Help Section

Help: Troubleshooting

---

Common problems using the calculators

How do I use VA factor?
The va factor value that you see near the bottom of each baseline profile is related to pressure. It is made up by combining elements of the pressure formula together to create a constant value in order to streamline calculating system pressure. If you provide a baseline pressure, the va factor is re-calculated to conform to your pressure requirements. Then when future pressure calculations are made, that va factor value is used.

If you do not know your system pressure, an estimated pressure is calculated for you using a standard va factor of 0.00075.

What number do I enter for overdrive ratio for blown engines?
The overdrive ratio is the amount over 1 (or 100%) your engine is running. That means the value is reduced to a value related to 1. For example:

• An overdrive of 10% would require you to enter a value of 1.10.
• An overdrive of 35% would require you to enter a value of 1.35.
• An underdrive of 10% would require you to enter a value of .9.
• An underdrive of 15% would require you to enter a value of .85.

Do I really need to enter elevation?
You will need to provide the elevation of your location if you are getting your barometer value from a local weather report. If you are using a portable weather station that provides an uncorrected barometer value, you should not enter the elevation into the elevation field in the calculators.

If you are working with a corrected barometer and need the elevation of your location, you can get it by entering your address into the field on the bottom of the free calculators page. Read more about barometer and elevation here.

What is the difference between volume and weight for nitro?
By volume: Measurements are decided by the amount of fuel added to the mixture. For example, 1 gallon of nitro added to 3 gallons of methanol would result in an addition of 25% by volume of nitro.

By weight: Nitro weighs more than methanol so adding a percentage by weight is a more involved process. Measuring by weight requires finding the specific gravity of the fuel. However if you are familiar with this process, this can be a better measurement of nitro percentages.

return to top

---

Problems getting your car to run well

I used the calc and my car still runs poorly. What do I do?
If you are having problems getting your car to run well, there could be other adjustments or problems outside of the jetting setup. There are a few steps you can take to troubleshoot your issues:

• Make sure the correct engine specifications are entered into the calculator. It's possible you are getting poor jetting results because the engine specs are incorrect. Double check your numbers and when in doubt, contact the manufacturer for more exact details.
• Check that other systems in your car are in good condition. Examples include but are not limited to:
• check ignition
• check fuel system: fuel tank, breather, fuel lines (not collapsing), spark plug gap, timing, cam phasing, etc.
• If you are not easily able to diagnose a problem, contact the manufacturer or an engine professional to assist you in troubleshooting the problem.

Please note: This site is a reference for racers to check their jetting. It is not intended as a diagnostic tool for complete engine function. Checking results against another source is recommended. Ultimately the racer, crew chief, or car owner has final say in which engine modifications are made.

I am a new racer and still learning how best to run my car. How can I learn more?
Congratulations on getting into racing! This site is built in partnership with Racecarbook.com. That site has many free articles as well as books for sale in order to learn about engine tuning.

Joining a racing organization such as NHRA or IHRA can provide a number of resources. Additionally, a google search can provide many good sites.

Finally, checking out your local track and meeting fellow racers is a great way to see how others run their cars.

return to top

---

General account questions

My account doesn't stay logged in even though I've checked the box.
In order for this feature to work you must have cookies enabled on your browser. If you do not, you will have to log in every time you wish to access the site.

Also, this feature only works when logging in repeatedly from the same computer. If you are logging in on different computers you will need to re-login every time.

After a few attempts I am locked out of logging in. Why?
For security reasons, if you attempt to access the site 5 times with a failed login your ip address will be banned for a span of 1 hour. Additionally, if the site detects more than 5 different ip addresses using the same login information, those ip addresses will also be banned for a span of 1 hour.

What do I do if I've forgotten my password?
It can be easy to forget your password if you've logged in once and checked the "remember me" box. In the event that you get logged out and cannot remember your password, click the forgotten password link found in the login form on the login page. You will be prompted to enter the email address you signed up with. A password reset email will be sent to that email address. Follow the instructions from there. If you do not receive a password reset email, check your spam folder.

If you do not remember the email address you signed up with, you can contact us via the online contact form with your user name. We will reset your password for you. Please be aware, we sometimes take a couple of days to respond to contact form emails so we may not be able to reset your password right away if you go this route.

How do I renew my membership on this site?
Memberships are for 1 year from the date of signup and are not automatically renewed. In order to renew for another year, you pro-calc signup page and click on the paypal link. From there you will be prompted to enter your payment information.

A renewal email will be sent 7 days prior to expiration.

Sometimes I have problems accessing the site from different locations. What can I do?
This website needs an internet connection in order to process calculations. If you are having problems accessing the site, check that your internet connection is enabled and strong.

return to top

---

Please contact us if you need further assistance.