924Board.org

[Fasteddie313]

I have this rattle coming down from 4.5k to 3k rpm, only on decel, any accel instantly makes it go away.
Free revving sitting still its not as pronounced but barely there, it does not matter if the clutch is in or not. More on rev down than rev up but with no engine load it will do it on rev up just a little if its a soft rev..
It cannot be heard under the hood, or under the car, or hanging out the door driving listening under the car, it is heard most in the cabin with the windows up. I had my stethoscope on the head and block and oil pan and everywhere on the engine and it's not in there, phew.. Stethoscope on the cross member doesn't turn up anything either..
It feels like it is coming from in front of the steering wheel and you can feel it in the steering wheel, can't feel it in the shifter.
I have gone through all the exhaust/WG and it's not there either.
I thought doing my exhaust hangers better would solve this but I think it made it worse, this rattle has appeared intermittently since before my last turbo but only on hard cornering and decel at the same time and now has progressed to any deceling regardless of cornering and is much less intermittent, more constant now..
Cornering on decel still makes it worse, especially to the right I think, and can be felt in the steering wheel, I remember thinking it could have been my front left wheel bearing a long time ago because of this aspect..

This is proving very hard to find because it really can only be heard in the cabin, most with the doors closed and windows up because it stops road noise..

Does this sound like a motor mount?

My suspicions are..
Motor mount..
Charge piping on steering rack.
WG top port adaptor on firewall.
German gremlins living in my firewall.

I'm going to go softer mount some charge piping, jamb some cardboard in a couple paces, hunt some more, stare at that drivers side motor mount..

Anyone have any ideas?
_________________
80 Turbo - Slightly Modified

[gerben1986]

The first thing I thougt/suspect are the bearings of the torque tube.
_________________
911SC - 1980

[Grenadiers]

Check the heat shield above the muffler, but, this would probably rattle at idle as well. And, if you have a heat shield below the shifter. When cold grab that stuff and see what happens.
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

[michaelodonnell123]

Two things I hate: rattles and chasing down rattles. I feel your pain. With that said - i suggest that you put your car on a lift while you stay in the car, turn the car on and rev it until you recreate the rattle...while doing that have your mechanic listen for the rattle. Hope you find it.
_________________
MOD
1988 Porsche 924S
2007 Jaguar XK
2012 Fiat 500

[morghen]

Pop-off valve
_________________
Supercharger and EFI kits
https://www.the924.com

[Fasteddie313]

Turbo oil drain vs crossmember.. Not the cast piece that bolts onto the turbo, but the flange fitting just after that was vibrating against the crossmember..

Darn good thing I found that, I never loosened that fitting to where it would index vs the turbo mount part, all I had to do was loosen and twist it up 1/4" and its smoothe as silk now, the real big nut on the line by the turbo..

Maybe my engine mounts lost 1/16th of an inch since I've had the car or that mount went on a bit different this time, idk..

Man I am happy that cured the scary noise with no damage done or expensive pieces to replace..

I'll snap a pic of the interference proof sometime..
_________________
80 Turbo - Slightly Modified

[Fasteddie313]

Theres the culprit, the grayer spot on it just above that high point on the crossmember..


_________________
80 Turbo - Slightly Modified