robk

iTrader: (22)

The bodies are all pretty much shoeboxes. Run what you like :-)

k_bojar

iTrader: (30)

woody almost lost his head in one rollover

didn't notice the lights issue - but originally that was all lit up and with lights all over, but he pulled them when he found out no concourse

Meradin

iTrader: (19)

+ YouTube Video

Here is a vid of the A-main of our Friday night races. VTA has quickly become the class to race at our track. We typically have enough cars every Friday to fill an A, B, C and D main events!

As you can see, it is rather small but we still have a lot of fun. Recently we changed to a RPM limit. Before we had used a FDR limit but due to motor differences there were still cars that could walk away from other cars.

We want this class to be as even as possible and slower than the other classes so we use a RPM measurement on the wheels to make sure each car does not exceed a set RPM limit. We have been doing it for a few weeks and it is working out nicely. The RPM fluctuates with motor temp a bit but not much. The Drivers really like it.

240Z

iTrader: (6)

What tool do you use to measure RPM at the wheel?

jgraham37128

iTrader: (25)

I love the guy screaming hit em Todd, hit em... I thought it was a boxing match not an rc car race.

Meradin

iTrader: (19)

Yeah, we manage to have fun. Some night it's less about the racing and more about giving each other a hard time. It comes down to how "hopped up on mountain dew" we are. That is why I painted my car in the dew scheme.

Meradin

iTrader: (19)

We ordered a bunch of these.

http://www.amazon.com/Digital-Photo-...-2147483554-20

We stick the reflective sticker right on the side wall of the tire. Before each race the cars get tech'd before putting them on the track.

We found that it is best to back the timing down to around 30 degrees and get close to the limit with gearing. Then use timing to fine tune. There are small differences in speed on the track as we are only testing RPM under no load but the racing is a lot closer. Way more fun as well.

muahdib4

So, are you folks not running the spec motors? Is there going to be such a huge difference in each one that you have to do this? The only difference I can see that would make cars slower or faster are gearing, timing and how free things spin in the chassis right? If you are slower, change those things to be faster. Am I missing something here?

jgraham37128

iTrader: (25)

Well it for sure sounded like everyone was having fun and there is for sure the same amount of excitement at our track too. We've been know to have a leader leave the pack and make a mistake and flip his car over we wait on the field to come thru and then set him back down on his tires just to see if he can work his was thru again!

Meradin

iTrader: (19)

Yes, we are all running Ballistic 25.5 motors (one person has the SS). There are differences in every motor and at any other track you can adjust timing and gearing to make up for these differences. Before we did the RPM limit there were some very frustrated racers. Imagine you setup your car perfectly, run a clean line and not touch a single wall but you are still a full second behind the pace.

This actually happened...a lot more than you would think. We did some testing and running clean laps, in the same car we switched motors and the times dropped a full second. Yes, there are surprising differences in motors.

Due to the size of our track and the fact we want a slower class we originally decided to cap the FDR to 6.9. We wanted the class to be noticably slower than a 17.5 class. The trouble is with a 45 degree timing limit and a gearing limit is if you have a slower motor there is nothing you can do. Everyone is gearing their car to the max gearing allowed and cranking their timing to the limit. There is no room for adjustment if you find yourself the slow car.

At other tracks with no gearing limitations you can adjust accordingly to keep pace. Not so at our track. The only thing you could do is buy another motor and hope to get a faster one. This goes against the spirit of the VTA class by forcing racers to buy more gear to keep up. We needed to change something but also keep a limit in place.

I looked at serveral dyno designs and eventually we decided to keep it simple and just tach the wheels. Racers could buy their own tach at a cheap price to tune their cars as needed. The handheld tach works great.

With the new RPM limit racers need not go out an gamble that they are getting a fast motor, they can use the gearing and timing to adjust the cars to meet the rpm requirement. I know we are no where near the limit of these motors and not following the VTA rules exactly but we are having a ton of fun every Friday on out little track.

muahdib4

I've seen handout motor races and the fast guys are always still fast even without having the "fastest" motor. If it works for you guys, that's fantastic and I don't mean to take anything away from what you are doing...but sounds like a lot of work.

Meradin

iTrader: (19)

It was a little bit of work for the racers to find a suitable combination for the gearing. Most people are running very similar setups so it didn't take long to get people close. From there they just tweaked the timing. Didn't take too long at all and was pretty painless.

There will always be guys that setup/drive/maintain better than others and they will be faster. This just gives those that got the shortend of the stick a chance to compete on our track.

There were some pretty skilled drivers who couldn't keep up no matter how they drove and tweaked their cars for speed. Whe you have a slow motor and a limit on options there is only so far ability will take you.

At the handout races drivers can still tune their car with gearing and timing which you couldn't at our track. The fastest cars on the track were at 6.9 and 45 degress timing. If you couldn't match that speed you were getting lapped no matter how you setup your car and drove.

It is working great and no trouble at all. The drivers go to the tech station where they weigh their car and run it up for a speed check.

howardcano

iTrader: (37)

I was wondering which tach you decided to buy. That's pretty inexpensive!

Do the stickers stay on the tires, or do you just put them on temporarily while testing RPM?

Meradin

iTrader: (19)

It only takes a small dot to register on the tach. There is plently of material provided with the tach to last for a while. I have been cutting it in half length wise ans then cutting little squares from that. They measure about 3x3mm. As long as you clean the area first they stick really well and don't come off while racing. A hard hit or wall ride can take them off but that is about it.

I clean the sidewall with some motor spray and then stick them on.Ii am still running with the first sticker I put on and it have been there for 3 weeks of racing.

There are a few things that can throw off the measurement but the biggest is the chrome rims. You just have to make sure that the laser dot doesn't hit the shinny rim. Tire decals can also give a weird reading sometimes. I haven't found a pattern to this yet. Some do...some don't.

For those running tire decals or who are worried about the sticker coming off due to impacts we have been putting the sticker on the inside edge of the tire. Works well there.

anr211

iTrader: (11)

What is your tracks rpm limit, and what fdr are most cars at to obtain this rpm?