Correcting my original statement based on the newer dyno to make it less "Troll-y".



See torque drop after 4000?

Torque comes from high average cylinder pressure. (MEP, or mean effective pressure- google it)
MEP, or high cylinder pressure comes from cylinder filling.

Torque is dropping after 4000 RPM - look at the graph.
Clearly, the induction system (cam included) cannot feed cylinders with enough air per stroke after 4000 rpm. The farther you go over 4000, the bigger the deficit becomes.

Math aside, theory aside, circle track racing aside, look at the data from the test. It shows not enough air per combustion event at high RPM.

Lou is achieving excellent results at his racetrack because his engine is relatively efficient down at 3500-4000 RPM, where it's needed for his track.

P.S. Will's math is correct.

quote Originally posted by KurtAKX: P.S. Will's math is correct.

Correct? Yes.

Complete? Accurate? No. The next step in "modeling" the port flow would be to integrate the actual airflow vs. lift curve over the valve event, scaled to actual pressure difference across the port.

However, my rough math was only to show that Lou's 60 CFM estimate to fill the cylinder to 100% VE was far too low, and in fact neither head would do the job.

I only meant you were making the point that the intake valve isn't open 720 degrees of crankshaft rotation- a point that he wasn't readily connecting when saying that the cfm of the heads in the steady-state fully-open condition was sufficient to meet the needs of the engine.

quote Originally posted by Will: Correct? Yes. Complete? Accurate? No. The next step in "modeling" the port flow would be to integrate the actual airflow vs. lift curve over the valve event, scaled to actual pressure difference across the port. However, my rough math was only to show that Lou's 60 CFM estimate to fill the cylinder to 100% VE was far too low, and in fact neither head would do the job.

quote Originally posted by lou_dias: Everything I've posted so far...

Who gives a **** , it's still a 6 banger with slightly over 200 horses.

Kevin

quote Originally posted by KurtAKX: I only meant you were making the point that the intake valve isn't open 720 degrees of crankshaft rotation- a point that he wasn't readily connecting when saying that the cfm of the heads in the steady-state fully-open condition was sufficient to meet the needs of the engine.

Yep.

quote Originally posted by Will: Take a look at the Nissan VQ35DE engine for what qualifies as good VE by modern standards. It's a port injected engine that makes over 300 HP from 3.5 litres in a fully streetable, emissions compliant, pump gas burning state of tune. At 280 ftlbs, it makes WAY more specific torque than the L98 TPI. So that's what a 3.5 litre engine with GOOD heads can do.

Are these SAE verified numbers? Let's not forget that the Camry and Civic Si lost 11hp and 3hp respectively when SAE tested them while the Z06 and STS-V picked up 5hp and 29hp respectively. Careful with horsepower claims form Asian automakers.

Also, there are twenty more years of technology in that Nissan motor.

Those changes happened when SAE updated the standard for measuring horsepower. The older standard had "wiggle room" in certain aspects of the test configuration. Honda and Toyota were taking advantage of this wiggle room, but were testing according to the previous standard and *WERE COMPLIANT* with that standard. They were NOT lying.

The newer standard removes the wiggle room and improves the accuracy of the test. That's all.

My point is EXACTLY that there are 20 more years of technology in the Nissan engine... And there are close to 20 more years of technology in the 3500 heads than in the iron heads.

quote Originally posted by Will: My point is EXACTLY that there are 20 more years of technology in the Nissan engine... And there are close to 20 more years of technology in the 3500 heads than in the iron heads.

Fair enough. Sometimes I miss a persons intent when I can't hear the tone in their voice.