YellowClip

At our local hobbyarena we race this class called ''Slow-Mo''. I am not sure, if this class has any similar classes raced elsewhere. The basic of the class, is that every car is put on a dyno and regulated to drive 20 km/p (12mph). As the cars are slow, we can use bodies that replicate real cars. The A-final upper part races very close and there can't be any mistakes, even though the race is 20 min in lenght. We have found, that the key to victory has been putting a modified gearing on a stock motor and using batteries with low resistance and high mAh and punch. Are there any other ideas, how to make those cars go faster slow?

Roelof

larger tires.

gigaplex

iTrader: (2)

I'd actually go with smaller tires. Less weight so they accelerate quicker, and since the dyno removes the top end advantage of the larger diameter, there's no point in larger ones.

The Captain

iTrader: (6)

Upgraded bearings for less rolling resistance: replace all factory bearings with better ones, may even want to replace the motor bearings as well.
Weight reduction: smaller gauge wiring, removing unnecessary material from chassis/components, aluminum/titanium screws, very minimal coats of paint on body (no decals), swap out ESC/Servo with less performance handling capabilities in exchange for a lighter part, weight relieved gears
Try to reduce drag without compromising handling: No wing, streamlined body, low ride height, less toe out/in

Thats all I've got off the top of my head. I'd be shaving off material (within reason) from the A arms, chassis, body, bumper, etc. It doesn't sound like much, but when you do a bunch of stuff it all adds up.

gigaplex

iTrader: (2)

It wasn't stated, but I'd guess there would be a minimum weight limit, so getting that carried away with weight reduction modifications is probably unnecessary. I'd suggest trying to minimise excessive drivetrain weight rather than static weight.

IndyRC_Racer

iTrader: (9)

Since it is a slow class, you should be able to get away with plastic parts in the diffs/drive-line instead of steel/aluminum if that is an option.

You didn't mention if you are using spec wheels/tires. If this is open, then I would make sure to run durable but as light as possible wheels to help get the car up to speed.

How much battery are you using during your 20 minute race? If it isn't too much, you could even consider running a shorty lipo to help save weight. In my VTA car, I'm only using about 1000-1200 mah during an 8 minute race. A good shorty battery might be able to maintain a good voltage curve for 20 minutes since you aren't going that fast.

To mirror what the previous post said, if you go too far with weight savings you can end up making your car fragile. You don't want to lose a race because a lightened part broke and put you out. For example titanium turnbuckles may be lighter than steel, but are more prone to breaking (at the threads) than steel turnbuckles.

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It sounds like you are running an interesting class that is meant to keep the playing field level. However the reality is that the slower you go the more people will try to find ways to "go faster slowly". Hopefully people keep the spending in check.

YellowClip

The only rules that the class has is, that the car must drive 20km/h on dyno and A-finalists must use replica bodies. There aren't any rules about weight or tires. Most people use regular racing tires, some have dremeld the rim on racing tires and some use foam tires. I am not sure about the battery usage, maybe 1000 mAh.
We can't also use the voltage limiters.

gigaplex

iTrader: (2)

Wow. Those are some interesting rules. What is the aim of the class? It sounds like a recipe for wallet wars.

In that case, use the lightest rim/tire combo you can get. Foams sound like they'd be pretty good, although I don't know how much diameter (and thus speed) they'd lose in a 20min run. Alternatively use narrow rubber tires (22mm or less). Are these cars run on the dyno for every race? At the start or finish? Tire wear would affect the results.

Do the cars have to be 4WD? Might be worth considering a lightweight 2WD TC, such as a Tamiya FF04. Do they even have to be a touring car?

YellowClip

The aim of the class is to help new drivers learn driving and offer very close racing for the experienced ones. In the finals the cars are put on the dyno in the beginning. In qualification, they are put in the end, if car seems faster than others. The roller is free. Most use touring kits, one once tried a 4wd buggy and was quite fast (he modified it quite a lot).

niznai

I think this says something about the different mindsets around the world and why some have such a hard time trying to get people into the hobby. Sounds like some people are waaay too competitive to allow for others to join in.

Well done, the class sounds really good and a brilliant idea.

We have a competition like that here, it's an enduro race. We have three driver teams, each drives for 30 minutes, each team has a 21.5 driver, one stock and one mod driver. Guess what. Driving for that long means it is not speed that wins the race, but reliability and clean driving (and there's plenty to avoid). And it is not rare that the difference between the first and second team is in the tenths of a second. Over 1 hour and a half, that is not too shabby racing, I reckon.

And from experience, the mod car doesn't make that much of a difference in spite of the open, fast track. I was on the team that got second place once and we didn't have a mod driver, but two stock drivers. If the last car wouldn't have broken a wire, we would have probably won. We lost by two seconds after we repaired it and sent it back on the track.

YellowClip

Here is a video about last years final race. The 20 min A-final race starts at 6.00.00 (5.58.00, if you want to see girls dance). This single race had more drivers than stock entries throughout the season (87 drivers).
https://www.youtube.com/watch?v=IruHD2f2UQE

IndyRC_Racer

iTrader: (9)

Thanks for posting a link to the video to show us what kind of racing you are doing. I really like the top speed of the cars as it looks more realistic for the scale of the cars. Unfortunately the launch speed of these cars isn't very realistic. There isn't much penalty for making a mistake as the zero to top speed seems almost instantaneous. If I was making rules for that class I would make the cars heavier/higher minimum weight so it took a little longer for them to accelerate.

For the most part in watching the video, the drivers that were running the best lines were the cars doing the best. I saw a lot of people running very bad lines, which was holding them back more than the handling of their cars.

After watching the video, my best advice for going faster would be to work on setup and driving more than worrying about lightening components or drive-line parts. Best example is to watch the TQ/leader in the green & white car driving the straight. For the most part that car takes a straight line on the straight without wasting energy swerving around the chicane. He also takes better lines through most of the rest of the layout. By running a better line, that car is in effect running a shorter physical distance each lap. Over the length of the race, this will save time & battery.

YellowClip

You are welcome! That race winner, the one with the green-white car, still holds the record for the best result. There have been 10 races after that race, with 11-th this Sunday. I will propose a minimum weight rule for next year, let's say 1500g.
What changes should we do with the cars?

IndyRC_Racer

iTrader: (9)

The catch-22 of chassis weight is too heavy and it can make the motors work too hard/heat up, make the tires wear out quicker, and drain the batteries faster. But a heavier car with weight low on the chassis will feel a bit more planted into the track.

You might consider something like 1450 grams as a minimum weight, which is what the USVTA rules are for their cars. This weight would allow heavier and/or older chassis cars to be more competitive without putting them on a huge weight diet. This would also allow some of the tub chassis cars to be more competitive. However some of the newer chassis might need to add weight.

I would think the goal of a minimum weight in a class such as this would be to discourage people from spending crazy amount of money and/or time on lightened components. However if the bulk of the racers are using lighter cars such as 2wd pan cars (200mm pan cars), then the weight rules may need to be a bit lighter.

cartix

iTrader: (36)

I wish we had a class like this when I was an active racer, brilliant idea.