wayboarder

iTrader: (14)

that is sooooo far off I dont even know where to start.

Ill begin with correcting the wrong statements.

1.timing is not the pulses the motor uses to spin the motor.*

Timing is the placement of the hall sensors in relation to the motor stators. The further away the Hall sensors are from the stator(advanced timing) the earlier that phase will fire. More timing does equal more rpm.

If you retard the timing, it does not give you more punch. but it does give less speed(rpm)

This is brushless. It has a different set of rules then our old brushed counterparts. Brushless operates as a 3 phase AC synchronous motor. But instead of using 3 phase AC it uses three phases of pulse width modulation. If you increased the timing of a brushed motor it decreased torque because the speedo never counteracted the difference between the field and magnets. The brushless does. It increases field current to increase the field made by the stator when the hall sensors are further away. So in saying that, torque is a function of your battery and what the speedo can handle. If unlimited power was available, theoretically it would make an unlimited amount of torque. So in saying this torque has little to do with timing. But it does... If you increase timing on the motor the speedo will see a big difference in current and will increase the amount of current going to the stator creating a stronger field so that the rotor can catch up to the field. This translated to more power all across the board by increasing timing. However, with the increase in timing and the increase in stator current you have an increase in temperature which creates more IsquaredR losses (heat) this decreases the efficiency of the field and lessens the strength of the magnets. So that is where the physical limitations occur.

This advanced motor timing that the current crop of speed controls makes a big change. It allows RPM to be increased way beyond that of a static timed motor. It allows you to gear down to increase the efficiency (less torque required to move the car) and raises your top end by increasing timing and pulls the ceiling off of stock motors.

Now this is where it should change. Ive played around with dynamic timing a lot with mod motors as well as stocks. In stock motors (17.5/13.5/10.5) its absolutely necessary and the motors are mellow enough that the increase in timing isnt a violent increase in power and is very manageable. However mod is a different story. The increase in timing even at low rates on a mod is very unmanageable and makes a very violent throttled car that is a pain to drive even with the traction to use it (high bite clay). Jumping is even harder as a long straight into a jump will kick in timing and make jumps impossible to land as it causes wheelys heading in. the biggest thing though is mid range punch. I had a 13.5 running down a straight just as fast as the 8.5s, but the increase in timing just wasnt enough to get the mid range punch back. Thats why im back to running 8.5 with no timing added, and im no pro or anything but... The factory guys dont run dynamic timing on their mods either.

There are probably a lot of holes in what I just typed because it was hurried , but all this and AC motor theory and what not can be found here....
http://www.usna.edu/EE/ee301/interna...Principles.pdf
or you can call up some of the speedo guys like Shawn Palmer from speed passion. Hes a great guy that is extremely knowledgeable.

Krio

iTrader: (159)

None of the springs are progressive...cutting 2 rings increases the spring rate and nothing more.

No one ever said a 17.5 is now a 10.5, but looking at lap times with the new v203 RS software they a 17.5 is in the range of a 13.5 on a "normal" esc. There is a "perfect" theoretical timing map out there for every motor and max timing has nothing to do with it.

Wild Cherry

Clear a big jump with a 17.5 and that v203 verses a 13.5....


no matter what your lap times with 17.5 will not be the same if you fail to clear...


So my point is a 17.5 will never be as fast as a 13.5 timing & all...

Krio

iTrader: (159)

Ok, let me rephrase then. At our track there is a triple the fastest 17.5 stocks could clear on occasion if they swung rather wide and a 13.5 could clear it by several feet if they wanted to. I now have 5 or more 17.5's I have set up with 203 that are easily clearing it to the same degree a 13.5 could with a gtb or other static timing esc.

rcman1993

iTrader: (33)

I was giving him the basic concept, not the real thing. A phase can be the same thing as a pulse unless you are talking about the details. I didn't think he needed that faint paragraph when I had the concept there. Sorry to rag on you but you dot need to be politically correct on this.

Wild Cherry

Dude , which is faster ?


A 13.5 or 17.5 ?


Which motor will be easier to clear that jump of yours ?

There not the same nor even close are they ?

My point again , a modified power profile will not make up for lack of torque...

UltegraSTI

iTrader: (20)

in onroad it can be done, especially if u can drive and keep ur car wound up. the gap can be closed (til the 13.5 hits the 'pills' too)

but... in offroad, i tried it, it hurts and why? torque yes, but the answer is jumps. yeh i thought it could help in offroad with using a lesser motor, controlling wheelspin but still having snot up on top to go down the straight. well try as i may, i preferred a 'bigger' motor in a more standard profile then all the boostin stuff.

need a mention what happens in 2wd especially when u somehow manage to hit 'boost' in the middle of a jump or launchin off a jump or coming off jump a lil 'slideways' or there's an abscess in the jump that ur wheels come up off the ground and the rpm jumps up? not good, and folks wonder whey their flip or just come down motor 1st at random.

R

wayboarder

iTrader: (14)

you didnt even have the concept right, otherwise I wouldnt have made a post correcting bad information. No need to rag on anyone. \

To shorten everything, if you run a 17.5 or a 13.5 its mandatory that you run a dynamic timing esc anymore . Especially in the hardcore competitive scene onroad, offroad has quite a bit of fudge factor. In off road you have the rogues such as this guy Joe Smalley, who runs a novak gtb and still beats on the pro guys with significantly less motor. Its all in the driver.

Krio

iTrader: (159)

Notes in red

QUOTE=wayboarder;6837947
Timing is the placement of the hall sensors in relation to the motor stators. The further away the Hall sensors are from the stator(advanced timing) the earlier that phase will fire. More timing does equal more rpm.

If you retard the timing, it does not give you more punch. but it does give less speed(rpm)
Less timing DOES give more punch in the form of more torque, but there is an optimum timing for every RPM range of every moto for maximum torque.

This is brushless. It has a different set of rules then our old brushed counterparts. Brushless operates as a 3 phase AC synchronous motor. But instead of using 3 phase AC it uses three phases of pulse width modulation.
It is still 3 phase AC. Pulse width is what is used for "partial" throttle where you are still firing a single phase, but within that phase you are pulsing the power on/off at several thousand kilohertz. The actual power per phase is the sum-average of the power applied during the phase.

If you increased the timing of a brushed motor it decreased torque because the speedo never counteracted the difference between the field and magnets. The brushless does.
Brushless works just like brushed in this regard and each phase is the same length of time in radians no matter what the timing is. You are just changing the angle between the induced magnetic field and the field of the permanent magnet.

It increases field current to increase the field made by the stator when the hall sensors are further away.
The current is increased because there is less "magnetic resistance". Voltage is induced when a magnet moves past a wire. When you apply power to your motor and the rotor is spinning it is inducing voltage in the opposite direction of the voltage applied by the esc on the next phase. This is why a motor can only spin so fast. Once the induced voltage equals the input voltage you cannot spin the motor any faster unless you increase the input voltage or increase the angle (the timing) relative to the magnetic field of the rotor.

So in saying that, torque is a function of your battery and what the speedo can handle. If unlimited power was available, theoretically it would make an unlimited amount of torque.
This is only at absolute zero rpm. Once you are moving the "magnetic resistance" is far greater than the esc or battery resistance and is basically the sole calculation for determining how much current can flow.

So in saying this torque has little to do with timing. But it does... If you increase timing on the motor the speedo will see a big difference in current and will increase the amount of current going to the stator creating a stronger field so that the rotor can catch up to the field.
The current is increased with increased timing, but because you are creating the field at a greater angle from the rotor you can say there is less "leverage" on the rotor. It is a balance between the current and the "slip" angle.

This translated to more power all across the board by increasing timing.
Increased INPUT power, but not necessarily output power.

However, with the increase in timing and the increase in stator current you have an increase in temperature which creates more IsquaredR losses (heat) this decreases the efficiency of the field and lessens the strength of the magnets. So that is where the physical limitations occur.

This advanced motor timing that the current crop of speed controls makes a big change. It allows RPM to be increased way beyond that of a static timed motor. It allows you to gear down to increase the efficiency (less torque required to move the car) and raises your top end by increasing timing and pulls the ceiling off of stock motors.

Now this is where it should change. Ive played around with dynamic timing a lot with mod motors as well as stocks. In stock motors (17.5/13.5/10.5) its absolutely necessary and the motors are mellow enough that the increase in timing isnt a violent increase in power and is very manageable. However mod is a different story. The increase in timing even at low rates on a mod is very unmanageable and makes a very violent throttled car that is a pain to drive even with the traction to use it (high bite clay). Jumping is even harder as a long straight into a jump will kick in timing and make jumps impossible to land as it causes wheelys heading in. the biggest thing though is mid range punch. I had a 13.5 running down a straight just as fast as the 8.5s, but the increase in timing just wasnt enough to get the mid range punch back. Thats why im back to running 8.5 with no timing added, and im no pro or anything but... The factory guys dont run dynamic timing on their mods either.

There are so many of degrees of "dynamic timing" its not even funny. v198 for the RS and v203 are both dynamic timing, but 203 blows the doors off of 198 because you can more accurately apply the correct degree of timing for every rpm. Again, its not about max timing but the correct timing.

Krio

iTrader: (159)

Dude, read my posts please. A 17.5 on DYNAMIC TIMING is very close to a 13.5 on STATIC timing. A 13.5 would also produce more power if it was paired with a dynamic esc, but that is NOT what I was comaring.

wayboarder

iTrader: (14)

Thanks Krio for explaining even further.

Problem is ideally a low timing motor makes more torque. In testing, increasing timing has always yielded a punchier motor, otherwise the manufacturers wouldnt have come out with static timing on there motors at 30 degrees.

Its nice to see someone else has a clue though.

For everyones information sake, all of that information Krio posted can be found in that link i put down.

Davidka

iTrader: (86)

That's not timing either, just the tools used to measure it. If you're going to bash somebody, you'd do well to be correct yourself. Timing is the placement of the electromagnetic pulses relative to the position of the magnet (rotor).

Something everyone has failed to touch on in the timing advance/retard and torque/punch conversation is that if you run a variable timing profile, you don't run the same gearing as you would with a static profile. If you gain RPM at a rate less than you lose torque then the difference is made up in gearing. I've never even seen a variable timing speed control in an off road car but I Have in a 13.5 sedan. NO car with a standard static timing speed control had punch with the timing advance speed control. The static guys were gearing 5:1, the timing guys were gearing 8:1 to 9:1 and the timing profile allowed them to take advantage of it- BIG TIME.

Stock/spec racing dies all over again. Maybe it's a good thing, if stock and or superstock is as fast as mod then it cuts the number of classes in half. This is a big reason why nitro is so popular.

Wild Cherry

I did read, you miss the point ....

IE : Torque

Krio

iTrader: (159)

I'm sorry, but can you please give reasons with logic and not just throw out "your wrong".

fwiw, at zero rpm a 17.5 makes more torque than a 13.5 or even a 6.5 because the magnetic field is more saturated. However, to take advantage of this torque and gain more top end the 17.5 is geared up which reduces the torque output at the wheel. With the new dynamic timing we are dropping all sorts of teeth on our 17.5's and I am actually running my stock sc10 and b4 at or below ratios of others running a 13.5 on static timing. Mathematically speaking I now have more torque then them. Now the dynamic timing effectively adds up to 50% on the KV rating of the motor. A typical 17.5 with static timing runs about 2200kv and a 13.5 is about 3300kv. A dynamic 17.5 will now match or even out rev a static 13.5. This puts a DYNAMIC 17.5 in the league of the old STATIC 13.5.

wayboarder

iTrader: (14)

tomato tomato, if you wanna get into things well call it slip. I wanted to correct the vast original error. no need for corrections, the information I gave is correct. we can keep having a pissing match if ya want...
In our little RC world.

but yes gearing is crucial now with the advanced timing land. No need to gear for temperature. Gear for efficiency. While messing around, and a certain pro driving my car, we started with a Orion 13.5 geared on the b4 30/72 and after a few laps the typical average laptimes were 20.8.

We upped the motor timing and kept the SPX on profile 4. average lap times were 20.7 with a few hero laps.We then decreased motor timing back to the start and upped the SPX to profile 7. 20.5 average. Increased motor timing and all it did from there was get hot and make the back half of the 5 minutes very slow. So we geared down to 28/72, it ran cooler and new lap averages were at 20.4, then went to 26/72 and it got faster around the track and ran even cooler. Increasing motor timing with dynamic timing on yielded no faster times but slower times and a vast increase in temperature. We ended up stopping and got the best laptimes at 26/72 on profile 7. Profile 8's only difference was the motor ran about 15 degrees warmer. These runs were all done with fresh packs/new packs. The typical 13.5 lap times were around 21.5 second laptimes. my best ever with the car was a 21.4 hero lap so lets say this kid is good to knock out the times he did, and with a mod he can run in the 19's on the border of 18's. The car got better and better each time we geared down and only hit a point of diminishing returns when the position of the motor effected the steering on the car.