So when all cars are roughly the same speed, can you still find an advantage somewhere well that’s the question we’re exploring today and hopefully answering it while we take this stock b74.1 buggy and completely rebuild it to be the ultimate stock racer in the modified racing classes? If you want to go faster, you just put in a faster motor in your car, but for stock racers. You can’t do that so for stock racing. If you want an advantage on the track, it’s got got, ta come from somewhere else, and that place is usually with the weight and the rolling resistance of the car with weight. Most cars are heavier than they need to be, so you can trim some of that fat off in a few different ways. Première, you can reduce the weight of the vehicle chassis or the dead weight inside the car. Deuxième, you can reduce the weight of the spinning mechanical drivetrain parts, which ultimately reduces the load on the motor. The result of all this is that the motor doesn’t have to work as hard which ultimately boosts your efficiency and ultimately gives you the feeling that the car has more torque and with more torque in there. Your ability to gear up another tooth on the pinion without causing more heat in the motor may be achievable, but to really maximize this effect and efficiency. We really need to have our drive train as friction free as possible, and we achieve this by using ceramic bearings.
Now we have a four wheel – drive buggy here that we’re using for this video, but all of these principles can be applied to a two wheel: buggy short course: Camions, stadium, trucks and so on now the one thing to consider with weight. When you add a lot or remove a lot from your vehicle is that it will affect the setup on the car which will need to be tweaked later on now with vehicles. We always want a low center of gravity, especially with these high performance machines, so for shedding weight. We recommend that you start at the high points, if possible and then work your way down. Body weight, par exemple,, is often overlooked. If you add a lot of paint, decals or velcro to your body, c'est, probably heavier than it needs to be. Our body, par exemple,, has one color six stickers and small velcro strips weighing in at only 25 Grammes. How much does your body weigh lightweight aftermarket shock, Tours, shock, standoffs and titanium screws in these high areas can be good ways to reduce your weight and center of gravity, some other things to think about a slipper eliminator. If one is available for your car is one of the best ways to drop weight for your drivetrain and it’s highly recommended, as one of those first upgrades to do. Malheureusement, there’s no lockouts available for this particular buggy right now, but there are tons of them for other vehicles.
Now servos are kind of interesting, because a low profile servo will often be about 20 À 30 Grammes, lighter than a standard size servo. That difference may slightly change how the car steers by swapping servos but it’s, actually pretty easy weight to lose with fans. Almost all electric racers out there are using them now, and this aluminum pro tec fan is about 5 Grammes. Heavier than this plastic eco power fan and 5 grams doesn’t seem like a whole lot, Mais 5 grams here and 5 grams there, and it adds up to be quite a bit now with motor weight. I would never choose a motor on its weight alone, but i would for opinion gear. We found the trinity ultra light aluminum gears to be the lightest weight, aluminum pinion gears available, but the jk plastic pinions are the lightest pinions available, but they’re only for stock racing. With lipo batteries i’m sure you guys have seen these new lcg or low center of gravity, packs and they’re about 60 Grammes, lighter than your standard shorty, because they have a reduced capacity and it seems tempting 60 grams is a lot to lose for stock racing very Easily but those lcg packs are not for stock racers, now here’s a graph of two pro tech li hv batteries. The blue line is the full size, 6100 milliamp shorty, and the red line is the 4900 lcg. Both batteries were charged to 8.4 volts and discharged at a constant 35 Ampères.
Our y axis are volts, representing the punch and power of the battery, and the x axis is amp hour or the capacity of the battery. Looking all the way to the right, it’s very obvious, the blue line outlasted the red line in terms of capacity as it should, Mais, most importantly, the blue line stayed at a higher voltage level, the entire time that basically means that the 6100 milliamp battery had more Power and punch in it even at the end of the race, so i guess it can be said that not everything that can help you drop weight is beneficial for you. Now those lcg packs are from modified racers who, when they need to alter their power and speed, they just change the motor hey. Did you know if you hit that subscribe button, vous êtes 33 more likely to tq your next race it’s? True now for specific ways of dropping weight, let’s focus on our car now, which is a four wheel, drive one tenth scale: electric buggy and according to roar rules, our buggy must be at least 1613 grams to be legal. Maintenant, if you live outside the united states or canada, then your rules may differ on the scale. Our car weighed a total of 1743 Grammes, which means we can lose up to 130 grams and still be legal. Soda dropped some weight in our car and to show you the weight difference in the process. We’Re going to install these team associated six millimeter and eight millimeter titanium ball studs in every location, then we’re going to add the team associated cva aluminum cups to the center driveline.
Now we also have these titanium, lower arm stud kits for the front and back we have a full aluminum nut kit, Roue, nut kit and wing buttons, all from 175 rc and since a mains colors are orange and blue. We also have the balstead washer kit just for looks to add more titanium. We have these j concepts, titanium turnbuckles in black. Aussi, we have these protect carbon fiber side guards just to try, although i think those side guards are a bit more of a tuning aid than an item to add for weight savings, but we’ll try them out. Enfin, we have the wits hyper glide ceramic, bearing kit made specifically for this car that, once added should provide exceptional rolling performance. There is no easy way to dive into this and swap all these parts, especially if we’re going to weigh it all. So we start with tearing down the buggy to replace the stock bearings with the ceramic bearings. Interestingly, the stock bearings weighed in over 29 grams when dirty and after being cleaned, weighed down into the 28s for comparison. The ceramic bearing set is the lightest at 27 Grammes. Now this set includes everything but the steering bearings, but that won’t help our drivetrain so that’s. d'accord. The next item are the center drive shaft cva couplers, which are steel in the car and we’re, replacing them with aluminum, which will wear out faster. But as the only item to lighten our drivetrain, we needed them impressively.
The aluminum pieces are only one gram. Each next is an easy weight savings with the aluminum serrated wheel, nuts, which compared to the steel nuts, are less than half the weight. Next are the wing buttons which are not really wing buttons, ils sont, actually titanium motor screws, which we thought we could just use them as wing buttons to get the free, titanium screws and it worked well it fit. I mean because it didn’t work to save us weight. How about the aluminum nut set, Si, because those are pretty lightweight well on the scale? The full steel nut kit included with the car was over six and a half grams, and the aluminum pieces came in at over 2.3 Grammes. Nearly one third of the weight, the titanium lower shock studs, are next and we’re, showing only two, even though we have all four, but do you think they’re lighter than a screw? Bien, it turns out they are next. We turn to the black titanium turnbuckles on the scale the stock turnbuckles weighed in at over 15 Grammes, but with the titanium turbuckles, we dropped that down to only 10 Grammes. As a note, these turnbuckles require a 3.7 millimeter wrench like this one. The last of our titanium upgrades for weight savings are the team associated titanium ball studs on the scale, the stock steel ball, studs weighed in at over 16 Grammes, whereas the shiny titanium pieces came in at a little less than 9 Grammes.
The only thing we have yet to add are the carbon side guards, but in its current upgraded state, rb 74.1 weighs in at 17.05 Grammes, so we’ve dropped about 40 grams or about an ounce and a half with the biggest improvement being. How smooth this drivetrain is, especially when you compare it to before to now wow now full disclosure. These diffs were built with two shims on one side to have tight gear mesh to break in the gears. When we opened up these diffs to change the bearings, we took one of those shims and put it on the other side for a one to one setup, that’s contributing to how well this rolls compared to before. But the bearings are making a dramatic improvement. It feels uh like super freed up when i let off the gas it just rolls and rolls and rolls it seemed like there was a bit more resistance there, Comme. Maybe i had some drag break, but i don’t have any, but it definitely feels like kind of light and a bit more, i don’t know agile that’s. The right word like i feel like down the back straight it’s tacked out pretty quickly, so i think we could definitely gear up out here for this track, it’s weird, because it feels it feels i could just be imagining it like it. It settles and lands just a little bit better. I don’t know why, but sometimes with these cars on this carpet track man, if you land a little wrong it’s disastrous, but it feels just a little bit more forgiving.
I don’t know if i’m just imagining it could be. This is the trinity ultra lightweight pinion, on the left and the ae aluminum on the right. The trinity is two teeth: larger and almost darn near a whole gram lighter and yeah we’re jumping two teeth. The very last thing to do is add our carbon side guards we’re racing on carpet. So these are going to be a great addition for weights. The stock plastic side guards weigh in at 46 grams with the hardware for comparison. The pro tec. Carbon guards are just over 27 Grammes, but we can make that better, using titanium screws and more 175 flanged aluminum nuts. We cut down that weight to 23 and a half grams. If i can do math those carbon side guards are the most significant weight savings item, we’ve added to the car, and we didn’t even get them to save that much weight. I didn’t think it would be that significant over the plastic, but it is in total. Our new final weight is 682 Grammes, C'est 61 Grammes, less than where we started two teeth larger on the pinion and with the addition of ceramic bearings, going two teeth larger up on that pinion is going to work out for us because it’s, cold and wintry here, The challenge will be in the hot summer days: we’ll probably have to gear down for that, but in the meantime, we’ll just be watching our motor temps, big thanks to world champion rc, Racer, spencer rivkin, who helped us out with some ideas and tips for this video.
Like for stock racing, you can put the plastic diff gears in your b74.1 to help lighten them up a little, but you can only do that on dirt using the center differential.