Piston design and Ring packages for the Duramax
The Diesel piston design for high performance engines and stock style engine are as far apart as a stock gas piston and all-out lite weight race piston.
Each piston design should reflect the intended use. Some of the factors include RPM intended hp, and whether its a drag race only , or endurance piston IE pulling .
I look at piston bowl design as allowing the fuel the ability to be exposed to as much oxygen as quickly as possible.
The stock bowl piston is designed for just that stock fuel loads. These small bowls keeping that combustion in a small area to burn as much of the small amount of fuel completely for fuel economy and emission.
I have gone to as flat a bow design as practical , and ultra wide angle injectors that put the fuel in a wide of distribution. These flat bowls require considerable less timing. Timing advance in any engine gas or diesel is a crutch. Reducing the need for leading the start of combustion process before TDC will make more power.
The bowl absolutely must be round , don't know where the oval pistons idea came from, but its in not based in combustion dynamics.
In this thread I will go over compression ratio, both static and effective . I run a very high static compression ratio, I also have the intake valve closing event around 40 to 45 degrees After BDC. this means the piston is on its way back up and the intake is still open. The trick is to close this valve when the airflow thru the port stops being effective .
The way I have learned that point is on an engine dyno with a air turbine.
The heads and design on the current stock style heads suck, even when ported. I look at Volumetric efficient of the engine , I keep moving the cam closure event and watch the VE numbers . I was seeing VE numbers at around 52 to 55 % . everything we retarded the cam the VE number would pick up 1 or 2 % .
here are the piston pictures
here was my first venture in to Dmax pistons it was a big pin Dmax . This piston was the second set of pistons for the Mustang . I ventured in to small rings and it loved it
Here is a 19 to 1 2.6 pulling piston I designed the top on for a 6.7 block and a 4.5 destroked Cummins 382 cid motor . This is a Ross piston . It was a 1/16 1/16 3/16 ring package this was about 6 years ago. Notice the o ring in the block . This is part of a system to make the 6.7 big bore hold a head gasket.
here is a JE , its has 1/16 1/16 3/16 rings and used a Polydyn ceramic coating
This pistons was 18 to 1 . I had not started doing lateral gas ports
This is the latest inboard skirt design Diamond. I have continued to push towards this design for a year or so. The inboard skirt facilities the piston being lighter and stronger. I would not use this design in a true street engine.
This is the latest billet pistons on the left and my old JE pistons on the right. Both are the 1.156 Top Fuel pin design
The new Diamond Piston is around 150 grams lighter then to JE . Total was about 400 grams lighter then stock.
The JE piston is before hard anodizing and coating
The JE is 17.2 to 1 the Diamond is 19.5 to 1
The Diesel piston design for high performance engines and stock style engine are as far apart as a stock gas piston and all-out lite weight race piston.
Each piston design should reflect the intended use. Some of the factors include RPM intended hp, and whether its a drag race only , or endurance piston IE pulling .
I look at piston bowl design as allowing the fuel the ability to be exposed to as much oxygen as quickly as possible.
The stock bowl piston is designed for just that stock fuel loads. These small bowls keeping that combustion in a small area to burn as much of the small amount of fuel completely for fuel economy and emission.
I have gone to as flat a bow design as practical , and ultra wide angle injectors that put the fuel in a wide of distribution. These flat bowls require considerable less timing. Timing advance in any engine gas or diesel is a crutch. Reducing the need for leading the start of combustion process before TDC will make more power.
The bowl absolutely must be round , don't know where the oval pistons idea came from, but its in not based in combustion dynamics.
In this thread I will go over compression ratio, both static and effective . I run a very high static compression ratio, I also have the intake valve closing event around 40 to 45 degrees After BDC. this means the piston is on its way back up and the intake is still open. The trick is to close this valve when the airflow thru the port stops being effective .
The way I have learned that point is on an engine dyno with a air turbine.
The heads and design on the current stock style heads suck, even when ported. I look at Volumetric efficient of the engine , I keep moving the cam closure event and watch the VE numbers . I was seeing VE numbers at around 52 to 55 % . everything we retarded the cam the VE number would pick up 1 or 2 % .
here are the piston pictures
here was my first venture in to Dmax pistons it was a big pin Dmax . This piston was the second set of pistons for the Mustang . I ventured in to small rings and it loved it
Here is a 19 to 1 2.6 pulling piston I designed the top on for a 6.7 block and a 4.5 destroked Cummins 382 cid motor . This is a Ross piston . It was a 1/16 1/16 3/16 ring package this was about 6 years ago. Notice the o ring in the block . This is part of a system to make the 6.7 big bore hold a head gasket.
here is a JE , its has 1/16 1/16 3/16 rings and used a Polydyn ceramic coating
This pistons was 18 to 1 . I had not started doing lateral gas ports
This is the latest inboard skirt design Diamond. I have continued to push towards this design for a year or so. The inboard skirt facilities the piston being lighter and stronger. I would not use this design in a true street engine.
This is the latest billet pistons on the left and my old JE pistons on the right. Both are the 1.156 Top Fuel pin design
The new Diamond Piston is around 150 grams lighter then to JE . Total was about 400 grams lighter then stock.
The JE piston is before hard anodizing and coating
The JE is 17.2 to 1 the Diamond is 19.5 to 1
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