That really does make sense Lawrie. SU's rely
on a bit of vacuum to pull fuel into the carb throat.
K&N's (any free flow filter) doesn't 'restrict' enough to create the
proper vacuum needed for the carbs to work just right.
Sure WOT doesn't need any restriction. But who only drives
at WOT except while racing.
>From my own experiments, you need about a 1.5 foot long
ram pipe on an HS4, between the carb and K&N air filter to
get the same in/Hg drop in pressure to match the effects of
the stock filters and housings.
Take note everyone...Ever notice the that the stock air
filter housing 'snorkels' have the same size openings as the
carb throat diameters? :-)
There was a very good reason for that design.
I'm still running open K&N's with the single 'logo' plate that spans both
filters. Mostly for the 're-usability'. I've now blocked off the bottom
half of the filters and my mpg has gone up. After they get a bit dirty
I rotate the filters to expose the 'clean' side that had not been
'breathed through'. This means I can go twice as long before
having to pull them off and clean them properly.
Paul Tegler ptegler@gouldfo.com www.teglerizer.com
----- Original Message -----
From: "Lawrie Alexander" <Lawrie@britcars.com>
To: "David Hayes" <David.Hayes@gmx.net>; <mgs@autox.team.net>
Sent: Thursday, February 28, 2002 8:59 AM
Subject: Re: MGB Improvements
David,
FWIW, one of my wealthier customers some years ago tried every different air
cleaner available (four different types, including the expensive K & Ns) on
his otherwise stock MGB. He carefully measured performance (time to
accelerate between two fixed landmarks) and fuel economy with each set,
comparing the data to the numbers as delivered with the original, factory
air cleaners. He was surprised by the results of the test - and gave me back
all the aftermarket ones. 'Twould appear the factory engineers were smarter
than some people nowadays give them credit for being.........
Lawrie
British Sportscar Center
-----Original Message-----
From: David Hayes <David.Hayes@gmx.net>
To: mgs@autox.team.net <mgs@autox.team.net>
Date: Thursday, February 28, 2002 5:02 AM
Subject: MGB Improvements
>Hi
>Now my Mg ('73 Roadster) has been behaving for quite some time I have
turned
>my mind to thinking about some improvements I could make.
>As far as I can tell the car is standard apart from an unleaded head and
the
>engine has been relativly recently tuned profeessionally.
>My aims are to improve performance and/or reliabilty but my budget is
>smallish (200 GBP or so)
>My initial thought was to replace the air filters with better ones. Any
>other suggestions and which air filters are best? I presume after replacing
air
>filters I would need to adjust the tune of the engine?
>Thanks for all your help in advance
>David Hayes
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