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And once I got it running it stole about 100hp from me! But there are a couple things that look very off to me in the intake waves.....I'll need to spend some time with this.

Ok. I decide it was the software that was wrong and sent in a bug report. Sure enough, the new release with the bug fix came out today but I haven't had that long to play with it.

It now does tri-y header without me need to run 2 separate simulations and that looks to be giving answers that I'd expect.

On the intake side things are a bit different and I'm not sure if its right....or.....the intake runner length result is quite different from -5 and I'm not 100% sure I believe it....I'll need to play with it some more and wish I had good data to check the output against. -5 wanted me to have a pretty long runner tuned to the 2nd pulse and this made sense to me since the engine has enough flow to rev well past redline, so in my mind it made sense a long runner with strong wave that would restrict flow above my redline came out best...like tuning for mid range. -6 says NO! to that. It wants a short runner ...6" on the 5th pulse is best at 945hp, 7.5 on the 4 is 932, 9.5 on the 3rd is 919 and 13" is 913hp on the 2nd. -5 told me 17-18" was the 2nd and 940hp and 12-13 was the 3rd and cost 20+hp, but gave about the same number for that stack as -6 does. I'm confused. I think 13" will fit under the stock hood so I like that answer but I find it hard to believe a 6" runner with pretty low pulse energy left is best, and its too short to build so I'll never know for sure.....I might be able to do a 9.5, I guess it that is better than 13ish I'll know

Anyway, -6 is different and I don't have data to know which is right(er).

I upgraded to 6 as well and noticed the odd results. Haven't really had a lot of time to play with it. The addition of exhaust tuning will be nice if it's accurate. I need to update Engmod4T, that one really relies on accurate modeling of the intake and exhaust, primarily wave dynamics. Still a steep learning curve with it, wish I had more time.
For exhaust I also use Pipemax, that one is very accurate for exhaust designing, however I can't help but feel it's a bit of chicken vs egg with these programs, input known data and adjust to meet real world.

The main bug is now fixed with rev13. The waves are stronger and more pronounced in -6 compared to -5, but tuned points are now pretty close to the same.

I was doing tri-y as a high to and low rpm design and overlaying them which seem yo work in -5. The results is -6 using the tri-y selection is quite similar, so it seens good.

What i don't think is right is that it now thinks shorter tuned runners work better than longer tuned runners. Below it a 6"runner vs 16", both tuned yo peak at the same rpm....the 6" wins in every way. A 9.5 and 13 are also tuned and fall between in a shorter is better order. That can't be right.....but I thing the shapes are right

Fogot this part. Pipemax does NOT spit out and option like the burn stainless design I built, but does agree the lengths in the design are good and DM5 said better than the PM design.

Which brings us to YES to the chick or egg......lots of iterations are the only solution I've found, but it takes forever.

I've never used Pipemax or DM, but I'll share thoughts on intake and exhaust tuning.

I have always calculated the lengths manually using the equation for acoustic resonance.
f = (n * v) / (4 * l)
f = firing frequency in hz = RPM/120 for 4-strokes
n = harmonic wave (integer)
v = speed of sound (calculate at your gas temperature) in m/s
l = length of runner in m

This works for both the intake and exhaust and will tell you either what length you need for a certain RPM and wave, or what RPM you will see acoustic affects at, but you need to know the gas temperature for each. It won't tell you how strong the engine response will be. But, the lower the wave, the stronger the effect. This is also true for the anti-waves (i.e. wave 2.5) which hurt the engine performance. Using a short runner means you get less effects overall, including less negative effects. Of course this all changes with temperature. There is also no requirement that all cylinders have the same runner lengths.

In general I just dyno test to verify. However, all of my test engines are turbocharged so it's hard to get good simulation results.

Hopefully starting from this will simplify the chicken-egg problem of using simulation alone to come to the correct values.

_________________
"Sometimes, the elegant implementation is a function. Not a method. Not a class. Not a framework. Just a function." ~ John Carmack

"Any sufficiently advanced technology is indistinguishable from magic" ~Arthur C. Clarke

This is not completely stopped. I found a free online cad package called onshape the seems pretty good. I redraw the stack I printed and can now easily change the length to make sets for the dyno when that day comes.....but I think I'm going make 4 or stack sets to make it look neater, then I can start printing.

I've been using OnShape for a little bit now. It's kitschy, has some philosophical differences with higher end CAD systems and the documentation is terrible, but it mostly works. It's like it was set up by a bunch of new CompSci grads who wanted to build cloud CAD, but had never used CAD professionally.

This is to bolt a small block Chevy into an AMC Eagle... my dad's project. The gray plate bolts to the engine and the light blue supports the Dana 30 front differential. These will be laser cut from 1/4" steel.

ETA: not sure if I miss a notification and the system doesn't send any more until I visit again or what...

Nice to see I didn't miss much

I haven't figured out how do do assemblies with onshape yet....it wasn't obvious to me. Also I had a sales person call, but I think I was means enough that they won't call back.

I'm really confused about what length stacks I need now. Dynomation6 has had a couple more updates but continues to insist shorter tuned lengths are better for hp, about 10.25" is about the best...i need to confirm that is posdible to build. It seems though like it's assuming flow losses build with length, which is true for a straight tube but I'm pretty sure that with enough taper its not true so the answer is suspect.

The other place -5 and -6 differ is the strength of the pulses with 6 really showing peaks as the stacks move in and out of tune.....im going to need to dyno a few options. But first I need to modify the printer to make the z more reliable and I'm not allowed to run it in the basement so I need windows and doors on the new garage.....some day

You don't have a fume hood built into the garage design?

I haven't done "assemblies" yet either. The screen cap above is one part studio.
My impression is that assemblies are only necessary if you want to put together things that move.