No Prep? No Prep RC? NPRC? Street Outlaw? Whatever you call it, it's outlaw style street racing, on a no prep surface, with an RC Car and it's hot right now! Locally, we’ve been at it for two years now, but a lot of areas in the nation are just getting started. Scanning the posts on social media, I've noticed many questions keep repeating. It’s a fact, people do not scroll. So, I figured it might be nice to write an article and have some basics in one place. The kinda stuff we tell people in our hobby shop.
Please keep in mind this is relevant right now, as I type (02-01-2020). Things change. Things change very quickly in racing. I may update the article every now and then. Please feel free to e-mail me if something doesn't seem right (e-mail info at the bottom).
Much of this is based on what’s working for us, your area may be different. Please keep in mind that there’s more than one way of doing things. For example, there’s multiple ways of setting up shocks and they can all be fast. Test, Tune, Take Notes. Yep, that’s racing. You’ve got to roll up your sleeves and enjoy making some test hits (with friends is best). Make a few changes, scribble some notes, and test some more. The more you try, the more you will understand what the changes do. The more you understand, the more you will know what a fast set-up is.
That said, here's some basic info on No Prep RC Drag Racing.
The Rules: (as of 02-01-2020)
Short course based chassis, 2wd.
2cell Lipo, 8.44v max.
Body must cover the tires.
Must have 4 shocks, each controlling the stability of a wheel as intended by the MFG. Shocks must have movement. No tie rods or locks downs.
No “assist” receivers or gyros. No TSM or AVC receivers.
No saucing tires with anything that leaves a sticky mark on the ground.
Tires must be dry the time of your race, absolutely no VHT type traction additive.
Chassis: So far, most the racing has been built around Traxxas parts. A Slash or Bandit, with an LCG chassis, is the most cost effective way to get started In No Prep Drag Racing and either is capable of being very competitive. The main difference is the width. Slash is wider and Bandit is narrow. The width is dependent on the body you want to run (see body section). Usually, but not always, wide is easier to get down the track, but narrow can be more aerodynamic.
Pro Tip: There are aftermarket carbon fiber chassis on the market. These will help lighten the car, make the chassis more rigid, and make it look cool. We like the Xtreme Racing chassis set. We also like rear motor set-ups. Out here mid engine just hasn’t shown the speed (yet?).
ESC: Is there black magic in the speedo? Yes, with some companies there is. HobbyWing and Tekin (and a few others) offer more adjustments and tuning options, than let's say Castle does. You can add timing electronically, with ESC settings, essentially making the motor gain Kv (Rpm) during the run. Details are for another article, but let's just say it allows you to run a smaller pinion to get off the line quickly and ramp in a bunch of timing to get the speed needed on the 2nd half of the track. Yes, it can be like hitting the NOS button (only you don’t press a button).
Pro Tip: Lipo cutoff. If you have slight “surges” in power, or even a major stumble that seems to reset if you lift and get back on the throttle, try disabling your LiPo cutoff. Just be aware that you have done this, check your Lipo often and charge as needed.
Bonus Pro Tip: Brakes. No drag brake, brake strength turned down, easy on the brakes. The brake "spike" is really hard on the ESC's ....
Super Bonus Pro Tip: 20 to 40 degrees of Turbo Timing is normal, but depends on other settings. Read those ESC instructions, watch some youtube, ask questions, but BE SURE you understand the settings you’re tuning on. Too much timing is a bad thing…
Battery: 2s lipos charged to 8.44 volts max (checked at the line, before each race). I’m assuming most of you know about batteries basics. You do need a good quality LiPo for drag racing. Even though a pull is only 132feet, we’re trying to do this as quickly as possible. We’re pushing our equipment hard and drawing a lot of current. So, 100c is minimum. Most use at least 5000mah. Keeping the battery topped off during the day is important, as voltage = speed.
Opinion: The jury is still out about the HV packs. Yes, they are legal if only charged to 8.44 volts. But, the ability to easily bend the rules means someone will always question you when they are run and there’s gonna be a doubt in everyone’s mind.
Plugs: Big plugs are a must. 5mm bullet plugs, like XT90’s and EC5’s and Castle plugs are minimum to pass the current needed to go fast. Also, good clean soldering skills are very important. Keep wires short. Check your plugs often, replace as needed.
Motor: Another big discussion that I will keep short. Sensored is fastest. Right now, 4, 4.5, 5 and 5.5 turn motors are the most popular. We sell a ton of Hobbywing stuff and guys are fully competitive with it. Around 30 degrees of endbell time is normal, but depends on the ESC settings. Sensorless products will not keep up when things get serious.
Gearing: Oh man, this is a BIG question and it depends on the motor and ESC settings. At its most basic, high Kv (high RPM) motors need big spur/little pinion, while low Kv (low RPM) motors need a small spur/big pinion. Gearing, motor timing, esc settings all need to be adjusted together to get the best performance. Test, Tune, Take notes.
Pro Tip: Kv is a way of rating the RPM of a motor. Kv = Motor RPM per volt, unloaded. So, higher Kv means higher RPM.
Bonus Pro Tip: On a 4.5 motor and an ESC with some turbo dialed in, start with a 90 spur and 19 or 20 pinion. While a Traxxas VXL system would need something like a 76/28.
Super Bonus Pro Tip: When changing to a lower turn, higher Kv motor, or a motor that might pull more current, be sure to drop a few teeth on the pinion gear and detune your esc settings a little, then work your way back up.
Diff: Traxxas transmissions come with a geared, open diff, with grease installed. This is great to make a few test runs on and get your basics sorted out. You’ll want to thicken that grease, or replace the diff with a sealed one (Hot Racing makes one) so you can tune with diff fluids. Most fast guys in our area replace the whole Trani with the Pro-Line Slash Trani. Same idea here, it allows tuning with diff fluids.
Pro Tip: Diff fluids come from 1/8th scale off-road. It’s like super thick shock oil. Comes in many different weights and allows consistent tuning and rebuilds. Try somewhere between 25k and 100k.
Bonus Pro Tip: Locked diffs are seldom used. Locked in the rear is really hard to drive on a no prep surface. Thick oil will give you a similar feel, but still allow some diff action.
Tires: At the moment, Pro-Line Hoosiers seem to be most popular. MC compound being the go to. JConcepts Hotties are a good choice as well. Belted versions have not caught on yet, but seem like they might be a hot weather tire. Either Pro-Line of JConcepts make great wheels. Take your time with gluing the tires on the wheels. It’s important to get it right. Beadlock wheels are heavy, still toss the tires and often require some glue.
Suspension: I’m not going to get into suspension too much as it’s one of those things that varies so much from builder to builder (and we’ve seen it all!). Get the chassis low. Make sure the suspension is smooth and the geometry is proper. Some guys like thick shock oil, others thin. You gotta ask some guys in your local area about suspension setting and start testing and tuning. You might try 20 to 40 weight oil in the front, and 40 to 70 in the rear.
Pro tip: Use preload in the rear shocks to get the car to run straight on power. Opinions differ on what to do, so test and tune here. If the car is pulling one way, try adding a ¼” spacer in one side, then the other, note the changes.
Wheelie Bar: It’s a must. 10” bars seem to be best. Carbon fiber is the way. Fine tune the height of the bar, Too high and the wheelie will run the whole track, too low and the car will climb the bar and raise up too high. Tweak the bar left to right to fine tune your launch (test and tune).
Pro Tip: Most bars come with plastic wheels, or bearings. Both will get you by, but getting some rubber tires on there will help soften the hit, help the bar track better and run smoother.
Bonus Pro Tip: Be sure the wheelie bar is mounted securely. The more rigid at the train the better. If the bar can flex around, it will not hold a setting and will not be consistent.
Body: The style is up to you. Yes, Nova’s are super popular. There are only a handful of manufactures making bodies for the No Prep scene. Parma makes all wide bodies. Pro-Line/Protoform offers some narrow and wide. J Concepts offers narrow bodies. Depending on which body you want to run, you will build your chassis width to match. Slash width = wide, Bandit width = narrow.
Pro Tip: Did you know that racecar spelled backwards is racecar?
Wing/spoiler: Almost every car body out there benefits from having a spoiler and side dams added. We are going that fast. Study body photos on your favorite social media pages and see what others are doing. Grab some paper to make templates and some lexan and screws to build your own. There is not a one size fits all as every body is different.
Pro Tip: Study photos of the winning cars, not just random builds. Random builds are great for random ideas to try. Photos of the top guys offer proven set-ups.
Burnout: Develop a routine and stick with it. Yes, it might vary with surface and air temps, but only in the time you burnout. You should have a routine on how you stage the car, from start to finish, that should remain constant to get the most consistent results. And yes, this includes when you are testing.
Attitude: Having a positive attitude goes a long way to actually enjoying any hobby. It's tough in racing, where things can get competitive and “speed secrets” closely guarded. And, the most challenging is social media with all the keyboard cowboys and trolls out there ... But, do your best to enjoy your hobby. Be a positive role model for others. Be helpful and supportive. How do you wanna be remembered? What mark do you want to leave? Are you going to help build it up? Or are you gonna tear it down ... (You do not want to be “that guy” who out dollared everyone, rubbed everyone’s nose in it, and then wondered where the local racing
Pro Tip: Remember what Grandma said “If you don’t have anything nice to say, don’t say anything at all …”
Bonus Pro Tip: Remember what Tim Smith said “Aw, Come On MAN! We’re just trying to have FUN!”
If you made it this far, thank you so much for reading! It was just gonna be a short article, but kept growing. If you have any input, suggestions, and such, please email me at: [email protected]
PS: Our shop has been enjoying the No Prep Drag scene since the beginning. We’ve literally helped a ton of people get into the fun, locally and across the nation. Our locals, the 707 Outlaws, Sonoma County NPRC, are some of the fastest in the nation and the whole crew is competitive and quick. We are stoked to be a big part of this.
We are happy to answer questions, and do so all the time. But, there are other great sources of info out on the interweb and on FaceBook. Search Sonoma County NPRC. Search Sonoma County RC Drag Racing. Search Tim Smith TSR Speed Shop. Search Daniel Judd (usually posts on Sonoma County NPRC). Lots of great people out there, doing great things for the NPRC community …