It's all about the area under the power curve, that matters far more than peak numbers.

Greatness

I've been called crazy for saying a cam wont always do the same thing with boost vs NA. thanks for proving it, and a very good explanation of all the concepts. keep it up :)

Great stuff! I'm assuming you used initial PV curve to define new valve events. Would love to see before and after cam swap combustion chamber PV curves. Any chance?

Great to see and understand the data / actual events happening in the combustion prosess to be able to catch and use the available energy with an average/modern valvetrain. Truly "Secret Squirrel"🐿️

Best class ever.

Best understandable explanation ever thanks

,,,,,,,,,,,,,,,,,,,Thank you Ben Strader for the working man's explanation , and most importantly your easy to understand graph......I have been reading and studying the basic comp cams graph [ just as all the other grinders explain it in their catalogs ] , When they show the flat graph in degree's [ Like you stated ] ,,,They discuss area under the curve,,,,,They show two hoops up and down ; It looks like an alternating current diagram ; anyway , I have drawn it out on paper to try and understand what is going on. Since my beginning in my teen years ; I had bought the Isky book from back in the sixties ; that circular diagram with events shown at between 180 degrees , with overlapping lines within the circle for intake and exhaust events was confusing.... In my later years , I found that ; what was vital to know was when the valves opened and closed ; in their relation to the four cycles , Int. Comp. power. Exh. As many builders write it as ; Exh. Int. Comp. Power. It's easy to see the intake begins to open before TDC , [on the exhaust stoke ] .....Piston then travels down 180 degrees , and comes up on the compression stroke to be fired and then rolls down in the power stroke , whereas at the end near BBDC , the exh. valve opens.........Thanks again..................

Having in-cylinder pressure data is /huge/. Especially if it's still accurate during combustion. If we had a "simple" loss in VE, it would've still lost under boost, but what's actually occurred here is while VE is down, there's also less "air waste" under boost, i.e. fresh intake charge escaping through the exhaust. Same blower speed makes roughly the same airflow (though because the pressure ratio changes, efficiency does as well, but how far do we want to split this hair?), but more of it being used to spin the crank is what made power. I also lean towards the overlap being the problem (and also the problem you identified causing you to change cams in the first place) at low revs with the initial cam, rather than the late IVC event. Too late IVC has the same reversion effect, but it doesn't make 50ft-lb holes in the torque curve like wasting a third of the useful intake event drawing exhaust back in.

great knowledge makes some of us that thought we had a reasonable handle on things , understand ......well yea right...lol

Always good stuff🏁

Don't tell DV and RH... 🤫

Good illustration of the four valve events. Thank you for also showing that LSA is a result of these events, not a goal.

With all the variables have been exhausted on this engine. Tt would be interesting to change to turbo charger and start with the same cam that was optimum for the supercharger, then optimize the engine with the turbo charger, exactly the same way and see the difference in volumetric efficiency’s back pressure versus boost pressure.

Way interesting… Is the cylinder pressure data able to be logged in a real world situation, like on track / road, for a truly relevant data logging, or is this strictly a dynamometer applicable tool?

You may have "reduced" VE, but you increased trapping efficiency and reduced pumping loss (and less dilution). That smaller cam will be a much nicer driver too. Which rpm did you use to drive the new cam design? I don't recall who said it, but a hole in the torque curve isn't just a lack of power. It's a sign that the engine won't pull well. Water brakes don't show that at 300 rpm/s. Stock 2016 Stingrays accelerate at over 1000 rpm/s in first gear.

Pretty cool you can plug into the head to see what's going on. Is there a way you can see that or get an indication of what's going on without installing sensors in the head? That was a pretty drastic move for most people.

If anything what their explaining only solidifies what DV and RH are already saying. You picked the camshaft that you want that's going to produce the horsepower and torque curve that you want for your particular setup. If you want more upper RPM pick a camshaft that gives you more upper RPM you want more torque under the curve pick up cash chef is going to do that.

Was intake temps the same between the different boost levels? I can see how this works on a fixed volume supercharged application but I believe the results would be closer to the NA curve if turbocharged where the boost number is maintained the same.

As Gale Banks has elaborated, you're pumping mass. Cool to see the P-V chart plot out work done during the combustion cycle. You didn't say it, but this illustrates the advantage of variable cam timing, especially if the exhaust and intake are independently clocked.

Maybe increase intake duration and decrease exhaust.

Or Vairiable speed booster or ss it! Sometimes super charged😅

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Like the show but the lake speed dude needs a Xanax! Always overly animated and interrupting!! It's extremely annoying.

Yup, Richard Holdener proved every cam is boost/turbo cam.