Everything You Wanted to Know About NASA's Time Trial Program

Compete for the best lap time in your street or race car!

In NASA Time Trial competition, anything goes, from prototype racecars and converted production cars to the current crop of electric cars. Weight-to-horsepower ratios make for fair classes and lots of creative freedom to build the car you want. NASA Time Trial provides a venue for spirited on-track competition with a high degree of safety and convenience. NASA Time Trial allows qualified individuals to compete in a “best lap time” format in a prepared car in advanced level open-passing sessions, and bridges the gap between NASA HPDE 4 and wheel-to-wheel racing.

NASA Time Trial is an automobile road course competition series focused on time trial-style competition, and shall function as an advertising and marketing tool for the series sponsors, the independent sponsors of each team, as well as the official sanctioning body of the series.

Virtually anything from Acura to Volkswagen in race or street trim is eligible to compete in NASA Time Trial. There are the usual classes for internal-combustion-engine cars, and now EVs also have a Time Trial class in NASA. 

Because you can run anything in NASA Time Trial, donor prices to build a new Time Trial car range from several hundred dollars to several thousand. Daily driven street cars also are eligible to compete in Time Trial. From shop floor to showroom floor, all cars are welcome.

There are no engine specs, per se, but according to the rules, “the Adjusted Weight/Power Ratio for each vehicle will be calculated based on a simple competition weight to average chassis dynamometer (Dyno) horsepower ratio (Wt/Avg HP), followed by the adjustment of the resulting ratio by adding to, or subtracting from it, based on the list of “Modification Factors.” Competition Weight is defined as the minimum weight of the vehicle, with driver, any time that it competes in a qualifying session or race. Average horsepower calculation (Avg HP) is defined in Section 7.2.”

All vehicle weights will be measured to the tenth of a pound (xxxx.x), and then rounded off to the nearest pound for all calculations. Any weight ending in “.5” (xxxx.5x) NASA Super Touring (ST1-4 & SU) Rules 2020 v14.1 Page 13 of 28 will be rounded up or down to the benefit of the competitor. All horsepower measurements will be rounded off to the nearest whole number, and any number ending in “.50” (xx.50x) or less will be rounded down. Any “Adjusted Weight/Power Ratio” calculation ending in “.995” (xx.995) or greater will be rounded up to the benefit of the competitor.


TT1 = “Adjusted Wt/HP Ratio” equal to, or greater than, 6.00:1

TT2 = “Adjusted Wt/HP Ratio” equal to, or greater than, 8.00:1

TT3 = “Adjusted Wt/HP Ratio” equal to, or greater than, 10.00:1

TT4 = “Adjusted Wt/HP Ratio” equal to, or greater than, 12.00:1

TT5 = “Adjusted Wt/HP Ratio” equal to, or greater than, 14.00:1

TT6 = “Adjusted Wt/HP Ratio” equal to, or greater than, 18.00:1

Nitrous oxide use is prohibited. Pre-existing tanks must be removed. Methanol/alcohol-water injection is permitted provided that the mixture does not exceed 50% alcohol by volume. Methanol is not permitted as a fuel. (See CCR 15.19 and 18.3)

Because the cars in TT are so varied and because some of them are street driven, there really is no average cost. Figure $10,000 to $15,000 for a race-prepped TT5 or TT6 car. From there, prices rise with speed and horsepower.

You can buy anything from a used first-generation Spec Miata for $5,000 to a $250,000 prototype. Your budget will determine how fast and powerful a car you get.

That’s the beauty of Time Trial. You choose which modifications work best on the car you have chosen to build. The rules allow for freedom and creativity.

Average cost to run a weekend — $500 to $1,000.

Tires, size, brand and prices

Because wheels vary widely with car choice, figure $192 for 205-50-15 Toyo Proxes RRs to $315 for a 275-35-18 Proxes RR.

Brakes, brands and prices

$150 to $250 depending on the car you choose.

Hawk Performance, Maxxis Tires, Hoosier Tires, Hankook Tires, Spec Clutches, NISMO, Mazda Motorsports.

NISMO, Mazda Motorsports.

  • Build whatever car you want
  • Variety of competing cars
  • Lots of creative freedom within the rules
  • Lots of tire choices available
  • Competitive cars can get pricey
  • Electric cars are coming on strong!
TTEV (Electric Vehicle) Classing

TTEV is an open class for Tesla Model 3, Tesla Model S, Porsche Taycan, and other performance electric motor vehicle models as added in the future. HPDE technical safety inspection rules shall apply. No modifications are permitted to the factory motor, software, EV related safety features, or batteries (other than replacement of the 12-volt lead-acid accessory battery). All vehicles must use either tires with a UTQG treadwear rating of 180 or greater or the Toyo R888R. Note that future additional classing rules and/or Modification Factors may be added (although none are expected for 2020).

TT Classification Forms

In order to accrue points or compete, each year/season, all NASA TT competitors (except TTU competitors) must submit a current year, completed NASA ST/TT Car Classification Form (and certified Dyno report) to the Regional TT Director prior to having lap times count toward competition. Once a form has been submitted during a season, if there are no modifications to the vehicle that would change the form, a new form does not need to be submitted at subsequent competitions in the same region. A new ST/TT Car Classification Form copy (and certified Dyno report) must be submitted when a competitor competes in a different region or at a Championship event, or if changes have occurred to the vehicle that would change the form.

Driver Requirements/Licensing

A NASA TT license can be revoked for a variety of reasons, some of which include: giving false information on the application, failure to comply with the rules, unsafe driving, high incident count (spins/offs), car contact (with objects or other vehicles), and unsportsmanlike conduct on or off the track. Licensed racers participating in NASA TT that commit any of the above infractions may be subject to suspension or permanent ejection from NASA TT competition, as well as revocation of their NASA Competition Race license.

Timing Format

NASA TT competitors will be scored on a basis of their fastest lap time during an event day. Therefore, a regional NASA weekend would generally count as two separate event days, with points and awards for each day. NASA TT competitors will be timed continuously in each designated TT run session that they participate in (which could be a combined HPDE 4/TT run session or a TT-only run session). The sessions are typically between 15 and 30 minutes long. The fastest lap time from all of the sessions will be used as the basis for his/her score for the event. The first run session of the weekend will not count for TT competition, and will function as a warm-up practice session. The first session of subsequent days will count toward competition.


Questions and Answers to Feed Your Curiosity

The National Auto Sport Association began its first full season with the Time Trial Series in 2004. NASA Time Trial is a national and regional competition with participation from all 14 of NASA’s mainland regions. NASA TT uses a car classification system that is easy to understand, and gives HPDE drivers a taste of competition by allowing them to record their top lap times and compete against similarly prepared cars for awards, prizes and recognition.
Registration fees for Time Trial are often the same as for HPDE4. Car prep and safety equipment requirements are the same as HPDE4. All you need is a transponder mounted on your car to record lap times. If you don’t already have one installed, rentals are usually available at the track from your region. There is an annual $20 processing fee for a NASA TT License.

1. Contact your regional TT director if you are unsure if you meet the driver eligibility requirements listed in the TT Rules. NASA TT is for advanced road-course drivers and racers only. Also, you can contact your regional TT director to obtain a permanent TT car number assignment prior to your first TT event.

2. Fill out the national TT license application and bring it to your first event.

3. Fill out the online ST/TT vehicle classification form and bring a hard copy to the regional TT director at your first event.

4. Attach a permanent or temporary transponder to your car.

5. Register for a regional TT event, include your transponder number if possible, and purchase a provisional TT license online.

6. Attach car numbers and TT class identifiers on both sides, and the front and rear of your car.

That’s it! Your registration will provide your name, TT class, car number and transponder number to timing and scoring, and you will be set for the weekend. Access the TT rules and car classification forms here.

From the standpoint of driving, there is no difference. In fact, at some events, the Time Trialers drive in the same group with HPDE4 drivers and under the same set of driving rules. If you have driven in HPDE4 in the past year, you may have had TT drivers out on the track with you in many NASA regions. TTers are having their lap times recorded. Once you have successfully completed an HPDE4 event, you are eligible to participate in the Time Trial program under a TT license application, and after approved, with your national TT license.

After each driving session, results are usually posted just outside the timing and scoring building. They are also often posted on Race Hero. Soon after or during the event, all results are posted and saved for future viewing on the NASA Timing and Scoring website.

Daily winners receive medals, certificates, trophies, or plaques for first, second and third place in each car class. Season winners will be awarded trophies for first, second and third place at the annual awards banquet. Eligibility for season honors varies by region, but often requires participants to drive in at least six days of competition, or three two-day weekends.

NASA uses the MyLaps timing system at all events. There are various options available from MyLaps for purchase and subscription. Get one for circuit racing, which will be compatible with NASA’s timing and scoring system as well as virtually every other racing organization you may encounter. Prices range from about $160 for one year to $600 for an unlimited subscription. You can purchase a transponder directly from MyLaps.

Yes. You can rent a transponder from most of the regions. It is easy to install, and rechargeable transponders are available from registration in the regions that have rentals. These units are mounted with a few zip tie straps and take about five minutes to mount. The cost varies, depending on the region, and you can rent one when you register online, and sometimes at the track if there are any left. It is better to sign up for the transponder rental when you register for your TT event.

Yes. If you have a NASA competition race license, you do not also need to purchase a NASA TT license, and you can register for a TT event occurring on the same day as your race competition. You will have a busy day, and will still be required to go to all mandatory TT meetings and racer meetings. You may end up missing some TT sessions due to scheduling, but there are no “makeup” or substitution sessions available.

Yes. You can, and the ST/TT online car classification form will apply a modification factor that will allow you a bit more power or less weight than the identical vehicle on race tires.

Once you have a national TT license, or a NASA competition race license, and you have completed the minimum number of TT events for the season listed on the NASA Championships website, you will be eligible to compete at the “big show.”

In some regions, and generally at the NASA Championships, we run more than one TT group, and they are separated based on the faster classes being grouped together. However, most regions run a single group, and we help to provide a safe and productive experience to all by gridding vehicles based on lap times for each session.

Reach out to us via our #DRIVENASA Community Forums. The regional TT director will also be available to answer any questions you have during the events at the Time Trial download meetings.


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