# Is a 21.5 a 21.5?



## ScottH (Nov 24, 2005)

I have seen a few posts referring to one 21.5 being better than another.

If the 21.5's are to meet the same specs, and they pass tech. What is it that you guys are seeing that makes one better than the other?

Is it finding the correct rollout?

Will the Novak, Tekin, Trinity/Speedpassion roll out different to be at the top of thier games?

Those of you making the statements that one is better than the other, have you really spend time finding the correct ESC settings and rollout for the "other" motor? Or did it get dropped in the car and tried with the setup that was on the car without making any changes?

Does one have more torque?

Does one have more bottom, middle or top end?

Does one have better efficiency?

Thanks for helping a Nitro guy out. :wave:


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## hankster (Jan 1, 1998)

Yes, yes and yes. It is no different then brushed motors, not all 27t stock brushed motors are created equal either.


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## ScottH (Nov 24, 2005)

Yeah, that is what I was trying to avoid. I know that not even two Novak 21.5's are exactly the same.

I remember and still see, _"You gotta run brand x widgets, if you run brand Y then you are slow"_

What I am trying to find out is this. If you put a N in the car find the rollout and ESC settings, then put in a T and spend the same effort, will you still be just as fast with either one?


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## swtour (Oct 8, 2001)

Scott

How many times did you see/read things like The REEDY MVP STOCK motor is JUNK, and most guys race a TRINITY/EPIC based motor. Then a NATIONAL event would come around, and the STOCK Class would use HANDOUT REEDY MVP motors, and 4-5 cars would SHATTER the track record (that had been set by a TRINITY/EPIC based motor)

I know it always made ME laugh.

I know guys who use to LOVE proving that the socalled 'Crap' motor, could/would run just as fast...it just took a different setup to do it.

If you lock the motors IN with ONE MFG. guys who don't like THAT BRAND will try to find reasons the rules should be open to their favorite motor... Then once THEIR brand is allowed, they will try to tell you about THAT Brands superiority (*REAL or NOT REAL)...but if it IS superior, how does that HELP the racing other than if it's a QUALITY CONTROL issue making it better...not a PERFORMANCE issue!


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## ScottH (Nov 24, 2005)

Joe -- How many times? I do not know of a number that high. That is really my point of the question.


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## swtour (Oct 8, 2001)

Scott, 

I kinda figured...


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## Butters16 (Dec 14, 2002)

But is there guide lines for the motor manufacturers to follow, if brand x uses say 18 ga wire does brand y use the same size wire . i know they are limited to the number of coils. and do the rotors all measure the same size between the brands? 

I know that with brushed motors Roar had set guide lines on the motors wire size and length , Is there similiar rules for the Brushless motors?

And does the inductance readings between brands vary widely? more of a tech question ,since i get stuck doing that at the track.


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## hankster (Jan 1, 1998)

Yes, there are guidelines set by ROAR that all the manufacturers follow. Yes, inductance does vary, the rules are changing to measure resistance instead as inductance is not a very good way to check.... a lot of factors can affect inductance, not just winds and wire size.


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## NovakTwo (Feb 8, 2006)

The wire used in the Spec motors is defined by the ROAR rules, but there is a slight variation allowed in the rotor diameter. The magnetic material used was also not defined. We use very high temp materials in our Vel rotors and a higher temp composite in our Tuning rotors (which are not allowed in spec racing, anyway.)

Defining the wire specs was a bit of an issue. The Chinese manufacturers (and their importers) did not want to use the wire that our motors had been designed to use because it was too expensive for them---they wanted everyone to use cheaper Chinese wire. But our wire ultimately prevailed.

We are now using resistance readings to QC all of our motors, with the readings on labels inside on the wound stators.


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## DOUGHBOY (May 7, 2008)

Will Running The 13mm Touring Rotor In A 21.5 Ss Motor Will It Actually Increase The Performance I.e. Rpm, Torque. Or Will It Just Change The Way It Feels Like It Says On Your Web Site


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## swtour (Oct 8, 2001)

lol DOUGHBOY -- my bet on the 21.5 w/ a 13.0 mm rotor... 

about a 5-7% % drop in LOADED RPM, and an increase in TORQUE (beyond the incredible amount they already produce) 

My guess is that it would take the rated 1800Kv x say 7.4v which under load is probably close to 7500 RPM and drop it to closer to 7200....and cause you to go up about 3 more teeth on the gear.


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## DOUGHBOY (May 7, 2008)

Well I Guess What Your Saying Is That I Actually Need Novak To Make A 11.5 Rotor To Increase Rpm And Drop Torque Lol


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