G-curve meter

[Watson, Bill]

Well, I didn't join this page to sell a product (I'm DFI injecting a
twin-
turbo 302) but there's been enough G-meter talk that I must at least
bring up 
our product for those who would find it useful.  We don't have a web
page and 
we don't have datalogging, but the price is right ($ 75) and it IS
accurate 
on hills since we get speed from the speedometer rather than integrating
g's 
vs. time.

It's called the g-curve.  It is an 11 inch-across analog g-meter.  It's
a 
fluid-filled glass tube with a ball inside, mounted on a calibrated
anodized 
machined aluminum plate.  Before you write it off, I'll tell you right
now 
that it is very accurate.  Getting the right damping ratio for the ball,
independent of temperature, was the key to making this thing right.
There 
are no batteries or wires, you just suction cup mount it to the
passenger 
window for accel/decel, or to the rear view mirror for cornering.
Included 
is a user's guide with all the formulas.

We've noticed that although most people have down the basic equations
(HP at 
tires = (g's * Speed (mph) * Weight/375) + wind drag), most people
forget to 
include the power requirements of angularly accelerating the powertrain 
(rotating inertia).  Don't fool yourselves here; during a WOT accel, my
240 
HP net engine shows only 180 making it to the rear wheels in low gear,
213 in 
second, and so on.  All of this is included in the user's guide,
including 
corrections to SAE Net HP with Altitude, temperature, and humidity 
correction.  Wind drag is as simple as lifting off the throttle and
coasting 
in neutral and getting the decel reading.  Again, very key here, YOU
COULD DO 
THIS ON A 10 PERCENT GRADE AND STILL BE WITHIN A HALF A PERCENT ERROR.  
Smooth roads are much more important than grade.

We invented it primarily for generating HP and TQ curves, but you can
also 
use it for braking, cornering, measuing grades, determining proper shift
rpm, 
estimating 1/4 mile trap speed, and other things like your traction
limit.  
At first, some people think being analog isn't as handy, but you can't
beat 
it for laptop tuning on the fly... The driver stands on the gas, calls
out 
'now' at the rpm of interest, and the passenger reads the g-value
directly 
from the face of the curve.  The passenger tweaks the fuel curve on
their 
laptop, and 10 seconds later you're at full throttle again, checking if
your 
fuel curve mod generates less, the same, or more g's.

The kit includes a 3.5" diskette that has the HP calculation spreadsheet
that 
uses Microsoft Excel.  We've been reviewed in Hot Rod, Popular
Mechanics, 
Turbo and Hi Tech Performance, Vette, Fast Fours (an Austrailian 
Publication), Muscle Car review and a few others.  We've been selling
them 
since 1989.  I can include any of the writeups as a .TIF file for those
of 
you who can read attachments and have Paintbrush, Adobe Photoshop, or
similar 
paint program.

Sorry for being 'ad-boy' for a day.  If you have questions, e-mail me
rather 
than the whole list so we don't clutter it up.  Thanks.

bill.watson at alliedsignal.com