Louvered Listers
As a past owner of a number of road and racing Morgans with and without
louvers I have observed the following:
The most effective improvement to the cooling is the rubber air dam
mentioned here by others. I have used this trick since the truck guys
figured it out years ago.
The Morgan SLR which I raced for years never over heated and had no louvers.
I agree that there is a low pressure area just behind the headlamp. I have
been trying to decide if ducting to this area would make my 4/4 (with dry
sump Lotus Twin Cam) run better if I ran it to the carb box or used it to
pull air from the radiator area. I guess it is also a possibility that front
downforce would be improved if this area was louvered to the wheel well.
For Daytona I fabricated a front belly pan and very carefully calculated
the cross sectional area of the louvers I put in it so that the total for
the bonnet and belly pan was 10% more than the radiator opening. It worked
great! (Beat all the Porsche 356's and most of the 2L 911's in the enduro)
Not a hint of overheating. I just ran the car in 90 degree heat two weeks
ago and confirmed that it stays cool. In other words on my car the hot air
has to come out through the louvers, and it does.
Now that I know this I am going to start working on the ducting to the carbs
to give them a little more positive pressure to work with.
I have used foam rubber around the radiator to keep all the air going one
way but never was able to verify that it made much difference.
New aluminum radiators work so well that all of the above is probably
unnecessary! If you go this route put a secondary screen in front of the
core to protect from stones etc.
SuperDave
----- Original Message -----
From: "Chas Wasser" <ohmog@fuse.net>
To: <morgans@autox.team.net>
Sent: Wednesday, May 31, 2000 4:10 PM
Subject: Louvers in the bonnet; conversations with Mauirce Owen & Chris
Lawrence
> As owner of a +8 which gets mighty warm in these Cincinnati summers,
> I've had conversations with two people who should really know about
> keeping Morgans cool.
>
> First was many years ago with Maurice Owen. Maurice's suggestion which
> I shared at the Morgans at MidOhio banquet in 1991 was to "put a piece
> of black tape over the temperature gauge so I couldn't see the needle!"
> He did go onto mention using the ISIS style air box which I bought at
> the Factory in 1986. (This is a scoop which drops below the front
> bumper to catch air and channel it into the bottom of the radiator.)
>
> My car also has the front air dam, made of sheet metal that Stuart
> mentions. Maurice commented that he didn't think the louvers helped
> much. The ISIS cars of a few years ago had louvers inserted into the
> inner fender valences next to the engine bay. I think these might
> actually accomplish more than the bonnet louvers.
>
> This leads to my conversation with Chris Lawrence. During a visit with
> him at the Factory in 1998, he described that during development work
> for the Aero 8, they did extensive wind tunnel testing of the current
> cars. He commented that the bonnet louvers "didn't do much" and that
> the problem was creating a low pressure area in the engine bay to
> encourage maximum air flow thru the radiator and then exit hot air out
> of the engine bay.
>
> His suggestion was not very pretty but sounded technically effective:
> cut valence holes or cooling slots in the inner wing area behind the
> headlamp pods on the downward slope of the wing. These holes would then
> be ducted to the inner fender valence and into the engine bay. Creates
> an extractor effect that would sort of be like the Austin Healey 3000
> rally cars extra venting gills on the front fender sides.
>
> Never seen anyone do this, but it would be interesting on say ... a
> racing Morgan. Maybe the idea will go forward from here. I doubt if
> anyone else has ever had this type of conversation with Chris.
>
> I still like the cool look of all the louvers on my 77 +8 though --
> especially the way their line varies slightly from louver to louver due
> to the hand stamping process used when my car was built!
>
> Cheers,
>
> Chas Wasser
> Oh Mog
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