1. What is a “Basic
Pull”?
In a Basic Pull,
your vehicle is placed on the dynamometer and the operator performs
a measurement of Torque and Horsepower. For clarity, we call it a
Basic Dyno “Session”, and refer to the individual runs as Pulls.
Check the Services section for a complete description of a
DynoServe session.
2. Do you do Diesel
Trucks?
You Bet! We’ve done a bunch of them.
3. What is the
difference between a Dynojet and a Mustang Dynamometer?
A Dynojet is
what is referred to as an “Inertial” Dynamometer. It has a roller
that simulates vehicle weight and also provides a simulated road
surface. Torque is computed from how fast the vehicle is able to
spin-up the roller (Inertia). The Mustang dynamometer, which is
referred to as a “Loading” dynamometer, has a similar roller, though
usually lighter in weight. To the roller, Mustang adds electric
“Power Absorption Units” (PAU’s) that acts as electronically
controlled brakes in conjunction with the roller to simulate the
actual weight of your vehicle as well as air and rolling
resistance. Torque is computed from the inertial load PLUS the
power being absorbed by the PAU’s. See the section on Dynamometer
Information to learn how much can be done with electronic loading.
4. Torque and
Horsepower! Is that all it measures?
Actually the
Mustang dynamometer only measures Torque and Speed. Horsepower is a
mathematically calculated value that is based on Torque and Speed.
Even though it’s popular to say that dynamometers measure
horsepower, it cannot be measured directly.
5. My engine is
running poorly. Will a Dyno pull tell me what the problem is?
No. The
dynamometer only measures Torque and does not perform diagnostics.
It does however, provide a wonderful platform to troubleshoot the
vehicle under almost any operating condition imaginable. The
technician, not the dynamometer, does the troubleshooting.
6. I’ve run my
vehicle on a “Brand X” Dyno previously. Will your Dynamometer
provide matching data?
Not likely.
Absolute accuracy (exact same figures) between dynamometers, even of
the same kind, is difficult to achieve. In the real world, there
are simply too many variables. If you are tuning and wish to
compare one vehicle configuration to another, your best bet is to
use the same dyno for the before and after tests.
7. All my previous
tests have been run on Inertial Dynamometers and I do not wish to
deal with the complexity of loading. Can you test with Inertial
Loading only?
Yes. Our
roller weight is 2,792.44 pounds. All other things being equal, the
dynamometer with the lightest weight roller will produce the highest
torque and horsepower figures.
8. I
have a modified diesel truck with very high torque. Word on the
street is that they cannot be held on a dyno and they will just
smoke the rollers. Is that true?
No. It was our
intention to be able to handle high torque, high horsepower vehicles
from the beginning. Our dynamometer was purchased with a heavy-duty
tie-down system that has provisions for additional strapping to pull
the drive axle straight down toward the rollers. While we don’t
install these routinely, they are put on whenever they appear to be
warranted or if slippage is detected. When this question came up,
we did a review of our data and found that when axle straps were
installed, no vehicle to date has ever had any loss of traction.
9.
Can you test Four-Wheel
or All-Wheel drive vehicles?
There is only a
single set of rollers on our dyno, so we can test them only if they
can be operated in Two-Wheel Drive mode.
10.
What is SAE correction
and do I really need it?
Production of
power by the Internal Combustion Engine is “very” dependant on
Barometric Pressure, Temperature and Humidity. “Very” could be as
much as several percent. For example, you have a 300 HP muscle car
tested in the winter, then without changing a thing, have it tested
again in mid-summer. It would not be a stretch to say that a 20 HP
difference, or even more would not be unexpected. This difference
in horsepower output is well known and documented. What SAE
correction does, is to adjust the horsepower and torque from the
current atmospheric conditions to what it would be if it were 77
degrees F, at 29.235 inches of mercury and zero percent humidity.
That means tests to the changes you made to your muscle car since
testing last winter can be directly compared today. Now, if you
want to know the difference in your engines’ horsepower between a
cool night and a hot afternoon, then you would test under those
conditions without using SAE correction.
11.
How do you handle
engine heat during testing?
We place a
four-foot fan that moves thirteen thousand cubic feet of air per
minute directly in front of the vehicle. With sustained testing,
heat build-up can still occur. We do monitor engine temperature
during test to assure that safe limits are not exceeded.
