Diesel World DRAG RACING 101
A BEGINNER’S GUIDE TO COLLECTING THE QUICKEST TIME SLIP POSSIBLE
As winter draws to a close and you brace yourself for spring and better driving weather, there is a lot to look forward to. For many, warmer temps mean they’ll be hitting the drag strip. Whether it’s to follow the racing organization they run points in (such as ODSS), to find out if the changes they performed over the winter yield quicker elapsed times, or they’re just looking to mix things up at the local test ‘n tune, drag racing is on their minds. This could be you. Trust us, there is a track in your area and an event on the calendar that’s intended for you and your diesel. For a lot of you it’ll be the first time you’ve ever pulled into the staging lanes—and that’s OK.
If any sport is to grow, there has to be newcomers willing to give it a shot.
Like any form of competition, there are a thousand things to learn in order to be competitive. From race prep to staging to the actual race itself to collecting your time slip and analyzing the data, drag racing is much more than simply lining up and matting the go pedal. For the A to Z basics, we’ve got you covered this month. Next month, we want to see you in the staging lanes. Follow the tips and tricks listed here and you’ll be able to hit the ground running when you decide to become more than a spectator.
Unless you plan to bolt slicks on the rear of a four-wheel drive diesel, always drag race in 4-Hi. If you’re making any significant amount of horsepower (and especially torque) over stock, you won’t be able to leave the line with any amount of meaningful boost on tap without lighting up the rear tires. Once that happens, the race is over. By racing in 4-Hi, your E.T. will be reduced by half a second or more.
Sending your truck down the drag strip at full bore with the kill tune uploaded is likely the hardest few seconds your engine will ever see. Under these circumstances, the chances of experiencing a blown intercooler boot increase. As part of your pre-trip inspection, do yourself a favor and snug up each clamp in your intercooler piping or at least verify that all of them are tight. Cooler weather in particular has a way of making clamps slightly contract, which increases the potential of a blown boot scenario.
Idrag racing with an automatic transmission seems simple on the surface, but there is a lot more to it than simply selecting Drive and inching forward. To get the quickest possible elapsed time, you may have to adjust or manually control converter lock up. The sooner you lock the converter, the sooner you can maximize the amount of power you’re sending to the ground. In applications such as the Allison, a second gear launch may be highly beneficial. Staging and leaving in second gear places more load on the engine, which means you can leave the line with more boost while also skipping the 1-2 shift delay that occurs almost immediately.
If you’ve got four-wheel drive, use it. A 4x4 diesel truck has the unique advantage of being able to distribute all of its power to four separate wheels rather than two out back. This means traction is guaranteed even if you’re leaving the line with considerable boost, and it’s why so many street trucks can cut 1.8 to 1.6-second 60-foot times. Note that if you’re using four-wheel drive, avoid the water in the burnout box and go straight into staging your truck.
Whether you’re making 500 hp or 800 hp, it always pays to drop the air pressure in your tires. Dropping air pressure increases your footprint, and more rubber coming in contact with the racing surface means more grip. Added traction means better 60-foots and ET’S with no ill-effect on trap speed or any other factor. Just don’t drop pressure too low (draw the line around 20-25 psi), and make sure you have a means to air back up once you’re done racing.
It’s important to keep in mind that the method you use to stage has a direct effect on your reaction time. When you shallow stage, your reaction time will be slower but your elapsed time quicker. However, when you deep stage you typically see a quicker reaction time but a slightly slower E.T. No matter what, don’t get too caught up in reaction time figures, as they have no bearing on E.T. One area where shallow staging really shines for amateur drag racers is if they’ve been leaving too early (i.e. red-lighting).
Assuming you’ve already locked the transfer case in 4-Hi (where applicable) and driven past or around the burnout box, begin creeping up to the starting line. You’ll want to do this slowly so as not to trip both the pre-staged and staged beams too quickly. Before tripping the first beam, start building boost by power braking the truck (brake pedal to the floor, moderate throttle applied). Working the brake and throttle, slowly inch your way into the second beam. Once the staged bulb is lit, the aforementioned three yellow lights will begin illuminating downward toward green in half-second intervals. Leave on the last yellow. Don’t wait until you see green to begin moving.
Staging is the most important part of drag racing, so it’s absolutely vital to know exactly how the Christmas tree works. For newcomers, it’s best to stick with a Sportsman tree (also known as a “full” tree or .500 tree). This is the default style tree that’s run at most test ‘n tunes and entry level type bracket racing classes. On a full tree, each of the three lights above green illuminate for exactly a half-second at a time (hence “.500“).
If you’re looking to get the best E.T. possible (say you’ve been 13.00 in the quarter and you want to try to squeak into the 12’s), shallow staging is the best way to do it, and luckily this is the most common form of staging on a Sportsman tree. When you shallow stage, you trip the “pre-staged” beam (illuminating the top-most amber) and stop as soon as you trip the second, “staged” beam (the second light from the top of the tree). By slowly inching into the second beam and barely lighting that second light, you give yourself precious extra inches (7 or 8) of travel before the E.T. timer begins. In a way, shallow staging offers you a head-start. This rolling head-start can be fairly significant if you’re running large tires.
The inspections don’t end at home. As you arrive at the racing venue, expect to wait in line for a tech inspection to be conducted by one of the track’s officials. Often nothing more than a quick once-over to make sure your vehicle is safe to send down the track, the inspection can entail a visual check for fluid leaks, nails in tires, cracks in the windshield, and confirmation that the batteries are properly secured. And just as you had to sign a waiver to race, you’ll likely have to fill out a tech card and jot down your John Hancock once more before they break out the shoe polish and assign you a number.
It’s true that dropping weight is the same as adding horsepower. Think about it, if you reduce the amount of mass you need to get moving (and keep moving) you can lower your elapsed time—and you can do it for free! Simple things like removing the spare tire, losing the tailgate, pulling the drop-in bed liner, leaving all of your tools behind, and even showing up on a quarter tank of fuel all play into your favor.
How quick you can get staged or how well you can build boost on the line for an effective launch is dependent on a lot of things. The size of your turbocharger(s), what horsepower level you’re at, and the stall speed of your torque converter are just a few of the variables that play into it. For example, a looser (higher stall speed) converter will allow you to build more boost than one with a tighter stall speed. So if you’ve added a bunch of fuel and a big single turbo but are still running a stock stall speed converter, you likely won’t be able to get off the line as quickly as you could with a higher stall.
Even though the weather can be warm at the height of the drag racing season, leave the shorts and sandals at home and wear closed toe shoes and pants when it’s time to climb into the driver seat. This tip is common sense 101, but you’d be surprised how many people show up expecting to race in flip-flops.
If your truck is capable of running 13.99 or faster in the quarter-mile, NHRA guidelines require you to wear a helmet. Helmets should have a SNELL rating of 2010 or 2015 (2010 helmets expire on January 1, 2022). If your truck runs faster than 11.50 in the quarter-mile, you’re probably not new to drag racing, and at this point you know you need a roll bar to legally go down the track.
While courtesy staging (as it’s formally known) isn’t always enforced, it’s always a good idea to practice it no matter what. Courtesy staging means competitors take turns tripping the pre-staged and staged beams. For example: you light your pre-stage, then wait for your opponent to light both the pre-staged and staged beams before you light your staged beam. This way, neither of you is rushed into staging. It’s the fairest way to play.
Leave your A/C off. Given the fact that most novices are racing their daily drivers or work trucks, this can be easy to forget to do, but adding moisture to the track is a big no-no. Also remember to roll up your windows when it’s your turn to stage.
Our last bit of advice is to refrain from hot-lapping your truck. Give things a break between passes and a chance for the engine and transmission to cool down. Even though your transmission temp gauge may not have gotten hot on the first pass, the torque converter still could’ve seen excessive heat, even if only temporarily. Even if you’re not making a ton of power, hot-lapping can take a lot of miles off of your equipment.
If you’re limited to your local, eighth-mile track but want to make an educated guess as to what your truck would run in the quarter, a conversion factor of 1.57 to 1.59 will get you real close. Simply take your eighth-mile elapsed time and multiply it by the aforementioned numbers (ex: an 8.00 eighth-mile equates to a quarter-mile E.T. between 12.56 to 12.72 seconds). If you’re estimating your quarter-mile trap speed, multiply your eighth-mile mph number by 1.25. These conversion factors hold true for most street-driven trucks.
Dynos are fun, but nothing is a better indicator of horsepower than the drag strip. As long as you know the weight of your truck on race day, you can calculate how much power it’s sending to the wheels using the elapsed time and trap speed listed on your time slip. Accurate online horsepower calculators can be found at Wallaceracing.com or Competitiondiesel.com. While both ET and mph can get you a very close ballpark hp number, using trap speed is always the more accurate of the two.
Diesel-only events are fun, but don’t forget that any old test ‘n tune at your local, small-town drag strip offers a great chance to hone your drag racing skills. Plus, it’s an exciting way to mix things up with late-model sports cars, classic muscle cars, and plenty of sleepers.
Whenever possible, data log your passes. Not forgetting to grab your time slip is one thing, but knowing how your engine performed throughout the duration of the run can be extremely beneficial in pointing out a problem, diagnosing that problem, or simply verifying that everything is working as it should. For instance, seeing what rail pressure you were able to sustain, what fuel pressure fell to, or how high your EGT was can be extremely telling.
Test ‘n tune events offer plenty of practice for a novice drag racer, especially on nights when turnout is low. With fewer competitors, you can get a lot more passes in, making adjustments to your driving style or the truck in between, and becoming more comfortable each time down the track.
While unfortunate, leaks, driveline breakage and outright oil-downs do happen from time to time, and when they occur all action on the track comes to a stop. If you suspect anything is drastically wrong during your own journey down the track, our best advice is to pull over to the side of the track immediately. By pulling over as soon as possible, you minimize the damage done to the racing surface and less clean-up will be necessary to get racing back underway.
So you’ve built adequate boost in your staging, cut a good light, and rocketed out of the hole and down the track as quickly as possible— now it’s time to collect your report card. The time slip you collect on the return road leading back to the pits has all the data you need to analyze you and your truck’s performance. The physical act of drag racing is beyond exciting, but this information will tell you where you need to improve, what went wrong, or if your truck is actually making the same horsepower that fancy dyno said you were…