Miasma
10+ Year Contributor
- 435
- 48
- Aug 22, 2012
-
Fort McMurray,
AB, Canada
Detailed Engine Stroke
I'm creating this thread for everyone to reference when trying to decide which stroke to build your motor. There are many different options to choose from, each with their own pros and cons. If any mistakes are made, please let me know.
To create horsepower you need acceleration, and when considering how to produce the most effective acceleration there are a few things to consider. (Note this thread is based only on the internal engine geometry, the valve train is an entirely different matter)
To simplify this discussion further, I have consider the bore size of each setup to be 0.02 over ( 4g63 - 85.5mm, and 4g64 - 87mm ), because most performance builds require the block to be bored out. I have also used a mean piston speed of 26.5 meters/sec. This number was determined through additional research, and is considered for performance applications.
I have applied specific deck heights for both 4g63 & 4g64 engines, to allow for proper clearance.
Most of us are not able to afford a Dog Box transmission which is required for really high rpm shifts, so I have based this on the assumption that 9000 would be a great target rpm for a street/track car.
One factor listed above is weight, which effects how quickly rpm will increase, but is not a limiting factor to the engine geometry. I have calculated each strokes rpm limit based on stroke and a mean piston speed of 26.5 m/sec.
Below is a chart I put together to help with choosing your stroke:
When putting this together I referenced magnus' engine detail
I have highlighted setup # 4 because I think this would be the most optimal setup. A 2.2 will still produce enough displacement to increase spool, while not creating to much torque that may lead to transmission failure at high rpm. I also believe this setup has the best r/s compromise out of all the setups.
Make sure to remember that regardless of which stroke you choose, all the basics still apply for both 6 and 7 bolt applications. Build smart, and always plan ahead.
Cheers!
I'm creating this thread for everyone to reference when trying to decide which stroke to build your motor. There are many different options to choose from, each with their own pros and cons. If any mistakes are made, please let me know.
To create horsepower you need acceleration, and when considering how to produce the most effective acceleration there are a few things to consider. (Note this thread is based only on the internal engine geometry, the valve train is an entirely different matter)
- Rod/Stroke Ratio
- Compressor Height
- Deck Height
- Bore Size
- Weight
To simplify this discussion further, I have consider the bore size of each setup to be 0.02 over ( 4g63 - 85.5mm, and 4g64 - 87mm ), because most performance builds require the block to be bored out. I have also used a mean piston speed of 26.5 meters/sec. This number was determined through additional research, and is considered for performance applications.
I have applied specific deck heights for both 4g63 & 4g64 engines, to allow for proper clearance.
Most of us are not able to afford a Dog Box transmission which is required for really high rpm shifts, so I have based this on the assumption that 9000 would be a great target rpm for a street/track car.
One factor listed above is weight, which effects how quickly rpm will increase, but is not a limiting factor to the engine geometry. I have calculated each strokes rpm limit based on stroke and a mean piston speed of 26.5 m/sec.
Below is a chart I put together to help with choosing your stroke:
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When putting this together I referenced magnus' engine detail
I have highlighted setup # 4 because I think this would be the most optimal setup. A 2.2 will still produce enough displacement to increase spool, while not creating to much torque that may lead to transmission failure at high rpm. I also believe this setup has the best r/s compromise out of all the setups.
Make sure to remember that regardless of which stroke you choose, all the basics still apply for both 6 and 7 bolt applications. Build smart, and always plan ahead.
Cheers!
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