Don't forget that the exhaust heat is a natural accelerant. So it doesn't act the same way as the intake. In other words, it doesn't hurt to make your throat size a little bigger.
So this throat mod countered the SSR center velocity gain from the last mod , but overall flow was improved , so are we seeing a correlation here between the throat area and the profile of the SSR ?
How did the average airspeed change? I bet you it changed less than half a percent. So weighing up the flow gains vs speed loss, I'd still call it a win overall.
Isnt it just a win at subsonic speeds were unbalanced velocities don't effect density as much ? but at higher velocities , transonic and so forth cant unbalanced velocities and densities turn into turbulence ? it may not be a win if its not relatively balanced , i/m assuming exhaust gases can go supersonic maybe im wrong in that assumption...
@@luckyPiston You are right they can, at very low lifts, because the pressure difference between the chamber and the port is such that you will get a sonic shock at the valve margin right when the valve comes off the seat. At that point, until around .200 lift, it is a supersonic diffuser, after that the valve/seat interface transitions to a subsonic diffuser. In that transition phase is where the most dangerous disturbance to flow occurs, as you correctly pointed out. *I will add, that this happens long before the piston starts it's travel from BDC. **On a four valve it would be closer to .100 lift.
The 90% rule of thumb is just that. It doesn't scale well and assumes that the throat is the minimum cross section in the port. Valve lift, chamber shape, valve size, and the placement of the minimum cross section will all play role, and then it's down to what you're doing with your Valve job.
Thank you Charles! Well done with this port! The audience is happy
@@mikkokuorttinen3113 Stay tuned. I beat it to death. Thanks
Charlie. Thanks for doing all the hard work and time. Not boring we will all learn from it. Very interesting.
Thanks
Short one, NOT Boring! love it! thanks, thats a great looking port
@@robtdougherty Thanks!
Agreed
Yes!
Don't forget that the exhaust heat is a natural accelerant. So it doesn't act the same way as the intake. In other words, it doesn't hurt to make your throat size a little bigger.
@@nw4167 Interesting. Thanks
Not boring at all Charlie
@@theshed8802 Thanks
Looks purdy
@@Patrick-xd8jv Purdy equals fast!
Yes Charlie's Purdy is fast
So this throat mod countered the SSR center velocity gain from the last mod , but overall flow was improved , so are we seeing a correlation here between the throat area and the profile of the SSR ?
@@luckyPiston Possibilty. Thanks
I calculated 1.411" throat which is 88.2%. Just my rule of thumb. What kind of valve job will you do on that?
@@chrisstavro4698 My standard. Thanks
How did the average airspeed change? I bet you it changed less than half a percent. So weighing up the flow gains vs speed loss, I'd still call it a win overall.
Isnt it just a win at subsonic speeds were unbalanced velocities don't effect density as much ? but at higher velocities , transonic and so forth cant unbalanced velocities and densities turn into turbulence ? it may not be a win if its not relatively balanced , i/m assuming exhaust gases can go supersonic maybe im wrong in that assumption...
@@luckyPiston You are right they can, at very low lifts, because the pressure difference between the chamber and the port is such that you will get a sonic shock at the valve margin right when the valve comes off the seat. At that point, until around .200 lift, it is a supersonic diffuser, after that the valve/seat interface transitions to a subsonic diffuser. In that transition phase is where the most dangerous disturbance to flow occurs, as you correctly pointed out.
*I will add, that this happens long before the piston starts it's travel from BDC.
**On a four valve it would be closer to .100 lift.
@@rolandotillit2867 Very interesting
Is there enough meat on the roof to mimick a tpi/lt1 D port?
@@tchapps88 Roof is basically stock.
@@servediocylinderheads i was asking if the roof had enough material to be raised into a D port
@@tchapps88 It is stock thickness now.
5 videos back he did a show n tell on a sliced in 1/2 (193) ex port check it out .
The 90% rule of thumb is just that. It doesn't scale well and assumes that the throat is the minimum cross section in the port. Valve lift, chamber shape, valve size, and the placement of the minimum cross section will all play role, and then it's down to what you're doing with your Valve job.
The radii on the SSR seems to be a significant player too ..