| aliaZ stated: “The only JWT engineer I consider an authority on anything concerning the VG30DETT is Mike Smith, and he has never cautioned me against removing the spark plug boss. He removes it on most of his builds, FWIW." Just because someone else jumps off a bridge, from your comment, you'd blindly follow?
Not a valid counterpoint. ailiaZ wrote:"No offense, but you're a relative n00b on this site,"
If you had actually read what I posted, and given what I posted some thought before pecking wildly at your keyboard, the fact of how long someone has been on some Internet forum absolutely has no bearing on the data presented.
Again, not a valid argument. ailiaZ wrote:"so it would only benefit your credibility to reveal your references" Again, see above.
I didn't ask permission with the Engineer I spoke with to "reveal" his name on the Internet, Nor will I waste mine and everyone else's time doing so. To even ask is asinine, to ask twice, well, I hate repeating myself... aliaZ wrote:"Otherwise, it is all too easy to conclude that you're talking out of your ass like so many others before you." My HS Football coach explained the word ASSUME on the chalkboard before our first practice. Obviously, you missed that first day of practice... aliaZ wrote: "particularly when you're posting info that is contrary to common belief." First of all, the title of my post was Head Porting OBSERVATIONS. The info that I posted are my observations while testing VG30 heads.
Prior to Christopher Columbus sailing to the "New World", the "common belief" was that the earth was flat. Do you really want to stand on the "common belief"? Again, not a valid counterpoint or argument. aliaZ wrote:"How about some more test data? Pictures of your test setup? Throw us a bone here..." Jesus, I gave the test data, and even presented mathematical evidence to support my observation point.
Did you not finish 6th grade? It’s elementary mathematics for crying out loud! If you insist on someone spoon feeding your ignorant helpless self, here's the "equation":
Valve Diameter X Pi= Valve Circumference
The NOMINAL Intake valve diameter=1.343 inches
Hence: 1.343 X 3.1416 (Pi)=4.2191 inches
1 mm =0.3937 inches
so 1.343+0.3937=1.3824 inches
1.3824 X 3.1416= 4.3429 Inches I also stated that approximately 1/3 of the stock Nominal size valve is shrouded, however with the Oversize valve, more of the valve is shrouded by the chamber. For argument’s sake, let's assume that 45% of the O/S valve is shrouded.
thus: 4.2191 x0.33=1.3923" (Nominal Valve shrouded Dimension)
for the O/S Valve:
4.3429 x 0.45=1.9543"
or 40% more shrouded than the OEM Nominal sized valve. aliaZ wrote:"I do agree, however, that the commonly used 1mm oversized valves can hurt flow in a stock chamber.
However, most people are able to sufficiently de-shroud the chamber to see flow gains" Unless you increase the bore size, and "move" the front and aft edges of the chamber wall, you cannot possibly "de-shroud" the intake and exhaust valves enough to see any flow gain.
I clearly stated in my previous post that "unless you go to 89mm bore..." If you "move" the chamber wall beyond the edge of the cylinder (which would be what is required to de-shroud the O/S valves), then you have created hot spots in an engine that is already prone to detonation.
Additionally, the chambers are only a small portion of the shrouding "problem".
In my previous posts, I presented the data of what happens to the flow when comparing the Bore Sizes (3.5" vs 4.00"), apparently, you missed that. The Cylinder wall is what is shrouding the valves. Which explains to me why Nissan designed the VG30 head with its inherent constraints therein (i.e the Ports were DESIGNED specifically to work that way). If you had done the normal, required simple calculations to port heads properly, the answer would be staring right back in your face. (i.e. CSAs, VTA / VL, Convergent Lift and Port Velocities are just a few).
Combine the above calculations with studying a sectioned VG30 Head, asking the right questions to the right people, and 0ver 29 years of porting cylinder heads, then MAYBE, you could conjure up a reasonable, maybe even valid counterpoint. Until then, why don't you go do to yourself like your obnoxious stupid cartoon does at the end of your pathetic posts.
Bottom line here is however long someone is active on some internet site is not germane to the data that they are presenting. You may want to READ and Digest that info BEFORE blasting your misinformed opinion all over the internet.
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