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Discussion Starter · #3 · (Edited)
The graph shows the air flow in CFM that can flow into a cylinder when the valve is at a certain postion above it's seat. Our low cams have ~ 7.25 mm (.29 inches) of valve lift. The VV or big cam has 11.2 mm of lift (.44 inches). If you look at the chart first posted, you can see that at the lifts being utilized, the head on our cars does quite well. It starts to lose out to the Honda at extreme valve lifts, but the Honda first has to make up for it's deficit at lower lifts before it pulls ahead of the Toyota head. BTW our heads say Yamaha on them, since they helped Toyota with the design. Power/Torque come from exploding air/fuel mixtures in the engine. Injecting more fuel is easy, it's not the limiting factor. Air is the limiting factor. If you can get more air into the combustion chamber, you can then burn more fuel, hence make more TQ/HP.
 

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Discussion Starter · #12 ·
Well if you guys are into swaps, the 1.8T motored Elises seem to scoot pretty well with their low, mid and high end oompth. Apparently some have about 350-400 HP. It's an iron block lump like most reliable turbo deals.

Of course that engine and the larger K/F Hondas don't rev high anymore...
 

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Discussion Starter · #15 · (Edited)
>>>I would have expected to see some kind of abrupt change in flow as the second cam took over, yet the graph is very smooth, no indication that the valves change lift rather suddenly. Does the flow bench not use the actual cams but somehow manually opens the valves through their range?<<<

The chart shows exactly what it states. But this might not be what folks want to know or are familiar with... If you mentally look at the graph and look at the air flow at the lifts achieved by our cams (0.29 inches and 0.44 inches) you can find that step for which you were looking.

Essentially the graph shows how much air can flow though the intake ports at various valve lifts. Regardless of which cam is used. A valve lift of zero is when the valve is closed. Our first cam opens the valve a maximum of 0.29 inches. Looking at the graph for the closest corresponding lift we find 0.30 inches at which point about 128 CFM of air can flow. This would be a bit less at the actual 0.29 amount, and remember that to get to the maximum you start from zero so we move through that lift range as the valve is opened and then closed. The cam spends relatively little time right at or near the peak opening range.

On the high intake cam the valve is lifted about 0.44 inches at which point the air flow is about 142 CFM. This is less than the Honda head, but we are still ahead net-net. Since while moving toward this maximum lift we traveled through the lower lifts, which allowed more air to enter the engine than the Honda. This is as far as the head itself goes, there are many other factors which affect things such as these. Also, you can't just look at lift, other things like duration matter on a cam. Some cams open valves faster so you spend relatively more time with the valve more open.
 
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