John Wallace2

A few years ago our race series allowed any 25.5 motor in VTA so I tired the SIMCO rotor. At that time I didn't have a way to measure the rotor strength but I did have a dyno and as I recall the SIMCO rotor, besides being more heat resistent it aloso had a slightly higher top end than with the stock rotor at the same timing (45 degrees).

scirocco14

iTrader: (5)

Without knowing the rotor strength data, then it is not possible to attribute the difference to the SmCo material or the rotor strength. If you had two rotors with identical rotor strength, then you would have a valid test.

Mark

John Wallace2

Yep - You would need to do as you say to make the claim as you state it; however, I said only that there was a difference in RPM. At the time, I was more interested in seeing if there was a way that my club could tech for a SMCO rotor without disassembling the motor for our 100% VTA legal races. As my posts back then indicate I was much more preoccupied with the 45 degree limit rule on the BOSS motor and the big differences between 45 degrees of end bell timing and how much timing was being actually being measured (Motorlyzers G-Force etc.).

Wasn't that SMCO rotor marketed several years ago as a RPM tuning rotor?

scirocco14

iTrader: (5)

Not sure about the RPM tuning rotor part.

We just have to be careful with 'conclusions' posted here on RCTech, because the next thing you know it'll be a 'fact' at tracks all over that a SmCo rotor gives more top end.

RoyB

iTrader: (19)

What is the "45 degree limit rule on the BOSS motor"?

mooby64

iTrader: (3)

The 45* timing rule has been eliminated. Set the timing anywhere you like.

John Wallace2

Fair enough. Around here the 25.5 TC class with the Novak motor is getting popular. With the high motor temps in this class (as well as VTA these days), perhaps we should be looking at the SmCo rotors more from of an endurance perspective (i.e., resistenace to heat) than performance, which in my case at least wasn't much at 45 degrees timing.

John Wallace2

Yep it is gone...RIP...you can set the timing at anything you want. Just be careful in using the endbell timing sticker to set your timing because of, as a fellow racer noted, the random nature in which the timing sticker is attached. For example, my first BOSS motor at 45 degrees timing on the endbell sticker was more like 68 degrees on my Motorlyzer. Others that I tested were less than 45 degrees. Today with no timing limit, it is easy to see why some BOSS VTA motors at 45 degrees endbell timing were awesome and some were better used as paper weights. At least now the playing field is more level for everyone.

theproffesor

iTrader: (66)

All this timing talk gives me a headache. It really means very little. There is ZERO reason to crank it to the moon and get high motor temps. I run mine around what on the can is between 35 and 40 degrees. My car accelerates faster than any other at our track and has equal top speed. I'm geared at 3.44 FDR and the motor could run without a fan if I wanted to. With a fan it comes off track around 100/110 temp.

If you are constantly running your motor hot enough that the neo magnet rotor can't handle the heat, you are loosing tons of power through heat in the armature.

The pros do it because they have one run or one race day motors. Burning one up, as long as it doesn't happen during the race means nothing. I bought a motor from company x. Asked then directly what is the suggested timing and gearing for the conditions I had. I went with it. The car was quick, but motor was around 180 with a fan. If had lost the fan, the motor would have smoked. I lowered the timing from 49 to around 35, and geared up a tooth or two. No real noticeable difference in overall power, but motor hovers around 120 with a fan. Now I don't worry about losing the fan. Motor will get hot without it, but I won't lose it.

You have the find the best timimg/gear combo for YOUR motor. It takes time and work to get to this point.

This part is to read on the voice of Yoda.

Excess timing is the path to a slow car
Timing leads to temps
Temps lead to resistance
Resistance leads to weak motor.

John Wallace2

Perhaps your most operative phrase is "finding the best timing/gearing combo for YOUR motor" and I might also add "for YOUR track". However, if as you state, you are using the timing label on the endbell to determine your timing, we can't even have a discussion about timing because your motor's real timing could be as much as 58 to 63 degrees if your timing label is as far off as mine is. My best VTA motor is now going into its 3rd racing season. If timed at real 35 to 40 degrees and with a 3.44 FDR on MY tracks (large flowing asphalt outdoor tracks); MY motor/car would be a VTA pig waiting to be slaughtered. Receently, I ran my VTA motor/car in a 25.5TC configuration (1400 grams) at ~61 degrees real timing (motorlyzer) without a fan (it was broken at the time) and it came off the track at 165F after a 6 minute run and I had plenty of battery left to make a 10 minute main. Hot but not excessively hot acccording to most motor gurus. BTW my lap times were slightly faster than USGT, which surprised me since this is a VTA legal motor and I'm not that great of a driver anymore.

robk

iTrader: (22)

rules update

http://www.usvintagetransam.com/rules/index.html

howardcano

iTrader: (37)

Rob, I want to double-check that USVTA is now at 1450g minimum weight, correct?

Kevin K

iTrader: (32)

You are correct...the 2 big changes are 1450g weight and 6000mah limit on lipos

howardcano

iTrader: (37)

And just to remind myself, the new rules will take effect on 8/1/2016.

Kevin K

iTrader: (32)

Yes...if your local track wants to adopt them early that is a choice your local track will have to make.

The new rules will go into effect when we start the next National Championship Point Series.