Another boat motor...

[edo]

As I said there was much in my awesome first pics that you couldnt see that GTSBoy was making assumptions about. In these pics you can see much more, you can see that firstly they are cast, secondly they are not a uniform diameter & thirdly they are not round.
If it was better to run straight round tubes then they would have done that because imagine how much easier that would be!

Oh, you cant see inside the runners either...

[GTSBoy]

Well, if you are telling me that there are things inside that I can't see, then we are talking about turning vanes or equivalent devices and that's fine.

The points about cast, non-uniform diameter and non-roundness don't really affect the reality that the flow would still crowd the outside of the bend, and with that geometry that would place the majority of the flow towards the bottom of the inlet port which I would have thought would be worse than putting it towards the top (because the bottom side leads to the short turn at the valve).

I still reckon I could make more air flow through them with a different layout - including the flow through the valve. Would have to squeeze the plenums together into a common unit (still internally divided) seeing as it looks hard to make the runners interleave each other without having to bend them fore/aft around each other.

The plenums are intriguing. Superficially they look like they shouldn't work too well either, being sort of small and of strange inlet configuration. I'm guessing there are lots of careful modelling and/or flow modifying devices in there too.

[GTSBoy]

No-one cares how well or how even the gasses are distributed - just that the thing makes power.

That's not true. You will always make more total flow with a more even distribution. Uneven distribution equates to increased pressure drop for any given flow. If an inlet port needs biased flow in the runner leading to it, then someone should look carefully about redesigning the port to work more optimally. That is basic engineering.

[edo]

Yeah, them arent empty boxes but not surprisingly you dont get to put pics of those bits on the interweb...unless I took them then it wouldnt matter

[The Pupat]

Remember GTSboy, motors don't work on averaged lineal flow etc it's quick on and off bursts.

Harmonics play a more important part on flow in then pipe layout which is probably why this thing looks more like a saxomophone. This would be setup up to put the half, 1st, 2nd, 3rd or whatever the fark they harmonic smack bang right where they want to make most power.

[2rismo]

That's not true.

Yes it sure is.

The goal for this application is clearly that it makes optimum horsepower with optimum reliability and not that the runners please or make sense to an engineer sitting at a computer. You mention basic engineering and redesigning the port. Those two things aren't always able to be used in the same sentence whereas redesigning a runner and basic engineering go hand in hand.

If it makes more horsepower this way, and the only person involved with it says it does, then there is no argument to be had. Period.

[oldcorollas]

technically, harmonics are about pressures, not flow.. ie, positive pressure at start and end of valve event, or negative then positive for exhaust..

if you have uneven flow to the runners and cylinders.. then you have cylinders making uneven power...

[The Pupat]

technically, harmonics are about pressures, not flow.. ie, positive pressure at start and end of valve event, or negative then positive for exhaust..

if you have uneven flow to the runners and cylinders.. then you have cylinders making uneven power...

Yep hence each runner looks identical to the one sitting beside it.

[Matt]

Anyway, there is a lot more to props than meets the eye.

Yep - especially when you start looking at variable pitch props.. (some of which can handle 60,000hp)

[edo]

But they would sink this boat & make people sad.

[oldcorollas]

Yep hence each runner looks identical to the one sitting beside it.

and the flow into the runner?
i do like the (apparent) decrease in runner size tho..

[Matt]

But they would sink this boat & make people sad.

Why not? Most airplanes with more than 200hp have variable pitch props and they get off the ground quite well.

If a plane can fly with one, im sure a boat can float with one.

[edo]

Oh, no...a 60,000hp prop would be off a ship & would likely be bigger than this boat, so it would sink.

A more appropriately sized one might work

[Matt]

lol - I see where youre coming from now

I hope some good footage of this sucker makes its way onto youtube (I think theres a different nizpro boat already on there)

[edo]

Yeah thats the wrecker 4.5 engine...with 2 turbos. This is a tad more serious.