Something Failed, let’s find it! Transmission Analysis.

[barbagris]

Just as well there are no golf balls on an inlet port. **** that is complicated. I can get 240rwhp on a rocket, with 10.5 comp, 1 3/4" od headers and 450 lift cams and Max rpm 8000, no dimples, not much science. All we need is a customer to pay for it. Not so many people here in oz. ....

Money - Ah yes - that!.

 

[joesoap]

I gave up trying to win points of view or arguments on the internet years ago so i tend to read than try convince these days...what i will say is with the fuel ingredients changing these days what was good 20-30 years ago with high octane/high lead content might not be the same these days regarding flow porting and the actual charge itself. Myself has always worked with the idea of getting it in as fast and smooth as possible down the inlet tract and as disturbed and mixed up as possible the last nano second before combustion (just infront of the valves) with a lot of effort on something that is very volitile in the first place like high octane fuels..For us guys with usable road bikes should we really be losing sleep over inlet ports being like a straight piece of smooth wide pipe, not really!!

 

[cootertwo]

Opinion probably has to do with your age. I'm 68, and in the "good ole days" mirror finish was the goal. However, that was probably before the discovery of shark/porpoise skin, golf balls, ripples, bumps, etc. etc. I believe the US Navy started using that kind of surface on the submarines, as it supposedly causes less drag going through the water. Live and learn I guess.

 

[barbagris]

For us guys with usable road bikes should we really be losing sleep over inlet ports being like a straight piece of smooth wide pipe, not really!!

Kill the heretic!.

 

[joesoap]

Kill the heretic!.

Another word i had to google before i replied...i knew it was a bad idea ending up in a borstal at 14

 

[R-III-R Turbo]

Fun Fact:

My bike literally has my name written on it, presumably while at Carpenter

Mine was like that too, can't get it off for love nor money

I see you already have the ARP head bolts, so you won't need to buy a set again.
Did you ask for them or is bob installing them standard now?

 

[Rocket Scientist]

Meanwhile back at the tranny problem

 

[Claviger]

Mine was like that too, can't get it off for love nor money

I see you already have the ARP head bolts, so you won't need to buy a set again.
Did you ask for them or is bob installing them standard now?

I honestly don’t remember, I didn’t have them in Hawaii, so they went in on this last trip in 2017 to NJ.

 

[Tripps]

I gave up trying to win points of view or arguments on the internet years ago

O won an internet argument back in 1982. Oh, wait, that was with my wife, and I lost, come to think of it.

 

[Speedy]

Just a reminder here: Intake ports are not golf balls. Nor are they aircraft foils. They are quite unique. There is a long list of attributes that make them so. The flow starts and stops thus the Reynolds number is constantly changing and very rapidly; some of the flow is dry and some laden with fuel; the ports are curved and not a straight tube; the combined fuel air flow must rotate in three dimensions as it enters the cylinder chamber (higher flow numbers in a head on a test bench do not necessarily equate to greater power production); the port must function at partial throttle; the higher the rpm, the greater variation in density and velocity; and the mean temperature changes from TB entry to valve face. These are just the obvious ones.

There is science behind the art of head porting. But the variation in engines, power output and application is endless. Thus what works for one may not work at all for the next. A golf ball is so simple by comparison that to deduce what works for it should work in an engine head is "magical" thinking.

The trend in moving injectors closer to the intake valve and injecting at ever higher pressures allows air in the intake port to remain dry longer and longer. The impact of liquid and vaporized fuel in constantly changing proportions on the performance of an intake system should not be under estimated. The example of rain drops running up the windshield is a good example. Now imagine tiny raindrops in a wind tunnel that changes air speed from 0 to 200mph and back to 0 in about .0023 sec every .009 secs at 6,500rpm. Some droplets vaporize and then re-condense, some droplets grow in size due to surface tension as they contact adjacent droplets but not all, some impinge on perimeter surfaces and then shatter into smaller droplets, some smaller ones reverse direction, some stall momentarily suspended motionless as in a cloud, some adhere to the surface and run along that surface combining into rivulets until something disturbs it breaking the rivulet back into suspended droplets. The system is not chaotic but largely unpredictable at small scale with current technology.

Mismatches between manifold and head port in wet intake systems can be intentional. The benefit of some introduced turbulence on fuel management in the runner can out weigh the cost to gross air flow. Managed turbulence can be more effective than a physical change in geometry to accomplish the same task. Dimples on a golf ball are one example, circumferential witness marks from CNC machining ports are another, as are differential surface finishes on floor, walls and roof of a port.

GM dedicated over a million hours to CFD developing the GenV V-8 port and combustion chamber. Nothing simple about intake systems in four stroke engines.