right?

Could be:
- Guibo
- Drive shaft main bearing/mount
- Brake dust shield catching on something or vibrating
- Wheel bearing that is periodically catching a bad spot on the race
- Belt with a chunk out of it (probably not as this would not last long before catastrophic failure of the belt)
- Loose piece of plastic on the bumper or in the brake cooling inlet that is periodically flapping in the air
- Sway bar bushing slip/genera; sway bar slop (not sure why that would give multiple thumps though)

[Vanne]

hi guys sorry for the late reply, Just got back from a red-eye Male return, so pretty shagged. Yesterday I just parked the car, went to bed and went to work..

Guibo -- possible, but very, very unlikely as its not a central noise/vibe, its deff something with the front right rotating mass.. I don't think its the brake dust shields as they would make the sound, but don't think it would have the associated viberation with it..

cant be a bloody wheel bearing (better bloody not be, there also spanking, and less than 2k miles on them

Belts are spanking new (2k miles) and once again, that would be more of a centralized sound/vibration...

brake duct... possible but unlikely as (just had a brain wave, the sound and vibration is exactly like a jack hammer, that you see on the side of the road, same intensity and same frequency)...

Sun going down as I am typing this.. time for tomorrow morning to pull the wheel.. failing finding anything obvious, ill drop it at the shop.. very badly in need of a wheel alignment anyways... car was a mess all over the road on the drive and I am hoping that its due to whatever is loose at the front right..

(thinking back now to the last alignment I had, ... took way to long and they were adusting toe in for some reason, which I had pegged perfectly before.)

anyways, thanks for the inputs guys, keep them coming, if anything it will at least arm me with things to look for..

I gotta post some pics of that Hatta drive.. it was Insane... I flew over the roads at Hatta(around 10000 feet)visually today on the way home and I was smiling all the way into DXB..
Awesome, awesome fun..
Some guys just don't get its a car thing ;D

[inTgr8r]

Did you check the infamous motor mount bolts.

[RADRACR]

Loose shift knob? (don't laugh, you said keep them coming)

I had the exact symptoms you describe and it turned out to be the knob, which strangely was very hard to audibly pinpoint. The sound fills the cabin from all directions. Next time, press firmly down on the knob during hard acceleration.

[Vanne]

Rad, thx man, had that before, glued the sucker down solid, this is def front right rotating mass…

Ian, i havent checked them.. added to the list.. a couple of more hours and the kids will be in school, giving me a free hour or so to have a look see..

[Vanne]

Pulled the wheel.. Nothing too obvious there... Mounts seem ok.. As do the bolts.. It's all tight...

I'll take it to the shop for said alignment and have a good look while she's on the lift..

[Vanne]

Fark.. From alignment shop directly to bmw service center. Vibration started to get worse..

So on the lift with inspection camera... Whola!

Center bearing completely shagged, cv joint rooted and guibo on the way out... All on the drive shaft.. So you guys were correct.. I could have sworn the vibration came from the front right....

Anyways.. While the car is there, getting a new egt sensor put on and get my new stop tech brake lines installed...

Bloody hell...
That's gonna hurt. :-)

Edit: and that will complete to total underside of the car refurb, anything that's rubber/Polly replaced in the last 3k miles.

[Finnegan]

The mystery deepens.