helmholtz with turbos

[barryogen]

I've been reading up on using helmholtz to tune intake runner length, and have got to the point of wondering what this does in a turbo car.

Do you could from the filter to the turbo and one tuned length, and from the turbo to the valves as a second tuned length, or would the entire intake length(from filter to valve) be counted?

Personally, I would think that they would have to be tuned separately(although they would still be linked).

My reasoning is that you will have waves bouncing of each of the turbine blades and back towards the filter, and vice versa in the first section, and pretty much the same in the second section from the valves to the blades, and vice versa.

Anyone done any research on this, my googling only seems to find patent applications, even with a "-patent" in the search.

[barryogen]

it just occurred to me that you can ignore what is prior to the turbo, as it(the turbo) is essentially the source of the air... and prior to the turbo would have to be sorted out in another way... using different physics I'd imagine.

actually, ignore is the incorrect term to use, as it will a/effect it.

To what extent I'm not sure, but I don't see the pressure wave going back through the turbo.

[barryogen]

The other things I was wondering with it, is do you make the calculations from the leading edge of the blades on the turbo, or the mid-point, or even the trailing edge, I would assume the middle, but I guess it would only make all of about 10mm difference, which at the speed of sound isn't much

[QikStarlie]

i dout the intercooler piping will have much effect. by the time it goes through the intercooler and the likes. but the lenght of the actual inlet manifold runners have a big effect just like on a n/a engine.

[RedMist]

The only time I've seen Helmholtz used in an intake is to damp noise. Although there is undoubtedly some reversion I doubt it would be anywhere near as strong as those pulses past the plenum in each of the individual runners.
I think you're confusing the calculations designed to calculate runner length from valve face to plenum bellmouth with total intake length. As far as I know, helmholtz isnt used to calculate total intake length. If it were it would only be from the tail end of the compressor wheel to the intake plenum. Even then I would think that the multitude of waves bouncing everywhere would spoil any helmholtz effect.
If you do choose to use Helmholtz to calculate runner length dont forget that its variable for turbos. The compressed air charge and temperature effect the required runner length.