Seat to intake valve ratio??????
12-27-2001, 05:56 PM
#1
Staging Lane
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Seat to intake valve ratio?????? What kind of seat to intake valve ratios are the <img src="graemlins/gr_hail.gif" border="0" alt="[hail]" /> "Pro Head Porters" <img src="graemlins/gr_hail.gif" border="0" alt="[hail]" /> using? I've heard anything from 89-92%.
I'm just wondering because Im at 90% right now with stock valves. Does the ratio need to change with bigger valves?
Thanks Shawn
I'm just wondering because Im at 90% right now with stock valves. Does the ratio need to change with bigger valves?
Thanks Shawn
12-27-2001, 10:16 PM
#2
Staging Lane
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Re: Seat to intake valve ratio?????? I thought this was ls1TECH!!!!!!!
I guess nobody knows!
[ December 27, 2001: Message edited by: TA2SLOW ]</p>
I guess nobody knows!
[ December 27, 2001: Message edited by: TA2SLOW ]</p>
12-28-2001, 06:58 PM
#3
Re: Seat to intake valve ratio?????? You might not be getting much response because your question is not clear... I think you are asking about the relationship between the diameter of the valve as compared to the inner flowpath diameter at the seat... Correct? Assuming that is your question I will answer it this way...
You need enough diameter on the (intake) valve seat to have at least .060" of valve to seat contact width (more for the exhaust) . Now, assuming that you locate this contact on the outer edge of the valve, and provide an equivalent mating surface at the seat, everything else (in theory) could be removed... Using this information and a little geometry, you could calculate the maximum percentage of throat area relative to the valve size that could be attained... However, you might want to leave some material in the throat to avoid step changes in direction to optomise the airflow. That's where the black magic is worked by the porting guru's... Good luck with your project.
Shirl
PS, BTW, I have ported a lot of heads... SD
You need enough diameter on the (intake) valve seat to have at least .060" of valve to seat contact width (more for the exhaust) . Now, assuming that you locate this contact on the outer edge of the valve, and provide an equivalent mating surface at the seat, everything else (in theory) could be removed... Using this information and a little geometry, you could calculate the maximum percentage of throat area relative to the valve size that could be attained... However, you might want to leave some material in the throat to avoid step changes in direction to optomise the airflow. That's where the black magic is worked by the porting guru's... Good luck with your project.
Shirl
PS, BTW, I have ported a lot of heads... SD
