Hmmm. At the end of the back straight at PIR my cheater TR3 read 123 mph
via radar gun. I think it's about the same at the end of the much longer
straight at SIR since I lift and hold at 6500 RPM. I'm running 3.7 gears
and TA's with a 60 series profile. Unless there's some other difference I
would guess you're doing a bit better than 100MPH (or that radar gun is
the source of all my tickets--I KNEW I wasn't speeding!!).
My front end feels light and airy, kind of like steering a ballerina
around. I wouldn't want to crank the wheel until hard braking had put the
front wheels into better contact. Of course with all the illegal stuff on
my TR3 I should have a full aero package, or maybe a auxiliary fan motor
to suck the bugger down.
My fiberglass bonnet bulges up like a '49 Chevy truck at those speeds.
I've got it pinned down in five places (honest!!) to keep it from turning
into a kite. I don't think blocking off air is the answer, I don't have
any inner fenders so there's lots of exit area. The nose is a big ol' wing
turned the wrong way (lifting).
I do have a semi spoiler under the nose--I don't really think it helps,
but it gives the tech guys one more thing to frown at.
-----Original Message-----
From: Brad Eells [mailto:bradlnss@lightspeed.net]
Sent: Monday, April 02, 2001 11:05 PM
To: fot@autox.team.net
Subject: RE: TR4 front spoiler vs. air dam?
Bob,
This is interesting actually...
I have had my road TR4A traveling in excess of 95mph. I will have to
exercise my right to the 5th Amendment if you ask where! ;-)
I found the steering becoming very light and assume that if I had tested a
corner at this speed that massive understeer might have resulted. I
assumed
this was aerodynamic lift caused by the shape of the front lower valance
panel.
A spoiler or air dam would seem to help if this is the effect. Most of the
SCCA racer types that I have seen have an air dam vs a spoiler. You might
weld a small 'lip' along the bottom length of the valance panel if you
didn't want to alter the vintage look. The lip would become a gravel scoop
if you went off course!
Since Joe has thrown down the gauntlet, you can install your air dam and
go
kick butts and take names!
Cheers,
Brad
62 TR4 - Without air dam
I've been told that the front end of my car is lifting, and the
bonnet is distorted by the air. I know I need to close off the air entry
better, which will involve pinning the bonnet at the front and some more
grill blocking, but what about air dams and spoilers
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