# Please tell me if this figure seems right

• knight92
In summary, the conversation discusses the use of GT Power software to calculate the heat transfer rate of a KTM 450 EXC bike engine. The software gave a value of 54kW, which the person questioning believes is too high compared to the engine's output of 50kW. There is also a discussion about the different places where the heat from combustion can go, including mechanical work, cooling system, and exhaust gas. The conversation also questions the accuracy of the engine's stock horsepower.
knight92
I am using a software called GT Power for a project and it is giving an heat transfer rate value of the gases to cylinder wall of about 54kW. Does this seem about right for an engine to produce? I have been told to use the initial model in the software for a KTM 450 EXC bike engine. The engine itself outputs about 50kW I think, the heat transfer rate of 54kW does not seem right to me. Statistically how much heat is transferred to a cylinder wall during combustion in an engine?

Thank you.

All the heat from burning the fuel has to go somewhere, and the three main places it can go are
(1) Mechanical work done by the engine
(2) Through the cylinder walls into the cooling system
(3) Out of the cylinder and into the tailpipe as hot exhaust gas.

If the efficiency of the engine is less than 50%, then (2) + (3) is greater than (1), so your numbers COULD be right. Whether they ARE right is a different question (and I don't know the answer to that).

knight92 said:
I am using a software called GT Power for a project and it is giving an heat transfer rate value of the gases to cylinder wall of about 54kW. Does this seem about right for an engine to produce? I have been told to use the initial model in the software for a KTM 450 EXC bike engine. The engine itself outputs about 50kW I think, the heat transfer rate of 54kW does not seem right to me. Statistically how much heat is transferred to a cylinder wall during combustion in an engine?

Thank you.

And 67hp sounds a bit high for a 450. Is that really its stock horsepower? My 2003 CRF450 puts out about 50hp.

## 1. Is the figure accurate?

The accuracy of the figure depends on the data and calculations used to create it. It is important to double check all numbers and sources before determining if the figure is accurate.

## 2. How was the figure calculated?

The figure was most likely calculated using a specific formula or equation. It is important to understand the methodology behind the calculation in order to determine if the figure is correct.

## 3. Can you explain the data used to create the figure?

The data used to create the figure should be clearly presented and explained. It is important to understand the source and reliability of the data in order to determine the accuracy of the figure.

## 4. Are there any limitations to the figure?

It is important to acknowledge any limitations or assumptions made when creating the figure. This can include sample size, data gaps, or other factors that may affect the accuracy of the figure.

## 5. How can we verify the figure's accuracy?

The best way to verify the accuracy of a figure is to double check the calculations and data used to create it. This can also involve consulting with other experts in the field or cross-referencing with other reliable sources.

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