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Common Problems
Q: My G indicator (on the main screen) doesn't seem to be working... when
I am stopped, it still indicates acceleration. What is going on?
The RR (and Competition) differ slightly from the SS regarding the display
of G force, but they function in a similar manner. This response is general
enough to apply to all Gtech products.
There are a couple of possibilities that explain why the Gtech would detect
a non-zero G force when you are not moving.
One scenario is when the Gtech is not oriented identically to how it was
on the last acceleration run. The Gtech needs to “re learn” its orientation
before it can measure lateral and forward Gs. If you just mounted your Gtech,
or moved/adjusted it since the last time you performed a run, you will need
to do another acceleration run (at least enough to start the race clock) before
the G bars are leveled.
Another possible cause: if the road has even the slightest slope to it, a
small amount of Earth's gravity will be picked up by the Gtech's sensitive accelerometers
and cause the bars to not “zero out.”
One last thing, if you believe you have not moved the Gtech since your last
run, and you are on perfectly flat ground, it is possible it is a mounting problem.
You should verify that the tensioning nuts are adjusted properly so that the
Gtech is rigid and does not move. You should also check your mounting system
and verify that nothing is cracked or damaged, including the rubber ball on
the mounting clip, and narrow top portion of the conical “A frame” piece.
Q: On my Gtech I see the word “Diagnostic”, some numbers, and then the
unit freezes. What can I do?
An internal error has been detected. Please contact
us by phone in
order to troubleshoot this.
Q: I am getting inconsistent results on my 1/4 mile runs. Why is this?
There are many factors that can affect your results. Read about them here.
Q: I am getting a message "The race has been discarded because the
Gtech moved during staging" - what is this?
The Gtech requires you to "stage" on a level surface before performing
a run. During staging, the Gtech is checking its calibration and
determining its orientation relative to the earth's gravitational field. If
the Gtech moves during or after this process, an accurate measurement cannot
be made. If the Gtech determines that this type of movement occurred,
it automatically discards the run because the results will be inaccurate at
best, and downright silly at worst.
Q: I am having trouble downloading stored runs from my Gtech into my PC
- what can I try?
This is almost always an issue on the PC. We
have a Tech Note on this topic here.
Q: I am getting consistent results, but when I compare my results to a
timeslip at the track, the numbers don't match. Why is this?
The largest culprit is rollout. In this case, nothing is wrong with
the track or the Gtech, it's just that the Gtech and the track are starting
the race clock at different times. The Gtech starts timing based on vehicle
movement, and the track starts timing at an absolute position on the track.
Read this document to understand the effects of rollout
and why matching the Gtech results to timeslip numbers is not too meaningful.
Another factor is vehicle pitch during acceleration and shifting. Consult
your product's manual about adjusting the Gtech's Pitch Correction Factor to "dial
in" your results.
Q: My Gtech powers up (the blue backlight and red lights behind the buttons
come one) but nothing appears on the screen, even after waiting a few minutes.
A sensor has failed inside of your Gtech. This is a hardware failure and
must be repaired before the Gtech will function properly. Please contact us
for service.
Q: I turn on my Gtech and a number of the LEDs blink in various patterns
for 10 or more seconds, the the screen reads: DIAGS FAILED and shows ACCX ACCY
ACCZ (or part thereof).
A sensor has failed inside of your Gtech. This is a hardware failure and
must be repaired before the Gtech will function properly. Please contact us
for service.
General Questions
Q: How many dragstrip runs can the Gtech store in its internal memory?
Up to 30.
Q: What are the dimensions of the Gtech?
Approximately 4 inches wide, 2 inches tall and 1.5 inches deep.
Q: I like the user interface of the SS - can I transform a Competition
into an SS model?
Sorry, we do not currently offer a way to transform a Competition into an
SS.
Q: I just bought a Competition recently and upgraded to the RR/4.0 firmware.
What is the difference between this product and the new RR model?
The Comp with RR/4.0 and the RR model have the same features.
Q: Can I use the Gtech on a motorcycle? Snowmobile? Boat?
Airplane? Rollercoaster?
The Gtech has not been subjected to exhaustive testing on these vehicles.
RPM pickup might be a problem, it is impossible to say if RPMs will definitely
work for any given vehicle.
Without RPMs, you will not have the following functionality:
- RPMs vs. Time graph
- HP & TQ vs. RPMs
- Max. torque (since it relies on RPMs)
- RPM-dependent shiftlights
- Tachometer
Also, in order for the Gtech's results to be accurate & meaningful, all
timing must start from a complete standstill, and all motion must be on a flat
and smooth surface. Motorcycles generally exhibit a bit of pitch under
hard acceleration, especially powerful/fast bikes. This pitch effect will
negatively impact the accuracy of your results (it cannot be quantified in a
blanket statement, the effect varies on a case-by-case basis.) Also be
aware that motorcycles will also experience problems with lateral G measurements
in turns, due to the severe banking angle motorcycles undergo in turns.
You should
be able to use the Gtech on a snowmobile if the snowmobile travels along a straight
flat surface like a frozen lake. Do not use it on rolling terrain or sloped
ground, your results will not be accurate.
Boats, planes and rollercoasters
are not good candidates, due to the rolling and banking nature of their motion.
Q: Do I need a serial port on my computer to use the Gtech?
No. You only need a serial port if you want to upload data from the Gtech to your PC. If your computer does not have a serial
port, you may use a USB-to-serial (DB9) adapter. There are many such adapters,
however we do not recommend or endorse any particular brand or product.
Q: How accurate is the Gtech?
The Gtech Pro Competition is extremely accurate and repeatable. We
routinely take 12 new Gtechs at random and subject them to testing in a
controlled environment that eliminates variables such as pitch, mounting system
problems, etc. Typically, all 12 Gtechs measure the same 1/4
mile time for a 1-g run, plus or minus five thousandths of a second.
For horsepower measurements, we have observed
accuracy and repeatability in the range of 1-3 percent.
The accuracy
and repeatability of your results can be influenced by many factors, such
as vehicle pitch, road surface, environment, mounting system, driving style,
etc.
Q: I am getting a message that says that "Two calibrations are needed
at different temperatures for best results" - what is this?
The Gtech has temperature-compensated accelerometer sensors that are highly
sensitive to temperature changes. For best results, your accelerometers
should be calibrated at 2 temperatures that are as far apart as possible. If
the Gtech determines the current temperature is far away from any temperature
where you did a calibration, you will see this message. If you see this
message, go into Configuration Mode and perform an accelerometer calibration.
Q: When does the Gtech start timing? When does it stop timing?
The Gtech starts timing when the car begins moving from a standstill and
has completed the requested rollout distance.
The Gtech stops timing when any of the following conditions have been
met:
- Vehicle is not accelerating and is not braking, i.e. it is "coasting
down."
- Vehicle has traveled approximately 4000 feet, which is about 0.8 mile
(more than 3 straight quarter-miles).
- Vehicle has reached a velocity of 300 MPH.
- Unit has been timing for almost 60 seconds.
For even more information, you may wish to download
the 3.1 User Guide.
Q: Will the Gtech work on my vehicle?
Generally, the only potential issue is RPMs. Nothing
else besides RPMs depends directly on your vehicle. Vehicles which travel in a flat, straight
line will experience more accuracy and repeatability
than those vehicles which crab, pitch, etc... on a run.
Q: Does the Gtech log lateral Gs?
Yes, in Road Racing Mode, the Gtech logs forward and lateral Gs as well as
RPMs.
Q: Does the Gtech have a “peak hold” for forward and lateral Gs?
In Road Racing mode, the Gtech stores and remembers the peak Gs in all 4
directions (left and right turning, forward acceleration and braking), as well
as peak RPMs.
Q: The Gtech stops timing shortly after I stop accelerating, is there
any way to disable this?
No.
Q: I use a throttle stop on my vehicle - will the Gtech still work for
me?
The Gtech simply requires a smooth, strong surge of acceleration from a stop
in order for it to "trigger" and start timing. If your vehicle
exhibits this behavior with the throttle stop mechanism, there will be no problem.
So far we have not encountered any problems with this.
Q: How do I determine my vehicle weight?
The very best way to do this is to get your vehicle weighed, in race trim,
with you in it, at a truck stop weigh station, town dump, recycling center,
etc. Actually weighing
the vehicle takes the guesswork out of HP measurements.
If you do not have access to this, the next best thing is to obtain the curb
weight of your vehicle, and add in the weight of any options, aftermarket parts,
fuel, your body weight, etc... Curb weight figures are available on the
internet from a variety of sources, including vehicle manufacturers. Unfortunately,
we cannot provide curb weight for your specific vehicle, nor recommend
any specific site for this information.
Q: I cannot get my 0-60 MPH time down to the figure that magazines publish.
Why is this?
In firmware 3.0, the Gtech starts the 0-60 clock as soon as the vehicle starts
moving. Many pieces of test equipment (such as some radar guns) don't start
timing until a rollout distance of 12" has been completed.
In a 13-second 1/4 mile car, the first 12" can take almost four tenths
of a second, and at the end of the 12", the vehicle is already moving at
about 4 MPH! This means the clock doesn’t start until the vehicle has been moving
for 0.4 seconds and has gone 12”.
Just as we urge people to not get too hung up on comparing results to the
dragstrip timeslip, you shouldn't be too focused on trying to match published 0-60MPH
figures.
Q: My mounting bracket occasionally falls off the windshield - what could
be wrong?
- Make sure the surfaces of the suction cup and the windshield are clean.
- While pressing the suction cup onto the windshield, press on the large
tensioning nut, not the outer bracket. This will expel the maximum amount
of air and create the strongest vacuum seal.
- Tighten the large tensioning nut all the way down and the bracket should
stay in place for many months.
We have a document that provides more detail on the mounting
system.
Sales/Orders
Q: Is there a trade-in program
so I can upgrade to a newer model?
Sorry, we do not have any kind of discount or trade-in program.
Q: I am an international customer, i.e. outside of the European Union.
What should I be aware of?
Please be aware of the following issues:
- The User Guide is only available in English
- The 120V AC power supply is made to work with U.S. wall outlets; other countries
may not have similar wall outlets
- For all warranty and returns, shipping costs in both directions are
the responsibility of the customer
Q: Can I buy more than one Gtech at a time from your website?
Currently the website is set up to handle purchases of a single unit. If
you would like to purchase multiple units at once, please contact
us by phone.
Q: Is there a discount if I buy more than one Gtech at once?
No.
Q: I lost my User Guide (product manual). Can I get another one?
You can download PDF versions of our user guides from our website. To purchase
a hardcopy of the latest manual, please contact us
by phone.
Q: How do I obtain accessories such as a spare serial cable, mounting
system, etc.?
To purchase accessories, please contact us by phone
to submit an order.
Q: Can I buy a specific component, such as a button, display or
connector?
Sorry, parts used in the manufacture of the product are not stocked and sold as
individual pieces. In other words, we do not sell individual displays, connectors,
LEDs, switches, etc....
Q: What do I get when I buy the Gtech RR, i.e. what is included
in the kit?
You get:
- Gtech Pro RR performance meter
- Portable mounting system
- Serial cable
- DC power cable for in-car use
- AC power adapter for indoor use
- CD-ROM with PASS PC Software
- User Guide
- Permanent mounting system
- 2 Gtech Pro stickers
Q: Do you sell internationally, i.e. customers outside the European Union?
Yes we do. But there maybe a customs fee in your country.
Q: How much will I pay for import duties/taxes?
This depends on your specific country and its regulations. Check with your
government’s import laws and fee schedule to determine this. Countries inside European Union won't pay any taxes or duties whatsoever.
Accelerometers
Q: What is the maximum number of Gs the G-tech can measure?
+/- 10 Gs.
Q: Do I have to calibrate the accelerometers in my Gtech?
All Gtechs shipped after August 2003 have factory-calibrated accelerometers.
Even though you can perform an accelerometer calibration yourself, it is unlikely
that you will be able to improve upon the factory calibration. If your Gtech
was delivered with factory calibrated accelerometers, we strongly recommend
that you neither erase the accelerometer calibration, nor re-calibrate the accelerometers.
Q: Can the Gtech output accelerometer readings in real time so that I
can log them with my PC?
No. However, in Road Racer mode, you can log forward and lateral Gs
at different logging rates, with different amounts of data smoothing, and then
upload the data to a PC for analysis with PASS.
Firmware
Q: Are there any firmware updates available for the RR?
No.
Q: My firmware version is earlier than the latest version available for
download on your website. Do I need to upgrade?
We strongly recommend that you upgrade your Gtech's firmware to the latest
available firmware version.
For some issues, such as accuracy questions, we cannot even begin to narrow
in on the problem until we know you are running the latest firmware.
Please note that upgrading your firmware will cause you to lose all stored
configuration information and all stored runs. Thus you will probably want to
make note of your configuration (vehicle weight, vehicle redline, vehicle shiftpoint,
vehicle name, etc...) and also download your stored runs to a PC using the Gtech
PASS software.
Q: I am having trouble upgrading the firmware in my unit, what should
I do?
Make sure you downloaded the correct firmware upgrade program. Owners of
Gtechs with firmware version 1.0 must follow a different procedure than owners
with firmware 1.2 and later. If you have firmware version 1.0, or cannot resolve your issue, please
contact us by phone.
Q: Will there be a firmware update for the RR or Competition? What will be in it?
We will not comment on future product development.
Hardware
Q: Can I hard-wire my Gtech, i.e. I want to power my Gtech in a way other
than through the cigarette lighter.
You can go to Radio Shack and buy a cigarette lighter outlet on a cord and
attach that anywhere to your car's 12V electrical system. Some users have chosen
to cut the Gtech cable at their own risk, and have attached it to their car's
electrical systems directly. If you do this we strongly recommend that you put
a 1 AMP fuse inline with your Gtech. Normally this fuse is inside the tip of
the cigarette plug and if you cut that off, you will no longer have the fuse
as protection.
Q: My car runs on a voltage higher than 12V. Can I still use a Gtech?
The Gtech can operate at voltages from 9-15 VDC. The higher the input
voltage, the warmer your Gtech might get. We don't recommend exceeding
15VDC.
RPMs
Q: Will the Gtech's RPM pickup definitely work on my vehicle?
We cannot guarantee with 100% definitiveness that the RPM pickup will work
with your vehicle(s). This is no different than an aftermarket tachometer.
Some vehicles present peculiar problems due to a variety of factors that
are beyond our control. We can say that the Gtech's RPM pickup works in
the vast majority of cars we have tested on. Unfortunately, the only way
to know for sure is to try it.
Q: I have an MSD/Jacobs/etc. ignition on my car, will the RPMs work?
The RR/4.0 firmware has major enhancements in the RPM processing engine that
work nicely with most aftermarket ignition vehicles we have tested. However,
it is impossible to say for sure if the Gtech's RPM pickup will work on your
specific vehicle, because there are so many factors that affect the
RPM pickup. We have even heard of inconsistent results within the same model
year and make, perhaps due to aftermarket parts, alternator wear, part tolerances, electrical
accessories, etc.. Some vehicles with aftermarket ignition systems work fine,
others don’t, each one is a unique situation.
Q: What features rely on RPM pickup?
- Tachometer
- Shiftlights
- Torque measurement
- RPMs vs time graph
- HP & TQ vs. RPMs graph
All of the acceleration-based measurements, such as 1/4 mile, 1/8 mile, 60
ft, 330 ft, 1000ft, as well as features like horsepower, cornering lights, braking
distance measurements, 50-70MPH sprints, etc. will still work fine without RPMs.
Q: RPMs aren’t working on my vehicle, so can I disable the shiftlights
so they don’t flicker randomly on and off?
Yes, you can disable the shiftlights, consult your User Guide for details.
Q: I moved my Gtech to another vehicle, but the Gtech's Tachometer doesn't
match up with the vehicle. Why is this?
RPMs must be calibrated on a per-vehicle basis. This is why the Gtech
supports up to 4 vehicles.
Q: Can I adjust the 2 RPM points at which I calibrate RPMs for my vehicle?
The two RPM calibration points are adjustable. Please
bear in mind, the further apart they are, the better the calibration will be. Also, unless you have
a diesel vehicle, we recommend that you do not go below 2000 RPMs on your low
setpoint.
Horsepower & Torque Measurements
Q: The HP result from my Gtech is lower than the manufacturer's HP specification
for my car's engine. Why is that?
The Gtech measures HP after all possible losses, including drivetrain loss,
rolling resistance, and aerodynamic drag. All these factors rob your car of
power. Manufacturer's specs are usually for an engine under ideal laboratory
conditions, measured right at the crankshaft.
Q: The HP result from my Gtech is different from the results from my local
rear wheel dyno - why?
The Gtech usually gives HP values which are lower than a traditional dyno.
Lower figures are due to aerodynamic losses incurred during driving,
and increased rolling resistance of the tires on a real road surface as opposed
to a smooth dyno drum. In any case, the power measured by the Gtech is truly
the amount of power left to propel your car forward, which is really what matters
when tuning a winning vehicle.
Q: Can you give me an example with some numbers, i.e. suppose the manufacturer
of my rear-wheel drive vehicle lists it as 320 HP... what will I see with the
Gtech?
Here is an example. These figures vary between vehicles and even within
a family of vehicles... they are just provided for the sake of this example.
- First of all, there is a variance as to the horsepower ratings within
a set of engines from the factory. Your engine may have been delivered at 310
HP instead of 320 HP.
- This 310 HP figure would be as measured in a lab, out of the vehicle,
with no major accessories attached, and perhaps a very low impedance exhaust
(if any exhaust at all.) You can lose about 10% with the engine actually in the car:
310 * 0.90 = 295 HP left over.
- The gearbox may sap a few percent: 295*0.98 = 288 HP left over
- The driveshaft may sap a few percent:
288 * 0.98 = 282 HP left over
- The differential may sap 4 percent: 282 * 0.96 = 271 HP
left over
(this would be higher in an AWD vehicle)
- At 65 mph or more, we may lose another 30 or 40 HP to rolling resistance
and aerodynamic drag, which drops us into the 230 HP territory.
- This 230 HP value is the net HP which is left to accelerate the vehicle
after all losses have been accounted for.
This is a very useful and meaningful value... for example, you
could have another vehicle (with similar weight and gearing) whose
engine is rated at 280 HP, and if that vehicle has fewer parasitic losses, it
might "dyno" at 230 HP with the Gtech as well. In this
case, you'd know the vehicle would perform similarly, even though engine was
rated lower than the 320 HP engine. It all comes down to how much power
is left to accelerate your vehicle.
Q: Does the horsepower / torque measurement work on a FWD vehicle? On
an AWD vehicle?
Yes, the Gtech measures net horsepower, which is to say, the horsepower delivered
through the driven wheels, no matter which wheels they are.
Q: Why does my dyno plot look "flatter" than the dyno plot I've
seen from chassis dynos for my car?
This is primarily due to aerodynamic drag on your vehicle. The amount
of horsepower that is spent overcoming aerodynamic drag is proportional to the
cube of the vehicle velocity. In other words, you use 8 times as
much horsepower just to overcome aerodynamic drag when your velocity doubles.
For example, if aerodynamic drag robs your vehicle of 3 HP at 25 MPH,
it will be robbed of 24 HP at 50 MPH... the velocity doubles, but the aero
drag loss goes up by a factor of 8!
So even though you are usually generating more horsepower at higher RPMs
in a particular gear, you are also going faster, and the horsepower needed to
overcome aerodynamic drag is much higher at the upper end of the RPM range.
This increasing "negative horsepower" due to aero drag is largely
cancelling out the increased horsepower generated by the engine.
Q: What is the difference between the HP measured by the Gtech, and the
HP measured at a dyno, and the HP given in publications?
First of all, there are variances even between dynos. That is to say, if
you take your car to 5 different dynos, you will probably get 5 different results.
None of them are “wrong”, it’s just that they all measure in a slightly different
way, under slightly different conditions. As any experienced tuner will tell
you, when you are tuning/modifying your vehicle, you should always go back to
the same dyno for comparison.
Most publications list the “crank horsepower”, which is the horsepower put
out at the crankshaft, with no transmission, etc... connected to the crankshaft.
Most dynos measure “wheel horsepower”, which is the power delivered through
the wheels (front, rear or all wheels); this power is what accelerates the vehicle
forward. Consider all the mechanical components between the engine crankshaft
and the wheels, as well as the friction (rolling resistance) between the rubber
tires and the surface of the dyno roller, and it is no surprise that dynos measure
a lower HP figure (after all, they are measuring power at a different place.)
Some dynos have “tweaks” and adjustments that raise the measured wheel HP figure
based on a number of factors, bringing the delivered number more in line with
the manufacturer’s crank HP figure.
As for the Gtech, it will read even lower than a dyno, because of additional
sources of power loss that affect a moving vehicle. One of the largest culprits
is aerodynamic drag. Some other factors include road surface irregularities,
environmental conditions such as wind and humidity, etc...
This document provides a lot of information on the Gtech and
horsepower measurements.
Q: I am getting inconsistent results when measuring horsepower and torque.
Why is this?
There are many factors that can affect your horsepower/torque results. Read
about them here.
SS Model
Q: What is the difference between the SS and RR products?
Q: Can I upgrade my SS into an RR product?
At this time the SS unit is simply an SS unit. We do not comment on
any future plans for upgrades or features. You should not buy an SS unit
with the expectation that it can be upgraded.
Q: Is the RR product more accurate (since it costs more)?
No.
Q: Can I upload runs from the SS and use the PASS PC Software to analyze the
data?
No.
PASS PC Software
Q: What are the system requirements for PASS?
Windows 98 SE or higher (English version, we have reports of problems with
some international versions of Windows), screen resolution of 1024x768 or greater,
32M of RAM, 20M of hard disk space.
Q: What features does PASS provide?
PASS allows you to view, analyze, export and share the data
acquired by the Gtech during drag strip acceleration runs. As of PASS
2.0, you can also analyze road racing / autocross / track sessions as well.
The best way to learn about PASS is to download
it and try it for yourself.
Q: Can I try PASS on my computer?
Yes, the PASS software can be downloaded from our website for free, and it comes
with some sample runs that you can use to “test drive” PASS. The sample
runs are located in a directory named "sample runs" in the PASS installation
directory. You can open a sample run by clicking on one of the 4 yellow
folders and selecting a run in the "sample runs" directory.
Q: Can I export data from PASS so that I can use it in another program
(like a spreadsheet)?
Yes, you can export the Main Run's data from the File pull-down menu. The
data is in CSV (comma-separated values) format, with 0.01 second granularity.
Note: we have reports of difficulties from users in some
European countries when this file is imported in Microsoft Excel. This
is due to the fact that some European versions of Excel use a comma where the
American version uses a period. If this is the case, you should use a
text editor to replace all the commas in the .CSV file with tabs, so that it
is tab-delimited instead of comma-delimited.
Q: The fonts in PASS seem to be messing up the screen - can I do something
about this?
This is a Windows issue that is specific to your computer and over which
we have no control. Also, different versions of Windows operating systems handle
fonts differently. Having said that, make sure that in Windows, your Windows
Font Size is set to "Normal" (Desktop->Properties->Appearance).
Also make sure that your DPI is set to normal/96 DPI (Desktop->Properties->Settings->Advanced).
With those settings, there are usually no display problems.
Q: When I compare my HP / TQ results in the Gtech vs. PASS, they don't
match - why? Which one should I use / trust?
Sometimes PASS may not come up with the quite the same results as the GTech
for HP/TQ measurements. The algorithm in PASS is virtually identical to that
in the Gtech, but PASS does some extra "smoothing" on the acceleration
data. We anticipate that when Gtech firmware version 3.1 is released,
and PASS version 1.2 is released, these numbers will be much closer to each
other
Due to the high precision of the Gtech's accelerometers, things such as gearshifts,
bumps in the road, etc. can add a little noise to the forward acceleration
data.
Both the Gtech and PASS smooth out the forward acceleration data to provide
a nice HP curve, but PASS uses a slightly different smoothing algorithm than
the Gtech.
We have a Tech Note which explains more about using
PASS -- download it from here.
As long as you compare PASS numbers against PASS numbers, or Gtech numbers
against Gtech numbers, you will be fine.
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