Offroad-Express

coxsy wrote:a big turbo I have ,plus a balanced engine, the high big volume intake all add up to a reasonable system,

exactly, if you get everything matched it works well.

of interest is one of the things old mav (and others) talks about is the small things that add drive ability rather than outright power.
that can mean turbo gets on boost a little earlier, is smoother and revs better. which when out in the field makes for a more controllable vehicle to drive.

flow bench ignores harmonics an resonance unless they now run valve simulation on them?
yeah couple atmo qd manifolds which will give my a good starting point then tune length with trumpets inside the plenum.
my setup is far from standard but being nosey never hurt

Nice looking work there fella.

I can see a problem with tuned length runners and that is they will only be tuned for one engine speed. As the frequency of the pulses increases the runners would need to be shorter to get the same effects.
I imagine it is much more useful in an atmospheric engine where gains are small but in a turbo diesel you would be better investing time and resources in keeping exhaust manifold pressures down. Does anyone know what their exhaust pressures are?

diogenese wrote:I can see a problem with tuned length runners and that is they will only be tuned for one engine speed. As the frequency of the pulses increases the runners would need to be shorter to get the same effects.

by mem from some very old books, intake tuning gives about effects about a 500 rpm band width. which actually be more useful on a limited rpm diesel than a high rpm petrol.
but the other factor is can you actually make use of it?
with ecu tuning possibly, but with mechanical IP i doubt you could tune it well enough to take advantage of any intake tuning.

boost just increases effective runner length,
all the gains in volumetric efficiency are to be had under 5000 rpm by what i can see.
like everything rather than just bat theory an research around i'll just get it done an feel out how it goes by the seat of the pants.
if it works for nissan on the ld and qd's in na form a nudge at a td one won't hurt as i'm still yet to find evidence of anyone trying it

slidenyo wrote:boost just increases effective runner length,
all the gains in volumetric efficiency are to be had under 5000 rpm by what i can see.
like everything rather than just bat theory an research around i'll just get it done an feel out how it goes by the seat of the pants.
if it works for nissan on the ld and qd's in na form a nudge at a td one won't hurt as i'm still yet to find evidence of anyone trying it

but there will be a reason nissan didn't do it on the turbo version and even on the eti version which could possibly have been able to take advantage of it.

seat of the pants doesn't mean much, to much placebo effect. a comparison run on a dyno is more meaningful.

it means plenty tbh.
if the wagon tows better an drives better an egts an afrs stay the same or better i'll be happy enough.
i'd imagine the eti version didn't get any development due to space constraints an pretty much the last hurrah for the td42

I say if you have the time and resources then go for it. Like you were saying, if afr and egt improve with a new design manifold then win win. If not at least you will know yourself.

old Mav has now throw a new angle into the mix,
the injection pipes , fuel volumes delivered to the injectors

brought a intercooler for the truck, the lump totally wrong for intercooling set up ,
so spare manifold see if i can knock up something more suitable ,

So snapped the crank on an rb style manifold better build a qd32 hybrid

Getting closer to some testing

Bit of an update.
New qd32 hybrid manifold on track
#kettlemods