Dyno Test: Trinity P-94

Changing modified racing forever?


Trinity claimed, "We will change modified racing forever!" Its splashy teaser ads for the new P-94 mod motor grabbed everyone's attention; what was the story with this motor? People even folded the ad in half like an Al Jaffee Mad fold-in to see whether there were any clues hidden in its ambiguous "radiation" logo. Surely, the new motor would be a radical departure from the mod motors with which we're all familiar—right? Not so—at least, at first glance.

The P-94 doesn't jump out as a motor that will "change modified racing forever," but when you take a closer look at the details and, as we did, strap one into a dyno, we think you'll agree that it just might be the next step in motor evolution that Trinity promised.

P-94 Features
• Larger brush face designed for optimum contact with commutator.
• Extra set of proprietary brushes included.
• Pattern-wound "featuring Jim Dieter's favorite winds."
• Stronger FB9 magnets.
• Silver-soldered comm tabs.

According to Trinity's team drivers, a 12-turn P-94 feels like a standard-brush 10-turn motor, so I decided to compare my 12-turn test P-94 with an 11-turn D4.

The number that most people look at is power in watts. "Power" in electric motors is like horsepower in a nitro engine: more is better. The P-94 clocks in with a more than healthy 239.4 watts of power compared with the D4's 233.6 watts. Torque is rated at 128.8 Newton millimeters with a very good efficiency rating of 82.5 percent, compared with 121.5 Nmm and 80.3 percent for the 11-turn D4.

What you can't see on the dyno is something Trinity claims is one of the big advantages of the P-94—less need to rebuild. Because of the brushes' larger contact patch, there is less pressure on the comm per square millimeter, and the larger brushes reduce harmful arcing. Trinity says the team drivers have been testing the new brushes for months and have found that the comm requires less maintenance. That's a big bonus for racers who don't have a comm lathe or simply don't want to cut the brushes after every other run.

To test Trinity's claims, I tore down the P-94 that we ran in the Team Losi Matt Francis Edition Triple-XT (reviewed in the January 2002 issue). Sure enough, the comm was far cleaner than I expected after the number of packs that the motor went through.


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Test results
Peak rpm
Peak power (watts)
Peak torque (Nmm)
Peak efficiency (%)
Test-setup specs
Comm diameter
12 double
Purple (stock)
22 degrees


The P-94's main feature is its brush size: they're larger. Oversize brushes aren't new, but Trinity's engineers say they've found the ideal size—larger than the current standard but smaller than the oversize brushes tried in the past; it measures 4.45x5mm (width x height); the old brush measures 5x5mm. The new brush is also designed to reduce "cogging," which Trinity defines as "dead spots in the commutating cycle when one of the three poles is not energized"; Trinity claims this is most pronounced in standard brush systems. Moving to a wider brush reduces the likelihood of cogging, but if a brush is too wide (as Trinity says the 5mm brushes are), the brushes will short one of the commutator's poles—not good. Either scenario will reduce efficiency and power, but with a 4.45mm brush, the cogging effect is eliminated, but there is no shorting, and that means maximum power and efficiency—if you believe Trinity's engineers. The dyno tells the real story. The brushes are the big story, but the P-94 isn't just the D4 with new brushes. Trinity dropped in FB9 magnets, which are claimed to be the strongest TDK has produced. The P-94 has silver-soldered comm tabs, layered winds and vented cans for higher turn motors to increase rpm.

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It's easy to suffer from big-brush envy; after all, they're bigger, deliver more power and last longer. But there's no need to be envious; even if you can't afford a hand-wound P-94, you can still enjoy the benefits of big brushes by getting a P-94 brush conversion kit (item no. RC4410; $12.99). It fits all Epic can-based motors, and it delivers all the advantages the brushes offer on the top-of-the-line P-94 series. I tested the kit on an otherwise stock Zircon (9-double) Speed Gem motor to see just how much performance there is to be gained.

When I compared the data, my first reaction was "holy crap!" I really didn't expect such a difference in performance just by installing the P-94 brush conversion, but the dyno shows a staggering jump in power from 196 watts to 230.2 watts. For you math-impaired folks, that's a 34.2W jump, or a 16.5 percent increase in power. There were also gains in torque and efficiency; the big brushes work.

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Does the P-94 "change modified racing forever"? Although it does not represent the dramatic leap with never-before-seen motor technology that some were expecting, the P-94 is nonetheless a major advance in brushed motor performance. The new brushes increase power and efficiency significantly and extend the time between rebuilds. It's amazing what a few millimeters can do.

SOURCE GUIDE: Trinity Products Inc., (732) 635-1600; http://www.teamtrinity.com/.