It would be really nice if you put in the Comments above, what your Testing, like Rotax 125cc, the Bore & Stroke & CR and Carb Size used, what the Factory Stock Rated hp@rpm is, and then what you really got for hp@rpm on your Dyno. Can you break it down to 100rpm or 250rpm Increments? Ideally, on a Perfect 2 Stroke Engine running 11.5cr, proper Size Carb with a Good Tuned Pipe for a Sled or Ultralight it takes 7cc to make 1hp. So a 125cc/7cc = 17.8hp@6500rpm. Also, a Material List and a Basic Schematic of the Dyno. Like what is the Max HP you can Test with it? Maybe put some web Links to the Parts you used. A 460 Honda/Clone 4 Stroke Single upgraded Dynoed 37.37@5000rpm, and Singles go up to around 676cc today. Like I'm more into Old Skidoo/Rotax 2 Stroke Singles for Snowmobiles (7000rpm) and Ultralight Airplanes (6500rpm). Most of these Engines only used a Can Muffler, so lots of hp to be found with a Good Tuned Pipe, a Bigger Carb, a Higher CR, and Porting. You have a 250, 292, 277F, 299/300, 318/320, 335/340 and the 277UL engine. On Sleds, you had the Standard Engines, the TNT Engines, and the Blizzard Free Air Engines. The 340 Blizzard was the Highest hp Single, Stock was 36hp. USA Part 103 Ultralights only need 25hp to 40hp Max. The Empty Weight of the Plane can only be Max 254 lbs. The 277UL was probably used on 85% of the Ultralights made in the World, rated 28hp@6400rpm with a Muffler.
Looks like an iame. Problem with dynos and motors is what's sitting in the seat. The variables go up exponentially. A moter that rips at the top end does not always equate to the best lap time depending on the driver. If I could dyno the driver the motor would be easy.
It’s an IAME X30. 125cc reed. 54mm x 54mm 27mm carb Venturi, pump diaphragm carb. Factory claimed 30HP. It’s a single gear class where the engine has to pull from as low as 8500 to 16000 so peak power is not a high figure.
A Polini Thor 250, 36hp@7500rpm is very similar to your Cart Engine, they just put a Belt/Gear Drive on it for Airplane use. www.polinithor.com/en/polini-thor-250-thor-250-ds-2/
Im just curious if you feel you can trust the O2 readings on a two-stroke knowing the scavenging cycle puts oxygen into the exhaust?
It’s a valid tool as long as you look at the relative values vs absolutes. It works well to help you find what works well for
a given engine setup.
It would be really nice if you put in the Comments above, what your Testing, like Rotax 125cc, the Bore & Stroke & CR and Carb Size used, what the Factory Stock Rated hp@rpm is, and then what you really got for hp@rpm on your Dyno. Can you break it down to 100rpm or 250rpm Increments? Ideally, on a Perfect 2 Stroke Engine running 11.5cr, proper Size Carb with a Good Tuned Pipe for a Sled or Ultralight it takes 7cc to make 1hp. So a 125cc/7cc = 17.8hp@6500rpm. Also, a Material List and a Basic Schematic of the Dyno. Like what is the Max HP you can Test with it? Maybe put some web Links to the Parts you used. A 460 Honda/Clone 4 Stroke Single upgraded Dynoed 37.37@5000rpm, and Singles go up to around 676cc today. Like I'm more into Old Skidoo/Rotax 2 Stroke Singles for Snowmobiles (7000rpm) and Ultralight Airplanes (6500rpm). Most of these Engines only used a Can Muffler, so lots of hp to be found with a Good Tuned Pipe, a Bigger Carb, a Higher CR, and Porting. You have a 250, 292, 277F, 299/300, 318/320, 335/340 and the 277UL engine. On Sleds, you had the Standard Engines, the TNT Engines, and the Blizzard Free Air Engines. The 340 Blizzard was the Highest hp Single, Stock was 36hp. USA Part 103 Ultralights only need 25hp to 40hp Max. The Empty Weight of the Plane can only be Max 254 lbs. The 277UL was probably used on 85% of the Ultralights made in the World, rated 28hp@6400rpm with a Muffler.
Looks like an iame. Problem with dynos and motors is what's sitting in the seat. The variables go up exponentially. A moter that rips at the top end does not always equate to the best lap time depending on the driver. If I could dyno the driver the motor would be easy.
It’s an IAME X30. 125cc reed. 54mm x 54mm 27mm carb Venturi, pump diaphragm carb. Factory claimed 30HP.
It’s a single gear class where the engine has to pull from as low as 8500 to 16000 so peak power is not a high figure.
No fan on the radiator 🤔
Hey James,
You are right, a portable fan is added in later tests.
A Polini Thor 250, 36hp@7500rpm is very similar to your Cart Engine, they just put a Belt/Gear Drive on it for Airplane use. www.polinithor.com/en/polini-thor-250-thor-250-ds-2/