BAM Motorsports

lets look at the formula use to find max amp draw

constant amp draw ( lets use a 1/10 130Amp esc) multiplied by 8 for burst amps then multiply the total by the percentage of acceleration given

giving (130amps x8 "burst current ampiflyer or instant load draw")x150% "the maxium throatle position of the Spectrum dx3s"= 1560Amp Maxuim draw

this does not take into count the turbo or boost timer in the esc's today



we use this formula in my job on a regular basis

Bradley Matheson

cannon

iTrader: (35)

That is the ESC !!! We are talking about Spec motors. Show me where a 17.5 or 21.5 motor draws 2000amps

BAM Motorsports

6mm wiring will fail at 3000 amps at 7.4v if you gear the car up as tall as you can ( means running the motor at temps up to 170 deg C will melt the wiring as i said a lot depends on the load on the motor

cannon

iTrader: (35)

We are talking about spec class motors. What dont you get?

CraigM

iTrader: (34)

I don't claim to know what the answer is, but as a 10.5 racer the relevance of the class is starting to get a bit lost. The fastest 10.5 guys would now be midfield in the mod amain at most events, so it makes sense to amalgamate the class with modified. 17.5 is now about as fast as 10.5 was before the latest gen speedos so it makes sense that it would become the superstock.

Beyond that I don't have any ideas for stock. I'd be interested to know how a 25.5t motor goes with the current crop of speedos, and if the times are similar to 17.5 a couple years ago. If that's the case then I think we're on the money. People will have choice of brands and scrutineering will be as easy as ever. I'm worried that even 25.5 will be quicker than stock used to be, and I don't think they can fit many more winds in a can.

A bit left field, but what do people think of going 1S lipo?

cannon

iTrader: (35)

Or has anyone thought about LIFE packs ... only 6.6 volts

BAM Motorsports

how hard is it to tell some one that the higher the load on a motor the higher the amps needed to run it. amps are based on the load on the motor. not the way the motor is build

the draw is based on dimond wound 17.5t spec motor

eg a motor in a car with a ratio of 3.0 to 1 will draw twice as much amps as the same motor with a ratio of 6.0 to 1

eg a motor at 6.0 to 1 draws 40amps constance with maxium acceleration amp draw of 480 amps

the same motor at 3.0 to 1 will draw 80 amps constace with a maxuim acceleration amp draw of 960 amps ( will be running very hot at this time)

same motor at 2.0 to 1 will draw 120 amps constant with a maxuim acceleration amp draw of 1440amps ( usually cooking a motor or esc at this point)



a motor that is on low revs being told it to accelerat and it can not, it's called over load usually trying to pullilng more amps than it can get resulting in overheating motor pulling maxium amps from esc and looking for more and a big white cloud around the car and a driver crapping them selves with a pile of melted electronics in the car

Besercoe

iTrader: (9)

Hi Craig

We tried a 25.5 with no timing and it was way too slow, we didnt try 25.5 with timing, but it sounds like a recipe for burning motors.

Re 1S lipo, you will run into radio dramas which require 6v to run properly.
If you look back in the Windsor and Stock thread, i suggested trying LIFE packs which are 6.6v nominal, and are quite readily available in decent capacity now. But everyone who commented complained they would need new chargers (although most lipo chargers do LIFE already), so i personally didnt pursue it any further.

I Still think people are not factoring in the cost of these open systems, an open motor and speedie rule, whether timed or not, will result in the serious guys, purchasing at least half a dozen motors and speedies to find the one they deem fastest.

A Spec system as has been used in mini, covers speed, cost, driveability etc. It is a given solution for Onroad, and i have yet to see a car that can not get to 60mm rollout with the appropriate gearing. People have cmmented that a 67 spur is used, yu can get much lower than 67 spurs.

In Offroad where you are stuck with a min size spur due to the slipper clutch, you might start running into problems attaining the correct gearing. Perhaps offroad should be 17.5 untimed? Either way we have test systems fr those wishing to give it a crack.

fleetmaster

iTrader: (16)

Beat me to it. Get a LI FE ! Lol.

cannon

iTrader: (35)

Very impressive. Beyond me . But what does this have to do with selecting a new Spec class system?

BAM Motorsports

if you can keep a motor cool under tall gear sets there is no reason that 21t or 25 t motors will keep up to a 17.5t might loose a bit on the acceleration

i use to run a speedpassion 540 bl1 motor in a stadum truck and was able to keep up to the mod guys. the biggest thing was heat management keeping the motor cool running very high gear sets it did expire after 2 years at a tempature of 231 deg C (cooling setup came off in a rollover)

just something to think about if dropping the motor class down people might start running there motors hotter and taking a risk, we could even see the introduction of the first 1/10th liquid cooled motor

Senna Racing

iTrader: (2)

Interestingly we were talking about this yesterday
at sma

and we maybe running 10.5 and mod as one
class for future point scores

But I think the class should change in oz

540
sports man 21.5 as my fastest time is 2.5 sec off my best stock
17.5
mod

barts71m

iTrader: (34)

Are 13.5s not readily available anymore??? Then you could run 21.5, 13.5 and mod.

I have run both 21.5 and 17.5 this year and I think at my local track my best lap times for both classes are within .4 of a sec..eg 18.09 to 18.40...21.5 with the advance is a little insane.

ant0276

iTrader: (2)

Maybe an idea a bit out of left field, but if the timing gets fixed, rather than blinking speedies etc as a control, why not just use a CRO to determine phase angle?

the rule could be 24deg advanced (static) like it was with the 27TRB. I.E. motor timing+speedie timing=24 deg +/- say 2.5 deg to account for motors not being put back together accurately.

At major meets, the A main/top 3/top 5 or whatever must have their cars checked.

All you need is a piggy back lead into the hall effect sensors and two probes to measure the pulse across two coil terminals. If it is 24degrees and doesn't move with throttle variation......you're good to go.

It's really not that hard to scrutineer, and old CROs more than capable of doing the job are cheap on ebay. The state sanctioning body such as orrca/aarcmarc/vortec etc just needs one for event scrutineering. At clubbies no ones gonna care. I'm sure there's at least one willing boffin in each state that will not be too busy re-programming firmware to make the LED blink in sequence despite a full throttle timing map in the code

p.s. I'm all for timing controls, as reducing motor winds just exports the problem and introduces dinner plates into the drivetrain. Just need to enforce it, which is not that hard.

jay m

iTrader: (16)

it seems to me that mod drivers just got to drive faster than we can keep 10.5 i dont think its going to be an easy fix either way. Li Fe for stock and ss possible i like the idea