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Re: cold air box

To: Jonathan and Carole Quandt <fourqz@earthlink.net>
Subject: Re: cold air box
From: Dave & Marlene <rusd@velocitus.net>
Date: Sat, 15 Jan 2005 14:01:04 -0700
Hi Juanito,
Cold air boxes can be quite effective to increase engine power. ie. air
density increases about 2% for each 10 degreeF drop in air temperature.
An example would be a drop from 200 degrees engine bay temperature to
100 degrees outside temperature would give 20% increase in intake air
density & 20% increase in engine power. You might need to use the richer
OA6 carb needles in place of the standard OA7 needles. Where else can
you get so much gain for so little work? A secondary benefit is that the
carbs run much cooler also.

As far as filters, I have had good results with a K&N cone type filter
mounted on the forward end of the air duct. To make servicing the filter
easier, I used wing nuts on the upper grille mounting studs. You can
reach in through the front wheel openings & remove the wing nuts without
raising the car. Once the upper nuts are removed, the grille just swings
out at the top & unplugs from it's lower mounting pegs. A straight &
open access to the filter which doesn't need to be serviced very often
anyway.

I used a K&N # RU2590 filter. It is a truncated cone with a 4" ID rubber
connecting flange, 5 3/8" diameter at the base, 4 3/8" diameter at the
end, & is 7" long.

To ease removal & installation of the box to carbs, I secured studs in
the air box threads with Loctite & use nuts on the carb side of the
studs. Much easier to push four studs into their respective carb flanges
than to fight each bolt one at a time into the holes. Once the air box
is on, it doesn't need to be removed very often.

As you probably know, the front top shroud bracket needs to be replaced
with an offset bracket & the vertical shroud support bracket bent
outboard to match the offset bracket.

I can give further info & pics if you wish.

Dave Russell
BN2

Jonathan and Carole Quandt wrote:
 > What is the purpose of fitting a cold air box on a Healey 100 ? Does
 > the box reduce the effect of overheated petrol for which these cars
 > are notorious. provide a minimum of supercharging, or render some
 > other benefit that would make the cost and hassle of installation
 > worthwhile ?
 >
 > Thanx, Jaunito




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