Date:         Mon, 30 Sep 2002 17:32:26 EDT
Reply-To:     FrankGRUN@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Frank Grunthaner <FrankGRUN@AOL.COM>
Subject:      Re: AW: On I4 and TIICO Exhaust Fixes
Comments: To: warmerwagen@hotmail.com
Content-Type: text/plain; charset="US-ASCII"

In a message dated 9/30/02 1:50:07 PM, warmerwagen@hotmail.com writes:

<< I installed the rubber mounts and the resonating and rattling is gone.

The Diesel rubber muffler isolation mounts are not cheap, and prone to break.
I am looking at a cheaper substitute, like radiator mounts.   >>

Robert,

Very good post. Sorry I missed your earlier comment. I'm afraid I put that
comment out without thoroughly reviewing all the relevant posts. Should have
checked the archives!

The only thing I would add to your observations is that I have fabricated
brackets that mount off the original diesel mounting points and let me use
the heavy duty truck muffler hangers (I believe that they are 6 ply or layer
fabric reinforced rubber). The hanging mount reduces the shear stress placed
on the original diesel mounts by the gasoline motors. Remember too that the
muffler temperature for the gasoline engine is at least 200 degrees F hotter
than the NA diesel.

BTW, I indicated that the best way to quench noise and reduce exhaust
temperatures at the muffler was to add a turbocharger to the system.
Expanding the hot gases through the turbine reduces the temperature of the
exiting gas and the turbine system breaks up the harsh pulse train coming
from the 4 cylinder exhaust. While there are many different numbers out
there, I recently had occasion to measure cat inlet temperatures on a '87
Porsche 944T and a '86 Porsche 944 NA. As I recall, the temperature
difference was around 220 degrees cooler for the turbo. The baseline for the
turbo was about 375 F. The effect would be larger for the Vanagon I4
configuration. I didn't measure the sound energy but without the muffler, the
turbo was quite pleasant. Without the muffler, the 944 NA was deafening.

So, perhaps the best muffler would incorporate a junkyard turbo, compressor
removed and with the shaft driving an alternator!

Frank Grunthaner