Subject: [Spridgets] Small project report

From: Weslake1330 via Spridgets <[email-masked]>
Date: Fri, 20 Sep 2024 17:58:19 +0100

--000000000000c87a0706228ff08a

--000000000000c87a0606228ff088

Hi list,

A small project report with some background history.  A few years back I
fitted a small airflow blanking device just inside the grille, on one side,
of my 69 Sprite and found it didn't make much difference to engine running
temperatures.  When tested in the full scale wind tunnel it was proven to
reduce drag and lift.

At the test everyone asked me why I didn't have one on the other side and I
explained I hadn't checked if further airflow reductions would increase
engine temperatures.  At a later date I made one and fitted it anyway.

In more recent times the Sprite engine temps ran hotter than I would have
liked and eventually I changed the radiator after some trouble in finding
something I thought appropriate. Well I don't think it worked as well as
the previous radiator and recently I finally found a company that would
make a copy of the design that I liked.  I fitted it and have done some
short drives and it works ok.  However, the engine temp is still a little
hotter than I would like.  What I did find was that with this new radiator
is that switching on the electric fan makes more of difference than it used
to.

On my second run I had a bit more data and found that because of a long
stretch of 50mph speed limit (with lots and lots of average speed camera
recording!) the engine ran 5 degrees C hotter than when I could drive at
70mph.  I have a rebuilt engine and there was a lot of traffic but I'm
confident my normal cruising speed of about 85 - 90 mph (car has a 5-speed)
engine temps would be were I would want them to be.

Note it's been warmer than usual for an English September and while not as
hot as a hot summer's day can get, about ok for my tests since while in the
middle of the day I would generally drive early morning or early evening
when the temps are lower on a warmer day.

So, not very scientific but based on lots of my experience with the same
Sprite.

One thing I did notice was that the Sprite was very warm inside and much
warmer than outside and there is no heater.

So, the long overdue mini-project was to cut a hole in the wing (passenger
side for me but exhaust manifold side for all of us) to let air out of the
engine bay - a bit like a big Healey.  The wings are ok and need minor
paintwork rather than replacing but I was content to take the risk on the
basis that I had funds to buy a new wing and get it painted if necessary.

I drilled 3 large holes with a hole saw and then used a fine blade for
metal in my jigsaw to cut straight (well very nearly) straight lines to
create the aperture with nice rounded corners (used the largest hole saw I
have).  Then I bought and then cut some stainless steel automotive mesh to
go in the inside of the aperture. I used U clips/speed clips on the mesh
and suitable B type sheet metal screws to fasten the mesh to the wing
(fender for you guys and gals I guess).  I did use countersunk head screws
but without countersinking the holes (in a hurry/sloppy/to be addressed).

I think the end result looks ok but the only photo I have is of the car in
my garage but just as I finished the project it rained.  I did a small
airflow test with the electric fan running and was surprised at just how
much air came out of the aperture.

So, a road test (but weather is now cooler than my previous tests) to
follow but I'm confident of 4 things: the engine temp will be slightly
lower as more air will flow through the engine bay and thus more readily
through the radiator, it will be cooler inside the car because the warm air
is leaving the engine bay through the side wing aperture, not stagnant in
the engine bay or passing through the trans tunnel as much, there will be
slightly less drag, there will be slightly less lift.

Regards

Daniel

--000000000000c87a0606228ff088
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">Hi list,<div><br></div><div>A small project report with so=
me background history.=C2=A0 A few years back I fitted a small airflow blan=
king device just inside the grille, on one side, of my 69 Sprite and found =
it didn&#39;t make much difference to engine running temperatures.=C2=A0 Wh=
en tested in the full scale wind tunnel it was proven to reduce drag and li=
ft.</div><div><br></div><div>At the test everyone asked me why I didn&#39;t=
 have one on the other side and I explained I hadn&#39;t checked if further=
 airflow reductions would increase engine temperatures.=C2=A0 At a later da=
te I made one and fitted it anyway.</div><div><br></div><div>In more recent=
 times the Sprite engine temps ran hotter than I would have liked and event=
ually I changed the radiator after some trouble in finding something I thou=
ght appropriate. Well I don&#39;t think it worked as well as the previous r=
adiator and recently I finally found a company that would make a copy of th=
e design that I liked.=C2=A0 I fitted it and have done some short drives an=
d it works ok.=C2=A0 However, the engine temp is still a little hotter than=
 I would like.=C2=A0 What I did find was that with this new radiator is tha=
t switching on the electric fan makes more of difference than it used to.</=
div><div><br></div><div>On my second run I had a bit more data and found th=
at because of a long stretch of 50mph speed limit (with lots and lots of av=
erage speed camera recording!) the engine ran 5 degrees C hotter than when =
I could drive at 70mph.=C2=A0 I have a rebuilt engine and there was a lot o=
f traffic but I&#39;m confident my normal cruising speed of about 85 - 90 m=
ph (car has a 5-speed) engine temps would be were I would want them to be.<=
/div><div><br></div><div>Note it&#39;s been warmer than usual for an Englis=
h September and while not as hot as a hot summer&#39;s day can get, about o=
k for my tests since while in the middle of the day I would generally drive=
 early morning or early evening when the temps are lower on a warmer day.</=
div><div><br></div><div>So, not very scientific but based on lots of my exp=
erience with the same Sprite.</div><div><br></div><div>One thing I did noti=
ce was that the Sprite was very warm inside and much warmer than outside an=
d there is no heater.</div><div><br></div><div>So, the long overdue mini-pr=
oject was to cut a hole in the wing (passenger side for me but exhaust mani=
fold side for all of us) to let air out of the engine bay - a bit like a bi=
g Healey.=C2=A0 The wings are ok and need minor paintwork rather than repla=
cing but I was content to take the risk on the basis that I had funds to bu=
y a new wing and get it painted if necessary.</div><div><br></div><div>I dr=
illed 3 large holes with a hole saw and then used a fine blade for metal in=
 my jigsaw to cut straight (well very nearly) straight lines to create the =
aperture with nice rounded corners (used the largest hole saw I have).=C2=
=A0 Then I bought and then cut some stainless steel automotive mesh to go i=
n the inside of the aperture. I used U clips/speed clips on the mesh and su=
itable B type sheet metal screws to fasten the mesh to the wing (fender for=
 you guys and gals I guess).=C2=A0 I did use countersunk head screws but wi=
thout countersinking the holes (in a hurry/sloppy/to be addressed).</div><d=
iv><br></div><div>I think the end result looks ok but the only photo I have=
 is of the car in my garage but just as I finished the project it rained.=
=C2=A0 I did a small airflow test with the electric fan running and was sur=
prised at just how much air came out of the aperture.</div><div><br></div><=
div>So, a road test (but weather is now cooler than my previous tests) to f=
ollow but I&#39;m confident of 4 things: the engine temp will be slightly l=
ower as more air will flow through the engine bay and thus more readily thr=
ough the radiator, it will be cooler inside the car because the warm air is=
 leaving the engine bay through the side wing aperture, not stagnant in the=
 engine bay or passing through the trans tunnel as much, there will be slig=
htly less drag, there will be slightly less lift.</div><div><br></div><div>=
Regards</div><div><br></div><div><br></div><div>Daniel</div></div>

--000000000000c87a0606228ff088--

--000000000000c87a0706228ff08a
Content-Disposition: attachment; filename="WP_20240919_14_57_37_Pro.jpg"
Content-Transfer-Encoding: base64
Content-ID: <f_m1ays81q0>

--000000000000c87a0706228ff08a
Content-Disposition: attachment; filename="WP_20240919_14_58_35_Pro.jpg"
Content-Transfer-Encoding: base64
Content-ID: <f_m1aysdlm1>

--000000000000c87a0706228ff08a
Content-Disposition: attachment; filename="WP_20240920_14_46_27_Pro.jpg"
Content-Transfer-Encoding: base64
Content-ID: <f_m1aysja22>

--000000000000c87a0706228ff08a
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

------------------------

[email-masked]

Archive: http://www.team.net/pipermail/spridgets  http://autox.team.net/archive

--000000000000c87a0706228ff08a--