Piper Tomahawk 125HP upgrade. Any difference in performance?


Pre-takeoff checklist
Jun 24, 2017
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Just curious, those of you who own or have flown the 125 HP engine Tomahawk. Did you see any increase in performance? more specifically the climb rate. I don't except any changes in cruise speed but for the climb out on hot/humid days, did the extra horse power make a difference? thanks.
There aren't many around, and I haven't flown one, but on a 1670 lb gross weight airplane, the additional 13 hp should give you ~205 fpm assuming an 80% efficient prop. That's a pretty big improvement. The calculation is 33,000 lbft/min/hp x 13 hp x 80%/1670 lbs.
Could you please extrapolate your equation?
Thank you

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FYI if you want one, you will have to buy an plane with it installed already, at least for the forseeable future. The STC owner, Ken Blackman, passed away on May 27. His son Grant is trying to figure out how to get his STC’s transferred to his name. Don’t know if he intends to continue offering the STC or sell it off, but in the meantime he’s fired the business’s only remaining employee, who used to do all the fab work for the baffles and oil cooler. I understand he’s had the business’s phone line disconnected as well.
I occasionally fly a 125hp Tomahawk here in New Zealand. I have over 500 hours on the standard 112hp T2 model. Most noticeable is the increased rate of climb, attaining typically another 200fpm (i.e 500fpm total) at mauw from my local field (110ft amsl). Also IAS @2400rpm cruise is up from 95kn to 100kn. Fuel 25 litres/hr (6.6USG/hr). On the downside, exaggerated yaw on reducing power can induce significant roll that isn't so noticeable with the 112hp model. Overall I much prefer the extra hp of this conversion.
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You could have trouble finding one. The people that have them like them and seem to keep them.
I'm currently giving instruction in one that a student pilot purchased. It performs much better than say a Cessna 150. It's been over 30 years since I instructed in an original one so a bit hard for me to compare. We took off today at gross weight & it took no time to climb to 4,500'. We were operating out of a field with a density altitude of 3,000 (field elevation is 644"). I quite like it.

Our ground speed according to the GPS was around 103 Knts. No wind.