What kind of realistic horsepower can i expect if I build a VH or VK?

[defrag010]

Paper figures like curtain area are dependant on alot of things including port area, port shape, chamber size and shape, among other things.

If you want to find some realistic numbers for flow based on "curtain area" and n/a power, take a look at ford 4.6 dohc motors, especially ones with B heads. They have Very similar siamese ports and valve sizes/angles as the siamese port VH45. Their intake valves are a hair smaller than VH45 in diameter (1.45), and on PAPER, the "curtain area" would limit them to flow less than .400" lift.... but on a flow bench, B head siamese intake ports jump up from [email protected]" to [email protected]". All of the horsepower record setters are all running cams up even above .500" lift with porting and stock valve sizes. The record setters are also making over 400/400 n/a pump as well, so 400/400 on a ~4.5L engine isn't something you have to use boost to get.

so, don't base valve lift on just the paper number of "curtain area" based on valve size.

[Q45tech]

Because a standard flow bench cannot simulate the reflected pressure wave which may momentarily [over 10-15 degrees of rotation] exceed 4-6 psi [above the normal 13.7 psi] at the intake valve..the total mass will be greater than flow bench additions [summations] at all lifts.

This M3 site has some interesting results from modifying an already tuned engine. Flow bench data seems to indicate that greater gains are possible from increasing inhead port area [porting and polishing].http://www.metricmechanic.com/pdfs/M3_Engine.pdf

[T45]

That is one hell of a 10,000th post!

[tmorgan4]

It was 9,999 earlier.

Too bad I don't understand a single thing he said.