Honda / Acura K20a K24a Engine Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
Hello everyone. What size of intake pipe makes more power? 3 or 3.5 or 4 inch? May be someone has dyno graphs?
Specs:
87:99, cr 13.0:1, k24 head ported, 36*31 valves, bc3 cams, 70mm tb, ported rbc, plm 4-2-1 header, 3 custom exhaust
 

·
Arouse the DAMPFHAMMER!
Joined
·
7,494 Posts
Welcome to K20a.org @zaza!

87:99, cr 13.0:1, k24 head ported, 36*31 valves, bc3 cams, 70mm tb, ported rbc, plm 4-2-1 header, 3 custom exhaust
What valve throat ratio does the intake and exhaust valve seats have? What fuel are you going to run?
 

·
Arouse the DAMPFHAMMER!
Joined
·
7,494 Posts
1 angle of 30° degrees.
Pretty interesting stuff. Only one side of the two intake valves or was it during the seat valve job photographed?

Hint - How does the valve be centered at higher engine speed? The flat angle gives an lower side support when the valve is oscillating and bending at higher engine speed. A good center force helps to set it sealed more quick and reduces the wear in the valve guides. It is likely to loose some torque in the higher engine speeds if it is not centered correctly under higher engine speeds. At lower engine speed it reduces massively the valve seat wear, so it is common for low speed engines like truck Diesel engines, which run 1 million km and more. Beside that, a 30° angle helps to increase the lower lift opened cross section, so it support the scavenging, but reduce flow in the higher valve lift region.

What is the throat diameter, the smallest diameter below (counter flow direction) the 30° valve seat cut? This would help to understand the flow velocity.

Pump fuel 100 octane in Russia. In Usa should be 95
Is that the stuff Gazprom Neft released in 2018 as G-Drive 100 in some areas in Russia? I didn't find a datasheet of it. Do you have one?
 

·
Registered
Joined
·
4 Posts
Discussion Starter #5
Pretty interesting stuff. Only one side of the two intake valves or was it during the seat valve job photographed?

Hint - How does the valve be centered at higher engine speed? The flat angle gives an lower side support when the valve is oscillating and bending at higher engine speed. A good center force helps to set it sealed more quick and reduces the wear in the valve guides. It is likely to loose some torque in the higher engine speeds if it is not centered correctly under higher engine speeds. At lower engine speed it reduces massively the valve seat wear, so it is common for low speed engines like truck Diesel engines, which run 1 million km and more. Beside that, a 30° angle helps to increase the lower lift opened cross section, so it support the scavenging, but reduce flow in the higher valve lift region.

What is the throat diameter, the smallest diameter below (counter flow direction) the 30° valve seat cut? This would help to understand the flow velocity.

Is that the stuff Gazprom Neft released in 2018 as G-Drive 100 in some areas in Russia? I didn't find a datasheet of it. Do you have one?
The photo was made during the process. And i don't know much about how it should be done. Made in engine build service. Just know that it has 1 angle 30°.
As to fuel you are right. Gasprom Neft, Lukoil, Rosneft have such fuel. What kind of datasheet do you whant me to find?
 

Attachments

·
Arouse the DAMPFHAMMER!
Joined
·
7,494 Posts
The photo was made during the process. And i don't know much about how it should be done. Made in engine build service. Just know that it has 1 angle 30°.
Understood. Looks like it has an top cut too. I would be curious if this head was tested on the flow bench what it would flow over the valve lift. With that result I would do engine simulations to find out what would be best as for intake pipe ID. My feeling, which is a result of many different engine tuning and simulation results, says keep a longer 3" pipe ID. Supporting the high end on this engine is not that efficient, but just a feeling.

What kind of datasheet do you whant me to find?
A datasheet of the fuel you have mentioned above.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #7
Understood. Looks like it has an top cut too. I would be curious if this head was tested on the flow bench what it would flow over the valve lift. With that result I would do engine simulations to find out what would be best as for intake pipe ID. My feeling, which is a result of many different engine tuning and simulation results, says keep a longer 3" pipe ID. Supporting the high end on this engine is not that efficient, but just a feeling.

A datasheet of the fuel you have mentioned above.
Research octane number 100.6
Motor octane number 89.3
Density kg/m3 746.9
Mass fraction of oxygen 1.4%
Mass fraction of sulphur mg/kg 4.1
 

Attachments

·
Arouse the DAMPFHAMMER!
Joined
·
7,494 Posts
Research octane number 100.6
Motor octane number 89.3
Density kg/m3 746.9
Mass fraction of oxygen 1.4%
Mass fraction of sulphur mg/kg 4.1
Many thanks, that is an amazing high MON. Here in Germany the highest MON gasoline is 88, even on RON 102 fuels. For high CR engines a pity. Good for your engine. Anyway, the header setup creates incl. the exhaust pressure drop much of the AKI/octane number demand. Also camshafts, as they influence the dynamic CR greatly, will affect this. If I would have the engine data I would be able to calculate the knock likeliness, but this cost me some hours of simulation setup and calculation time.

I made yesterday a simulation of an customer 87x99 engine, adapted a RBC and run 4" vs 3". The 3" helped up top, while the 4" was better in the midrange. As the length of the intake plays a big role in this game, not sure what your intake length will be.

Just know that it has 1 angle 30°.
For my curiousness, could you do a close up picture of one single intake seat so that one clearly can see the valve seat cuts? I would appreciate this.
 
1 - 8 of 8 Posts
Top