Re: Rec port intake on oval port heads?
Well, lets see, just about EVERYONE that has dyno work done ALWAYS has to revise the two parts of the tune up from what the dyno likes, altered higher timing and jetting, to run the engine on the street. If the dyno was such a good tool in TUNING, then, there wouldn't have to be any changes from on the dyno, to off it, to get the engine package right for street driving, now would there! We see posts all the time about why the engine ran perfectly ON the dyno, but wouldn't get out of its own way OFF the dyno. Plain truth of it is, NOBODY has EVER driven a dyno around the block, EVER.
Head flow is another place of great interest, as now, the truth is well known by saavy people that now WET flow the ports in development, not DRY flow them as just about EVERY unknowing head guru still does now. Ask the good folks at DART Engineering how they do it, and they will tell you they WET flow the heads, not dry flow them, gives them a real world picture of the actual way the ports work, not the dry flow method of only the potential.
On one set of their own excellent heads, they flowed and ported a set to their dry flow specs, checked the dry flow rates, found they were a good set to their own standards, then dyno'd them. They then pulled those same heads, and WET flowed them, got the same dry flow numbers, after revising the ports to favor the AIR/FUEL MIXTURE, not just the AIR, and gained 55 horsepower on the same engine, same dyno, same setup, but wet vs dry flowed heads.
That is proof enough for me, too bad some of you are still listening to both dyno and dry flow gurus that really don't have a clue.
I prefer to keep up to date on things, not do the same tired and old ways that are so out of date it isn't even funny.
Here is a small part of an article sent to me by my ignition person, it is from a publication he gets every month as part of his being in the industry. It is about head flow and new vs old technology, and mentions the DART and Edelbrock testing methods. Read on.
"Milt, here is part of an article from one of my industry publications you might be interested in. As I have always said, there is the old, out of date ways, and new ways. The new ways work much better, but, nobody wants to believe them. Too bad, they are the way things are going, and, more people will eventually become both aware of them as time goes on, and have to live with them vs the old ways. Same thing applies to dyno's as well, old full throttle only vs a programmed "drive" on the dyno. It's gonna get bloody in discussions until people start to realize the old style testing methods most hero's use, just ain't that accurate. Sure, a dyno is a GREAT tool for raw development, but, it isn't the finite answer most people firmly believe it is, and that is why so much variation in timing and jetting has to be altered once the engine is off the dyno. Remember the revisions I had you do after you had that first Chevy engine dyno'd, and it wouldn't drive the car down the road. That is what this stuff is all about. Enjoy! Dave.
HOTROD & RESTORATION
March, 2008 issue, pg. 41 & 42
"Article: Cylinder heads, Making Head Lines
Section titled: "Flows, real and virtual"
Computer technology is influencing how heads are designed, as well as manufactured. Edelbrock Corporation of Torrance, California has recently started to refine its cylinder head designs using Computational Fluid Dynamics (CFD), a sophisticated computer simulation that, "allows us to see the shape of the flow passage of any given part" said Smitty Smith. "That allows us to keep the flow equal in all the ports. The engineers can see on a computer screen where the flow is slow or fast - it shows up red or green - and that helps them tune the radii of the turns". Edelbrock used CFD to design the new NASCAR intake manifolds it is supplying for all four Sprint Cup engines - Chevrolet, Ford, Dodge and Toyota - in 2008. And Smith expects that CFD technology will, "absolutely, increasingly influence the design of street heads in the future".
At the same time, laboratory testing has become more sophisticated as well. "People tend to look at flow numbers", said Jack McInnis of Dart machinery in Troy, Michigan, "and we are trying to dissuade them from that, because (dry) flow numbers only indicate potential, whereas we are big believers in managing fuel as well as air." Dart founder and CEO Richard Maskin designed a wet flow bench for his own Pro Stock program, "but now we use it for our entire product line. It can flow 850 cfm at 55 inches of depression, and that's with fuel." (Dart engineers actually use a solvent that has the same specific gravity as gasoline, but is not as combustible.) "That allows us to monitor the air-fuel ratio, and to see how the fuel stream is behaving. Our small block Iron Eagle and our aluminum Pro 1 cylinder heads were both very good pieces, but when we redesigned them using wet flow technology, they showed a 55 hp increase - with virtually identical air flow as the previous versions."
Milton back again. I'll leave it at that, old dry flow and full throttle dyno, vs new, more informative wet flow and programmed dyno operations. Take your pick, but, don't discount the new ways you may, or may not be aware of, or are too set in your ways to take a closer look at. The world of performance is constantly changing, and both the active dyno and wet flow are here now, and ARE the future, even if you don't think so or, someone from the old school tells you different.
And, once Dave revised both the timing and jetting on my first dyno'd engine, it ran as it should have, extremely good, wouldn't run right straight off the dyno, and the dyno guys insisted it wasn't their "TUNE" they left it with that wasn't right.