[Vwdiesel] Quietening Intake System

[Roger Brown]

Doyt W. Echelberger wrote:
> My 85 Jetta TD has always made a very annoying loud noise that mostly goes 
> away when I test run it without the pleated disposable air filter in place.
> 
> Because the rattle is almost gone when I remove the disposable pleated air 
> filter, I believe the noise is associated with the way the filter is 
> supported by the rigid plastic air box. I don't think the rattle has much 
> to do with the injectors.
> 
> Jamming wedges of heavy cardboard between the air box and the passenger 
> front fender and otherwise stabilizing the air box as much as possible 
> resulted in only a minor improvement in noise level. It is still very noisy.
> 
> I explored replacing the entire air box/pleated air filter system with a 
> generic conical pleated standalone, but adapting the available 
> off-the-shelf conical units to the existing air intake tube did not appear 
> easy. I investigated the stock of several FLAPS and found stuff that was 
> designed mostly for Chevy/Chrysler/Ford intakes. The cost of experimenting 
> was significant and would have required ordering correct diameter parts 
> pre-paid which might not work anyhow, so I put off doing it.
> 
> I have seen the conical filters used on older Audi's which have stock air 
> boxes that are very difficult to access, and on hot rods that required air 
> filter adapters because the engine was not stock for the chassis.
> 
> I would welcome any information about how to eliminate the air intake 
> rattle on my 85 Jetta TD, other than by running without an air filter. 
> Maybe someone knows exactly where I can order a pleated conical unit that 
> will fit.

Not sure if it the same as on my '81 and '82, but I found that the K&N filter I have fits the filter housing much better than 
the paper ones do.  The main thing I noticed was that the K&N fits tight enough that it'll stay in place in the vertical air box 
while getting the cover in place to clip it on.  The paper filters just fall out as soon as you let go.  I had a similar issue 
in my old '78 gas Rabbit.

-- 
    Roger