Thread: DE head package - on a budget - infotainement

Helmholtz it is.... kinda.... the principle is Helmholtz resonance... that is correct

but being sneaky ... that is just the description....


NOT why I want to know?? :stoneface: so.... WHY do I want to know this?


Hint: it has to do with camshaft selection, and powerband




Now... does anyone have this measurement? :???:



Sam... I have no exp on the intake... so I can't really lend an opinion there... but the exhaust LOOKS very good... have you, your porter used a flowbench to determine HOW GOOD? Any photos of the short radius??

You have the port diameter and once you know the length of the runner you can determine the volume. With this you can determine the frequency of resonance. Since the diameter of the port is the variable here when reworking the head, you can change that resonate frequency by changing the diameter. Higher resonate frequencies means the cylinder can fill at a higher engine speed due to the air speed being higher. Right?

Oh my...... scientifically... yes???


but you are way over-thinking this.... although variance of the diameters can have an effect, the effect is truly minimal at the minimal amounts of change I'm introducing, if the interior volume of the ports were to change over 20%, I'd expect to factor the bore changes in....


I'm really after much simpler math...



I'm looking to have this heads heimholtz effect to "hit" 100-200 rpm before this engine hits peak torque... to MAXIMIZE the mid range....

Ahh I see

Dan, any news on the flowbench?
I need a stock head flowed to start crunching numbers on the cam choice .
Right now I have a few options....

Ah and the modified later as well would be cool...

I'm almost there.... I need a jig to keep a hand drill square so I can drill the appropriate holes........



speaking about drilling the appropriate holes.......

I wont make this a quiz... but... you'd think Nissan would have stuck with metric....




have you ever tried to find a 15/32" dowel??? Good luck!!! I eventually found a company who would make me 1000... at the cost of $195.00



So... its time to see if I can make something that will work... 1/2" thick wall aluminum tubing...




add an inline cut.... and viola... 15/32" dowel....




now that I have the dowel solved... lets go to the bench..... (and my first animated gif for the SR20 forum )



**IF** I were to try and use a "conventional" layout, the holes from the Toyota heads would interfere with the new holes needed for the 15/32" dowels... so a slight rotation of the layout provides me an unmolested area to drill to receive the dowels


So... once I have the jig, those holes will get drilled, and I'll be ready to re-calibrate the bench for the new 86mm bore. MartinS... I told you that this was a time consuming project.... yes once all this is finished, the next SR20 will be far less development(time spent) to get numbers from.... oh... and as to headorama... I have just acquired what appear to be a good used highport





More to come......

either you know... or you "saw" something... or its a good guess... but the manifold does have to "fit" the head... too much porting and all you do is lose out because the port can out draw the manifold. The result is once the air passes into the head it slows rapidly because the ports are now too big in reference to the manifold.

those here who have been following, have seen me use "within the lines" and "outside the lines" a few times... Let me try to show you what I mean.....

Intake: stock - "within the lines" - "outside the lines"




Exhaust: stock - "within" - "outside"



Both intake, and exhaust "outside" ports are still in the roughing out stage.... but you should still get the idea.






more to come.....

I see a lot of stuff and if that were I guess I reckon the proper punctuation should have been used.

I am looking forward to more updates, this is getting good.

So would you start with porting/ making the intake runners before the final porting of the head? Then you port match the head and blend from there? You could be limited by the intake runners or the head as far as porting goes.

thank you... thank you... thank you... thank you.... thank you.... x 1 million!!!


Port Matching - 90%+ of the car performance world do NOT understand what "port matching" is.... To make this as simple as possible.... "port matching" is using a flowbench to check that your port flows match. Let me repeat that... and for you to let it sink in... "port matching" is using a flowbench to check that your port flows match.


THIS is "port matching" I have the 4 exhaust ports flowing VERY similar volumes at similar lift points around similar valves... and with all of that, there is less than a 1% difference across the board.



Gasket matching is another story...... On the exhaust side... the gasket is what we'll change to fit what "we" want.....




And conveniently... that will make a nice segue (pronounced - segway) into where I got this "outside the lines" thing....





more to come.....


EDIT - managed to pick up the drill jig I needed