First test intake manifold (lots a pics)

[Evillusion]

Originally Posted by krazeteggie

how do you calculate plenum sizes?

x2


I have found several schools of thought on this.

1) Plenum should be 50-60% of engine displacement
2) Plenum should be 100% of engine displacement
3) Plenum should be the cumulative volume of all the runners

Trinababe: How did you arrive at your plenum volume?

Regardless of plenum volume, I believe that all air inside the plenum should have as straight a path down the runners as possible (i.e. no "remote resevoires" of air volume).


edit: this thread is one of the most interesting threads Ive read in a while. Between Trinababe's intake mani and TedB's cams...good stuff.

[TrinaBabe]

I started with roughly 75% of engine volume and then just let the volume change as I made adjustments to the shape. I also needed to make sure there was as little pressure drop from the throttlebody hole into the major plenum area. Im not sure the exact volume of just the plenum off the top of my head.

The 3d printer people didnt realize exactly what it was I needed printed Apparently it's larger than they expected so there is yet another delay. I am also going to talk to a few other people and see if I can get the ball rolling.

[TrinaBabe]

Well here are some stats from the DSM Version... not completely done but now its just the small details.

Inlet Total Pressure 16.91098345 psi
Outlet Static Pressure 14.69594727 psi
Hydraulic Loss 1.353754569 psi

Percent Loss 8.01%

[hopper]

woot im close to madison well kinda close appleton area i can buy your first one!! id prefer one for my talon tho

[homemade wrx]

Originally Posted by TrinaBabe

The 3d printer people didnt realize exactly what it was I needed printed Apparently it's larger than they expected so there is yet another delay. I am also going to talk to a few other people and see if I can get the ball rolling.

that sucks...I have the same problem with the one I have access to. The would have to chop the manifold into sectoins (drawing wise) to print it and then I'd have to assemble it once printed into printable sized sections...
so there is a way around it, just not as one piece

[KevinD]

Originally Posted by TrinaBabe

Well here are some stats from the DSM Version... not completely done but now its just the small details.

Inlet Total Pressure 16.91098345 psi
Outlet Static Pressure 14.69594727 psi
Hydraulic Loss 1.353754569 psi

Percent Loss 8.01%

those are some huge losses. are you sure that trying to get uniform flow from one cylinder to the next is worth such a dramatic loss in pressure?

[homemade wrx]

Originally Posted by KevinD

those are some huge losses. are you sure that trying to get uniform flow from one cylinder to the next is worth such a dramatic loss in pressure?

Kevin you beat me to it...well I guess its ok, you are another FSAE guy after all

[EVOlutionary]

Originally Posted by KevinD

those are some huge losses. are you sure that trying to get uniform flow from one cylinder to the next is worth such a dramatic loss in pressure?

Do you have any pressure loss figures from any other manifolds for comparison? Or are you just saying that 8% sounds like a lot? I'm not an engineer so I'm not familiar with what's considered standard.

EVOlutionary

[TrinaBabe]

Originally Posted by TrinaBabe

Here are the stats from a conventional style:

Oulet Total Pressure = 17.3307
Inlet Total Pressure = 18.0696
Inlet Dynamic Pressure = .629711
Hydraulic Loss = 1.27341
Percent Loss = 7.047%

The manifold I used for this test was technically for a DSM which has a larger throttle body and runners than the Evo one I tested with. If I actually switched the DSM version to use the ports and throttlebody from an Evo it has a worse pressure drop than mine. It is quite apparent that the only reason the DSM manifold has less of a pressure drop is because the throttlebody is bigger. The inlet pressure is only ~18psi on this one vs ~22 on the Evo version. Raising the pressure by 4 psi when only working in the 20psi range obviously will have a drastic effect on the pressure drop. I must say I am pretty pleased with the 11% that I have achieved. I promise you it it much less than a conventional intake manifold for an Evo. Also, if I change the throttlebody size for the Evo manifold the pressure drop will become less (Hence the reason throttle body swaps actually help).

I was testing the flow loss incorrectly

This is the same (incorrect) test done on a "conventional" DSM intake manifold. I will post the correct numbers shortly.

[SwiftEVO]

Any more updates? This sounds interesting.

--Josh

[TrinaBabe]

The pumping loss on those tests were done with all ports closed except the farthest. I am pretty sure that most numbers people look at are tested with all ports open. Testing the manifold with the equation:

(Inlet Total Pressure - Outlet Total Pressure)/Inlet Dynamic Pressure = Hydraulic Pumping Loss

with all the ports open it comes out to be a mere 0.344985 psi out of 16.0075 psi... if you think this is a bad loss you should test an intercooler


That is a 2.15% loss.

The Buschur Racing "Deluxe" Intercooler is claimed to achieve a 0.84 psi drop from 7psi.... this is a 12% loss at low lowrates... most likely would be worse at real pressures.

When you actually figure out the loss of just a pipe with no turns or anything you will still have some percent of a pumping loss.

[SaabTuner]

Originally Posted by TrinaBabe

The Buschur Racing "Deluxe" Intercooler is claimed to achieve a 0.84 psi drop from 7psi.... this is a 12% loss at low lowrates... most likely would be worse at real pressures.

Now now, that .84 psi is likely a static pressure measurement; god only knows how the probe was oriented in relation to the flow. The effect of temperature drop may skew the readings as well, so it may not be a fair comparison. (It might be worse! hah)

[slowTsi]

Any more progress on the DSM version? My snazzy 2.4 arrived from Polk the other day

[TrinaBabe]

Well the status is almost a standstill now. All the parts are made on the pc... my 3d printer cant reasonably make me the prototypes and I cant find anyone local to make them for cheap. I cant afford to spend the $5 grand to make a few test ones and I dont want to try to get it paid for by pre-selling or something strange like that. Im going to talk to a few more people to see what I can do but otherwise it may be down to re-creating the manifolds using sheetmetal work and then actually just cut, bend and weld it all together. I am now getting I tig welder for personal use so I could make a few in my spare time but I will need to redesign the manifolds quite abit and try to get the same flow numbers that I achieved with the cast method. If I need to abondon the cast version completely I will post up a bunch of pics and tests.

[Ackerson]

I'm sorry if this was already brought up for some reason I am unable to view pages 3-6. The manifold you designed looks very similar to the Magnus race manifold for Dsm's, that has been out for a few years.

http://www.magnusmotorsports.com/int...ifolds/dsm.htm