I wonder about that Don. I used the stock DV set up on my I4 install successfully. I did have to replace one rubber mount (the left hand side one that is at a different orientation than the other 2) over a 14 year stretch. But apart from that I had no exhaust cracking problems with either the single outlet diesel manifold or the 4 into 2 audi 90 manifold.

As to wether that mounting system is more or less effective in isolating NVH, I can�t say. I do suspect that somethings going on, I have noticed different NHV in similar installs. It might be a case of a few little things adding up to a noticeable result. Perhaps engine balance/tuning, engine mounting, exhaust mounting, muffler design all contribute to NVH.

alistair

On Feb 8, 2014, at 8:59 AM, Don Hanson <dhanson928@GMAIL.COM> wrote:

> Hmmmm.   That might be worth trying.  The rubber layer in those diesel
> mounts, that may be contributing to the fairly common exhaust fatigue
> problems we see on the inline gas conversations.  I wonder if eliminating
> that rubber would add noise and vibration inside the van?  Might be worth
> experimenting.  Maybe when I get off the desert trip I'll try that.
> On Feb 8, 2014 7:59 AM, "Dennis Haynes" <d23haynes57@hotmail.com> wrote:
> 
>> One thing I would do is get rid of the rubber mounts on the muffler. They
>> didn't work for VW. All the Waterboxer have the muffler firmly attached and
>> moving directly with the engine. One sold assembly.
>> 
>> Dennis
>> 
>> 
>> -----Original Message-----
>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
>> Of Neil N
>> Sent: Friday, February 07, 2014 3:54 PM
>> To: vanagon@GERRY.VANAGON.COM
>> Subject: Re: Exhaust Bushing Inner Weave Premature Failure
>> 
>> No doubt. I can see that movement even after one tack onto two plates.
>> 
>> I aligned and mounted the muffler-cat assembly first then built the join
>> between downpipe and J pipe. On the muffler brackets I made, some of the
>> holes were enlarged to allow adjustment. This certainly helped the recent
>> repair done in the muffler shop in Florence.
>> 
>> The challenging part in making the exhaust, was making accurate marks and
>> keeping them aligned during fabrication. I would make marks, then remove
>> cat and downpipe, tack the parts in basement, mount and check fit, repeat
>> as needed. A real PITA. Welding parts in situ is best but not really
>> feasible in my case.
>> 
>> Part of what I attempted to do was use parts that might be found in the
>> junk yard. (eg total downpipe-cat assembly). This was done to help others
>> as my WAG is that these parts can be found in good shape and had for a good
>> price. IIRC, I paid $50 for this near new part:
>> 
>> 
>> https://lh5.googleusercontent.com/-Q8RL7ZfES7A/Tt1_miL9h3I/AAAAAAAAFb4/SrFznBdv3wg/s1000/Jetta%25202002-2003%2520Downpipe%253Acat.jpg
>> 
>> assembly before bushing install
>> 
>> 
>> https://lh4.googleusercontent.com/-2tXy_bqA1SQ/UPYtUkEbT2I/AAAAAAAAGlY/2JwxaYgZm-8/s720/ABA%2520Downpipe%2520To%2520Cat.jpg
>> 
>> 
>> https://lh6.googleusercontent.com/-xEuPuiwGAWY/UboIAjZB2cI/AAAAAAAAHuI/13iua_Y1m2s/s600/flex%2520pipe%2520install.jpg
>> 
>> 
>> 
>> 
>> 
>> On 2/7/14, Don Hanson <dhanson928@gmail.com> wrote:
>> 
>>> Welding something can induce stress and misalignment.  I was shown
>>> this....pretty large movements were apparent as the welder worked.   On
>>> something as long and obviously vulnerable to stress as the exhaust
>>> systems on in lines seem to be, I'm guessing that it is common to
>>> screw up the exhaust with careless welding and leave it with welded-in
>>> stresses that lead to fairly quick cracking in a lot of cases.
>> --
>> Neil n
>> 
>> Blog: tubaneil.blogspot.ca
>> 
>> '88 Westy http://tinyurl.com/c8rlw6p
>> 
>> '81 VanaJetta 2.0 "Jaco"  http://tubaneil.googlepages.com/
>> 
>> Vanagon VAG *Gas* inline-VR Engine Swap Group:
>> 
>> http://tinyurl.com/d7gd5ej
>>