Please do not provide incorrect information as "fact". I know you have had your ear cocked to the Raby Engine Development program, and perhaps the Type 4 Porsche racing community where lots of fast loose information abounds. Some of it is even "useful", but your information must be vetted.Bleyseng wrote:I'd say 5500 rpms in first, second and third as this is where valve float is just starting on a stock type 4.
In reality a stock type4's hp tops out at 4400rpms so that would be the shift point.
"Valve float is starting at 5,500 rpm"? Whose valve spring pressures? If some engine has been beating on valve springs for thousands of miles, sure, a little valve float may occur. But you cannot tell me the factory specified valve spring pressures were giving it up at 5,500 rpm, not when your own 914 has a redline at 5,800.
"In reality, a stock Type 4's hp tops out at 4,400"? Again, the 1700s were peaking at 4,800 rpm, the 1700 Porsche and 411s were peaking at 4,900 rpm. The 2.0 engines were at 4,200-4,300 rpm.
What is the published stock hp/RPM of the Porsche 914 2.0?
Please do not make sweeping generalizations that blanket over the factory specifications published the world over. Many engines have exceeded the factory specs, because of the politics of output versus taxes! So Mercedes has been under-reporting output since Germany taxes based on output, while the phallically challenged Chrysler boys were over-reporting the Hemi's output, and Ford and GM were d**ksizing the musclecar hp readings right off the theoretical numbers! That is why we had to standardize in 1973 with the SAE net ratings off the flywheel with all ancillaries bolted up.
In reality, I have only run across a few Type 4 engines that were anywhere tuned well enough to put out the factory horsepower.
Colin