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Old 11-01-2014, 07:09 PM   #421
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17.5 TC.. what's the go to for timing and FDR? 48x80 Carpet, technical layouts.

Was playing around with the motor on a Motolyser, found it to be happiest at 50* timing at 4.0v, but at 8.0v can't get a reading past 54* timing without overloading the Motolyser.
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Old 11-01-2014, 08:03 PM   #422
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I believe pretty much everyone runs full timing which should be just short of 60 degrees.

I'd start around a 4.5 final, check temps, gear up and down and so forth.
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Old 11-01-2014, 09:29 PM   #423
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Full timing reads 60 on my motolyser.
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Old 11-02-2014, 11:30 PM   #424
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Wanted to know what a good starting point for gearing a Actinium 17.5 with a 13.0mm rotor?

Thank you,

Patrick
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Old 11-03-2014, 04:01 AM   #425
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two more class TQ and Wins in 17.5 and 13.5 TC -- this time at the 2014 Halloween Classic.
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Old 11-03-2014, 04:52 AM   #426
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Quote:
Originally Posted by XCELL View Post
Wanted to know what a good starting point for gearing a Actinium 17.5 with a 13.0mm rotor?

Thank you,

Patrick
We'd need a little more information - how large is the track, and what chassis is being used?
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Old 11-03-2014, 09:09 AM   #427
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Full timing reads 60 on my motolyser.
I'm getting 58 at the last timing mark (on my 21.5) and it will go a little bit further. One guy ran a Team Powers 21.5 at the zero timing mark with lots of gear and he was as fast in USGT as those of us at max timing and low (numerically big) FDRs. So where is the sweet spot on these motors?
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Old 11-03-2014, 09:29 AM   #428
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Originally Posted by John Wallace2 View Post
I'm getting 58 at the last timing mark (on my 21.5) and it will go a little bit further. One guy ran a Team Powers 21.5 at the zero timing mark with lots of gear and he was as fast in USGT as those of us at max timing and low (numerically big) FDRs. So where is the sweet spot on these motors?
I have found that running the motor at max timing and gearing it accordingly gives the motor the right combination of in-field and allows it to 'wind out' down the second half of the straight, picking up valuable tenths. A fast driver will still be fast with the motor at lower timing and steeper gear, but I doubt it would pull as strong in high-speed sections.

My 17.5 motor at max timing on a Motolyser read 60*, 60*, and 58* on the three sensors. It cogged a bit when it wasn't under load but it was never a problem on the track.

Just my $0.02
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Old 11-03-2014, 12:19 PM   #429
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More timing does not make the motor more powerful. It just moves the powerband higher in the rpm range while losing torque.... I prefer running 30* timing and gear to temp. At least I'll have the necessary torque to deliver the same power....just sayin.....
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Originally Posted by John Wallace2 View Post
I'm getting 58 at the last timing mark (on my 21.5) and it will go a little bit further. One guy ran a Team Powers 21.5 at the zero timing mark with lots of gear and he was as fast in USGT as those of us at max timing and low (numerically big) FDRs. So where is the sweet spot on these motors?
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Old 11-03-2014, 03:47 PM   #430
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We'd need a little more information - how large is the track, and what chassis is being used?
I am not sure of the track size, but it is the Yatabe arena, Tokyo. My guess would be 70 X 50. I have looked at 17.5 set-ups for the BD7 and they are geared 2.6 through 3.0 with 14.0mm rotors. I race an Awesomatix chassis.

Patrick

Last edited by XCELL; 11-03-2014 at 05:57 PM.
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Old 11-03-2014, 04:14 PM   #431
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Quote:
Originally Posted by XCELL View Post
Wanted to know what a good starting point for gearing a Actinium 17.5 with a 13.0mm rotor?

Thank you,

Patrick
Are you running offroad, otherwise I'm curious as to why you want a 13mm rotor??
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Old 11-03-2014, 04:16 PM   #432
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Are you running offroad, otherwise I'm curious as to why you want a 13mm rotor??
He's in Japan and that's how they roll over there.
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Old 11-03-2014, 05:55 PM   #433
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It is for on road, the AOC finals at Yatabe arena. I live in northern Japan right now, but will be moving back to the states next year. The 13.0mm is all I can get my hands on prior to this race. The local guys down there are running 14.0mm rotors in 17.5, but they follow different rules.

Patrick
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Old 11-04-2014, 04:27 AM   #434
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Originally Posted by bertrandsv87 View Post
More timing does not make the motor more powerful. It just moves the powerband higher in the rpm range while losing torque.... I prefer running 30* timing and gear to temp. At least I'll have the necessary torque to deliver the same power....just sayin.....
I'm looking at the dyno runs of my team powers 21.5 motor and as I increased the timing each dyno run from the Zero timing mark to the last advanced timing mark, the RPM at which I get the max power increases just as you say but so does the max power (i.e., more watts with more timing too at least over this range of timing). What is significantly different with increased timing, besides the amp draw, is that while the motor has higher RPMS it accelerate slower often taking more than a second longer to reach those higher max RPMs than with less timing. Which is why I use lower gear ratios when I use max timing; to allow the motor to accelerate faster out of turns to get to those high RPM quicker.
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Old 11-04-2014, 08:49 AM   #435
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Doesn't increased timing also increase the area under the curve? That's a term that people typically use when describing dyno results from full-size engines but I think with the death of boost it may have a real relevance in spec motor dyno results.

At least area under the curve from 5000rpm and up, its not like the car comes to a complete stop in the corners.
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