Don Terrill’s Speed-Talk

ECL = LSA + (LSA - ICL)

IVC = (Intake duration / 2) - ICL

EVC = (Exhaust duration / 2) - ECL

IVC = Duration - ( IVC + 180))

EVO = Duration - (EVC + 180)

Stan

If these are actual / real lobes then what are their 0.200" duration?

We can calculate average average velocity from 0.006" to 0.050" but that does not mean that the one with the higher average has the higher peak.

Stan

No question we need way more testing. But there is also the question of just how accurate these tests are?

Stan

Work of Los Alamos scientists suggests COVID-19 can turn really bad again much faster than it got better Los Alamos scientists estimated how fast the curve is flattened in 51 countries. They determined that arbitrarily re-opening societies can allow COVID-19 to undo that progress much faster than it...

How does greater valve seat angles which reduces effective curtain area at lower lifts come into play? I believe that this has been talked about before but can not find it. Stan Bill, If you measure the flow / pressure in the port and now have that same flow throw a 50 or 55 degree seat @ .100" val...

hoffman900 wrote: ↑

Wed Apr 29, 2020 10:25 am

My graph from an old thread. Simulated mass flow vs piston position vs valve lift profile.

Bob,
Does EngMod4T show / let you graph cylinder pressure? If so what is your cylinder pressure @ IVC.

Stan

If my intake valve closes @ lets say 80 ABDC. Then the piston has been compressing the air / fuel mixture for 80 degrees. How much above outside BP is the pressure on the back side of the valve to continue to have flow into the cylinder?

Stan

How does greater valve seat angles which reduces effective curtain area at lower lifts come into play?

I believe that this has been talked about before but can not find it.

Stan

What I like to do is look at the intake port flow graphed as a function on the valve lift curve.

Stan

Mike,
I know these are not your lobes. But looking at these lifter raise ATDC and rocker arm ratios I don't see how they could only be .290" ABDC. Are these that different than yours?

Stan

Little Mouse wrote: ↑

Wed Apr 22, 2020 6:41 pm

Thank you lots of useful detail. So it's hard to compare the two on volume as like in velocity.

I do not understand. You should want around the same velocity.

No different that a small valve small port SBC and a big valve big port SBC should want around the same velocity.

Stan

These are from PipeMax / Larry Meaux Int=5.339 Exh=2.818 Int=135.6 Exh=71.58 GM #3890462 SBC out-the-box shape 1.940-1.500 Int=5.975 Exh=3.380 Int=151.8 Exh=85.85 GM 781 BBC cast-iron Good-Port in ported shape Int=5.820 Exh=3.380 Int=147.8 Exh=85.85 GM 781 BBC cast-iron Bad-Port in ported shape Stan

Say in a 3300lb bracket car turbo 350 4k stall 456 gears 10/28 slick? Must run a solid flat tappet any intake or carb. Any racing fuel or E85. about 12/1 comp. :D How fast will 850hp push a 3,300# car ? Take an old SB2 NASCAR Cup engine, and add stroke, to get to 400" You wouldn't even need to chan...

My point being that if the mushroom and bucket diameter is the same they still have the same max velocity limit. I was looking for Mike to join in because I don't know if on the bucket one might be able to use a higher acceleration. Stan Right, they do. I thought this was interesting... Here are so...

My point being that if the mushroom and bucket diameter is the same they still have the same max velocity limit. I was looking for Mike to join in because I don't know if on the bucket one might be able to use a higher acceleration. Stan Right, they do. I thought this was interesting... Generally s...