Date: Tue, 20 Jan 2009 05:02:15 -0500
Reply-To: frankgrun@AOL.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Frank Grunthaner <frankgrun@AOL.COM>
Subject: Re: Need AFM adapter so different aircleaner or cold air intake
can be used- to cone or no!
In-Reply-To: <4678.192.168.0.148.1232424467.squirrel@hasenwerk.homeip.net>
Content-Type: text/plain; charset="us-ascii"
David,
I'm aware of the TDiClub tests and thread as well as several other more extensive test programs evaluating the K&N filter approach vs. the stock dry paper system. There are results that show enhanced flow as well as reduced flow when compared to the stock system. The primary issue often comes down to how well engineered the stock system is. For long transfer distances, I concluded that the K&N system was just fine. Why? I wanted the compact cross-section, maintenance through withdrawal out the brake light port and reasonable flow. My justification comes from a quick experiment done on my ho-made flowbench. Following a design crudely discussed in the excellent Australian online automotive geek magazine (autospeed.com) I fashioned a simple flow bench using a Plexiglas interface (4 ports with extended tubes coming from an face plate bolted to the 1.8l VW digifant manifold. The tubes entered the endcap of a 4 inch PVC pipe that in turn was drawn by a 300 cfm blower. The adapter manifold was bolted to the VW manifold using a spare gasket). I then setup a Dwyer differential pressure gauge measuring 0-15 inches of water. The reference port was the outside air and the measuring port was the tapped vacuum port on the manifold. I chose the 300 cfm blower because 1) I had it from a long forgotten foraging trip at C&H Surplus (now defunct) and 2) it represented the maximum flow of the ideal 1.8l digifant head at 6500 rpm.
I then mounted the manifold, the coupling tubing, AFM and several different air cleaner assemblies measuring the pressure differential developed in each case. The greater the pressure differential, the lower the effective flow through the air cleaner. The actual results are off in one of my unindexed notebooks, but the fastidious memory recall function says that the freshly oiled K&N unit came in a close third relative to the Audi 5000T (was the best) unit and the air cleaner assembly from the Audi 80 that I later took the Audi 3A 2.0 l engine from.. It was better than the stock digifant unit by a significant margin though I did the test with the K&N replacement filter in the factory box. The VW Fox unit was one of the worst performers, and the very worst was the cyclone unit made to the rough environment Vanagons (I got one from Karl later). I never independently tested the particle stopping ability, but a number of tests have indicated that the properly maintained K&N was just as good as the stock unit.
Therefore, I was pleased to go with the K&N filter. Your mileage may vary. As for me, as I have previously reported on this forum (er ... List), I put more than 100K miles on the Westfalia with this air cleaner system with no engine failure or oil burning. This was done with the DZ transmission and often consisted of 1500 mile runs with AC blowing, outside temperatures above 100 F and at speeds in excess of 80 mph. The engine sang sweet music at 6000 rpm for hours on end. After converting to the turbocharged Audi, I used the boroscope to checkout the cylinder sidewalls. No evidence of non-uniform wear. The cylinder blowdown tests gave the same results for each cylinder and numbers were the same as those obtained on my son's VR6 with 32000 miles on the clock. The engine still rests in the garage, but I never felt the need to crack the head. Did check the bearings though. They needed replacing by the book (con rod, not mains). Finally, none of the oil analyses ever indicated an unusual amount of silica.
Permit me one more aside ! When building the Audi 3A turbo, I flow tested the Audi AFM and the SAAB 900T system. The beat the Audi - hands down. This being one of the reasons that I went to the SAAB engine management system for the Turbo 3A project. Also, the Audi 3A manifold significantly out-flowed the digifant unit. Did the same tests on the TDI engine testing the 1Z manifold against several others. By far the best was the PD 150. The SAAB intercooler (Aluminum) also out-flowed the stock 1Z unit.
Ah, back to your regularly scheduled programming. Remember, your mileage, experience and observations will definitely vary. Garage experiments are anecdotal and simply for the enjoyment of the geek with the tools!
Frank Grunthaner
-----Original Message-----
From: David Marshall <mailinglist@FASTFORWARD.CA>
To: vanagon@GERRY.VANAGON.COM
Sent: Mon, 19 Jan 2009 8:07 pm
Subject: Re: Need AFM adapter so different aircleaner or cold air intake can be used- to cone or no!
Personally I think the K+N filters are over rated.? There's an
excellent posting at TDIclub.com has shown that there are several issues
with them and OE paper filters work better.
- Paper filters
better when dirty and when clean.
- Paper flow more than enough
presenting no restriction for a 2.0L TDI (which uses a lot of air).
-
The oil on K+N filters destroy MAFs and other sensors.
The most
restructive part of the system is the silencer for the air box - remove
this and you will have lots more flow.
I first hand can say
that in very dusty conditions - like extended dirt road travel - the oil
on the K+N becomes saturated with dirt and then MORE dirt goes past 'cause
it doesn't stick to the oil.? The one reason why a K+N filters at all
is the fact there is oil on it and the dirt sticks to the oil - nothing
special about cotton over paper!?
A stock filter works
just great for most applications - change it every time you change your
oil and you will be much better off - if you are really serious about
filtering in duty conditions a prefiltering cyclone works really well -
all Syncros have this and it is an easy retrofit to the 2WD.? I have
the MANN cyclone filter for my LT (OE original) and for my TDI Westfalia
(one from an LT) and that catches about 90% of the dust entering the
system.
If you do insist on running a K+N cone filter, a set of
panyhose over the filter goes a long way to help it filter better... seems
like a lot of stuff to do just to get away from paper.
David
Marshall
VW Adventure Driver and BMW Adventure Rider
http://www.hasenwerk.ca
On Mon, January 19, 2009 18:13, neil
N wrote:
>
> On Mon, Jan 19, 2009 at 4:27 PM, Frank
Grunthaner <frankgrun@aol.com>
> wrote:
>
>> Apologies for the technical nature of this post to those on the
list who
>> tolerate this sort of thing, but I couldn't
resist.
>>
>> Frank Grunthaner
>
>
> AFAIC, no apology needed! :) It does spawn some ideas.
Thanks.
>
> For my Jetta 2.0 ABA conversion, I stole a
trick from the Diesel
> Vanagon guys and mounted a Dodge Caravan
V6 air filter box in the
> driver side cubby hole. It has a
smaller surface area than the stock
> Jetta air filter box so I
"Swiss cheesed" it a little with several 1"
>
holes.
>
> I think it may still be somewhat restrictive
though.
>
> Maybe someday I'll put a K&N setup.
>
> Cheers,
>
> Neil.
> --
> Neil Nicholson '81 VanaJetta "Jaco
>
http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines
> http://web.mac.com/tubaneil
>
http://tubaneil.googlepages.com/
